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1. 0_TO_1 is the six character keyword 0_TO_1 1_TO_0 is the six character keyword 1_TO_0 MAX_PERIOD is the eleven character keyword MAX_PERIOD max_period is a positive floating point number assigned to the parameter MAX_PERIOD tran_after_pop_fail Controls behaviour if the POP analysis fails to converge This has three modes of operation as follows tran_after_pop_fail 0 Display error message then abort tran_after_pop_fail 1 Start a transient analysis with a run time equal to 100 x max_period see above tran_after_pop_fail t t gt 0 Start a transient analysis with a run time equal to t 136 Chapter 10 Simplis POP See Behaviour of POP Analysis after POP Convergence Failure on page 141 for more details of this feature The POP statement must be the first analysis statement among all types of analyses statements specified in an input file Upon reading the POP statement SIMPLIS performs a Periodic Operating Point analysis of the system If the Periodic Operating Point analysis is successful SIMPLIS will perform the next analysis specified in the input file If the Periodic Operating Point analysis is not successful SIMPLIS will print out an error message and exit Definition of the Start of A Switching Cycle During a Periodic Operating Point analysis SIMPLIS performs a sequence of time domain transient analyses on the system These transient analyses are invisible to the user Each time domain
2. cece 115 Switching Instance Data File for the POP Analysis 116 Data for the Periodic Operating Point Analysis 116 Print Plot File for Frequency Domain Analysis 116 Simplis TX Examples OVEIVIOW aioe tia a eee ee Nid eae Example 1 Rectifier with RC load Example 2 3 Phase Rectifier with Resistive Load 119 Example 3 Operational Amplifier with Saturation 121 Example 4 Unregulated Converter sccccceee 124 Example 5 Regulated Converter ccsceeeseee 126 Example 6 Saturable INGUCTOI c ccceeeeeeeteeees 129 Example 7 SCR with RL Load ccscecseeeeeeeees 131 Simplis POP OVEINVIOW heeii heo deeded itis ln elie Statements Relating to POP AnalySis c eecee POP Statement for POP Analysis Options Associated with POP Analysis Synopsis of the Periodic Operating Point Analysis 143 The Time Variable During POP Analysis 146 How POP Deals with Time Varying Sources 146 The POP_SHOWDATA option for POP Analysis 149 Example of Applying the POP Analysis Tool 151 Simplis FX OVEIVIOW A E A eis oi nade eens 155 Statements Relating AC AnalySis c cececeeeeees 157 AC Analysis Statement ecceeeeeeeeneeeeeeeeeeees 157 Option Statement Associated with AC Analysis 158 Statement Defining a Small Signal AC Source 159 Synopsis of Small Signal
3. c 4 4 Model for the simple transistor switch a Simple transistor switch controlled by a control signal cs t b the i Q vs v Q characteristic of the simple POS type transistor switch and c the i Q vs v Q characteristic of the simple NEG type transistor switch 61 SIMPLIS Reference Manual 62 ce 2h 4T ov a b 4 5 Model for the simple transistor switch a model of the simple transistor switch for LEVEL 1 when it is in a closed state and b model of the simple transistor switch for LEVEL 1 when it is in an open state If a physical transistor is being driven to act like a switch and detailed waveforms of the voltage across the transistor and the current through the transistor are not critically important it is recommended that such a transistor be modeled by a simple transistor switch with the parameter LEVEL set to 1 since the simulation is faster when a transistor switch has LEVEL set to 1 When a simple transistor switch is modeled with the LEVEL parameter set to 1 the value of the GAIN parameter has no effect on the modeling In addition the direction of current flow through the transistor switch is not restricted and the device behaves more like a controlled switch than a physical transistor Models for Simple Transistor Switches for LEVEL 2 When a simple transistor switch is modeled with the LEVEL parameter set to 2 it still assumes either an open state or a closed state The switchi
4. Model for exclusive OR gate The nodes ni1 and ni2 are the two input nodes The nodes no and nref are the output and reference nodes respectively The actual model implemented in SIMPLIS for an exclusive OR gate is shown in 4 10 a The source value of the voltage source vout in the output circuit depends on the logic state of the output of the gate The output state is equal to the result of the boolean EXCLUSIVE OR operation on the two input states OR Gate Model The format for the OR Gate model statement is MODEL mname ORk TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG where MODEL mname OR TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG Chapter 4 Model Statements is the six character keyword MODEL is a legal model name as explained in Model Names and Subcircuit Names on page 12 is the two character keyword OR to stand for OR type simple logic gates is an integer from 2 to 9 inclusively which defines the number of inputs for the OR gate is the three character keyword TH is a floating point number which defines the threshold value of the input voltage in volts and together with hystwd it determines the values of the input voltage at which the input states of the exclusive OR gate will be changed from a logic 0 to a logic 1 and vice versa is the seven character keyword HYSTWD is a
5. SUB1 has an initial branch voltage of 1 V in the subcircuit instantiation of both X1 and X2 In some situation it is desirable to be able to set the initial condition of a device in a subcircuit to different values for different subcircuit instantiations SIMPLIS allows the initial conditions for devices in a child subcircuit be overridden with an INIT statement in the parent circuit The extra INIT statement shown in example 6 1 b means that the initial voltage on capacitor CA in subcircuit SUB1 for the instantiations X1 and X2 should be 5 V and 2 V respectively The capability to override device initial conditions can be extended to lower levels of subcircuits For example the expression INIT X123 X456 D9 1 means that the logic gate D9 in the subcircuit referred to as X456 in a subcircuit referred to as X123 in the current circuit is set to have an initial output state of logic 1 Chapter 6 Control Statements The INIT statement in an ancestor circuit always overrides any initial condition specified in a subcircuit For example if INIT I L12 0 appears within the scope of definition of a subcircuit referred to as X123 in the main circuit and SINIT 1 X123 1L12 1 appears within the scope of definition for the main circuit the initial current for this inductor is set to 1 A not 0 A X1 1 2 SUB1 X2 9 8 SUBI SUBCKT SUB1 101 102 RA 101 103 1K CA 103 102 1U IC 1 ENDS SUB1 Example 6 1a X1
6. When the secondary state of a simple transistor switch is equal to ACTIVE it is modeled by a parallel combination of a linear resistor with a resistance equal to roff and a controlled current source ci f as indicated in 4 7 a The current ci t of the controlled current source is defined by the following equations if LOGIC is set to POS ci t gain cs t threshold hystwd 2 for VCQPOS type transistor switches and for ICQPOS type transistor switches AND ci t gain cs t threshold hystwd 2 for VCQNEG type transistor switches and for ICQNEG type transistor switches On the other hand the current ci t of the controlled current source is defined by the following equations if LOGIC is set to NEG ci t gain cs t threshold hystwd 2 63 SIMPLIS Reference Manual 64 for VCQPOS type transistor switches and for ICQPOS type transistor switches and AND ci t gain cs t threshold hystwd 2 for VCQNEG type transistor switches and for ICQNEG type transistor switches For example an NPN transistor can be modeled by a piecewise linear resistor to represent the base emitter characteristics and an ICQPOS type simple transistor switch with LEVEL and LOGIC set to 2 and POS respectively to represent the collector emitter characteristics Similarly the collector emitter characteristics of a PNP transistor can be modeled by an ICQNEG type transistor switch with LEVEL and LOGIC s
7. You may wish to run SIMPLIS on a netlist also known as an Input Deck created by hand or by another program To run a netlist from the SIMetrix GUI select the command shell menu SIMPLIS Run Netlist then select the file you wish to run Note that this will pass the netlist through the netlist pre processor before it is presented to SIMPLIS The pre processor provides some additional features to import and parameterize device models See Netlist Preprocessor on page 109 for details Note that a complete syntactically correct SIMPLIS netlist will not be functionally altered by the pre processor Running SIMPLIS from a Script SIMPLIS may be launched from a script using the command RunSIMPLIS RunSIMPLIS filename filename Name of file containing the SIMPLIS netlist If a full path is not supplied filename will be assumed to be relative to the current directory Note that the extension of the file must always be supplied no default is assumed The RunSIMPLIS command will not pre process the netlist This must be done separately using the PreProcessNetlist command See Netlist Preprocessor on page 109 RunSIMPLIS is the primitive SIMetrix command that launches SIMPLIS However when running a simulation on a schematic a number of other activities are performed 107 SIMPLIS Reference Manual These include pre processing the netlist generated by the schematic editor and also resolving a trigger device for POP analysi
8. Aperiodic Exponential Pulse Sources 0 0 36 Aperiodic Piecewise Linear SOurceS c0 38 Mutual Inductance S no 40 Linear Voltage Controlled Sources ccceeeeeeeeee 41 Linear Current Controlled Sources 0ce 42 Ideal Transformers monr iie a 43 Simple Swit S e iieiea aniei 43 Simple Transistor Switches c cccccceeeeeeeeeeeees 44 Piecewise Linear Resistors cceeeeeseeeeeeeeeees 45 Piecewise Linear Inductors and Capacitors 46 Simple Logic Gates ecceesceseseeseeeeeeeeeeeeeeeeeeeeees 47 Subcircuit Calls Instantiation cceceeeeeees 48 Model Statements OVEIVIEW 3 8 0 oii steits i heh eel eels Hee 50 Device Models Used in Simplis ccceeceeeeeeeeeenees 52 Piecewise Linear Resistor Models 00 52 Piecewise Linear Inductor and Capacitor Models 55 Simple Switch Models ccccceeeeeeeeeteeeeeseeeeeeeees 57 Simple Transistor Switch Models cccceee 59 Simple Logic Device Models cccesceeeseeeeeees 64 Subcircuit Definition OVOENVIOW EEEE AE ioe okt AE bat eth 86 Subcircuit Definition cc ceccececeeeeseeeeseeeeeeneeeesseeeeseeees 87 Parent and Child Relationships for Subcircuits 87 SUBCKT Statement cccccccecesceeessteeeseteeeeeeees 88 ENDS Statement End of Subcircuit Statement 88 Scope of Definition cccccececceeesneee
9. DAMP_COEF s the ten character keyword DAMP_COEF representing the damping coefficient of the source damp_coef is a floating point number assigned as the damping coefficient in 1 seconds The source function s t for all t is s f voff apeak e10r coeftt delw cos 2 10 freq t tdelay The value of tdelay computed from the value of pdelay if pdelay is given is 35 SIMPLIS Reference Manual 36 tdelay pdelay 360 freq If OFF_UNTIL_DELAY is assigned a value of YES then the value of s t for t lt tdelay is modified to s t voff for t lt tdelay The waveform s t of a typical cosinusoidal source is shown in the diagram below For t lt delay and OFF_UNTIL_DELAY YES the waveform s t is shown in bold dashed line For t lt delay and OFF_UNTIL_DELAY NO the waveform s t is shown in heavy grey line s t T 1 freq e a 3 7 Waveform s t of a cosinusoidal source Aperiodic Exponential Pulse Sources The formats for independent sources with aperiodic exponential pulse waveforms see waveform diagram below are as follows For a voltage source Vname n n EXP Vl vl V2 v2 DELAY_R delay_r DELAY_F delay_f TAU_R tau_r TAU_F tau_f For a current source Iname n n EXP Vl vl V2 v2 DELAY_R delay_r DELAY_F delay_f TAU_R tau_r TAU_F tau_f where V is the one character element keyword V for independent name n EXP Vil vl V2 v2 DELAY_R delay_
10. How POP Deals with Time Varying Sources on page 146 the source value of VI will be at 40V for the first 100 s in this transient simulation and at 30V for the rest of the simulation Waveforms as obtained in this time domain transient analysis for V VI V RL and I L are shown in fig 10 9 KL A Output V 11 11 T 11 69 0 2 04 0 6 0 8 t 7 2 14 7 6 8 2 time mSecs 200ySecs div 10 9 Waveforms obtained in time domain analysis for V VI V RL and KL Chapter 11 Simplis FX Chapter 11 Simplis FX Overview A small signal is applied to a system to investigate the small signal behavior around its equilibrium Small signal analysis is often carried out in the frequency domain because the resulting data can be succinctly displayed in various graphical forms such as semi log Bode plots and direct or inverse polar plots Various characteristics such as impedances transfer functions and stability information can be determined from these graphical plots The application of small signal frequency domain analysis to switching piecewise linear systems presents tremendous challenges A Laplace transform or Laplace transformed equivalent circuit analysis which is normally applied to a non switching system to extract the small signal frequency domain characteristics cannot be easily applied to a switching piecewise linear system due to
11. as shown in fig 9 20 is a sinusoidal voltage source rectified into an R L load through a silicon controlled rectifier In this example the SCR is modeled by the series combination of the simple switch S1 and the piecewise linear resistor R2 as shown in fig 9 21 The input file for this circuit is shown in fig 9 22 The comparator U2 D U2 in the input file the SR Flip Flop U1 D U1 in the input file and the elements E1 H1 and V5 together form a network that models the switching of the SCR When a sufficient gate current is applied between the gate and the cathode causing the voltage across the non inverting input of U2 to exceed 2 5 V the output of U2 will rise to approximately 5 V thus setting the SR Flip Flop which in turn causes the switch S1 to be closed When S1 is closed the model characteristic from anode to cathode is the series combination of a small resistance of the switch and a diode On the other hand if the SR flip flop is reset the switch S1 will be opened and the model characteristic from anode to cathode looks like a large resistor in series with a diode The flip flop is reset when the voltage across its reset input which is equal to the sum of the voltages across E1 H1 and VS exceeds 2 500001 V This situation occurs when the gate signal is absent and the current through the SCR is negative The presence of E1 makes sure that the reset input does not reach its threshold value of 2 500001 V whenever there is a ga
12. command shell menu SIMPLIS Abort Run or simply press the Abort button on the SIMPLIS Status Window This will abort SIMPLIS at the next suitable point in its execution which may not be immediately Note that there is no resume facility with SIMPLIS Automatic Program Suspension by SIMPLIS Sometimes the input circuit may contain a switching conflict which SIMPLIS cannot resolve For example connecting the input and output nodes of a SIMPLIS inverter together creates a situation where the inverter cannot locate a valid logic output state from which to operate Once such a switching conflict occurs the simulation enters an endless loop and it is unable to advance forward in time After attempting 200 times without any success in locating a correct operating state SIMPLIS prints a message to the message window similar to the following and aborts the simulation Unable to find a starting operating point or At t 1 2345e 06 it is unable to find the correct state of operation for some device For example check the following devices R1 R2 and R3 If such a message appears you should carefully inspect the input file and appropriate data files generated by SIMPLIS to locate the source of the switching conflict In a slightly different scenario the situation may occur when the switching logic is properly defined but a few circuit elements are connected in a manner which may cause the simulation to go through very fast and repetitive s
13. one break point at x1 y and is defined for currents in the range of i lt yl The last segment has one break point at xj 1 yj 1 and is defined for currents in the range of i yk 1 The two points x0 y0 and xk yk are used in conjunction with x y and xk 1 yk 1 to define the slopes of the first and the last segments of the characteristics For example the v i characteristics of the ordinary pn junction diode shown in diagram 4 1 a above and the v i characteristics shown in diagram 4 2 can both be considered to behave as nonlinear current defined resistors Therefore each can be approximated by an IPWLR type model On the other hand the tunnel diode characteristics shown in diagram 4 1 b cannot be modeled by an IPWLR type model since the values for the branch voltage are not uniquely defined for every value of current Similarly the v i characteristics shown in 4 2 cannot be modeled by a VPLWR type model 4 2 Example of a type of v i characteristics which can be described as a current defined resistor Piecewise Linear Inductor and Capacitor Models The model statements for piecewise linear inductors and capacitors are very similar to those for the piecewise linear resistors In the case of a piecewise linear resistor its characteristics are defined in terms of points on the current vs voltage plane In the case of a piecewise linear inductor the characteristics are defined in terms of points on the flux linkag
14. s t v for delay T 2 lt t lt delay T s t s t T for delay T lt t The source function s t for t lt delay is defined as follows s H s t T for 0 lt t lt delay and OFF_UNTIL_DELAY NO s H vi for 0 lt t lt delay and OFF_UNTIL_DELAY YES 29 SIMPLIS Reference Manual 30 where T 1 freq T is defined as the period of the waveform The waveform s t of a typical squarewave source is illustrated in the diagram below For t lt delay and OFF_UNTIL_DELAY YES the waveform s f is shown in bold dashed line For t lt delay and OFF_UNTIL_DELAY NO the waveform s t is shown in heavy gray line s t v2 delay T T 1 freq 3 4 Waveform s t of a squarewave source Pulse Sources with Zero Rise and Fall Times The formats for the independent rectangular pulse sources are Vname n n PUL Vi vl V2 v2 FREQ freq DRATIO dratio DELAY delay OFF_UNTIL_DELAY YESINO and Iname n n PUL Vl v V2 v2 F REQ freq DRATIO dratio DELAY delay OFF_UNTIL_DELAY YESINO where V is the one character element keyword V for independent voltage sources I is the one character element keyword I for independent current sources name is the individual name of the device n is the name of the positive node and is a nonnegative integer n is the name of the negative node and is a nonnegative integer PUL Vil vl V2 v2 FREQ freq DRATIO dratio DELAY dela
15. will be generated if the user instructs SIMPLIS to determine the voltage between two electrically isolated nodes Chapter 3 Device Statements Voltage and Current Polarity Conventions Most of the circuit elements discussed in this chapter are two terminal elements For any general two terminal element there is a positive node n and a negative node n as shown in the diagram below nt I n 3 1 Definition of the voltage and the current association for a two terminal element Whenever the voltage across a two terminal element is mentioned in this manual it refers to the voltage measured at the positive node with respect to the voltage at the negative node For example the voltage of the generalized two terminal device in See Definition of the voltage and the current associated for a two terminal element is equal to V Vn Vn as measured from the n terminal to the n terminal When the current through a two terminal device is mentioned in this manual it refers to the current measured in the direction from the positive node through the element to the negative node Thus a positive current indicates that there is a net flow of charge into the positive node through the two terminal element and then out of the negative node With these sign conventions for voltages and currents a positive voltage current product indicates that electric power is instantaneously flowing into the corresponding two terminal element w
16. zero damping coefficients 3 the source values of all periodic large signal time varying sources such as sawtooth sources triangular sources square wave sources pulse sources and sinusoidal cosinusoidal sources with zero damping coefficients are considered active during the small signal frequency domain analysis That is they maintain the same time varying waveforms as if they were used in a large signal time domain analysis These sources are not turned into DC sources because their time varying waveforms are essential to the periodic operation of the switching piecewise linear systems Turning these sources into DC sources is tantamount to eliminating the switching actions of the system under study and the small signal analysis would not be able to reveal the true small signal nature of the system around its periodic equilibrium Behaviour of AC Sources in Transient and POP Small signal AC sources have no effect on any analysis other than the small signal frequency domain analysis For example a small signal voltage source is turned into a short circuit during the time domain transient analysis and during the periodic operating point analysis Similarly a small signal current source is turned into an open circuit during the time domain transient analysis and during the periodic operating point analysis As a result leaving small signal AC sources in the input file has no effect on any analysis except the small signal frequency domain an
17. 1 seconds The source function s t for all t is s t vofftapeak etarr F dela sin 2 r freq t tdelay The value of tdelay computed from the value of pdelay if pdelay is given is tdelay pdelay 360 freq If OFF_UNTIL_DELAY is assigned a value of YES then the value of s t for t lt tdelay is modified to 33 SIMPLIS Reference Manual 34 s t voff for t lt tdelay The waveform s t of a typical sinusoidal source is shown in the diagram below For t lt delay and OFF_UNTIL_DELAY YES the waveform s f is shown in bold dashed line For t lt delay and OFF_UNTIL_DELAY NO the waveform s f is shown in heavy grey line sit T 1 freq 7 a Pdamp_coef t tdelay UE voff apeak e apeak voff gt tdelay 3 6 Waveform s t of a sinusoidal source Cosinusoidal Source The formats for independent cosinusoidal voltage and current sources are Vname n n COS VOFFSET voff APEAK apeak FREQ freq TDELAY tdelayIPDELAY pdelay OFF_UNTIL_DELAY YESINO DAMP_COEF damp_coef and Iname n n COS VOFFSET voff APEAK apeak FREQ freq TDELAY tdelaylPDELAY pdelay OFF_UNTIL_DELAY YESINO DAMP_COEF damp_coef where Vv is the one character element keyword V for independent voltage sources I is the one character element keyword I for independent current sources Chapter 3 Device Statements name is the individual name of the device n is the name of the pos
18. 15 14 AC 1 VREF 13 0 2 5 L 4 15 40u IC 0 14 R12 0 10 10k X1 11 12 PERIODIC_OP 2 R13 10 8 10k RC 6 15 50m RL 15 0 10 R11 10 14 40k C1 9 7 100n IC 800m R14 8 7 2k C14 7 8 1n IC 0 CC 6 0 50u IC 12 48 Q1 2 3 5 0 Q1 TP_VCQ IC OPEN MODEL Q1 TP_VCQ VCQPOS VSAT 700m RSAT 100m ROFF 10Meg GAIN 10 TH 2 5 HYSTWD lu LOGIC POS LEVEL 1 IR R1 0 3 RISTP_SSPWLR IC 1 MODEL R1 TP_SSPWLR VPWLR NSEG 2 X0 0 YO 0 X1 0 7 Y1 10U X2 0 8 Y2 1 00001 RX 4 3 10m SUBCKT PERIODIC_OP 2 13 NODE_MAP IN 1 NODE_MAP OUT 3 D_CYCLE 3 0 1 302 M1M IC 1 VREF 302 0 DC 2 5 MODEL M1M COMP RIN 10MEG ROUT 50 VOL 0 VOH 5 HYSTWD 0 001 DELAY 0 ENDS PERIODIC_OPS2 SUBCKT SIMPLIS_COMPS 1 201 100 101 102 DCOMP 201 100 101 102 MCOMP IC 1 MODEL MCOMP COMP RIN le 007 ROUT 10 VOL 0 VOH 5 HYSTWD 0 1 DELAY 0 ENDS SIMPLIS_COMP 1 SUBCKT opamp 2 3 1 NODE_MAP VINN 1 NODE_MAP VINP 3 NODE_MAP VOUT 2 RIN 3 1 5Meg EOP 2 0 3 1 1Meg ENDS opamp END 11 4 Input File as generated by SIMetrix Notice that a small signal AC source VSS is inserted in the feedback loop between the output and control nodes If the impedance from the control node to ground is 168 Chapter 11 Simplis FX much higher than the impedance from the output to ground the loop gain G jw of such a regulated system is accurately approximated by the following complex ratio GG Voutput ja Vcontrol ja This is the function of the Bode Plot Pr
19. AC Analysis 0 160 Amplitude of Small Signal AC Sources 161 Phase Delay of Small Signal AC Sources 162 Sample Waveforms of AC Sources Continuous Domain cccecseceeeseeeseteeeeeseeeeeeees 162 Sample Waveforms of AC Sources Discrete DOMAIN cccccececeeeeeeeeeeeeeeeteeeeeeeeeeees 163 Table of Contents Continuous and Discrete Domain Differences 165 AC Analysis Behaviour of Time Varying Sources 165 Behaviour of AC Sources in Transient and POP 166 Example of Applying the AC Analysis Tool 166 SIMPLIS Reference Manual Chapter 1 Introduction Overview This manual provides detailed reference material for the SIMPLIS SIMulation for Piecewise LInear System simulation package It is intended for those who want to develop a more in depth understanding of this software package SIMPLIS is a computer software package specifically designed for the simulation and analysis of switching power supplies In a typical switching power system the transistors and the diodes function as switches allowing the system to be characterized by acyclical sequence of linear circuit topologies By taking advantage of the repetitive piecewise linear structure of such systems SIMPLIS is able to perform the simulation in an efficient and accurate manner In order to avoid potential problems caused by simple syntax errors SIMPLIS automatically checks the syntax of the in
20. SUB3 SUBCKT SUB3 201 203 R3 201 202 1K C3 202 203 1U IC 1 ENDS Example 5 1 If sname is given in an ENDS statement then sname must be the name of the subcircuit currently defined or the name of a subcircuit which is an ancestor of the subcircuit currently defined In this case the definition of the current subcircuit its parent its grandparent and the subcircuit whose name matches sname are all terminated at this ENDS statement For the statements in the example below the statement ENDS SUB2 terminates the definition of subcircuits SUB2 and SUB3 but not the definition of subcircuit SUB1 The line immediately following the ENDS SUB2 statement is considered part of the definition of subcircuit SUB1 which is the parent of subcircuit SUB2 SUBCKT SUB113 Rl 1 2 1K CI 2 3 1U IC 1 X1 2 3 SUB2 SUBCKT SUB2 101 103 R2 101 102 1k C2 102 103 1U IC 1 X2 102 103 SUB3 SUBCKT SUB3 201 203 R3 201 202 IR C3 202 203 1U IC 1 ENDS SUB2 Example 5 2 Notice that there is a unique correspondence between each SUBCKT statement and the start of a subcircuit while each LENDS statement may be shared by several subcircuits The recommended practice however is to terminate each subcircuit with a unique ENDS statement having a matching subcircuit name instead of using the 89 SIMPLIS Reference Manual implied termination This will make reading the input file easier and will make the subcircuit definit
21. Set Reset flip flop is considered to be triggered when the logic state of the clock input changes from 0 to 1 Similarly a logic 1 to logic 0 transition for the clock input is considered to trigger this type of flip flop if TRIG_COND 1_TO_0 The logic state of each output will not change except at the triggering moment At the triggering moment the logic of the clocked Set Reset flip flop is same as that of the unclocked Set Reset flip flop Chapter 4 Model Statements 4 13 Clocked SR Flip Flop model a Symbol for a SIMPLIS Clocked S R flip flop b Model for a SIMPLIS Clocked S R flip flop Clocked J K Flip Flop MODEL mname CLK_JKFF TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG TRIG_COND 0_TO_1 1_TO_0 MODEL is the six character keyword MODEL mname is a legal model name as explained in Model Names and Subcircuit Names on page 12 CLK_JKFF is the eight character keyword CLK_JKFF to stand for CLK_JKFF type simple logic gates TH is the three character keyword TH threshold is a floating point number which defines the threshold value of the input voltage in volts which together with hystwd determines the values of the input voltage at which the input states of the exclusive OR gate will be changed from a logic 0 to a logic 1 and vice versa HYSTWD is the seven character keyword HYSTWD hystwd is a positive floating point number which defines th
22. X1 1 Y1 1U X2 1 1 Y2 2 000001 S1 12 6 2 10 S1 TP_SSVSW IC Open MODEL S1 TP_SSVSW VCSW ROFF 10Meg RON 10u LOGIC POS TH 2 5 HYSTWD 20u SUBCKT SIMPLIS_COMP 2 201 100 101 102 DCOMP 201 100 101 102 MCOMP IC 0 MODEL MCOMP COMP RIN 5000 ROUT 50 VOL 0 VOH 5 HYSTWD 0 002 DELAY 0 ENDS SIMPLIS_COMP 2 SUBCKT SIMPLIS_SRFFS 1 201 202 100 101 102 D_SIMPLIS_SRFF 201 202 100 101 102 MSRFF IC 0 MODEL MSRFF SRFF RIN le 007 ROUT 50 VOL 0 VOH 5 HYSTWD 2e 006 DELAY 0 TH 2 5 LOGIC POS ENDS SIMPLIS_SRFFS 1 ENDS scrl END 9 22 Input File for Example 7 generated by SiMetrix 133 SIMPLIS Reference Manual US L1 A Vs V 2 4 6 8 10 12 14 16 18 20 time mSecs 2mSecs div 9 23 Waveforms for Example 7 134 Chapter 10 Simplis POP Chapter 10 Simplis POP Overview In the analysis of a switching piecewise linear system the steady state solution is essential For example in the study of the line load regulation of a regulated switching power system the relevant information is the steady state load voltage over a range of line load conditions Although carrying important information in its own right the transient information on how the system settles to the new steady state under the new line load condition is not the focus of such a study To carry out such a study the load voltage is measured
23. a logic 0 to a logic 1 and vice versa is the seven character keyword HYSTWD is a positive floating point number which defines the hysteresis width of the input voltage in volts is the four character keyword VOL is a floating point number representing the low value of the output voltage in volts is the four character keyword VOH is a floating point number which defines the high value of the output voltage in volts and must be larger than vol is the four character keyword RIN is a floating point number which defines the input resistance is the five character keyword ROUT is a floating point number which defines the output resistance in ohms is the six character keyword LOGIC is the three character keyword POS is the three character keyword NEG is the thirteen character keyword ENABLE_LEVEL The actual model implemented in SIMPLIS for the clocked latch is shown in 4 17 b The first input node in the device statement is the Data input terminal and the second input node in the device statement is the enable input terminal If ENABLE LEVEL 1 the latch is considered to be enabled when the state of the enable input is logic 1 Similarly if the state of the enable input is logic 0 a latch is considered to be enabled if ENABLE_LEVEL 0 The logic state of the output will not change except when the latch is enabled When the latch is enabled the output logic state of the latch follows the logic sta
24. appeared in the input netlist Currently only subcircuit devices are resolved in this library search All primitive devices defined using MODEL must be defined in the input netlist Note also that currently only the SIMetrix global library will be searched The LIB control is not supported Chapter 7 Running SIMPLIS Parameters Parameters may be defined using the VAR control which has the following syntax VAR parameterName parameterExpression parameterName may be any alphanumeric sequence and must start with a letter or underscore paramterExpression may be any valid SIMetrix expression as detailed in the script reference manual String expressions are acceptable parameterExpression may reference parameters defined in earlier VAR controls Any part of the netlist following a VAR control may contain parameter expression enclosed with curly braces E g VAR resval 1K Rl 1 2 resval 2 VAR may be used inside subcircuit definitions in which case the have local scope This means that the parameter definition is only valid within that subcircuit definition Note that this scope is not inherited by nested subcircuit definitions However parameters defined at the top level have global scope Passing Parameters to Subcircuits Parameters may be passed to subcircuits via the subcircuit call The syntax is Xxxx nodes subname vars paraml valuel param2 value valuel 2 may be constants or an expression enclosed in
25. as Xnamez2 in the subcircuit referred to as Xnamel in the current circuit SIMetrix vector name will be of the form Xname1 Xname2 DName pinname where pinname will be p for the first pin and n for the second pin V Xname1 Xname2 Node1 Node2 Differential voltage from node Node to node Node2 where Node and Node2 are node numbers in the subcircuit referred to as Xname2 in the subcircuit referred to as Xname in the current circuit NODE_V Print all node voltages in the main circuit with respect to the ground node node 0 in the main circuit ALL Print all node voltages in the main circuit with respect to the ground node node 0 in the main circuit and print all branch currents of the two terminal devices in the main circuit The two terminal devices refer to those whose branch current can be printed through the form of I DName In the normal case no more than 50 output variables can be created for printing plotting in one simulation If more than 50 output variables are needed the output variables can be generated through more than one pass of the simulation If the print variable NODE_V or ALL is used then node 0 must be present in the main circuit Although the number of output variables that are associated with NODE_V or ALL are obviously large NODE_V or ALL is counted as one print variable in counting towards the maximum number of 50 print variables allowed in one simulation Simulation can be substantially slower with NODE_
26. device statement is defined as follows DeviceName NodeName Values ModelName InitConds where DeviceName is a legal device name NodeName is a sequence of legal node names Values is either a floating point entry to stand for value or a sequence of parameter assignments ModelName is the legal name of a compatible model The symbol Values ModelName means Values and ModelName are mutually exclusive If a device requires a model name no Values would be given in the device statement and vice versa InitConds is a sequence of legal initial condition specifications The symbol InitConds means the presence of the InitConds fields is optional since only some devices require initial conditions The individual fields in each device statement must appear exactly in the order indicated in this chapter Any different sequence will cause SIMPLIS to misinterpret the statement or generate an error message Node Names Each node in the circuit must be assigned a unique name A legal node name is either a positive integer or zero Remember that node 0 is traditionally reserved to represent the ground node Also note that 1 SIMPLIS does not require the presence of node 0 in the system unless the user wants to inspect the voltage of a particular node with respect to a certain ground node 2 SIMPLIS does not require every node in the system to be connected to each other allowing the system to have isolated subsystem However error messages
27. domain and then using fast fourier analysis techniques the necessity of developing state space averaged equivalent circuits is avoided SIMPLIS FX accurately computes the frequency response from the same schematic used for time domain simulation Organization of this User Manual This user manual is made up of the following chapters Chapter 1 is the introduction this chapter Chapters 2 6 explain the syntax and format of input files Chapter 2 describes the organization and the basic rules governing the input file Chapter 1 Introduction Chapters 3 and 4 cover the format rules for specifying various device types Chapter 5 explains the definition of subcircuits Chapter 6 describes control statements Chapters 7 9 explains the execution of SIMPLIS Chapter 7 explains the SIMPLIS commands and command line options Chapter 8 gives a synopsis of the data files generated by SIMPLIS Chapter 9 provides a set of examples illustrating the capabilities features and the simulation options Chapter 10 explains the SIMPLIS POP Periodic Operating Point analysis tool Chapter 11 explains the SIMPLIS FX small signal frequency domain analyzer SIMPLIS Reference Manual Chapter 2 Input File Organization Overview SIMPLIS uses a single text input file to define 1 The interconnections and components forming the circuit 2 The options that apply in the analysis and 3 The specific analyses to be performed In this chapter Gen
28. flux linkage versus current characteristic of the saturable inductor The input file for this circuit is shown in 9 18 The saturable inductor is modeled by the piecewise linear inductor L1 L L1 in the input file with the flux linkage entered in units of weber turns The variables of interest are the input voltage V VI plus the voltage V L1 and the current I L1 of the PWL inductor The simulated waveforms for these variables are shown in fig 9 19 129 SIMPLIS Reference Manual 9 17a The circuit diagram Fiux linkage Current 9 17b Flux linkage vs current characteristics of inductor Cosine Wave Driving A Resistor And A Saturable Inductor VI 1 0 COS VOFFSET 0 APEAK 75 FREQ 10K PRINT ALL OPTIONS PSP_NPT 201 TRAN 200u 0 V1 1 0 COS VOFFSET 0 APEAK 75 FREQ 10k TDELAY 0 OFF_UNTIL_DELAY NO DAMP_COEF 0 LSL1 2 0 LISTP_SSPWLL MODEL L1 TP_SSPWLL PWLL NSEG 3 X0 0 1 YO 500 5U X1 0 05 Y1 500U X2 0 05 Y2 500U X3 0 1 Y3 500 5U RI 2 1 10 END 9 18 Input file for Example 6 130 Chapter 9 Simplis TX Examples 6 4 lt 0 4 6 60 40 3 20 3 gt 20 40 60 6 4 A 2 S Qa 21 4 6l 0 20 40 60 80 100 120 140 160 180 200 time uSecs 20uSecs div 9 19 Waveforms for Example 6 Example 7 SCR with RL Load The system studied in this example
29. in the range of v lt x1 The last segment has one break point at xk 1 yk 1 and is defined for voltages in the range of xk 1 lt v As such x0 y0 and xk yk are used to define the slopes of the first and last segments instead of being used to define their break points As an example the diagram below shows the v i characteristics of an ordinary pn junction diode and that of a tunnel diode It is apparent from the diagram that the characteristics of these two devices satisfy the voltage defined requirement and each of these two devices can be modeled by a VPWLR type piecewise linear resistor b 4 1 The v i characteristics of a an ordinary pn junction diode and b a tunnel diode IPWLR Type Model The IPWLR model type is reserved for piecewise linear v i characteristics which are current defined in the sense that the value of voltage is uniquely defined for every value of current In such a case the voltage current coordinates at the points of definition of the v i characteristics must satisfy the following restrictions Chapter 4 Model Statements 1 Values of the currents must be entered in a strictly ascending order yO lt yl lt y2 lt yk 2 The slopes of the first and last segments must be positive x0 lt xl and xk 1 lt xk Other than the first and the last segments each intermediate segment j has two break points and is defined for currents in the range of yj 1 lt i lt yj The first segment has
30. input node and the reference node The output circuit is modeled by a resistor in series with a voltage source The resistor has a resistance rout and the source value of the voltage source vout depends on the logic 68 state of the output of the comparator ni1 no ni2 nref a rin rout no ni1 vout ni2 rin nref b 4 9 SIMPLIS comparator model a Symbol for comparator b Model for comparator The nodes n1 n2 are the two input nodes The nodes no and nref are the output and reference nodes respectively Chapter 4 Model Statements Tf the output state of a comparator is equal to logic 1 the value of the voltage source vout in the output circuit is set to voh In this case the output state of the device is changed to logic 0 when V nil ni2 lt hystwd 2 where V nil ni2 represents the voltage of the first input node with respect to the voltage of the second input node If the output state of a comparator is equal to logic 0 the value of the voltage source vout in the output circuit is set to vol In this case the output state of the device is changed to logic 1 when V nil ni2 hystwd 2 Exclusive OR Gate Model The format for the Exclusive OR model statement is MODEL mname XOR TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG where MODEL is the six character keyword MODEL mname is a legal model name as explained in Model Names and Subcirc
31. is the one character element keyword V for independent voltage sources name n SQU Vl vl v2 FREQ freq DELAY delay Chapter 3 Device Statements is the one character element keyword I for independent current sources is the individual name of the device is the name of the positive node and is a nonnegative integer is the name of the negative node and is a nonnegative integer is the three character keyword SQU to signify that this is a square source is the three character keyword V1 representing the source at the start of a normal cycle is a floating point number assigned as the value of V1 in volts for a voltage source and the value of V1 in amperes for a current source is the three character keyword V2 representing the source at the end of a normal cycle is a floating point number assigned as the value of V2 in volts for a voltage source and the value of V2 in amperes for a current source is the five character keyword FREQ is a positive floating point number assigned as the frequency of this source in hertz is the six character keyword DELAY is a floating point number expressing DELAY in seconds OFF_UNTIL_DELAY YES is the sixteen character keyword OFF_UNTIL_DELAY is the three character keyword YES NO is the two character keyword NO The source function s t for t gt delay is defined as follows s t v2 for delay lt t lt delay T 2
32. logic convention is used in defining the logic states If the LOGIC parameter is set to POS positive logic is used to determine the logic states of the inputs and the output This means a state of logic 0 is represented by a lower voltage level than that of a state of logic 1 In this case the input logic state of an input node is defined to be at logic 1 if V ni nref threshold hystwd 2 where ni and nref are the node names of the input node and reference node respectively The input logic state is considered to be at logic 0 if V ni nref lt threshold hystwd 2 The output logic state is equal to the result of the boolean operator associated with the gate applied to the input logic states If the output state is equal to logic 1 the value of the voltage source in the output circuit is set to voh If the output state is equal to logic 0 the value of the voltage source in the output circuit is set to vol The two parameters vol and voh are specified in the model statement If the LOGIC parameter is set to NEG negative logic is used to determine the logic states of the inputs and the output Negative logic means a state of logic 0 is represented by a higher voltage level than that of a state of logic 1 In this case the input logic state of an input node ni is defined to be at logic 1 if V ni nref lt threshold hystwd 2 and it is considered to be at logic 0 if V ni nref threshold hystwd 2 The output logic stat
33. name is only made known to this subcircuit and its name is not made available to other subcircuits In the example below the device names CA RA and XSUB are known only within the subcircuit SUB1 but not in the subcircuit SUB2 Similarly the device names CB and RB are known only within the subcircuit SUB2 For devices which are controlled by the voltage or current of another device such as some controlled sources simple switches and simple transistor switches the controlling device must also be defined in the same circuit as the controlled device or SIMPLIS will not be able to locate the controlling device Similarly the scope of definition for a node is the youngest subcircuit whose scope of definition encompasses the node name in question For the statements in the example below the nodes 101 102 and 103 are considered to be defined in the subcircuit SUB2 whereas the nodes 1 2 and 3 are considered to be defined in the subcircuit SUB1 Each node is considered to be local in its circuit and its name is not made available to other circuits This rule for the scope of definition of a node applies to all nodes defined in a circuit except for node 0 If the option MAPNODE is turned off which is the default case node 0 in any subcircuit is treated as the same node as node 0 in the main circuit If the option Chapter 5 Subcircuit Definition MAPNODEO is turned on through an OPTION statement then node 0 in any subcircuit is cons
34. node of this device and Chapter 3 Device Statements sname is the name of a subcircuit definition compatible with this device Through the use of the subcircuit feature one can model an n terminal physical device by building an n terminal subcircuit made up of the simple basic devices outlined in this section The subcircuit feature is further explained in See Subcircuit Definition on page 86 49 SIMPLIS Reference Manual Chapter 4 Model Statements Overview 50 For a simple device the number of parameters required to model the device is relatively small and the parameters can be easily blended with the device statement For example the resistance the inductance and the capacitance of a linear resistor inductor and capacitor respectively are all defined in the device statements For devices such as simple switches piecewise linear elements and simple logic gates a large number of parameters is needed to describe the device performance In such cases the model statements provide a convenient and organized way to define the model parameters There are two additional advantages in using the model statements Quite often several devices in the system being studied may have the same model parameters In such cases one single model statement can provide the model parameters for all of the devices of the same type Another benefit of this arrangement is when several devices are described by the same device model then
35. number assigned as the value of initial condition It is the initial current in amperes for an inductor or the initial voltage in volts for a capacitor Independent Voltage and Current Sources DC Sources The formats for the dc sources are Vname n n DC value Iname n n DC value where Vv name is the one character element keyword V for independent voltage sources is the one character element keyword I for independent current sources is the individual name of the device 23 SIMPLIS Reference Manual 24 n is the name of the positive node and is a nonnegative integer n is the name of the negative node and is a nonnegative integer DC is the two character keyword DC to signify that this is a DC source value is a floating point number assigned as the source value It is the voltage across the source element in volts for a de voltage source or the current through the source in amperes for a dc current source Sawtooth Sources The format for the independent sawtooth voltage source is Vname n n SAW Vi vl V2 v2 FREQ freg DELAY delay OFF_UNTIL_DELAY YESINO The format for the independent sawtooth current source is Iname n n SAW Vl v V2 v2 FREQ freq DELAY delay OFF_UNTIL_DELAY YESINO where V is the one character element keyword V for independent voltage sources I is the one character element keyword I for independent current sources name is the individual nam
36. number which defines the high value of the output voltage in volts It must be larger than vol is the four character keyword RIN is a floating point number which defines the input resistance in ohms is the five character keyword ROUT is a floating point number which defines the output resistance in ohms The actual model implemented in SIMPLIS for an inverter is shown in 4 8 b The input circuit is represented by a linear resistor of resistance rin placed between the input and reference nodes The output circuit is modeled by a Thevenin equivalent network between the output and reference nodes The value of resistance for the resistor in the Thevenin network is equal to rout The value of the voltage source in the Thevenin network depends on the output state of the inverter Chapter 4 Model Statements ni no nref a ni rout no rin vout nref b 4 8 SIMPLIS inverter model a Symbol for inverter b Model for inverter The nodes ni no and nref are the input output and the reference nodes respectively Tf the output state of an inverter is equal to logic 1 the value of the voltage source vout in the output circuit is set to voh In this case the output state of the device is changed to logic 0 when V ni nref threshold hystwd 2 where V ni nref represents the voltage of the input node with respect to the reference node If the output state of an inverter is equal to logic 0 the value of the
37. of Legal and Illegal Floating point Entries The following entries are all valid floating point entries 15 SIMPLIS Reference Manual 16 0 3 3 0 3 31 12 12E 06 3 12e 3 1 1K 150U The entries 0 and 3 are in integer format The entries 3 0 3 and 31 12 are in simple floating point format The entries 12E 06 and 3 12e 3 are in exponential format The entries 1 1K and 150U are in engineering format The following are illegal floating point entries 0 7 3 12E 345 4 7 K They are illegal because 1 0 7 contains the illegal positive sign 2 The exponent in 3 12E 345 is more than two digits long 3 4 7 K has an extra space between the number 4 7 and the scale factor K Units SIMPLIS works with System Internationale ST units The table below gives a summary of all units expected for different types of variables Units are not allowed to be specified with the values of the corresponding variables For example a capacitance of 1 25 microfarads may be represented by 1 25U or 0 00000125 but not 1 25UF or 0 00000125F Variable Units Time second Resistance ohm Capacitance farad Inductance henry Voltage volt Current ampere Charge coulomb Unit Types Length of Fields and Lines Each field of entry should be restricted to no more than 80 characters long Each input line should be restricted to no more than 160 characters long This restriction does not limit the length of a statement since it can continue over seve
38. periodic operating frequency computed in the POP analysis SIMPLIS FX is reasonable in computation speed When the excitation frequency is 1 decade or more above the periodic operating frequency computed in the POP analysis the computation time taken by SIMPLIS FX will be much longer since SIMPLIS FX must determine the high excitation frequency affect on the system response This brief synopsis is adequate as a reference for using the SIMPLIS FX Small Signal Frequency Domain Analyzer It is recommended that any first time user as well as those interested in more details of SIMPLIS FX read the following subsections of this Section to better understand the behavior of small signal AC sources and various large signal time varying sources during the small signal frequency domain analysis Behaviour of AC Sources in Transient and POP on page 166 describes how the small signal AC sources are treated in both the time domain transient analysis and the periodic operating point analysis Amplitude of Small Signal AC Sources Tf the continuous domain is chosen for the small signal frequency domain analysis all of the small signal AC sources are sinusoids If the discrete domain is chosen instead the waveforms of all of the small signal AC sources are the result of applying a sample and hold process to a sinusoid In both cases the original sinusoidal waveform is completely defined by three parameters the frequency the amplitude and the phase of th
39. phases interspersed between successive transient analyses the time variable as pointed out in See The Value of the Time Variable During the Periodic Operating Point Analysis has no real physical meaning and significance because the POP analysis is not following any true transient experienced by the system To make it easier to review the print variables in this data file the time variable in this data file is artificially set so that 1 it appears to be continuous and monotonically increasing and 2 the time instant at the end of each transient analysis carried out by the POP analysis also appears to be the instant at the start of the next transient analysis Since the prediction phase carried out between two successive transient analyses adjusts the capacitor voltages and inductor currents so as to predict the steady state solution jump discontinuities in the print variables are expected in this data file at the boundary between successive switching cycles As a result it is not uncommon to see discontinuities in the capacitor voltages and inductor currents if a plot is made from this data file A typical waveform plotted from the XXXX t4 data file for a successful POP analysis is shown in fig 10 6 a The switching frequency for this example is 10 kHz and discontinuities in the waveform are observed at intervals of 100 microseconds Typical waveforms plotted from the XXXX t4 data file for unsuccessful POP analyses are shown in fig 10 6 b
40. readable A comment is identified by an asterisk C as the first character at the beginning of a line Comment statements which are several lines long must have a comment character at the beginning of each line Comment statements are ignored during program execution Chapter 2 Input File Organization In line Comments An in line comment is a comment that starts in the middle of a line The in line comment is identified by the semicolon character placed at the beginning of the comment section The portion of the line to the right of the in line comment symbol is ignored by SIMPLIS For example in SIMPLIS the following two lines are equivalent RC 10 1K esr of cl RC 10 1K Continuation of Statements A statement can be continued to the next line by using the line continuation character the plus sign Any line whose first non blank character is the line continuation character is considered the continuation of the previous line For example the following lines form one single statement vl 1 0 PUL V1 0 V2 1 FREQ 1MEG DRATIO 0 1 DELAY 0 1 OFF_UNTIL_DELAY YES A comment statement cannot be followed by a line continuation statement Device Names The name of a device is formed by the concatenation of two parts the element keyword and the individual name The element keyword is a character string of one or two characters The individual name is a character string of arbitrary length You should keep the individua
41. result of the boolean NOR operation applied to the k input states AND Gate Model The format for the AND Gate model statement is MODEL mname ANDk TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG where MODEL mname AND is the six character keyword MODEL is a legal model name as explained in Model Names and Subcircuit Names on page 12 is the three character keyword AND to stand for AND type simple logic gates is an integer from 2 to 9 inclusively to stand for the number of 73 SIMPLIS Reference Manual 74 TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG inputs for the AND gate is the three character keyword TH is a floating point number which defines the threshold value of the input voltage in volts which together with hystwd determines the values of the input voltage at which the input states of the exclusive OR gate will be changed from a logic 0 to a logic 1 and vice versa is the seven character keyword HYSTWD is a positive floating point number which defines the hysteresis width of the input voltage in volts is the four character keyword VOL is a floating point number representing the low value of the output voltage in volts is the four character keyword VOH is a floating point number which defines the high value of the output voltage in volts and must be larger than vo
42. small signal excitation are inherently noisy and noise can easily lead to measurement errors In summary the features of SIMPLIS FX are as follows Chapter 11 Simplis FX 1 Itis based on time domain simulation via SIMPLIS TX 2 It relies on SIMPLIS POP to compute the large signal periodic operating equilibrium of the system 3 It is general and versatile it handles any pulse width modulated PWM circuit topologies such as boost buck buck boost Cuk SEPIC half bridge full bridge etc it handles any resonant circuit topologies such as series resonant parallel resonant quasi resonant phase shifted resonant etc it handles any mode of operation such as continuous mmf CMM mode discontinuous mmf DMM mode etc it handles any control scheme such as voltage mode control peak current mode control average current mode current charge control etc it handles both fixed frequency as well as variable frequency systems and it easily handles multiple switch multiple output converters it can evaluate the loop gain of a system while the loop is closed it can evaluate the effect of the parasitic elements on the frequency response it is accurate for analysis frequencies above the switching frequency and it is accurate to within 0 5 dB and 1 degree Statements Relating AC Analysis The small signal frequency domain analysis is a sequence of individual analyses at a set of discrete excitation frequencies Since the e
43. sources is the one character element keyword I for independent current sources is the individual name of the device is the name of the positive node and is a nonnegative integer is the name of the negative node and is a nonnegative integer is the three character keyword TRI to signify that this is a triangular source is the three character keyword V1 representing the source at the start of a normal cycle Chapter 3 Device Statements vl is a floating point number assigned as the value of V1 in volts for a voltage source or the value of V1 in amperes for a current source V2 is the three character keyword V2 representing the source at the end of a normal cycle v2 is a floating point number assigned as the value of V2 in volts for a voltage source or the value of V2 in amperes for a current source FREQ is the five character keyword FREQ freq is a positive floating point number assigned as the frequency of this source in hertz DRATIO is the seven character keyword DRATIO dratio is a dimensionless floating point number between 0 0 and 1 0 exclusively assigned as the value of DRATIO DELAY is the six character keyword DELAY delay is a floating point number assigned as the value of DELAY in seconds OFF_UNTIL_DELAY is the sixteen character keyword OFF_UNTIL_DELAY YES is the three character keyword YES NO is the two character keyword NO The source function s t for t gt dela
44. system includes conditional and looping features using the controls IF and WHILE Launching Preprocessor The preprocessor is launched using the script command PreProcessNetlist The syntax is PreProcessNetlist inAppend extralnputLines simulator SIMPLIS SIMetrix inFile outFile where inFile Input file name to be processed outFile File to receive result extralnputLines Additional lines appended to input file Each line separated by a semi colon The simulator switch allows the specification of the simulator that the netlist is intended for and affects library searching and the effect of the SIMULATOR control The default value is SIMPLIS The PreProcessNetlist command called automatically when a SIMPLIS simulation is initiated and the user does not usually need to be aware of this Library Search The SIMetrix library will be searched for any device referenced in a subcircuit call that is not present in the input netlist Only devices that are explicitly designated as SIMPLIS models will be recognized in this search Unless simulator SIMetrix is specified at the PreProcessNetlist command line SIMPLIS models are identified in the model files using the SIMULATOR control The syntax of this control is SIMULATOR SIMPLIS SIMetrix The SIMULATOR control applies to all models that appear after it until the next SIMULATOR control If the device is found in the library its text will be entered as if it had
45. the frequencies of all small signal AC sources are set to the same value the analysis frequency and their amplitudes are set to infinitesimally small values Since the frequency of all small signal AC sources are set to the analysis frequency the analysis frequency is also frequently called the excitation frequency 2 The equilibrium of the system under perturbation from the small signal is computed next This new equilibrium although at an infinitesimally small distance away from the large signal equilibrium computed by the periodic operating point POP analysis is definitely not the same as the large signal equilibrium While the large signal equilibrium is periodic with a frequency equal to the periodic operating frequency or the switching frequency as determined by the POP analysis this new equilibrium is periodic with a frequency that is equal to the highest common factor between the analysis frequency and the periodic operating frequency 155 SIMPLIS Reference Manual 156 3 Fourier analysis is then applied to the new equilibrium to extract the small signal response of the system at the analysis frequency Since SIMPLIS FX is based on time domain simulations it can handle a switching piecewise linear system with any structure topology any mode of operation and any control scheme and under fixed or variable switching frequency as long as the following two conditions are satisfied 1 The system can be simulated in the
46. the circuit contains several instances of the same device then the model circuit in 5 1 b has to be repeatedly defined For each incidence care must be given to make sure that 1 The node names are unique compared to the other similar definitions and 2 Unique names are given for the seven basic elements in each definition Obviously this can be quite a tedious and error prone task when the size of the circuit gets larger If the network shown in 5 1 b is defined as a subcircuit instead every incidence of the physical transistor in the circuit can be described by the following three steps 1 give each instance of the same type of transistor a unique device name 2 define unique node names for the three terminals of each transistor 3 reference the subcircuit defining the type of transistor involved The tedious and error prone steps involved in giving unique names to the seven device elements in the model of 5 1 b and giving unique names to the three internal nodes in the model are automatically handled by the subcircuit feature of SIMPLIS The definition and the usage of the subcircuit feature of SIMPLIS is explained in detail in this chapter Chapter 5 Subcircuit Definition c c c Bon B B E r E a b 5 1 Ebers Moll model of an NPN transistor a Circuit symbol b the Ebers Moll model Note B C and E are the internal nodes introduced for modeling purposes Subcircuit Definition The main circuit
47. the input file with the following exceptions 1 In the definition of a general circuit the Start Circuit Statement and the End Circuit Statement must be the first and the last statements respectively 2 Analysis statements are special control statements The order in which analysis statements appear in the input file determines the order in which SIMPLIS performs different analyses Main Circuit Title Statement Start of Main Circuit Statement The first line in the input file is the Title Statement This statement is the Start Circuit Statement for the main circuit and it is copied to some of the data files generated by SIMPLIS for annotation purpose The Title Statement must be only one line long It cannot be extended over additional lines by using the line continuation character 17 SIMPLIS Reference Manual 18 END Statement End of Main Circuit Statement The first statement in the input file that has the first field matching the keyword END is the end of main circuit statement This statement is the End Circuit Statement for the main circuit Any input lines following this END statement in the input file are ignored by SIMPLIS Since END is a keyword its interpretation is case insensitive No other fields are allowed in this statement It cannot be extended over additional lines by using the line continuation character Subcircuit The details of the SIMPLIS subcircuit feature are explained in Subcircuit Definiti
48. the main circuit is created For this example this list includes V1 R1 R2 and R3 Sometimes devices such as the one represented by X1 are referred to as pseudo devices because there is no actual device element corresponding to the keyword X Chapter 5 Subcircuit Definition After reading the main circuit SIMPLIS reads the circuit instantiation statements in the main circuit and starts instantiating the subcircuits Each subcircuit instantiation can be summarized in a four step procedure 1 Perform a one to one mapping of the names of external nodes to the names of corresponding nodes in the subcircuit instantiation statement 2 Map the name of each local node to a new node name different from any existing node name This new node name is then added to the list of existing node names 3 Map the name of each device defined in the subcircuit to a new device name having the same element keyword but an individual name different from any existing one This new device name is then added to the list of existing device names 4 Carry out subcircuit instantiation for each subcircuit instantiation statement in the current subcircuit In example 5 3 node 1 of subcircuit SUB1 would be mapped to node 2 when the subcircuit instantiation for the pseudo device X1 is carried out Then local nodes 2 and 3 in SUB1 are each mapped to a new node name The device names R1 and R2 are each mapped to a new name for a linear resistor and device nam
49. the transistor Q1 on and off In this case the start of a switching cycle is best defined in terms of the transition of the output of U1 The comparator D2 in this figure serves this purpose and the input statements defining D2 and the POP analysis may look as follows 139 SIMPLIS Reference Manual 140 D2 101 0 102 103 M2 IC 0 MODEL M2 COMP RIN 10MEG ROUT 8 HYSTWD 10 VOH 5 VOL 0 v6 103 0 DC 6 POP TRIG_GATE D2 TRIG_COND 0_TO_1 MAX_PERIOD 200U With these input statements the output of the logic gate D2 is equal to logic 1 and logic 0 respectively when the output of U1 is above 11 V and below 1 V When the output of U1 is between 1 V and 11 V the output state of D2 remains unchanged Fig 10 2 b illustrates the relationship between the output state of U1 and the output state of D2 From this figure it can be deduced that the start of a switching cycle is now recognized to occur when the output of U1 is rising and equal to 11 V The output of U1 as shown in Fig 10 2 b has finite time transitions when it switches between 0 V and 12 V If U1 is a SIMPLIS logic gate we can use U1 instead of an additional logic gate as the triggering gate for the POP analysis Comparator D l CONTROL BASE UNIT U1 DRIVE B1 rme l a o Vv V 102 0 V b 10 2 a A sample circuit used to define the start of a switching cycle for a variable fre
50. transient analysis is stopped when the operation of the system reaches the start of a new switching cycle The user can define the condition constituting the start of a switching cycle through the TRIG_GATE and TRIG_COND parameters in the POP statement Let us examine the two POP statements below POP TRIG_GATE D1 TRIG_COND 0_TO_1 MAX_PERIOD 100U POP TRIG_GATE X1 D1 TRIG_COND 1_TO_0 MAX_PERIOD 100U The first POP statement defines the start of a switching cycle as the time instant when the output of the logic gate named D1 switches from logic 0 to logic 1 The second POP statement defines the triggering gate as the logic gate named D1 in the subcircuit referred to as X1 in the main circuit and it defines the start of a switching cycle as the instant when the output of the triggering gate switches from logic 1 to logic 0 The two POP statements above are shown here for illustration purposes Only one POP statement can appear in a SIMPLIS input file The second POP statement also demonstrates that the triggering gate is not restricted to the logic gates defined in the main circuit It can be any logic gate defined in the input file Definition of the Start of A Switching Cycle for a Driven System In a driven system the driving periodic source is a good candidate to define the start of a switching cycle Fig 10 1 a shows a small section of a hypothetical circuit driven by a periodic triangular source V1 whose minimum and maximum
51. voltage source vout in the output circuit is set to vol In this case the output state of the device is changed to logic 1 when V ni nref lt threshold hystwd 2 Comparator Model The format for the comparator model statement is MODEL mname COMP HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout where MODEL is the six character keyword MODEL mname is a legal model name as explained in Model Names and Subcircuit Names on page 12 67 SIMPLIS Reference Manual COMP HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout is the four character keyword COMP to stand for comparator type simple logic gates is the seven character keyword HYSTWD is a positive floating point number which defines the hysteresis width of the differential input voltage in volts is the four character keyword VOL is a floating point number which defines the low value of the output voltage in volts is the four character keyword VOH is a floating point number which defines the high value of the output voltage in volts It must be larger than vol is the four character keyword RIN is a floating point number which defines the input resistance in ohms is the five character keyword ROUT is a floating point number which defines the output resistance in ohms The actual model implemented in SIMPLIS for a comparator is shown in 4 9 b There is a resistor of value rin placed between each
52. 0 x0 YO y0 KK xk YK yk and Iname n n PWL NSEG k X0 x0 YO y0 KK xk YK yk where name n PWL NSEG x0 YO yO X1l xl Yl yl x2 Y2 Chapter 3 Device Statements is the one character element keyword V for independent voltage sources is the one character element keyword I for independent current sources is the individual name of the device is the name of the positive node and is a nonnegative integer is the name of the negative node and is a nonnegative integer is the three character keyword PWL to signify that this is an aperiodic piecewise linear source is the five character keyword NSEG representing the number of linear segments for this source is an integer defining the number of linear segments and can take on values from 2 to 253 inclusively is the keyword XO representing the time or x axis coordinate of the start of the first linear segment is a floating point number which defines the value of XO in seconds is the three character keyword YO representing the voltage or current y axis coordinate of the start of the first linear segment is a floating point number which describes the value of YO in volts for a voltage source and in amperes for a current source is the keyword X1 representing the time or x axis coordinate of the end of the first linear segment and the start of the second linear segment is a floating point number which describe
53. 01 RX 4 3 10m SUBCKT SIMPLIS_COMP 1 201 100 101 102 DCOMP 201 100 101 102 MCOMP IC 1 MODEL MCOMP COMP RIN le 007 ROUT 50 VOL 0 VOH 5 HYSTWD le 006 DELAY 0 ENDS SIMPLIS_COMP 1 END 9 11 Input file for Example 4 Drive KL Output 4 gt lt A 3 o 2 a 1 25 lt 15 2 oa t 0 28 a B 28 5 O 28 28 1 2 0 10 20 30 40 50 time uSecs 10uSecs div 9 12 Waveforms for Example 4 125 SIMPLIS Reference Manual Example 5 Regulated Converter The diagram shown in fig 9 13 is the schematic of a regulated current step up buck converter operating under a fixed frequency control law The modeling of the switching transistor the diode the energy storage inductor the output filter capacitor and the load of the power stage is similar to the modeling of the corresponding components in Example 4 and is not elaborated on here Again with the transistor modeled as a simple controlled switch the base drive shown in 9 13 does not need to be modeled in the input file as the output of the comparator can directly control the simple transistor switch The error amplifier in the controller is shown separately in 9 14 a and its piecewise linear equivalent is shown in 9 14 b The operational amplifier is modeled with an input resistance RIN between its differential inputs and the voltage controlled voltage source EOP at its ou
54. 1 2 SUBI X2 9 8 BUBI SUBCKT SUBI 101 102 RA 101 103 1K CA 103 102 1U IC 1 ENDS SUB1 INIT V X2 CA 2 V X1 CA 5 Example 6 1b Control Statements for Printing Variables The PRINT statement is used to specify the output variables to be recorded for printing plotting Note that with the SIMetrix SIMPLIS PRINT only specifies data to be saved in the binary file and does not create ASCII tabular output PRINT instructs SIMPLIS to send the specified data to the SIMetrix front end SIMetrix saves the data as a vector in its binary file The actual vector name used is described in the following paragraphs The format of PRINT is PRINT varl var2 where varl var2 and are legal print variables Forms of legal print variables and their meanings are listed below V DName Branch voltage across a two terminal device in the current circuit DName is the device name of a device whose element keyword is one of the following R L C V I E G H F Q S R L and C 101 SIMPLIS Reference Manual SIMetrix vector name will be DName V NodeName Voltage on mapped node NodeName Mapped nodes are created using the NNODE_MAP statement SIMetrix vector name will be NodeName I DName Branch current through a two terminal device in the current circuit DName is the device name of a device whose element keyword is one of the following R L C V I E G H F Q S R L and C SIMetrix vector name
55. 1001 76 Similar to an integer entry a floating point entry cannot begin with a positive sign Exponential Floating point Format The exponential floating point format is defined as fJE d d or sfpf E d d where if is a number in the integer format sfpf is a number in the simple floating point format E is either the character e or the character E is either the positive sign or the negative sign Chapter 2 Input File Organization a is a numeral in the range of 0 through 9 and d is an optional extra digit in the exponent The following examples are equivalent entries 27000 2 7e 04 27E 3 Engineering Floating point Format The engineering floating point format is defined as if S or sfpf S or efpf S where if is a number in the integer format sfpf is a number in the simple floating point format efpf is a number in the exponential floating point format and S is one of the character strings used to represent one of the scale factors The string can be entered in either lower or upper case The following examples are equivalent entries 27k 27K 27000 27000 2 7E 4 27e 03MEG The table below shows all the engineering prefixes recognized by SIMPLIS and their corresponding scale values Symbol Prefix Scale Factor F femto 10 15 P pico 10 12 N nano 10 9 U micro 10 6 M milli 10 3 K kilo 10 3 MEG mega 10 6 G giga 10 9 T tera 10 12 Prefix Types Illustrations
56. 2 are repeated here for illustration V1 1 0 AC 2 45 v2 4 0 AC I3 7 9 AC 5 60 163 SIMPLIS Reference Manual 164 Suppose the analysis frequency is 1 kHz and the switching frequency or the periodic operating frequency computed by the POP analysis is 50 kHz Fig 11 2 a shows the sinusoidal waveforms associated with V1 and I3 in dash lines and their actual waveforms in solid lines It can be seen that the waveforms of V1 and I3 are obtained by applying sample and hold to the corresponding sinusoidal waveforms The associated waveforms of V2 are expressly omitted in fig 11 2 a to reduce the cluttering of the figure The waveforms associated with V1 and I3 should sufficiently illustrate the sample and hold process Fig 11 2 b show similar waveforms of V1 and I3 when the analysis frequency is at 2 kHz 11 2 Waveforms for the small signal AC source examples V1 and I3 Chapter 11 Simplis FX Continuous and Discrete Domain Differences The most obvious difference between using the continuous domain or the discrete domain in the small signal analysis is the source values of the small signal AC sources As illustrated in the previous subsections the source value of a small signal AC source is a continuous sinusoidal waveform if the continuous domain is used If the discrete domain is used the waveform of a small signal AC source is the piecewise constant waveform resulting from the application of a sample and hold to a relate
57. 51 54 L LATCH 48 51 83 Latch 83 LEVEL 59 Library Search 110 Lines max length 16 LOGIC 57 59 69 70 72 73 74 75 77 79 80 82 83 Looping 112 M MAPNODEO 96 MAX_PERIOD 136 MAX_TOPOLOGY 97 Model Statements 18 50 Models AND gate 73 clocked J K flip flop 79 clocked set reset flip flop 77 clocked toggle flip flop 82 comparator 67 exclusive OR 69 inverter 65 latch 83 NAND gate 74 NOR gate 72 OR gate 70 PWL Capacitor 55 PWL Inductor 55 PWL Resistor 52 set reset flip flop 75 172 Index simple logic device 64 simple switch 57 simple transistor switch 59 N N_WIND 43 Names device 11 model 12 subcircuit 12 NAND Gate Model 74 NANDk 48 51 74 Netlist adding extra lines 106 Netlist Preprocessor 109 NEW_ANALYSIS 98 Node Names 20 NOR Gate Model 72 NORk 48 51 72 NSEG 38 52 55 O OFF_UNTIL_DELAY 24 26 28 30 32 OPEN 44 Operational Amplifier 121 Option Statements 95 OR Gate Model 70 ORk 48 51 70 P Parameters 21 111 Passing Parameters to Subcircuits 111 PDELAY 32 Periodic Operating Point 135 Piecewise Linear Resistors 45 POP 135 POP_CONVERGENCE 142 POP_ITRMAX 96 142 POP_OUTPUT_CYCLES 97 143 POP_SHOWDATA 97 142 149 POP_USE_TRAN_SNAPSHOT 96 142 Preprocessor 109 PSP_END 96 PSP_NPT 96 PSP_START 96 173 SIMPLIS Reference Manual PWL 38 PWLC 51 PWLL 51 R Resistors linear 22 PWL 45 PWL Model 52 RIN 65 67 69 70 72 73 74 75 77 80 82 83 ROFF 57 5
58. 9 RON 57 ROUT 65 67 69 70 72 73 74 75 77 79 80 82 83 RSAT 59 Running SIMPLIS aborting run 109 external netlist 107 from a script 107 from DOS prompt 108 schematic 106 RunSIMPLIS command 107 S Saturable Inductor 129 SAW 24 SCR 131 Set Reset Flip Flop Model 75 Simple Logic Device Models 64 Simple Logic Gates 47 Simple Switch Models 57 Simple Switches 43 Simple Transistor Switch Models 59 Simple Transistor Switches 44 Simplis Data Files 113 Simplis FX 155 Simplis POP 135 SNAPSHOT_INTVL 98 SNAPSHOT_NPT 98 Sources AC 159 cosine 34 current 23 current controlled 42 exponential 36 fixed 23 174 Index independent 23 pulse 30 PWL 38 sawtooth 24 sine 32 square 28 triangular 26 voltage 23 voltage controlled 41 SRFF 48 51 75 Subcircuit Definition 86 Subcircuits 18 calls 48 92 definition 86 external nodes 91 instantiation 48 92 local nodes 91 passing parameters 111 scope 90 Switches simple 43 simple transistor 44 Switching Instance Data File 116 T TAU_F 36 TAU_R 36 TDELAY 32 TH 57 59 65 69 70 72 73 74 75 77 79 80 82 83 Thyristor 131 Time domain Data Output 114 Title Statement 17 Transformers ideal 43 TRIG_COND 77 79 80 82 136 TRIG_GATE 136 Vv VCQNEG 45 51 59 VCQPOS 45 51 59 VCSW 51 VOFFSET 32 VOH 65 67 69 70 72 73 74 75 77 79 80 82 83 VOL 65 67 69 70 72 73 74 75 77 79 80 82 83 VPWLR 51 53 175 SIMPLIS Referen
59. E_TRAN_SNAPSHOT POP_OUTPUT_CYCLES n Number of cycles of steady state POP Data to show After a successful POP analysis SIMPLIS will generate the steady state time domain waveforms for an integral number switching cycles Tf set the option value must be a positive integer between 1 and 16 inclusively Tf this option is not set it defaults to 5 Example OPTIONS POP_OUTPUT_CYCLES 3 When the POP_SHOWDATA option is turned on a print plot file named XXXX t4 where XXXX is the name of the input file is generated during the periodic operating point analysis The format of this print plot file is the same as that described for the TIME DOMAIN PRINT PLOT FILE or the XXXX t2 file in Time domain Data Output on page 114 It contains columns of all print variables versus the time variable The user is reminded that the print variables are specified through the PRINT statement as outlined in Control Statements for Printing Variables on page 101 The data in this data file can be plotted to reveal the progress of the POP analysis More will be discussed on this data file in the next section The POP_ITRMAX option puts a limit on the number of iterations of the periodic operating point analysis that will be carried out by SIMPLIS When the periodic operating point analysis fails to converge to a steady state solution after this limit is reached SIMPLIS prints out an error message and exits Synopsis of the Periodic Operati
60. ID 47 IL 46 IR 45 AC 157 ELSE 111 END Statement 18 ENDIF 111 ENDS Statement 18 88 ENDWHILE 112 JF 111 MODEL 50 OPTIONS 142 158 POP 136 SIMULATOR 107 110 SUBCKT Statement 18 88 TRAN 104 VAR 111 WHILE 112 A Aborting run 109 AC Analysis 155 continuous 165 discrete 165 AND Gate Model 73 ANDk 48 51 73 APEAK 32 C Capacitors linear 23 PWL 46 PWL Model 55 CLK_DFF 48 51 80 CLK_JKFF 48 51 79 CLK_SRFF 48 51 77 CLK_TFF 48 51 82 Clocked Data Flip Flop 80 Clocked J K Flip Flop 79 170 Clocked Set Reset Flip Flop 77 Clocked Toggle Flip Flop 82 CLOSE 44 Comments 10 11 COMP 48 51 67 Comparator Model 67 Conditional Lines 111 Continuation lines 10 11 Control Statements 19 95 D DAMP_COEF 32 Data Files 113 DELAY 24 26 28 30 DELAY F 36 DELAY R 36 Device Statements 18 20 DRATIO 26 30 E ENABLE_LEVEL 83 Examples 117 Exclusive OR Gate Model 69 EXPAND 96 F F11 106 Fields max length 16 Format device statements 20 FREQ 24 26 28 30 32 FREQ _ DOMAIN 98 158 G GAIN 59 Gates simple logic 47 H HYSTWD 57 59 65 67 69 70 72 73 74 75 77 79 80 82 83 I IC 45 46 47 ICQNEG 45 51 59 ICQPOS 45 51 59 ICSW 51 Index 171 SIMPLIS Reference Manual IGNORE_UNITS 99 Inductors linear 23 mutual 40 PWL 46 PWL Model 55 saturable 129 Initial Conditions 99 Input deck 17 Input netlist 17 INV 48 51 65 Inverter Model 65 IPWLR
61. IS Reference Manual This is the title line v1 1 0 DC 10 R1 ke 2 K R2 2 3 K R3 3 0 K X1 2 SUBL SUBCKT SUB1 R1 Te 2 K cl 2 0 U R2 2 3 0K C2 3 0 U IC 0 XA 2 SUB2 XB 3 SUB2 SUBCKT SUB2 101 R101 101 102 1K C101 102 0 U IC 0 ENDS SUB2 ENDS SUB1 TRAN 1 0 END Example 5 4 Subcircuit Calls Instantiation 92 The format for a statement defining a subcircuit call or instantiation has been elaborated in and is repeated here for convenience Xname nl n2 sname Such a device statement has a device name that begins with the one character keyword X followed by a set of node names and the name of a subcircuit at the end In order for SIMPLIS to be able to find the referenced subcircuit the subcircuit instantiation and the subcircuit named sname must be defined in the same general circuit In addition the number of nodes listed in the subcircuit instantiation must match the number of external nodes listed in the subcircuit definition During the reading of the input file SIMPLIS first combs through the main circuit to register the node names that have already been employed in the main circuit In example 5 3 the nodes 0 1 2 and 3 have been utilized in the main circuit These node names form a list of existing nodes so that new node names introduced later during subcircuit instantiation will not duplicate these existing node names Similarly a list of device names already employed in
62. MESSAGE STATE CONDITIONS REACH MAXIMUM OF NO ITERATIONS PRINT ERROR MESSAGE all NO CONTINUE TO ABORT NEXT ANALYSIS 10 3 Actions carried out by the periodic operating point analysis tool NO ERROR Periodic Operating Pt Analysis Unable to find a periodic operating point after 20 attempts Check your input file for errors A change in the initial condition may be necessary During each iteration or pass of the algorithm shown in Fig 10 3 the periodic operating point analysis tool provides a glimpse of the progress of the analysis by printing out short messages on the screen The messages on the screen from a typical successful periodic operating point analysis will be similar to the following PERIODIC OPERATING POINT ANALYSIS PASS 1 6 545582e 00 PASS 2 2 848722e 01 PASS 3 5 397469e 02 SIMPLIS Reference Manual 146 PASS 4 5 006216e 03 PASS 5 6 267872e 05 PASS 6 1 004039e 08 PASS 7 1 173411le 14 The number next to each pass index represents a measure of the maximum percentage difference between the values of each capacitor voltage and inductor current at the start and end of the corresponding transient analysis Thus at the end of the 4th transient analysis in this example the error between the initial and final state vectors is less than 0 005 The periodic operating point analysis tool considers steady state operation has been reached when this percentage difference is sm
63. N tstop tsave where TRAN is the five character keyword TRAN tstop is a positive floating point number in seconds to stand for the time instant at which the time domain transient analysis stops tsave is a positive floating point number smaller than tstop The transient analysis starts with the time variable t equal to 0 0 and stops at t equal to tstop The result of the simulation is not saved however until the time variable t reaches tsave Output data for the time domain transient analysis can be generated for printing or plotting for any time instant between tsave and tstop inclusively POP Periodic Operating Point Analysis See Simplis POP on page 135 for a detailed description AC Frequency Domain Analysis See Simplis FX on page 155 for a detailed description 105 SIMPLIS Reference Manual Chapter 7 Running SIMPLIS Overview The version of SIMPLIS covered by this manual may only be used within the SIMetrix environment Usually circuits are entered using the SIMetrix schematic editor which takes care of many of the syntax details covered elsewhere in this manual Using SIMPLIS in this manner is covered in the S Metrix User s Manual but brief details are repeated here It is also possible to run SIMPLIS using a netlist prepared by hand or with another schematic entry tool This must be done within the SIMetrix environment and the following sections describe how Some features of the SIMetrix
64. OS and ICQNEG The formats for these four model types are MODEL mname mtype VSAT vsat RSAT rsat ROFF roff GAIN gain TH threshold HYSTWD hystwd LOGIC POSINEG LEVEL 112 where MODEL is the six character keyword MODEL mname is a legal model name as explained in Model Names and Subcircuit Names on page 12 mtype is a six character keyword equal to one of the following keywords VCQPOS VCQNEG ICQPOS and ICQNEG VSAT is the five character keyword VSAT vsat is a floating point number which defines the saturation voltage 59 SIMPLIS Reference Manual 60 RSAT rsat ROFF roff GAIN gain TH threshold HYSTWD hystwd LOGIC POS NEG LEVEL 1 2 of the transistor switch in volts It is the voltage across the transistor switch when it is saturated and the current through it is negligibly small It is a positive number for VCQPOS type and ICQPOS type transistor switches and it is a negative number for VCQNEG type and ICQNEG type transistor switches is the five character keyword RSAT is a positive number which defines the saturation resistance in ohms of the transistor switch is the five character keyword ROFF is a positive number which defines the leakage resistance of the switch in ohms when it is at the open state It must be larger than rsat is the five character keyword GAIN is a positive floating point number which defines the gain of the transistor swi
65. SIMPLIS FX uses a proprietary algorithm to make sure that the amplitude of all small signal AC sources are infinitesimally small so as to generate linear responses and the infinitesimally small responses are accurately resolved in the presence of the large signal switching noises Phase Delay of Small Signal AC Sources Similar to the amplitude parameter the phase parameter in the device statements defining a small signal AC source is a relative quantity rather than an absolute quantity Suppose again that the following device statements appear in the input file Vl 1 0 AC 2 45 V2 4 0 AC I3 7 9 AC 5 60 The amplitude and the phase parameters of V2 are not specified so the default values of 1 0 unit and 0 0 degree are used The phase parameter is a relative quantity In this example the phase of I3 is set to 60 degrees ahead of the phase of V2 at any excitation frequency and the phase of V1 is set to 45 degrees behind the phase of V2 You will rarely need more than one small signal AC source with different phase delay in the small signal frequency domain analysis of switching piecewise linear systems The phase parameter has been provided for backward compatibility with existing circuit simulators such as SPICE Sample Waveforms of AC Sources Continuous Domain The waveform of a small signal AC source is sinusoidal if the continuous domain is used for the small signal frequency domain analysis For example the following device stateme
66. SIMetrix Schematic 00 106 Adding Extra Netlist Lines eeen 106 Running SIMPLIS for an External Netlist 107 Running SIMPLIS from a Script eceeeeeeeeeeeeeeeeeees 107 Running SIMPLIS from a DOS Prompt eceeeee 108 SIMPLIS Execution eccececeeesesseeceeeeeeeeseeeeeaeeeneeeeees 108 Aborting a SIMPLIS RUN eceeeeeseeeeeeeeneeteeeeeeeeees 109 Automatic Program Suspension by SIMPLIS 109 Netlist Preprocessor cscceceseceeeserereseeeeeneneenseeeenes 109 QOVENIEW is e i ia diel dink tals a i 109 Launching PreproCeSSot csceessseresteeeesneeeeees 110 Library Search isser arietans 110 Parameter Sennacia a a Aas 111 Passing Parameters to Subcircuits 00 111 Conditional Lines ecceeceeeeeeeeeeeeeeeeeeeeeneeeeaees 111 LOOPING ini ona tt a narnia ae ae 112 Running Monte Carlo and Multi step Analyses 112 Chapter 8 Simplis Data Files OVENI Wae e ooo ee ated ete en ee 113 The Listing Data File eeecccescseeeeseceeeeeeeseeneneseeeeees 113 Error Message Data File 113 The State of Exit Data File csceesssseeeeseeeeeteeeees 113 Switching Instance Data File cccsccssseeeeeteeeeeees 114 SIMPLIS Reference Manual Chapter 9 Chapter 10 Chapter 11 Time domain Data Output eeeeeeeeeeeeeeeeeeeeeeneetees 114 The Topology Information File 115 Taking Advantage of Existing Files
67. SIMetrix SimPLis Advanced Power System Simulation SIMPLIS Reference Manual Copyright 1992 2007 Catena Software Ltd Contact Catena Software Ltd Terence House 24 London Road Thatcham RG18 4LQ United Kingdom Tel 44 1635 866395 Fax 44 1635 868322 Email info catena uk com Internet http www catena uk com SIMPLIS is a product of Transim Technology Corporation Transim 433 NW 4th Avenue Suite 200 Portland OR USA 97209 Ki H Phone 503 450 1355 Fax 503 295 2720 S MPLIS info transim com _ http www transim com Catena Software Ltd is a member of the Catena group of companies See http www catena nl Table of Contents Table of Contents Chapter 1 Introduction OETA AEE A ETT 8 Organization of this User Manual sccceeeeeeeeeeeees 8 Chapter 2 Input File Organization OVENI EW ia orainaren i Andel tiered aed 10 General Rules for the Input File eeeeeeeeeeeeeeeeeeeee 10 Statements and Continuation of Statements 10 Blank Characters ccccccccccccccccececeeesecsesesseesesersees 10 Blank Lines cccccccceecececeessesesecceceeseeeesenaeeansseees 10 Comment Statements cccccccccesssseeeeesessseeeeees 10 In line Comments ccccecccseeeseessssssseeeeeeeeeeeeeeeees 11 Continuation of Statements ccccceeeeeeessseeeeees 11 Device Names cccccccccceccceesssseseceeeceeeeeeenaeeesseees 11 Model Names and
68. Subcircuit Names 00 12 Uppercase vs LOWEIrCASE eseeeseeeeeneeeeenteeeeeees 13 Integer Entri eSenior 13 Floating point Entries 14 URO aaar t aae e a e aa 16 Length of Fields and Lines ee eeeeesseeeenreeeeees 16 Organization of the Input File eee eeeeeeeseeteeeeeneeeees 17 General Girej nimee eien a a aa 17 Maim GirGU i a bance ais aaa iiias 17 SU O CUT 8 no Shinichi hoes oan es een 18 General StateMent c ccccccccsssccecsesseeeeeesssseeeeees 18 Chapter 3 Device Statements OVOIVIOW noei ean shevieees cet do aa obi ect vetoes 20 Device Statement Format ccceeeeeeeeeeseeeereeeeees 20 Node Names ii c csicinadt aie dati 20 Voltage and Current Polarity Conventions 21 Parameter Assignments seeren 21 Controlling D ViICES eeeceeeeeereeeeeeeeeeeeteeteeeeeeeeeaes 22 SIMPLIS Device Type s ceccessceeseeseeeeeeeeeseeteeeeeseetaes 22 Linear Resists e aaee aanere aieeaa iA 22 Linear Inductors and Capacitors ccceeeeeeeeees 23 Independent Voltage and Current Sources 23 Triangular Sources cecceceeeeeeeeeeeneeeeeeseaeeeeeeeeneeees 26 SIMPLIS Reference Manual Chapter 4 Chapter 5 Chapter 6 Square Wave Sources esccesceeeeeeeeeteeeeeeeeeseeeeas 28 Pulse Sources with Zero Rise and Fall Times 30 Sinusoidal SourceS e ra a a S 32 Cosinusoidal Source ccccccesceeeeeteeeeeeeeeeeseeeeees 34
69. T and ENDS statements A control statement can be classified as one of the following types 1 Options 2 Initial conditions 3 Printing of variables 4 Analyses All types of control statements can appear within the scope of definition of the main circuit but only the control statements related to the setting of initial conditions and the printing of variables are allowed to appear inside the scope of definition of a subcircuit In general control statements can appear in any order of sequence The one exception to this rule is the order of the analysis statement which dictates the sequence in which SIMPLIS performs the different analyses Option Statements As its name implies option statements are used to set various options to appropriate values More than one option statement can appear in the input file The format of an option statement is OPTIONS opt opt2 where opt opt2 and are various options Some options only take on the values of ON or OFF The defaults values for such options are OFF and the option values are turned ON by having the corresponding keyword present in an option statement Some other options assume the form of the parameter assignment outlined in Option statements are not allowed to be placed within the scope of definition of any subcircuit because the options apply to the entire system under study The various options and their meanings are EMSG_MAX k Sets the Maximum number of error message
70. The main circuit is the ancestor of all subcircuits defined in the entire input file and it does not have a parent SUBCKT Statement In this section a brief description of the SUBCKT statement is given The format of the SUBCKT statement is defined as SUBCKT sname nl n2 n3 where SUBCKT is the seven character keyword SUBCKT signifying the start of the subcircuit definition sname is a legal subcircuit name as explained in Model Names and Subcircuit Names on page 12 A subcircuit name must be unique within a general circuit If a name is used as a subcircuit name in a general circuit it cannot be used as a model name in the same general circuit and vice versa nl is the node name of the first external node of the subcircuit n2 is the node name of the second external node of the subcircuit n3 is the node name of the third external node of the subcircuit and so on The elements defined in a subcircuit interact with the subcircuit s parent circuit only through the subcircuit s external nodes and the ground node node 0 Node 0 the ground node is not allowed to be used as an external node unless the option of MAPNODEO is used in an OPTION control statement Refer to Sections Scope of Definition for a Device and for a Node on page 90 and Option Statements on page 95 on the properties of MAPNODEO ENDS Statement End of Subcircuit Statement In this section a brief description of the ENDS statement is gi
71. V or ALL as a printing variable In addition if ALL is used as the print variable other print variables defined in the main circuit or in any of its descendant subcircuits are ignored Mapping Names to Node Numbers The SIMPLIS input deck format requires all nodes to be defined as numbers The names used for the SIMetrix vectors for the voltage on a node always use the name of that node So the SIMetrix vector names will be numbers as well This can be inconvenient so a method is available to instruct SIMPLIS to use a user defined name for any node voltage vector This is done using the NODE_MAP statement The format of the INODE_MAP statement is NODE_MAP mapped_name node_number 103 SIMPLIS Reference Manual where mapped_name User defined name Must have at lease one alphabetic character and may comprise any alphanumeric character in addition to the underscore _ node_number Node number to be mapped For example NODE_MAP VOUT 27 If the above line is included in the SIMPLIS input deck the vector for the voltage at node 27 will be named VOUT The NODE_MAP statement may also be used inside subcircuits If such a NODE_MAP statement is used to map an external node then NODE_MAP statements must be issued for all external nodes Mapping external nodes also controls the naming of current vectors into the subcircuit s terminals See Control Statements for Printing Variables on page 101 for further details Creatin
72. VSAT 700m RSAT 100m ROFF 10Meg GAIN 10 TH 2 5 HYSTWD 100u LOGIC POS LEVEL 1 R R1 0 3 R1 TP_SSPWLR IC 1 MODEL R1I TP_SSPWLR VPWLR NSEG 2 X0 0 Y0 0 X1 0 7 Y1 10U X2 0 8 Y2 1 00001 RX 4 3 10m SUBCKT SIMPLIS_COMP 1 201 100 101 102 DCOMP 201 100 101 102 MCOMP IC 1 MODEL MCOMP COMP RIN 1e 007 ROUT 50 VOL 0 VOH 5 HYSTWD 1e 006 DELAY 0 ENDS SIMPLIS_COMP 1 SUBCKT opamp 2 3 1 NODE_MAP VINN 1 NODE_MAP VINP 3 NODE_MAP VOUT 2 RIN 3 1 5Meg EOP 2 0 3 1 1Meg ENDS opamp END oOoangqwzaaAaanAD 9 15 Input File for Example 5 generated by SiMetrix Chapter 9 Simplis TX Examples KL i gt lt Output E Saw tooth 2 1 1 8 I 44 a T 0 6 0 gt 4 g 3 Q fe z i ao 1 12 5 gt gt 12 5 amp 124 5 O 12 4 12 4 0 10 20 30 40 50 time uSecs 10uSecs div 9 16 Waveforms for Example 5 Example 6 Saturable Inductor Depending on the system design a magnetic element may be intentionally or unintentionally driven into saturation during transient or during steady state operation This example illustrates the usage of piecewise linear PWL inductors in the input file The system under study is shown in fig 9 17 a which comprises of a sinusoidal voltage source driving a resistor in series with a saturable inductor Fig 9 17 b shows the piecewise linear
73. after the system has settled to new steady state operations under new line load conditions Depending on the damping and the regulation circuitry of the system it may take the system hundreds to thousands of switching cycles before settling to a new steady state operation after each change in the line load condition While carrying out such a study with a brute force simulation is possible it can be time consuming Hence there is a need for a special analysis tool that can accelerate the convergence of the system towards its steady state operating condition without going through the actual transient Another example where the steady state operation of a switched piecewise linear system is essential is in the study of the load transient of a regulated switching power system In such a study the transient experienced by the system in response to a load change is monitored When this study is carried out through simulation one must initialize the circuit simulation to the initial steady state solution of the system before the load change is initiated Without using a steady state solution to start the simulation the transient obtained will be different from the transient measured in the laboratory A special algorithm for speeding up the computation of the steady state solution of switched piecewise linear systems have been incorporated into SIMPLIS as a special analysis tool While it is mathematically more challenging and computationally more i
74. age across the voltage source or the current through the current source the value of the source function s t in the diagram below for t gt delay is defined as s H v1 v2 v1 t delay T for delay lt t lt delay T and s H s t T for delay T lt t where T 1 freq is the period of the waveform The source function s t for t lt delay is defined as follows s t s t T for 0 lt t lt delay and OFF_UNTIL_DELAY NO and s t v1 for 0 lt t lt delay and OFF_UNTIL_DELAY YES Whether the delay is positive or negative the time domain transient analysis performed by SIMPLIS always starts with the time variable set equal to 0 0 The diagram below shows the waveforms of a sawtooth source For t lt delay and OFF_UNTIL_DELAY YES the waveform s t is shown in bold dashed line For t lt delay and OFF_UNTIL_DELAY NO the waveform s t is shown in heavy gray line 25 SIMPLIS Reference Manual 26 v1 s t Dt CIRM delay T T 1 freq gt lt gt 3 2 Waveform s t of a sawtooth source Triangular Sources The formats for independent triangular voltage and current sources are Vname n n TRI Vl vl V2 v2 FREQ freq DRATIO dratio DELAY delay OFF_UNTIL_DELAY YESINO and Iname n n TRI Vl v V2 v2 FREQ freq DRATIO dratio DELAY delay OFF_UNTIL_DELAY YESINO where Vv name n TRI Vil is the one character element keyword V for independent voltage
75. aller than the convergence parameter POP_CONVERGENCE which has a default value of 1x10 14 or 1x10 12 The Time Variable During POP Analysis In the periodic operating point analysis our major goal is to find the steady state operation of the system How the system reaches the eventual steady state operation from the original initial state is not as important In addition the action carried out by the prediction phase shown in fig 10 3 does not correspond to any real operation experienced by the system Hence it is impossible to assign a true value to the time variable during a POP analysis With no other better choices and without any loss of generality we can reset the time variable at the exit of a POP analysis to its original value at the entry of the POP analysis Since the POP analysis is the first analysis allowed this means that the time variable is artificially reset to 0 0 at the end of a POP analysis Consequently if there is a time domain transient analysis immediately following a POP analysis the time variable for that time domain transient simulation will start at 0 0 and the time variable will advance forward as usual in the regular time domain transient analysis How POP Deals with Time Varying Sources At the entry of a periodic operating point analysis all time varying sources are classified as either periodic or aperiodic Sawtooth triangular square and pulse sources are always considered to be periodic A sinusoi
76. alysis Hence it is not necessary for you to remove the definition of the small signal AC sources from the input file in order to run other types of analyses Example of Applying the AC Analysis Tool The regulated converter used in the illustration of the Periodic Operating Point Analysis in Chapter 10 is repeated here to show how the SIMPLIS FX Small Signal Frequency Domain can be applied to determine the loop gain of a closed loop regulated converter The schematic of this converter including the small signal AC source is shown in Fig 11 3 The input file of this analysis is shown in Fig 11 4 Chapter 11 Simplis FX N F Jour OUT IN a tom 40u 1C 0 14 n MN RX L Rc mie Output 40 50m v Ri RL a 10 AC 1 v2 L 50u 1C 12 48 Q L Control x1 VSAW 25 F VREF R12 re 10k T 11 3 Small signal excitation to determine the loop gain of the regulated converter 167 SIMPLIS Reference Manual Example in User Manual with Small Signal Analysis NODE_MAP Output 15 NODE_MAP Control 14 AC DEC 40 lu 50k PRINT ALL OPTIONS PSP_NPT 2001 POP_ITRMAX 40 POP TRIG_GATE X1 D_CYCLE TRIG_COND 1_TO_0 MAX_PERIOD 50u X U2 9 13 8 opamp VSAW 11 0 SAW V1 0 V2 5 FREQ 100k DELAY 0 OFF_UNTIL_DELAY NO X U1 5 0 9 11 SIMPLIS_COMP 1 vl 2 0 40 v2
77. amp VSAW 12 0 SAW V1 0 V2 5 FREQ 100k DELAY 0 OFF_UNTIL_DELAY NO X U3 6 0 11 12 SIMPLIS_COMP 1 2 0 PWL NSEG 3 X0 0 Y0 40 X1 100U Y1 40 X2 100U Y2 30 X3 100M Y3 30 REF 14 0 2 5 4 5 40u Ic 0 14 2 0 8 10k 12 13 PERIODIC_OP 2 3 8 10 10k RC 7 5 50m L 5 0 10 1 8 5 40k 11 9 5n IC 800m 4 10 9 40k 4 9 10 10p IC 0 C 7 0 50u IC 12 48 2 3 6 0 Q1STP_VCQ IC OPEN MODEL Q1 TP_VCQ VCQPOS VSAT 700m RSAT 100m ROFF 10Meg GAIN 10 TH 2 5 HYSTWD 1lu LOGIC POS LEVEL 1 R R1 0 3 R1 TP_SSPWLR IC 1 MODEL R1I TP_SSPWLR VPWLR NSEG 2 X0 0 Y0 0 X1 0 7 Y1 10U X2 0 8 Y2 1 00001 RX 4 3 10m SUBCKT PERIODIC_OP 2 13 NODE_MAP IN 1 NODE_MAP OUT 3 D_CYCLE 3 0 1 302 M1M IC 0 VREF 302 0 DC 2 5 MODEL M1M COMP RIN 10MEG ROUT 50 VOL 0 VOH 5 HYSTWD 0 001 DELAY 0 ENDS PERIODIC_OPS 2 SUBCKT SIMPLIS_COMP 1 201 100 101 102 DCOMP 201 100 101 102 MCOMP IC 1 MODEL MCOMP COMP RIN 1le 007 ROUT 50 VOL 0 VOH 5 HYSTWD 0 001 DELAY 0 ENDS SIMPLIS_COMP 1 SUBCKT opamp 2 3 1 NODE_MAP VINN 1 NODE_MAP VINP 3 NODE_MAP VOUT 2 RIN 3 1 5Meg EOP 2 0 3 1 1Meg ENDS opamp END wxvnag S lt S OOGA G Dw 10 8 Input File To obtain the transient response in this study a time domain transient simulation with the voltage of VI set at 30V is carried out after a periodic operating point analysis is applied to the system with the voltage of VI set at 40V Notice that the initial conditions defined for the various components fro
78. an NPN bipolar transistor and an N channel MOSFET For model types VCQNEG and ICQNEG the Chapter 4 Model Statements voltage across the transistor switch measured as the voltage of the positive node with respect to the voltage of the negative node assumes non positive values under normal operation like a PNP bipolar transistor and a P channel MOSFET Models for Simple Transistor Switches for LEVEL 1 When a simple transistor switch is modeled with the LEVEL parameter set to 1 it can assume either an open or a closed state The switching diagram in 4 3 a applies when LOGIC is set to POS while the switching diagram in 4 3 b applies when LOGIC is set to NEG The only difference between a simple switch and a simple transistor switch with LEVEL set to 1 is the model of the closed state When a simple transistor switch with LEVEL set to 1 is in the closed state it is modeled by a linear resistor with the value rsat in series with a constant voltage source with the value vsat When the simple transistor switch is in the open state it is modeled by a resistor with the value roff The block diagram and the V I characteristic of the model are shown in Figure 4 4 The circuit element model of the simple transistor switch with LEVEL set to 1 for the closed and open states are shown in diagram 4 4 below n slope 1 tgat i a la 4 cs t Va z 4 Vsat Va NC n slope 1 roff a b Vsat lo r slope 1 roff slope 1 rgat m Va
79. and fig 10 6 c The waveform in fig 10 6 b is representative of a high gain closed loop regulated system where a small change in the capacitor voltages or inductor currents can cause a dramatic change in the mode of operation of the system In such a case the user may want to run a regular time domain transient analysis until the system settles to a stable mode of operation read off the capacitor voltages and inductor currents and then run a POP analysis with the new initial conditions The waveform in fig 10 6 c is representative of a system where the initial conditions for a few devices as supplied by the user in the input file are very far away from the values that they should be during steady state operation For instance the waveform in fig 10 6 c suggests that to approach steady state operation the initial condition associated with the capacitor CC should be increased to at least 100 V Although the example waveforms shown in fig 10 6 are either capacitor voltages or inductor currents all voltage and current variables specified in the PRINT statement are generated in this data file for the user to examine the progress of the POP analysis Chapter 10 Simplis POP V CA 100 200 300 400 LB I c 10 6 Typical waveforms obtained using the POP_SHOWDATA option a Successful POP analysis waveforms settle in a periodic steady state b Unsuccessful POP analysis waveforms fluctuate with large variations from on
80. ansistor switch is used by SIMPLIS only as a suggestion Giving a correct initialization however eliminates the computation time required by SIMPLIS to search for the correct initial state and thus leads to a faster simulation Piecewise Linear Resistors The format for piecewise linear resistor is Rname n n mname C seg_num where IR is the two character element keyword R for piecewise linear 45 SIMPLIS Reference Manual 46 resistors name is the individual name of the device n is the name of the positive node and is a nonnegative integer n is the name of the negative node and is a nonnegative integer mname is the name of a model compatible with a piecewise linear resistor IC is the three character keyword IC representing the initial segment of operation for the piecewise linear resistor seg num is a positive integer assigned as the initial segment of operation for the piecewise linear resistor It must be larger than or equal to 1 and less than or equal to the number of segments defined in the model The parameters describing a piecewise linear resistor are defined in a model statement Refer to Piecewise Linear Resistor Models on page 52 for the explanation of the model statements associated with the piecewise linear resistors There are two types of models that are compatible with piecewise linear resistors VPWLR for voltage defined piecewise linear resistors and IPWLR for current defined piecewis
81. apped to node 9 2 Node 102 is mapped to a new node name that is not in the list of existing nodes Then this new node name is added to the list of existing nodes 3 Devices R101 and C101 are mapped to appropriate new device names that are different from existing device names Then these device names are added to the list of existing device names 93 SIMPLIS Reference Manual 4 Since there is no subcircuit defined in the subcircuit SUB2 the instantiation of XB has been completed The four step procedure is repeated until all subcircuits have been instantiated Notice that the definition of a subcircuit only provides a model subcircuit with a reference name The subcircuit does not come into being until the appropriate subcircuit instantiation 94 Chapter 6 Control Statements Chapter 6 Control Statements Overview The device statements model statements and subcircuit definition statements discussed in Chapters through See are all related to circuit definition There are additional statements that control the type of analysis to be performed and the type of output data to be generated by SIMPLIS These types of statements are not related to circuit definition They are collectively called the control statements All control statements start with the period as the first character in the statement However not all statements starting with a period are control statements The exceptions are the MODEL END SUBCK
82. as shown in 9 4 It is made up of a three phase ac voltage source in a Y configuration which is rectified into a single load connected to the neutral line The three voltage sources are modeled as cosinusoidal voltage sources of the same frequency with delays equal to 0 1 3 and 2 3 of the period The variables of interest are the three line to neutral voltages V 1 V 2 and V 3 and the load voltage V 4 The SIMPLIS input file for the circuit of Example 2 is shown in 9 5 Waveforms for these four variables are plotted in 9 6 119 SIMPLIS Reference Manual 120 R1 R3 are PWL resistors designed to have the characteristics of diodes vi 9 4 Three phase Rectifier with Load 3 Phase AC Voltage Source In A Y Configuration PRINT ALL OPTIONS PSP_NPT 1001 TRAN 2m 0 V1 1 0 COS VOFFSET 0 APEAK 5 FREQ 1k PDELAY 0 OFF_UNTIL_DELAY NO DAMP_COEF 0 V2 3 0 COS VOFFSET 0 APEAK 5 FREQ 1k PDELAY 120 OFF_UNTIL_DELAY NO DAMP_COEF 0 V3 4 0 COS VOFFSET 0 APEAK 5 FREQ 1k PDELAY 240 OFF_UNTIL_DELAY NO DAMP_COEF 0 RL 2 0 50 RSR1 1 2 R1IS TP_SSPWLR IC 1 MODEL R1STP_SSPWLR VPWLR NSEG 2 X0 0 YO 0 X1 1 Y1 5u X2 1 1 Y2 1 RSR2 3 2 R2 TP_SSPWLR IC 1 MODEL R2STP_SSPWLR VPWLR NSEG 2 X0 0 YO 0 X1 1 Y1 5u X2 1 1 Y2 1 RSR3 4 2 R3 TP_SSPWLR IC 1 MODEL R3STP_SSPWLR VPWLR NSEG 2 X0 0 YO 0 X1 1 Y1 5u X2 1 1 Y2 1 END 9 5 Input File for Example 2 as generated by SiMetrix Chapter 9 Simp
83. ase is 0 0 degree Since device statements can appear within the scope of definition of any general circuit the small signal AC voltage current sources can be defined in the main circuit 159 SIMPLIS Reference Manual as well as in any subcircuit For a more detailed explanation of the amplitude and the phase parameters see Synopsis of Small Signal AC Analysis on page 160 Synopsis of Small Signal AC Analysis 160 After the periodic operating point trajectory of the system has been determined by the periodic operating point POP analysis the SIMPLIS FX Small Signal Frequency Domain Analysis can then be applied to compute the small signal response of the system in a small neighborhood around the large signal periodic equilibrium For illustration purposes let us assume that the following AC analysis statement was specified in the input file AC DEC 10 250 25K This analysis statement instructs SIMPLIS FX to carry out the small signal frequency domain analysis by sweeping the excitation frequency of all small signal AC sources in a logarithmic manner from 250 Hz to 25 kHz The number of analysis frequencies per decade is set to 10 You can easily verify that this analysis statement leads to the following excitation frequencies 250 000 Hz 314 731 Hz 396 223 Hz 1 57739 kHz 1 98582 kHz 2 50000 kHz 3 14731 kHz 3 96223 kHz 15 7739 kHz 19 8582 kHz 25 0000 kHz As the sequence of small signal analyses at these excitatio
84. ash of the input file in a more organized manner If you have elected to specify the EXPAND option in the input file additional information illustrating how the subcircuit calls are being expanded will be written to this listing file Error Message Data File The error message data file is named XXXX err where XXXX is the name of the input file to SIMPLIS If there is a syntax error detected in the input file or if a simulation error is encountered error messages will be recorded in this error message file You can examine this error message file and other data files generated by SIMPLIS to determine the cause of the problem SIMetrix automatically displays in the command shell the contents of this file if it exists The State of Exit Data File At the end of a time domain simulation SIMPLIS always writes out the state of the system under study to a State of Exit file This data file contains the voltage across each linear capacitor or piecewise linear capacitor 113 SIMPLIS Reference Manual 1 The current through each linear inductor or piecewise linear inductor 2 The state of each simple switch or simple transistor switch 3 The segment of operation of each piecewise linear resistor and 4 The output logic state of each simple logic gate The State of Exit data file is written out only if a time domain analysis has been specified Traditionally this file is named XXXX init where XXXX is the name of the input f
85. at the initial current of linear inductor L12 is set to 0 A whereas the initial current of PWL inductor L22 is set to 2 milliamperes 99 SIMPLIS Reference Manual 100 Seiting of Initial States for S and Q Switches The INIT statement can be used to override the initial states of simple switches and simple transistor switches INIT Q1 OPEN SA CLOSE means that the initial state of the Q switch Q1 is set to OPEN whereas the initial state of the S switch SA is set to CLOSE Setting of Initial Segment for PWL Resistors The INIT statement can be used to override the initial segment of operation for PWL resistors INIT R100 3 means that the initial segment of operation for the PWL resistor R100 is set to the 3rd segment of this device Seiting of Initial State for Simple Logic Gates The INIT statement can be used to override the initial state of a simple logic gate For example INIT D9 0 D8 1 means that the initial output state for logic gate D9 is set to logic 0 whereas the initial output state for logic gate D8 is set to logic 1 Initial Conditions for Devices in a Subcircuit Since initial conditions are either specified in the device statements or through the INIT statements discussed so far two subcircuit instantiations referencing the same subcircuit definition naturally have identical initial conditions Let us examine the statements in example 6 1 a The capacitor originally named CA in subcircuit
86. aveform where the source value is equal to v2 The source function s t for t lt delay is defined as follows s s t T for 0 lt t lt delay and OFF_UNTIL_DELAY NO 31 SIMPLIS Reference Manual 32 s t v for 0 lt t lt delay and OFF_UNTIL_DELAY YES The waveform s f of a typical rectangular pulse source is shown in the diagram below For t lt delay and OFF_UNTIL_DELAY YES the waveform s t is shown in bold dashed line For t lt delay and OFF_UNTIL_DELAY NO the waveform s t is shown in heavy gray line s t T T 1 freq v1 delay t1 dratio T 3 5 Waveform s t of a pulse wave source Sinusoidal Sources The formats for defining independent sinusoidal voltage and current sources are Vname n n SIN VOFFSET voff APEAK apeak FREQ freq TDELAY tdelaylPDELAY pdelay OFF_UNTIL_DELAY YESINO DAMP_COEF damp_coef and Iname n n SIN VOFFSET voff APEAK apeak FREQ freq TDELAY tdelay IPDELAY pdelay OFF_UNTIL_DELAY YESINO DAMP_COEF damp_coef where V is the one character element keyword V for independent voltage sources I is the one character element keyword I for independent current sources name is the individual name of the device n is the name of the positive node and is a nonnegative integer SIN VOFFSET voff APEAK apeak FREQ freq TDELAY tdelay PDELAY pdelay Chapter 3 Device Statements is the name of the negative nod
87. ce Manual VSAT 59 X XOR 48 51 69 Copyright Transim Technology Corporation 1991 2007 SIMPLIS Reference Manual 5 10 07 176
88. ceptable model type is PWLL For a piecewise linear capacitor the only acceptable model type is PWLC Simple Logic Gates The format for a simple logic gate is Dname nol no2 nref nil ni2 mname IC Ol1 where D is the two character element keyword D for simple logic gates name is the individual name of the device nol is a nonnegative integer representing the name of the first output node of the logic gate no2 is a nonnegative integer representing the name of the second output node of the logic gate if there is more than one output nref is a nonnegative integer representing the name of the reference node The logic state s of the output s of a simple logic gate are defined in terms of the voltage s of the output node s with respect to the reference node The logic state s of the input s of a simple logic gate are defined in terms of the voltage s of the input node s with respect to the reference node nil is a nonnegative integer representing the name of the first input node of the logic gate ni2 is a nonnegative integer representing the name of the second input node of the logic gate if there are more than one input mname is the name of a model compatible with a simple logic gate IC is the three character keyword IC representing the initial output state of the logic gate 0 is the integer 0 to indicate that the initial output state of this gate is logic 0 1 is the integer 1 to indicate that the initial output s
89. ctively An example in Example of Applying the 135 SIMPLIS Reference Manual POP Analysis Tool on page 151 illustrates the application of the POP analysis to a closed loop regulated switching power system Statements Relating to POP Analysis The statements relating to the Periodic Operating Point analysis can be all classified as control statements of the type defined in Chapter 6 An analysis statement to invoke the POP analysis and three option statements are associated with the Periodic Operating Point analysis POP Statement for POP Analysis The POP statement instructs SIMPLIS to perform a Periodic Operating Point analysis on the system under study Just like any other analysis statement the POP statement can only appear within the scope of definition of the main circuit In addition there can be no more than one POP statement in an input file The format for the POP statement is POP TRIG_GATE gate_name TRIG_COND 0_TO_1I1_TO_0 MAX_PERIOD max_period TD_RUN_AFTER_POP_FAILS tran_after_pop_fail where POP is the four character keyword POP TRIG_GATE is the ten character keyword TRIG_GATE gate_name is the device name of a defined logic gate This device is considered the triggering gate of the POP analysis Together with the parameter value of TRIG_COND it determines the condition that constitutes the start of a new switching cycle in the POP analysis TRIG_COND is the ten character keyword TRIG_COND
90. curly braces The expression may use values defined in previous VAR controls and if the X line is itself inside a subcircuit definition values passed to that definition The expression may not however reference other passed parameters on the same X line E g value2 may not reference param Conditional Lines The IF control may be used to define lines that are passed to the output only if specified conditions are met The syntax is as follows JAF expression netlist lines ELSE netlist lines wd ENDIF 111 SIMPLIS Reference Manual If expression resolves to a non zero value then the lines up to ELSE will be output otherwise the lines between ELSE and ENDIF will be output The ELSE is optional IF ELSE ENDIF may be nested to any level expression may be any valid arithmetic expression and may refer to previously defined parameters including those passed through a subcircuit call Looping The preprocessor may be instructed to output a repeated sequence of lines using the WHILE control The syntax is WHILE expression max_loop_count netlist lines ENDWHILE The block between WHILE and ENDWHILE will be repeated as long as expression is non zero up to a maximum of max_loop_count times If max_loop_count is omitted it takes a default value of 100 max_loop_count is intended as a safety measure to prevent an endless loop from filling the user s fixed disk to its capacity Running Monte Carlo and Mu
91. d continuous sinusoidal waveform Another difference between using the continuous domain and the discrete domain in the small signal analysis is the way the responses are analyzed In the case of the continuous domain Fourier analysis is directly applied to any response of the system to extract the harmonic with the same frequency as the analysis frequency In the case of the discrete domain a sample and hold process is applied to each response of the system and Fourier analysis is then applied to the result of this sample and hold process The sampling is set to occur just like the small signal AC sources at the beginning of a switching cycle where this beginning is defined through the POP analysis statement Whether continuous domain or discrete domain is used the effects of the implicit sample and hold that occurs in a switching system are taken into consideration by SIMPLIS FX For example if a simple switch S is controlled by a control signal cs t an effective sample and hold process of cs t is taken place at every moment switch S switches position Another example of implicit sample and hold occurs at the two inputs of a comparator Whenever the comparator switches its output logic state we have in effect a sample and hold of the two analog inputs of the comparator If you are familiar with the peak current control of energy storage dc to dc converters recall that peak current control would approach unstable operation as th
92. d must be larger than delay_r is the six character keyword TAU_R representing the time constant of the rising edge of the source is a floating point number assigned as the value of the time constant of the rising edge in seconds is the six character keyword TAU_F representing the time constant of the falling edge of the source is a floating point number assigned as the value of the time constant of the falling edge in seconds The source function s t is defined as follows s j v1 for t lt delay_r s f v2 v1 v2 e7 delay taur for delay_r lt t lt delay_f 37 SIMPLIS Reference Manual 38 s t v1 s delay_f v1 e ODF for delay_f lt t In the case where tau_r is equal to 0 the source function rises instantaneously from vl tov2 att delay_r s v2 for delay_r lt t lt delay_f In the case where tau_f is equal to 0 the source function falls instantaneously from v2tovl att delay_f s j vl for delay_f lt t The waveform s f of a typical aperiodic exponential pulse source is shown in the diagram below s t tau_r delay_f 3 8 Waveform s t of an exponential pulse source Aperiodic Piecewise Linear Sources An aperiodic piecewise linear source has its source function s t defined in terms of a finite number of linear segments See diagram below for a typical example The formats for independent aperiodic piecewise linear sources are Vname n n PWL NSEG k X
93. d with the right key The top item Edit file at cursor will open a text editor with the file name pointed to by the cursor or selected text item if there is one Chapter 7 Running SIMPLIS The simulator command window can be resized using the splitter bar between it and the schematic drawing area You can add anything you like to this window not just simulator commands The contents are simply appended to the netlist before being presented to the simulator So you can place device models mutual inductor specifications OPTION controls or simply comments The Choose Analysis dialog will parse and possibly modify analysis controls and some OPTIONS settings but will leave everything else intact Some schematics may be simulated with both SIMPLIS and the SPICE based SIMetrix simulator The commands referred to as controls in SIMetrix documentation for these simulators are however incompatible For this reason SIMetrix and SIMPLIS commands are separated using the SIMULATOR control The syntax for this is SIMULATOR SIMPLIS SIMetrix DEFAULT SIMPLIS All lines following and until the next SIMULATOR control will only be passed to the netlist in SIMPLIS mode SIMetrix All lines following and until the next SIMULATOR control will only be passed to the netlist in SIMetrix mode DEFAULT All lines following and until the next SIMULATOR control will be passed to the netlist in both modes Running SIMPLIS for an External Netlist
94. dal or cosinusoidal source is considered to be periodic if its damping coefficient is equal to 0 0 otherwise it is considered as aperiodic Exponential pulse sources and piecewise linear sources are always considered to be aperiodic Periodic sources are left unchanged during a POP analysis i e they remain as sources with time varying source values The treatment of the aperiodic sources during a POP analysis however are quite different They are turned into DC sources during a POP analysis with each source held constant at its value just before the entry of the POP analysis Aperiodic Sources Aperiodic sources are held at a constant value during the POP analysis This is necessary in order to find the periodic operating point After the POP analysis has finished the source values of the aperiodic sources are allowed to be time varying according to their definition in the input file Take the piecewise linear source defined in the following lines of statements as an example V1 101 0 PWL NSEG 3 X0 0 0 YO 1 0 X1 1 0 Y1 2 0 Chapter 10 Simplis POP X2 2 0 Y2 0 5 X3 3 0 Y3 0 5 Normally the source value V V1 would be as shown in fig 10 4 a When a POP analysis is carried out the source value V V1 during the entire POP analysis is clamped by SIMPLIS at 1V the value of the source at the beginning of the POP analysis If there is a time domain transient analysis immediately following the POP analysis the waveform V V1 duri
95. domain simulation if the system under study spends a non zero amount of time in a certain circuit topology SIMPLIS will save the important information associated with this particular topology in a file called the Topology Information file In addition this file also contains a description of the system under study and it is named XXXX te where XXXX is the name of the input file to SIMPLIS Taking Advantage of Existing Files Often you will make multiple time domain simulation runs on the same system After the first simulation run is finished the Switching Instance Data file mentioned in Switching Instance Data File on page 114 and the Topology Information file outlined above are created After examining the waveforms from this simulation run you may decide to either repeat the simulation with a longer run time or repeat the same simulation run with a different set of print variables In either case there is no change in the system under study and the Switching Instance Data file and the Topology Information file contain valuable information associated with the time domain simulation In the next simulation run SIMPLIS can take advantage of the data stored in these two files and reduce the computation time in the simulation Every time SIMPLIS is invoked it looks for the presence of the Topology Information file the XXXX tc file If this file is present and the circuit it describes matches that of the input file SIMPLIS can ta
96. e and is a nonnegative integer is the three character keyword SIN to signify that this is a sinusoidal source with possible damping is the eight character keyword VOFFSET representing the DC offset of the source is a floating point number assigned as the DC offset value in volts for a voltage source and the DC offset value in amperes for a current source is the six character keyword APEAK representing the amplitude of the source at t tdelay is a nonnegative floating point number assigned as volts for a voltage source and amperes for a current source is the five character keyword FREQ representing the frequency of the source is a positive floating point number assigned as the frequency of this source in hertz is the seven character keyword TDELAY representing the time delay of the source is a floating point number assigned as the time delay in seconds is the seven character keyword PDELAY representing the phase delay of the source is a floating point number assigned as the phase delay in degrees The specification of TDELAY and PDELAY are mutually exclusive OFF_UNTIL_DELAY YES NO DAMP_COEF damp_coef is the sixteen character keyword OFF_UNTIL_DELAY is the three character keyword YES is the two character keyword NO is the ten character keyword DAMP_COEF representing the damping coefficient of the source is a floating point number assigned as the damping coefficient in
97. e cycle to the next and c Unsuccessful POP analysis waveforms approach unilaterally but do not settle in a periodic steady state Example of Applying the POP Analysis Tool The regulated converter in Example 5 of Chapter 9 is used here as an example in applying the periodic operating point analysis tool The schematic associated with this example is repeated here in fig 10 7 In particular we would like to examine the transient response of this regulated converter when the input voltage VI is abruptly changed from 40V to 30V with the load RL fixed at 10 The variables of interest are the output voltage V RL and the current I L through the filter inductor The input file describing this analysis is shown in fig 10 8 To make the transient response more pronounced some of the component values have been changed from those listed in Example 5 of Chapter 9 In particular the values on C1 C14 and R14 have been changed to 0 005 F 10 pF and 40k _ respectively 151 SIMPLIS Reference Manual 152 Qi au PONCE gata aout j RX E HG vt 50m Rt RL N 10 R11 40k 50u IC 12 48 cc VSAW 2 5 t vREF R12 _ 10k ii 10 7 Regulated Converter Chapter 10 Simplis POP pop example sxsch PRINT ALL OPTIONS PSP_NPT 2001 POP_ITRMAX 40 POP TRIG_GATE X1 D_CYCLE TRIG_COND 1_TO_0 MAX_PERIOD 50u TRAN 2m 0 X U2 11 14 10 op
98. e duty ratio of the power switch approaches 50 provided no compensation ramp is applied to the control Using existing modeling methods such instability can only be predicted by explicitly adding a sample and hold function block or any approximation of such from the controlling signal to the power stage Such explicit addition is not necessary when these control strategies are analyzed with SIMPLIS FX because the implicit sample and hold process that occurs in the circuit is taken into consideration in the computation of the frequency response As a result the schematic that is used for time domain simulation is the schematic that will be analyzed in frequency domain eliminating the need to replace parts of a schematic by averaged circuit equivalents and eliminating the need to add extraneous components or function blocks when small signal frequency domain analysis is performed Using SIMPLIS FX you can study how a converter under peak current control scheme approaches instability as the duty ratio approaches 50 when no compensation ramp is applied in the control and this instability can be analyzed using either the continuous domain or the discrete domain The discrete domain is useful if you want to study a system using digital control techniques For most applications the use of the continuous domain is adequate AC Analysis Behaviour of Time Varying Sources Since the SIMPLIS FX Small Signal Frequency Domain Analyzer is specifically design
99. e hysteresis width of the input voltage in volts VOL is the four character keyword VOL vol is a floating point number representing the low value of the output voltage in volts VOH is the four character keyword VOH voh is a floating point number which defines the high value of the output voltage in volts and must be larger than vol RIN is the four character keyword RIN rin is a floating point number which defines the input resistance 79 SIMPLIS Reference Manual ROUT is the five character keyword ROUT rout is a floating point number which defines the output resistance in ohms LOGIC is the six character keyword LOGIC POS is the three character keyword POS NEG is the three character keyword NEG TRIG_COND is the ten character keyword TRIG_COND 0_TO_1 is the six character keyword 0_TO_1 1_TO_O is the six character keyword 1_TO_0 The actual model implemented in SIMPLIS for a clocked J K flip flop is shown in 4 14 b The first two input nodes in the device statement are the J and K input terminals while the third input node in the device statement is the clock input terminal If TRIG_COND 0_TO_1 the clocked J K flip flop is considered to be triggered when the logic state of the clock input changes from 0 to 1 Similarly a logic 1 to logic 0 transition for the clock input is considered to trigger this type of flip flop if TRIG_COND 1_TO_0 The logic state of each output will not change
100. e is equal to the result of the boolean operator associated with the gate applied to the input logic states If the output state is equal to logic 1 the value of the voltage source vout in the output circuit is set to vol If the output state is equal to logic 0 the value of vout is set to voh Inverter Model The format for the inverter model statement is MODEL mname INV TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout where MODEL is the six character keyword MODEL mname is a legal model name as explained in Model Names and Subcircuit Names on page 12 INV is the three character keyword INV which identifies the 65 SIMPLIS Reference Manual 66 TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout inverter type simple logic gates is the three character keyword TH is a floating point number which defines the threshold value of the input voltage in volts Together with hystwd it determines the values of the input voltage at which the output states of the inverter will be changed from a logic 0 to a logic 1 and vice versa is the seven character keyword HYSTWD is a positive floating point number to represent the hysteresis width of the input voltage in volts is the four character keyword VOL is a floating point number which defines the low value of the output voltage in volts is the four character keyword VOH is a floating point
101. e linear resistors The initial segment of operation is used by SIMPLIS as a suggestion SIMPLIS automatically computes the circuit voltages and currents to determine the correct initial segment of operation Piecewise Linear Inductors and Capacitors The formats for piecewise linear inductors and piecewise linear capacitors are Lname n n mname IC init_cond Cname n n mname C init_cond where IL is the two character element keyword L for piecewise linear inductors IC is the two character element keyword C for piecewise linear capacitors name is the individual name of the device n is the name of the positive node and is a nonnegative integer n is the name of the negative node and is a nonnegative integer mname is the name of a model compatible with a piecewise linear inductor or a piecewise linear capacitor IC is the three character keyword IC representing the initial condition Chapter 3 Device Statements init_cond is the value of initial condition It is the initial current in amperes in the case of a piecewise linear inductor and the initial voltage in volts in the case of a piecewise linear capacitor The parameters describing the piecewise linear inductors and capacitors are defined in a model statement Refer to Piecewise Linear Inductor and Capacitor Models on page 55 for the explanation of the model statements associated with these two devices For a piecewise linear inductor the only ac
102. e of the device n is the name of the positive node and is a nonnegative integer n is the name of the negative node and is a nonnegative integer SAW is the three character keyword SAW to signify that this is a sawtooth source Vl is the three character keyword V1 representing the source value at the start of a normal cycle vl is a floating point number assigned as the value of V1 in volts for a voltage source and the value of V1 in amperes for a current source V2 is the three character keyword V2 representing the source value at the end of a normal cycle v2 is a floating point number assigned as the value of V2 in volts for a voltage source and the value of V2 in amperes for a current source FREQ s the five character keyword FREQ Chapter 3 Device Statements freq s a positive floating point number assigned as the frequency of this source in hertz DELAY s the six character keyword DELAY delay s a floating point number assigned as the value of DELAY in seconds OFF_UNTIL_DELAY is the sixteen character keyword OFF_UNTIL_DELAY YES s the three character keyword YES NO s the two character keyword NO The plus characters shown in the format definition are not necessary if carriage returns are not used in the statement The plus characters and the carriage returns have been added to break the statements over different lines to make them easier to read Using the function s t to represent the volt
103. e sinusoidal waveform The frequency of each small signal AC source is set to the analysis frequency defined by the sweep_type and n_pt parameters in the AC analysis statement The amplitude parameter is explained in this subsection The amplitude parameter in the device statement defining a small signal AC source should be regarded as a relative quantity rather than an absolute quantity Suppose the following statements appear in the input file V1 1 0 AC 2 45 V2 4 0 AC I3 7 9 AC 5 60 Since the amplitude and the phase parameters of V2 are not specified the defaults of 1 0 unit and 0 0 degree are used Although the amplitude parameter of V1 is set to 2 the actual amplitude of V1 during the small signal frequency domain analysis is not equal to 2 0 V By definition a small signal analysis is the examination of the behavior of a system around its equilibrium when it is perturbed from its equilibrium with stimuli of infinitesimally small amplitude The amplitude of the three sources V1 V2 and I3 are all set to infinitesimally small values by SIMPLIS FX during the small signal analysis However the ratios between the amplitude of these three sources are maintained according to the amplitude parameters in the statements defining the small signal AC sources In this example the amplitude of V1 is always set to twice the amplitude of V2 and the amplitude of I3 is always set to five times as large as the amplitude of V2 Another way to inter
104. e versa is the seven character keyword HYSTWD is a positive floating point number which defines the hysteresis width of the input voltage in volts is the four character keyword VOL is a floating point number representing the low value of the output voltage in volts is the four character keyword VOH is a floating point number which defines the high value of the output voltage in volts and must be larger than vol is the four character keyword RIN Chapter 4 Model Statements rin is a floating point number which defines the input resistance ROUT is the five character keyword ROUT rout is a floating point number which defines the output resistance in ohms LOGIC is the six character keyword LOGIC POS is the three character keyword POS NEG is the three character keyword NEG TRIG_COND is the ten character keyword TRIG_COND 0_TO_1 is the six character keyword 0_TO_1 1_TO_0 is the six character keyword 1_TO_0 The actual model implemented in SIMPLIS for a clocked toggle flip flop is shown in 4 16 b The first input node in the device statement is the Toggle input terminal and the second input node in the device statement is the clock input terminal If TRIG_COND 0_TO_1 the clocked toggle flip flop is considered to be triggered when the logic state of the clock input changes from 0 to 1 Similarly a logic 1 to logic 0 transition for the clock input is considered to trigger this type of flip
105. e vs current plane In the case of a piecewise linear capacitor the characteristics are defined in terms of points on the charge vs voltage plane The model statement format for a piecewise linear inductor or capacitor is MODEL mname mtype NSEG k X0 x0 YO y0 55 SIMPLIS Reference Manual 56 Xl x Yl y X2 x2 Y2 y2 Xk xk Yk yk where MODEL mname mtype NSEG X0 x0 YO yO X1 xl Yl yl X2 x2 Y2 is the six character keyword MODEL is a legal model name as explained in Model Names and Subcircuit Names on page 12 is a four character keyword equal to PWLL or PWLC which stand for the model types for a piecewise linear inductor or capacitor respectively is the five character keyword NSEG representing the number of linear segments in this device model is an integer defining the number of linear segments and can take on values from 2 to 255 inclusively is the keyword XO representing the x axis coordinate of the beginning of the first linear segment of the device model is a floating point number which defines the value of XO and has units of amperes for a PWL inductor and volts for a PWL capacitor is the keyword YO representing the y axis coordinate of the beginning of the first linear segment of the device model is a floating point number which defines the value of YO and has units of weber turns for a PWL inductor and coulombs for a PWL capacitor is t
106. ed for small signal analysis of switching piecewise linear systems in the near neighborhood of the periodic operating point trajectory large signal time varying sources are treated the same way in the small signal analysis as they were treated 165 SIMPLIS Reference Manual 166 during the periodic operating point POP analysis All periodic large signal time varying sources are treated as active periodic sources with time varying source values while all aperiodic large signal time varying sources are treated as DC sources during the small signal frequency domain analysis Section 10 3 2 explains the treatment of the time variable and the treatment of various large signal time varying sources during the periodic operating point POP analysis The key features of these treatments are summarized here for convenience 1 Simplis resets the time variable t to zero at the end of a POP analysis i e at the end of the circuit s period as defined by the circuit and the POP trigger gate Simplis FX starts its simulations for each excitation frequency at the same t 0 point 2 during the small signal frequency domain analysis aperiodic sources are changed to DC sources The value of each DC source is set equal to the calculated values of the corresponding aperiodic source at the time equivalent to the end of the circuit s period Aperiodic sources include exponential pulse sources piecewise linear sources and sinusoidal cosinusoidal sources with non
107. eeeeeeesneeeesseeeeennees 90 The Scope of Definition for the Main Circuit 90 The Scope of Definition for a Subcircuit 90 Scope of Definition for a Device and for a Node 90 External and Local Nodes ccceseseeeeeeeeeeteeeeeeeseees 91 Subcircuit Calls Instantiation ccceccesesseeseteeeeeees 92 Control Statements OVGIVIOW naia a onre tieda tes Sedan Aie ad aaia 95 Table of Contents Option Statements ccceeeeeeeeeceeeeeeeeseeeeaeeeeeseaeeeseetaas 95 Control Statements for Setting Initial Conditions 99 Linear and PWL Capacitors c ecceeseeseeeeeeeeeees 99 Linear and PWL Inductors eee eeeeeeeseeeeenteerenees 99 Setting of Initial States for S and Q Switches 100 Setting of Initial Segment for PWL Resistors 100 Setting of Initial State for Simple Logic Gates 100 Initial Conditions for Devices in a Subcircuit 100 Control Statements for Printing Variables 00 101 Mapping Names to Node Numbers c eee 103 Creating SlMetrix Plots eceeceeeeeeteeeeeeeneeseeeenneeeees 104 Control Statements Associated with Analyses 104 TRAN Time Domain Transient Analysis 104 POP Periodic Operating Point Analysis 105 AC Frequency Domain AnalySis ceeee 105 Chapter 7 Running SIMPLIS OVENIEW 35 ice Sa a eA 106 Running SIMPLIS on a
108. el Names and Subcircuit Names on page 12 NOR is the three character keyword NOR to stand for NOR type simple logic gates k is an integer from 2 to 9 inclusively indicating the number of inputs for the NOR gate TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG Chapter 4 Model Statements is the three character keyword TH is a floating point number which defines the threshold value of the input voltage in volts and together with hystwd it determines the values of the input voltage at which the input states of the exclusive OR gate will be changed from a logic 0 to a logic 1 and vice versa is the seven character keyword HYSTWD is a positive floating point number which defines the hysteresis width of the input voltage in volts is the four character keyword VOL is a floating point number representing the low value of the output voltage in volts is the four character keyword VOH is a floating point number which defines the high value of the output voltage in volts and must be larger than vol is the four character keyword RIN is a floating point number which defines the input resistance is the five character keyword ROUT is a floating point number which defines the output resistance in ohms is the six character keyword LOGIC is the three character keyword POS is the three character keyword NEG The output state is equal to the
109. eral Rules for the Input File on page 10 defines the general rules for the input file and Organization of the Input File on page 17 explains the organization of the input file General Rules for the Input File 10 Statements and Continuation of Statements The input file for the SIMPLIS package is organized into different statements Ordinarily the end of a line signifies the end of a statement However a statement can be continued on to the next line by using the line continuation character the plus sign Refer to Continuation of Statements on page 11 for more about the continuation of statements Blank Characters Within a single statement the data are organized into different fields Fields are separated by one or more spaces or tabs Spaces and tabs are called blank characters While blank characters must be used to separate different fields the presence of at least one blank character between two groups of non blank characters does not always mean the two groups of characters belong to two different fields Blank characters may be present within a single field In general blank characters are used to separate different fields or to improve the readability of the input file Blank Lines Blank lines can be placed anywhere in the input file to make the file more readable Blank lines have no effect on the execution of the program Comment Statements Comment statements are used to make the input file more
110. ere are two acceptable model types for piecewise linear resistors 1 A voltage defined piecewise linear resistor VPWLR 2 Accurrent defined piecewise linear resistor IPWLR The formats for the model statements associated with these two model types are MODEL mname mtype NSEG k X0 x0 YO y0 Xl xJ Yl yl X2 x2 Y2 y2 Xk xk Yk yk where MODEL mname mtype NSEG x0 YO y0 X1 is the six character keyword MODEL is a legal model name as explained in Model Names and Subcircuit Names on page 12 is a five character keyword equal to either VPWLR or IPWLR is the five character keyword NSEG representing the number of linear segments in the resistor model is an integer which defines the number of linear segments for this piecewise linear resistor and can take on values from 2 to 255 inclusively is the keyword XO representing the voltage x axis coordinate of the beginning of the first linear segment of the piece wise linear resistor is a floating point number which defines the value of XO in volts is the keyword YO representing the current y axis coordinate of the beginning of the first linear segment of the piece wise linear resistor is a floating point number that defines the value of YO in amperes so that the straight line passing through x0 y0 and terminating on the break point x1 y1 forms the first segment of the piecewise linear characteristic is the keyword X1
111. es Chapter 9 Simplis TX Examples Overview Examples are provided in this chapter to help the user get familiar with the syntax of the input file of SIMPLIS and understand various features of SIMPLIS TX Examples from using SIMPLIS POP and SIMPLIS FX are given in Chapter 10 and Chapter 11 respectively The system studied in these examples represent a variety of systems encountered in power electronics Each example is intentionally restricted to be small to make the illustration concise For the same reason the device models in this example have been kept simple but functionally adequate These simple device models serve as the basic building blocks from which more complex models can be formulated All the examples in this chapter are installed as ready to run SIMetrix schematics under the directory root Work Examples SIMPLIS Manual_Examples The input files shown in this chapter are in fact the simulation decks as created by SIMetrix but with plotting statements removed Example 1 Rectifier with RC load The system under study in this example is the simple rectifier circuit shown in Figure 9 1 The ac voltage source V1 is a 154 V peak to peak 60 Hz sinusoidal voltage source The variables of interest are the voltage across the ac voltage source the voltage across the filter capacitor and the current through the diode which is modeled by the piecewise linear resistor R1 R R1 in the input file The input file for the circuit of Exa
112. es C1 and C2 are each mapped to a new name for a linear capacitor The actual new node names or device names introduced in the mapping are not important to the user as they are only used internally by SIMPLIS For the purpose of illustration here let us assume that nodes 2 and 3 in SUB1 are mapped to nodes 7 and 9 respectively When SIMPLIS carries out the subcircuit instantiation for the pseudo devices XA in the subcircuit definition of SUB1 the four step procedure is repeated 1 Node 101 of subcircuit SUB2 is mapped to node 2 in subcircuit SUB1 Since node 2 in SUB1 has already been mapped to node 7 node 101 of SUB2 is mapped to node 7 2 Node 102 the only local node of subcircuit SUB2 is mapped to a new node name that is not in the list of existing nodes Then this new node name is added to the list of existing nodes 3 Devices R101 and C101 are mapped to appropriate new device names that are different from existing device names Then these device names are added to the list of existing device names 4 Since there is no subcircuit defined in the subcircuit SUB2 the instantiation of XA has been completed When SIMPLIS carries out the subcircuit instantiation for the pseudo devices XB in the subcircuit definition of SUB1 the four step procedure is repeated 1 Node 101 of subcircuit SUB2 is mapped to node 3 in subcircuit SUB1 Since node 3 in SUB1 has already been mapped to node 9 node 101 of SUB2 is m
113. et to 2 and NEG respectively When the secondary state of a simple transistor switch is equal to SATURATE it is modeled by the small network as shown in 4 7 b which comprises a linear resistor with a resistance equal to rsat in series with a voltage source with source value vsat When the secondary state of a simple transistor switch is equal to REV_BIASED it is modeled by a large resistor with resistance equal to roff as shown in 4 7 c 4 n n leat 4 loff Va y Ig Va al Vsat la Y O n n b c 4 7 Model of a simple transistor switch in the closed state with LEVEL 2 a Model for the ACTIVE secondary state b Model for the SATURATE secondary state c Model for the REV_BIASED secondary state By selecting LEVEL 2 in the simple transistor switch model you can more accurately model a physical transistor and are able to obtain more detailed waveforms on the voltage and current for the device The penalty is an increase in the simulation time since more variables need to be monitored and computed throughout the simulation Simple Logic Device Models To aid the understanding of the models for simple logic devices the concept of positive and negative logic is discussed first Except for inverters and comparators Chapter 4 Model Statements all logic gates use a parameter called LOGIC in the model statement The purpose of this parameter is to define whether a positive logic or a negative
114. except at the triggering moment At the triggering moment the logic of the clocked J K flip flop is same as that of the unclocked Set Reset flip flop with one exception if the states of both the J and the K inputs are equal to logic 1 at the triggering moment the states of each output of a clocked J K flip flop will be set to the complement of its logic state right before the triggering moment Hence if the state of the normal output Q is equal to logic 1 0 right before the triggering moment it will be set to logic 0 1 at the triggering moment if the states of both the J and the K inputs are equal to logic 1 at the triggering moment rin rout not ni1 b 4 14 Clocked J K Flip Flop model a Symbol for a SIMPLIS Clocked J K flip flop b Model for a SIMPLIS Clocked J K flip flop Clocked Data Flip Flop MODEL mname CLK_DFF TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG TRIG_COND 0_TO_1 1_TO_0 80 MODEL mname CLK_DFF TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG TRIG_COND 0_TO_1 1_TO_0 Chapter 4 Model Statements is the six character keyword MODEL is a legal model name as explained in Model Names and Subcircuit Names on page 12 is the seven character keyword CLK_DFF to stand for CLK_DFF type simple logic gates is the three character keyword TH is a floating point number w
115. flop if TRIG_COND 1_TO_O The logic state of each output will not change except at the triggering moment At the triggering moment the logic state of each output remains the same as the logic state before the triggering moment if the state of the toggle input is logic 0 On the other hand the logic state of each output is complemented if the state of the toggle input is logic at the triggering moment rout1 no ni1 o Toggle Q mot i2 mi o Clock Q _po2 nref nref a b 4 16 Clocked Toggle Flip Flop model a Symbol for a SIMPLIS Clocked Toggle flip flop b Model for a SIMPLIS Clocked Toggle flip flop Latch MODEL mname LATCH TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG ENABLE_LEVEL 01 1 MODEL is the six character keyword MODEL mname is a legal model name as explained in Model Names and 83 SIMPLIS Reference Manual LATCH TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG ENABLE_LEVEL Subcircuit Names on page 12 is the five character keyword LATCH to stand for LATCH type simple logic gates is the three character keyword TH is a floating point number which defines the threshold value of the input voltage in volts which together with hystwd determines the values of the input voltage at which the input states of the exclusive OR gate will be changed from
116. g SiMetrix Plots SIMPLIS supports the GRAPH statement for creating plots while the simulation proceeds For full documentation on GRAPH please refer to the S Metrix Simulator Reference Manual Note that the names used for signals in GRAPH must comply with SIMetrix vector names rather than the format SIMPLIS uses for PRINT For example the following instructs SIMPLIS to save and plot the voltage on node 2 PRINT V 2 GRAPH 2 CurveLabel Voltage at Node2 Note that 2 is prefixed with a colon This is to distinguish node 2 from the constant value 2 0 Another example NODE_MAP VOUT 224 PRINT V VOUT GRAPH VOUT CurveLabel Output voltage In the above node 224 has been mapped to the name VOUT Subsequently the data on node 224 may be referenced as VOUT Control Statements Associated with Analyses 104 The analyses supported by SIMPLIS at this point are the time domain transient analysis the periodic operating point analysis and the frequency domain small signal AC analysis TRAN Time Domain Transient Analysis The TRAN statement instructs SIMPLIS to perform a time domain transient analysis The initial conditions for various devices are taken from the device statements and any Chapter 6 Control Statements overriding initial conditions supplied from the INIT statements The time domain transient analysis always starts with the time variable set to zero The format for the TRAN statement is TRA
117. ge 12 mtype is a four character keyword equal to either VCSW or ICSW indicating whether the switch is voltage controlled or current controlled RON is the four character keyword RON representing the resistance in ohms of the switch when it is in the closed or on state 57 SIMPLIS Reference Manual 58 ron ROFF roff TH threshold HYSTWD hystwd LOGIC POS NEG is a positive floating point number which defines the resistance in ohms of the switch when it is in the closed or on state is the five character keyword ROFF representing the leakage resistance in ohms of the switch when it is in the open state is a positive floating point number which defines the leakage resistance of the switch in ohms when it is at the open state is the three character keyword TH representing the threshold value of the controlling signal Together with HYSTWD it determines the values at which the state of the switch will be changed from an open state to a closed state and vice versa is a floating point number which defines the threshold value of the controlling signal and is measured in volts for a voltage controlled switch and measured in amperes for a current controlled switch is the seven character keyword HYSTWD representing the hysteresis width of the controlling signal is a positive floating point number which defines the hysteresis width of the controlling signal and has the same unit of measureme
118. ger d is a numeral in the range of 0 through 9 and d is an optional string of extra digits The following are legal entries 34 0 25 27 301 The following are illegal integer entries L 23 24 9 They are illegal integer entries because 1 The negative sign is not followed by a numeral 2 l begins with a positive sign which is illegal 3 The numbers 23 and 24 5 have decimal points 13 SIMPLIS Reference Manual 14 Floating point Entries From time to time a certain field or parameter in a statement calls for a floating point entry A floating point entry can be typed in several possible formats 1 Integer format 2 Simple floating point format 3 Exponential format 4 Engineering format Integer Format in Floating point Entries Whenever a floating point entry is expected the entry can be typed in the integer format as defined in Integer Entries on page 13 if the corresponding entry turns out to be an integer For example if 34 is to be typed as a floating point entry it can be typed as 34 without the accompanying decimal point Simple Floating point Format The simple floating point format is defined as d d d or d d where is the negative sign associated with a negative integer d is a numeral in the range of 0 through 9 is the decimal point and d is an optional string of extra digits Examples of the use of the simple floating point format are 9 37 0 5
119. ger 2 lt k lt 9 ANDk Simple Logic Gate k input AND where k is an integer 2 lt k lt 9 NANDk Simple Logic Gate k input NAND where k is an integer 2 lt k lt 9 SRFF Simple Logic Gate Set Reset Flip Flop CLK_SRFF Clocked Logic Gate Clocked Set Reset Flip Flop CLK_JKFF Clocked Logic Gate Clocked JK Flip Flop CLK_DFF Clocked Logic Gate Clocked D Flip Flop CLK_TFF Clocked Logic Gate Clocked Toggle Flip Flop LATCH Latch Device Model Types Used by SIMPLIS The keyword MODEL the model name and the model type must be entered in the exact order as indicated Following these three fields are a number of fields each made up of a parameter assignment The actual number of parameters assignments depends on the model type The number of parameter assignments must be exactly equal to what is required by the model type Extra or missing parameter assignments will lead to error messages Within the set of fields for the parameter assignments however the fields can appear in any order of sequence For example the following two statements are both acceptable MODEL S1 VCSW TH 2 HYSTWD 2U RON 10m ROFF 10MEG LOGIC POS SIMPLIS Reference Manual or MODEL S1 VCSW RON 10m ROFF 10MEG TH 2 HYSTWD 2U LOGIC POS Parameter assignments in SIMPLIS do not assume default values Therefore each required parameter must be assigned a proper value in the MODEL statement Device Models Used in Simplis 52 Piecewise Linear Resistor Models Th
120. gest period expected There are several reasons that SIMPLIS may fail to find a triggering condition for the system under study within the set maximum period One is an error in the definition of the triggering condition Given correctly defined triggering conditions it is also possible that the transients resulting from the initial conditions specified for the system would prevent the system from reaching the triggering condition within the set maximum period Usually a regular time domain transient analysis would reveal the reasons that the system failed to trigger the start of a new switching cycle Behaviour of POP Analysis after POP Convergence Failure There are two choices of action that SIMPLIS will take when POP fails to converge These are 1 Abort the run and output an error message The error is written to a file but will also be displayed in the command shell message box This action is taken if the POP parameter TD_RUN_AFTER_POP_FAILS is set to zero 2 Start a time domain transient analysis The initial conditions for this time domain analysis will be exactly the same as the initial conditions used for the POP run and will continue for a period controlled by the TD_RUN_AFTER_POP_FAILS parameter on the POP line See POP Statement for POP Analysis on page 136 for details If a normal time domain analysis had been specified to proceed after POP for example because a load transient study was being performed then t
121. he keyword X1 representing the x axis coordinate of the end of the first linear segment of the device model and the beginning of the second linear segment of the device model is a floating point number which defines the value of X1 and has the same units indicated for x0 is the keyword Y1 representing the y axis coordinate of the end of the first linear segment of the device model and the beginning of the second linear segment of the device model so that the straight line passing through x0 y0 and terminating on the break point x1 y1 forms the first segment of the piecewise linear characteristic is a floating point number which defines the value of Y1 is the keyword X2 representing the x axis coordinate of the end of the second linear segment of the device model and the beginning of the third linear segment of the device model is a floating point number which defines the value of X2 is the keyword Y2 representing the y axis coordinate of the end of the second linear segment of the device model and the beginning of the third linear segment of the device model so that the straight line passing through x y and terminating on Chapter 4 Model Statements the break point x2 y2 forms the second segment of the piecewise linear characteristic y2 is a floating point number which defines the value of Y2 and so on Xk is the keyword Xk representing the x axis coordinate of the end of the last linear segment of
122. he one character element keyword Q for simple transistor switches name is the individual name of the device n is the name of the positive node of the simple transistor switch and is a nonnegative integer n is the name of the negative node of the simple transistor switch and is a nonnegative integer nc is the name of the positive controlling node nc is the name of the negative controlling node cname is the name of a controlling device mname is the name of a compatible transistor switch model IC is the three character keyword IC representing the initial condition of the simple transistor switch OPEN is the four character keyword OPEN meaning the simple transistor switch is initialized to the open state CLOSE is the five character keyword CLOSE meaning the simple transistor switch is initialized to the closed state The parameters describing the transistor switch are defined in a model statement Refer to Simple Switch Models on page 57 for the explanation of the model statements associated with simple transistor switches There are four model types compatible with simple transistor switches These are VCQPOS VCQNEG ICQPOS and ICQNEG Model types VCQPOS and VCQNEG correspond to voltage controlled transistor switches Model types ICQPOS and ICQNEG correspond to current controlled transistor switches Similar to the initial condition given to a simple switch the initial condition given to a simple tr
123. he voltage of node nc with respect to node nc and s is the controlled voltage for a controlled voltage source and the controlled current for a controlled current source In the second format the value of the controlled source is given by s value v cname where v cname represents the branch voltage across the positive and negative nodes of the controlling device named cname Linear Current Controlled Sources The formats for current controlled sources are Hname n n cname value or Fname n n cname value where H is the one character element keyword H for linear current controlled voltage sources F is the one character element keyword F for linear current controlled current sources name is the individual name of the device Chapter 3 Device Statements n is the name of the positive node of the controlled source and is a nonnegative integer n is the name of the negative node of the controlled source and is a nonnegative integer cname is the name of a controlling device and is not restricted to a voltage source value is a floating point number assigned as the proportionality constant for this controlled source The value of the controlled source is given by s value i cname where i cname represents the branch current through the controlling device named cname Ideal Transformers The format for ideal transformer differs from the typical format defined in Device Statement Format on page 20 T
124. hether it is a voltage or current source a resistor or any other two terminal element Parameter Assignments Parameters such as the initial conditions for devices are entered in a format called parameter assignments The format is KEYWORD value where 21 SIMPLIS Reference Manual KEYWORD is the corresponding keyword representing the descriptive name of the parameter is the equal sign and value is the value assigned to the parameter To make the input file more readable blank characters can appear before and or after the equal sign In addition if the equal sign is the last significant character in the current line the value can appear in the next line through the use of the line continuation character the plus sign Controlling Devices The four controlled sources the simple transistor switch and the simple switch are each controlled by a controlling variable that is external to the device There are three types of controlling variables 1 A differential voltage across two nodes in the same circuit 2 A branch voltage across the positive and negative nodes of a controlling device in the same circuit or 3 A current through a controlling device in the same circuit A controlling device can be any one of the following device types Linear resistors Linear inductors Linear capacitors All types of independent voltage sources All types of independent current sources All four types of
125. hich defines the threshold value of the input voltage in volts which together with hystwd determines the values of the input voltage at which the input states of the exclusive OR gate will be changed from a logic 0 to a logic 1 and vice versa is the seven character keyword HYSTWD is a positive floating point number which defines the hysteresis width of the input voltage in volts is the four character keyword VOL is a floating point number representing the low value of the output voltage in volts is the four character keyword VOH is a floating point number which defines the high value of the output voltage in volts and must be larger than vol is the four character keyword RIN is a floating point number which defines the input resistance is the five character keyword ROUT is a floating point number which defines the output resistance in ohms is the six character keyword LOGIC is the three character keyword POS is the three character keyword NEG is the ten character keyword TRIG_COND is the six character keyword 0_TO_1 is the six character keyword 1_TO_0 The actual model implemented in SIMPLIS for a clocked data flip flop is shown in 4 15 b The first input node in the device statement is the Data input terminal and the second input node in the device statement is the clock input terminal If TRIG_COND 0_TO_1 the clocked data flip flop is considered to be triggered when the logic state
126. his option the line in the following Example section should be output to the SIMPLIS simulation input deck Example OPTIONS IGNORE_UNITS Control Statements for Setting Initial Conditions As outlined in initial conditions are required to be supplied in the device statements However an INIT statement can be used to override the initial conditions supplied in the device statements INIT statements are allowed to be placed within the scope of definition of a subcircuit and more than one INIT statement can appear within the same scope of definition Linear and PWL Capacitors The INIT statement can be used to override the initial voltage of a linear capacitor or a PWL capacitor For example INIT V C11 0 V C23 12 0 means that the initial voltage of linear capacitor C11 is set to 0 V while the initial voltage of PWL capacitor C23 is set to 12 V C11 and C23 must be in the same scope of definition as the INIT statement Notice that more than one initial condition setting can be supplied in the same INIT statement Each initial condition setting is in the form of a parameter assignment as outlined in Whatever initial voltages were specified for C11 and C23 in the device statements they are superseded by 0 V and 12 V respectively Linear and PWL Inductors The INIT statement can be used to override the initial current of a linear inductor or a PWL inductor For example INIT I L12 0 I L22 2m means th
127. his option does not take on any value It is either turned ON or turned OFF If it is turned ON SIMPLIS will ignore any relevant data files from a previous simulation even if the circuit and the initial conditions between the two simulation runs are the same If this option is turned OFF SIMPLIS will try to take advantage of any relevant data files from the previous simulation if the circuit and the initial conditions have not changed from the previous simulation run To turn ON this option the line in the following Example section should be output to the SIMPLIS simulation input deck OPTIONS NEW_ANALYSIS Domain in small signal AC analysis The small signal AC analysis can be carried out in the continuous s domain or in the discrete z domain If set the option value must be either the character S or Z If this option is not set it defaults to S Example Chapter 6 Control Statements OPTIONS FREQ_DOMAIN Z IGNORE_UNITS Ignore Units This option does not take on any value It is either turned ON or turned OFF If it is turned ON SIMPLIS will ignore any trailing units or strings when it is looking for a floating point number For example in specifying the voltage of a DC voltage source SIMPLIS would not complain the trailing V here 1 23V if this options is turned ON The default is to not to turn ON this option and SIMPLIS would then complain about the trailing string or units To turn ON t
128. his time domain analysis will proceed normally as if the POP analysis had converged successfully This mode of operation makes it possible to study the load or line transient behaviour of systems for which POP convergence is difficult Examples are systems running at very light load whereby they enter a pulse frequency mode of operation Such systems do not have a well defined steady state which makes POP convergence almost impossible But by running a long enough time 141 SIMPLIS Reference Manual 142 domain analysis before applying load or line stimuli a near steady state condition may be reached If no time domain analysis had been specified after the POP analysis the data generated during the additional time domain analysis will be saved so that a diagnosis of the causes of POP convergence failure may be performed Options Associated with POP Analysis There are five options associated with the periodic operating point analysis and they can be specified through the OPTIONS statement explained in Option Statements on page 95 The options are specified in the form of OPTIONS opt opt2 where optl opt2 and are various options recognized by SIMPLIS The five options associated with the periodic operating point analysis and their meanings are listed below POP_SHOWDATA POP_ITRMAX n Shows the progress of the periodic operating point analysis The default is not to show the progress In general this option i
129. i L1 L2 Vo 200 uH 500 uH 1 M 15 uH 2 101 iy ip 210 eoeeee M eeeeee ee Va LA LB 1 mH 2mH o 100 M 30 uH aw 3 10 Examples of the definitions for mutual inductances Linear Voltage Controlled Sources The formats for voltage controlled sources are Ename n n Gname n n Ename n n Gname n n where E nc nc value nc nc value cname value cname value is the one character element keyword E for linear voltage 41 SIMPLIS Reference Manual 42 controlled voltage sources G is the one character element keyword G for linear voltage controlled current sources name is the individual name of the device n is the name of the positive node of the controlled source and is a nonnegative integer n is the name of the negative node of the controlled source and is a nonnegative integer nc is the name of the positive controlling node in the same circuit where the linear voltage controlled source is being defined nc is the name of the negative controlling node in the same circuit where the linear voltage controlled source is being defined cname is the name of a controlling device in the same circuit where the linear voltage controlled source is being defined value is a floating point number assigned as the proportionality constant for this controlled source In the first format the value of the controlled source is given by s value v nc nc where v nc nc represents t
130. idered to be defined locally in that particular subcircuit Since each device or node is only locally defined in its circuit of definition it is acceptable to have the same device names and the node names used in different circuits SUBCKT SUB1 1 3 CA 1 2 10U IC 2 RA 2 3 10K XSUB 2 3 SUB2 SUBCKT SUB2 101 103 CB 101 102 10U IC 2 RB 102 103 10K ENDS SUB2 ENDS SUB1 Example 5 3 External and Local Nodes Nodes defined in the SSUBCKT statement are called the external nodes of the subcircuit Hence node 1 in the subcircuit SUB1 in the example below is an external node and node 101 is an external node for subcircuit SUB2 The statements in the example below represent the complete input file of an example system to be studied The TRAN statement in this input file has not yet been covered but its presence does not affect our discussion here In the definition of the subcircuit SUB1 in the example below nodes 1 2 3 and 0 appear in the device statements Unless the MAPNODEO option is turned on through an OPTION statement node 0 in a subcircuit is considered to be global in the sense that it is treated to be the same node as node 0 in the main circuit Any node in the device statements of a subcircuit that is neither an external node nor a global node is considered a local node So in this example nodes 2 and 3 are local nodes in subcircuit SUB1 and node 102 is a local node for subcircuit SUB2 91 SIMPL
131. ied out The start of a switching cycle is defined as occurring when the output of the logic gate DX is making a 0 to 1 transition The POP_SHOWDATA option for POP Analysis Under normal application of the periodic operating point analysis the POP_SHOWDATA option should be turned off If a POP analysis fails the user can run a regular time domain transient analysis without the POP analysis to make sure that the system has been correctly defined modeled and entered in the input file Typographical errors in entering the initial conditions for some devices or mistakes in the definition of the switching logic can often be revealed through such a regular time domain transient analysis 149 SIMPLIS Reference Manual 150 After debugging the defined system to make sure initial conditions are within reasonable ranges and the switching logic is properly set up the user can apply the POP analysis again to compute the steady state solution If the POP analysis fails again the user may want to examine the progress of the POP analysis by repeating the POP analysis with the POP_SHOWDATA option turned on When the POP_SHOWDATA option is turned on a print plot file named XXXX t4 where XXXX is the name of the input file is generated during the POP analysis This data file contains data for all of the print variables versus the time variable for the sequence of invisible transient analyses carried out by the POP analysis Due to the prediction
132. ile contains a description of the system under study and a snap shot of the system at every switching instance from tsave to tstop inclusively This data file is named XXXX tl where XXXX is the name of the input file to SIMPLIS The Switching Instance data file is only produced for a time domain analysis Time domain Data Output 114 During a time domain simulation SIMPLIS reads the Switching Instance data file and reconstructs detailed waveforms from the data stored in the Switching Instance data file Detailed waveforms are reconstructed for various print variables for the time interval from the value specified for PSP_START to the value specified for PSP_END You are referred to Option Statements on page 95 on the usage of option statements Chapter 8 Simplis Data Files to specify values for these two parameters The waveform data are sent to the SIMetrix front end which is responsible for storing and if required plotting the data This Time Domain data is only produced for a time domain analysis and only if PSP_NPT is specified as an option in the input file SIMPLIS also generates a file with the extension T2 which contains details of the data stored but not the actual data itself See example below 1 1006 6simplis DATA FOR PLOTTING Mon Nov 25 14 00 17 INPUT FILE demo01 Transient Analysis 7 DATA PTS 3 VARIABLES 0 TIME 1 V 4 0 2 I LL 3 V CC The Topology Information File During a time
133. ile to SIMPLIS The State of Exit file has been given the file extension init because it is written in a format such that it can be easily merged into the input file to provide initial condition s for a continued simulation Suppose a simulation has been carried out for 200 microseconds and after examining the data you have decided to run for another 200 microseconds One approach is to repeat the first simulation with the original initial conditions by changing the run time to 400 microseconds This approach has the disadvantage of repeating the simulation of the first 200 microseconds On the other hand if you are not particularly interested in the waveforms of the first 200 microseconds the init file can be used to override the initialization provided in the input file by including the contents of this data file in the input file In such a case the run time of the second simulation only has to be carried out for 200 microseconds as the init file already contains the state of the system at the end of the first simulation which is at t 200 microseconds Switching Instance Data File When a transient analysis is run the control statement TRAN tstop tsave instructs SIMPLIS to carry out a time domain simulation from t 0 to t tstop No data will be generated or saved until the simulation reaches t tsave Starting at t tsave every switching instant is recorded in a data file called the Switching Instance data file This data f
134. imulation starts saving data for the transient analysis Refer to the TRAN statement for details of the transient analysis For time domain transient analysis the print variables are generated for time values up to but not larger than the value of t2 PSP_END is the eight character keyword PSP_END and t2 is a positive number larger than the value of t1 If this option is not specified the default value for t2 is the stop time of the transient analysis as specified in the TRAN statement If the value of t2 in PSP_END is smaller than the value for t1 in PSP_START no output print file will be generated for the transient analysis Set the minimum number of data points generated for printing the output variables during the transient analysis PSP_NPT is an eight character keyword and n is an integer between 2 and 8001 inclusively PSP_END PSP_START PSP_NPT 1 is the step size of the time variable in the print file generated for the transient analysis If PSP_NPT is not specified no output print file will be generated for the transient analysis POP Iteration Limit This option sets the maximum number of iterations for the POP analysis If set the option value must be a positive integer between 1 and 200 inclusively If this option is not set it defaults to 20 Example OPTIONS POP_ITRMAX 50 POP_USE_TRAN_SNAPSHOT 96 This option instructs POP to take advantage of the last data point of a previous transient sim
135. ing node cname is the name of a controlling device mname is the name of a compatible switch model IC is the three character keyword IC representing the initial condition of the simple switch OPEN is the four character keyword OPEN meaning the simple switch is initialized to the open state CLOSE is the five character keyword CLOSE meaning the simple switch is initialized to the closed state use of OPEN and CLOSE are mutually exclusive The parameters describing the switch are defined in a model statement Refer to Simple Switch Models on page 57 for the explanation of the model statements associated with simple switches In SIMPLIS both the voltage controlled and the current controlled switches are modeled by the simple S switch If the switch model named mname has a model type of VCSW the switch is considered to be voltage controlled If the model type of the switch model is ICSW the switch is considered to be current controlled The initial condition provided for a simple switch is only used by SIMPLIS as a suggestion If the circuit condition on the controlling variable dictates a different initial condition SIMPLIS automatically overrides the given initial condition with the correct initial condition Simple Transistor Switches The formats for simple transistor switches are Qname n n nc nc mname IC CLOSEIOPEN Qname n n cname mname IC CLOSEIOPEN where Chapter 3 Device Statements Q is t
136. ions less susceptible to error Scope of Definition As pointed out in Sequence of Statements on page 17 the scope of definition for a general circuit begins at the Start Circuit Statement and stops at the End Circuit Statement inclusively The concept of the scope of definition is formally defined in this section The Scope of Definition for the Main Circuit The scope of definition of the main circuit which is the highest level of any circuit specified in the input file ranges from the title statement to the END statement inclusively The Scope of Definition for a Subcircuit The scope of definition for a subcircuit ranges from its start at the subcircuit statement to the ENDS statement that terminates it inclusively The user is reminded that it is possible for several subcircuits to share the same ENDS statement to terminate their definition The scope of definition of a child subcircuit must be inside the scope of definition of its parent circuit Scope of Definition for a Device and for a Node 90 The scope of definition for a device is the youngest subcircuit whose scope of definition encompasses the device statement of the device in question For the statements shown in the example below the capacitor CB is considered to be defined in the subcircuit SUB2 whereas the capacitor CA is considered to be defined in the subcircuit SUB1 Each device is considered to be local in its subcircuit in the sense that its
137. is a floating point number which defines the value of Xk in volts Yk is the keyword Yk representing the current y axis coordinate of the end of the kth last linear segment of the piece wise linear resistor yk is a floating point number which defines the value of Yk in amperes so that the straight line starting at the break point xk 1 yk 1 and passing through the point xk yk forms the last segment of the piecewise linear characteristic The slope of each line segment on the v i plane is the differential conductance in Siemens for the device The small signal resistance is then the reciprocal of the differential conductance VPWLR Type Model The VPWLR model type is used for piecewise linear v i characteristics which are voltage defined In other words the value of current is uniquely defined for every value of voltage In such a case the voltage current coordinates at the points of definition of the v i characteristics must satisfy the following two restrictions 53 SIMPLIS Reference Manual 54 1 Values of the voltages must be entered in a strictly ascending order x0 lt xl lt x2 lt lt xk 2 The slopes of the first and last segments must be positive yO lt yl and yk 1 lt yk Other than the first and the last segments each intermediate segment j has two break points and is defined for voltages in the range of xj 1 lt v lt xj The first segment has one break point at x1 y and is defined for voltages
138. is defined it allows SIMPLIS to insert the model characteristics for every device associated with that model name The Model Statement always starts with the keyword MODEL as the first field in the statement The following is a typical model statement for a diode modeled as a piecewise linear resistor MODEL MD1M VPWLR NSEG 2 X0 0 YO 0 X1 0 7 Y1 10U Chapter 2 Input File Organization X2 0 8 Y2 1 Model Statements on page 50 describes the syntax for model statements Control Statements Control Statements start with the period character C and can be classified into one of the following types 1 Options 2 Initial conditions 3 Resource limits 4 Analyses Although all control statements start with a period character not all statements which start with a period are control statements For example statements beginning with keywords such as MODEL SUBCKT END and ENDS which start with a period character are not control statements Control Statements on page 95 explains the meaning and syntax of all control statements supported by SIMPLIS 19 SIMPLIS Reference Manual Chapter 3 Device Statements Overview 20 Device Statement Format The device statement defines how a device is connected in the circuit and lists the values for the individual device parameters If a device requires a device model or some initial condition such information is also defined in the device statement The format for a
139. itical data of the simulation they have been created with a read only protection mode to prevent accidental changes being made to them Switching Instance Data File for the POP Analysis When the periodic operating point analysis is applied to a system a data file is generated named XXXX t3 where XXXX is the name of the SIMPLIS input file The periodic operating point analysis is discussed in detail in Chapter 10 This data file contains a description of the system under study and a snap shot of the system at every switching instance during a periodic operating point analysis While this file will not be directly used by you it is used by SIMPLIS to generate print plot file for the Periodic Operating Point Analysis described in the next section As a result this data file is created with a read only protection mode Data for the Periodic Operating Point Analysis POP analysis creates data in exactly the same manner as for time domain transient analysis See Time domain Data Output on page 114 Print Plot File for Frequency Domain Analysis 116 When the frequency domain small signal analysis is carried out the resulting data are sent to SIMetrix in the same way as for transient analysis The only difference is that small signal analysis data is complex SIMPLIS also creates a F2 file for small signal analysis with a similar format to the T2 file See Time domain Data Output on page 114 Chapter 9 Simplis TX Exampl
140. itive node and is a nonnegative integer n is the name of the negative node and is a nonnegative integer COS is the three character keyword COS to signify that this is a cosinusoidal source with possible damping VOFFSET is the eight character keyword VOFFSET representing the DC offset of the source voff is a floating point number assigned as the DC offset value in volts for a voltage source and the DC offset value in amperes for a current source APEAK is the six character keyword APEAK representing the amplitude of the source at t tdelay apeak is a nonnegative floating point number assigned as the amplitude in volts for a voltage source and in amperes for a current source FREQ is the five character keyword FREQ representing the frequency of this source freq is a positive floating point number assigned as the frequency in hertz TDELAY is the seven character keyword TDELAY representing the time delay of the source use of TDELAY and PDELAY are mutually exclusive tdelay is a floating point number assigned as the time delay in seconds PDELAY is the seven character keyword PDELAY representing the phase delay of the source use of TDELAY and PDELAY are mutually exclusive pdelay is a floating point number assigned as the phase delay in degrees OFF_UNTIL_DELAY is the sixteen character keyword OFF_UNTIL_DELAY YES s the three character keyword YES NO s the two character keyword NO
141. ke advantage of the existing knowledge on the different circuit topologies and the overhead spent in analyzing each known circuit topology is reduced As outlined in Overview on page 8 SIMPLIS is a two pass simulator when it comes to time domain simulation The first pass of the simulation is the regular simulation and it computes the state of the simulation at each switching instance and saves the data in the Switching Instance Data file the XX XX t1 file In the second pass 115 SIMPLIS Reference Manual called the Post Simulation Processing or PSP for short detailed waveform data are reconstructed from the data saved in the Switching Instance Data file Every time SIMPLIS starts a time domain analysis it looks for the presence of the Switching Instance Data file If this file is present SIMPLIS checks to see if it is usable This file is considered usable if it describes the same circuit and the same analyses as defined in the input file If the Switching Instance Data file is considered usable SIMPLIS can skip the first pass of the simulation and directly go to the Post Simulation Processing phase saving a substantial amount of simulation time Changing the PSP_START PSP_END and PSP_NPT parameters through the option statements is not considered to be a change in the analyses as these parameters only affect the PSP phase of the simulation Since the Topology Information file and the Switching Instance Data file contain cr
142. l is the four character keyword RIN is a floating point number which defines the input resistance is the five character keyword ROUT is a floating point number which defines the output resistance in ohms is the six character keyword LOGIC is the three character keyword POS is the three character keyword NEG The output state is equal to the result of the boolean AND operation applied to the k input states NAND Gate Model The format for the NAND gate model statement is MODEL mname NANDk TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG where MODEL mname NAND is the six character keyword MODEL is a legal model name as explained in Model Names and Subcircuit Names on page 12 is the four character keyword NAND to stand for NAND type simple logic gates TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG Chapter 4 Model Statements is an integer from 2 to 9 inclusively to stand for the number of inputs for the NAND gate is the three character keyword TH is a floating point number which defines the threshold value of the input voltage in volts which together with hystwd determines the values of the input voltage at which the input states of the exclusive OR gate will be changed from a logic 0 to a logic 1 and vice versa is the seven character keyword HYSTWD is a positive floating
143. l name descriptive and short no more than sixteen characters Element Keyword The table below shows the relationship between each element keyword and the type of corresponding circuit elements Element Keyword Type of Element R Linear Resistor L Linear Inductor C Linear Capacitor V Independent Voltage Source Independent Current Source Linear Mutual Inductance m Linear Voltage Controlled Voltage Source SIMPLIS Element Types 11 SIMPLIS Reference Manual 12 Element Keyword Type of Element G Linear Voltage Controlled Current Source H Linear Current Controlled Voltage Source F Linear Current Controlled Current Source IT Ideal Transformer Q Simple Transistor Switch S Simple Switch IR Piecewise Linear Resistor IL Piecewise Linear Inductor IC Piecewise Linear Capacitor ID Simple Logic Gates X Instantiation of subcircuits SIMPLIS Element Types Individual Name An individual name is a string made up of zero or more characters from the following character set Alphabetic characters a z A Z Numeric characters 0 9 Underscore Examples of Device Names The following entries are all legal device names for inductors L La LA L1 L_MAG Model Names and Subcircuit Names SIMPLIS supports the concept of device models and subcircuits in the input file The name of a model or a subcircuit is a string that is made up of the same characters as those outlined in See Individual Name for the individual
144. le See Synopsis of Small Signal AC Analysis on page 160 for a more detailed explanation of the difference between using the different domains in a small signal frequency domain signal analysis Statement Defining a Small Signal AC Source A small signal stimulus is defined via a small signal AC voltage or current source The formats for defining small signal AC voltage and current sources are Vname gt n n AC amplitude phase and Iname n n AC amplitude phase where Vv is the one character element keyword V indicating a voltage source I is the one character element keyword I indicating a current source name is the individual name of the device n is the name of the positive node and is a nonnegative integer n is the name of the negative node and is a nonnegative integer AC is the two character keyword AC to signify that this is a small signal AC source amplitude is a positive floating point number representing the amplitude of this small signal AC source relative to any other specified small signal AC sources The specification of the amplitude parameter is optional A default value of 1 0 unit will be used if no value is specified phase is a floating point number representing the relative phase of this small signal AC source in degree The specification of phase is optional If the phase parameter is to be specified for a certain source the amplitude parameter must also be specified The default for ph
145. linear controlled sources Simple transistor switches Simple switches Piecewise linear resistors Piecewise linear inductors Piecewise linear capacitors SIMPLIS Device Types 22 Linear Resistors The format for a linear resistor is Rname n n value where R is the one character element keyword R for linear resistors name is the individual name of the device n value Chapter 3 Device Statements is the name of the positive node and is a nonnegative integer is the name of the negative node and is a nonnegative integer is a floating point number assigned as the value of the resistance in ohms This value can be positive zero or negative Linear Inductors and Capacitors The formats for a linear inductor and a linear capacitor are Lname n n value C init_cond Cname n where L C name n value IC init_cond n value C init_cond is the one character element keyword L for linear inductors is the one character element keyword C for linear capacitor is the individual name of the device is the name of the positive node and is a nonnegative integer is the name of the negative node and is a nonnegative integer is a floating point number assigned as the value of the inductance in henries for an inductor or the value of the capacitance in farads for a capacitor The value can be positive or negative but not zero is the three character keyword IC is a floating point
146. lis TX Examples Output V1 v2 5 V3 gt 2 o 5 fo 4 gt 0 0 2 0 4 0 6 0 8 1 1 2 1 4 1 6 1 8 2 time mSecs 200uSecs div 9 6 Waveforms for Example 2 Example 3 Operational Amplifier with Saturation The system under study in this example is a simple operational amplifier circuit driven to saturation by a sinusoidal input voltage 9 7 a represents the circuit and 9 7 b is the piecewise linear model of the system The operational amplifier is modeled by the input resistance RIN between its differential inputs the voltage controlled voltage source EOP the output resistance ROUT and the piecewise linear resistor RSAT The purpose of the PWL resistor R1 R R1 in the input file is to model the saturation of the operational amplifier whenever the output voltage rises above 5V or drops below 5V Placing the PWL resistor R1 across the output of the opamp is one of many possible ways to model the saturation of an operational amplifier The variables of interest are the input sinusoidal voltage the voltage across the differential inputs of the opamp and the output of the opamp The SIMPLIS input file defining the piecewise linear model for the circuit of Example 3 is given in 9 8 and waveforms obtained from this simulation are shown in 9 9 121 SIMPLIS Reference Manual 122 U1 is a hierarchical block Select it then cntrl E to descend int
147. lti step Analyses 112 The SIMetrix environment has facilities to run multiple SIMPLIS analyses Facilities to sweep parameter values and to randomly assign parameters for Monte Carlo are provided For more information please refer to the SIMetrix User s Manual Chapter 8 Simplis Data Files Chapter 8 Simplis Data Files Overview As SIMPLIS carries out an analysis it creates additional data files in the same directory as the input file These files are created by SIMPLIS primarily for its own use It is recommended that everyone browse through this chapter to get an idea what these data files accomplish and as a result be able to take advantage of these data files during various analyses The section Taking Advantage of Existing Files on page 115 is particularly helpful for running time domain simulations In the illustration that follows the name of the input file is assumed to be XXXX Each data file generated by SIMPLIS is named XXXX extension where extension is a string of characters particular to the data file The version of SIMPLIS supplied with SIMetrix sends its simulation data to SIMetrix which is then responsible for saving it This data is usually stored in sxdat files located in the TEMPDATA directory The Listing Data File The listing file is automatically generated by SIMPLIS It is named XXXX lst where XXXX is the name of the input file to SIMPLIS Ordinarily this listing file is a reh
148. m Example 5 in Chapter 9 correspond to the steady state operating conditions when the voltage of VI is at 40V Obviously if one already knows the steady state solution there is no point in running a 153 SIMPLIS Reference Manual 154 POP analysis to find the steady state solution For the purpose of illustration the initial conditions in the input file shown in Figure 10 8 have been changed providing SIMPLIS with initial information which is not within the immediate vicinity of the steady state solution The input voltage source VI is now modeled as a piecewise linear source instead of a DC source Its source value jumps from 40V to 30V when t 100 s To find the steady state solution of the system when the voltage of VI is 40V the periodic operating analysis tool is invoked by using the POP statement as shown The comparator D U3 defines the start of a switching cycle as the moment when the value of the sawtooth source VSAW is decreasing and reaching the value of approximately 2 5V Since the source VI is a piecewise linear source its source value is held constant at 40V its initial value during the POP analysis As a result the steady state solution as computed by the periodic operating analysis tool corresponds to the steady state solution of the system when VI is at 40V After the POP analysis is finished SIMPLIS carries out a regular time domain transient simulation according to the TRAN statement for 2000s As explained in
149. mple 1 is shown in Figure 9 2 The time domain simulation is carried out for 84 milliseconds which is slightly longer than five complete cycles of the 60 Hz ac source The parameter PSP_NPT is set to 211 instructing SIMPLIS to create the Time Domain Print Plot File with the print variables V V1 V C2 and I R1 and a time resolution of 84 211 _ 1 0 4 msec Waveforms obtained from this simulation are shown in Figure 9 3 117 SIMPLIS Reference Manual 118 R1 is a PWL resistor designed to have the characteristics of a diode vi 4 R1 a Ri i Bs Output na v1 p ie 100u IC 0 100 mn 7 TL l 9 1 Example 1 Rectifier with RC Load Single RC Source Rectified into a RC Low Pass Filter PRINT ALL OPTIONS PSP_NPT 211 TRAN 84m 0 V1 1 0 SIN VOFFSET 0 APEAK 38 5 FREQ 60 TDELAY 0 OFF_UNTIL_DELAY NO DAMP_COEF 0 Ca 3 0 100u IC 0 RSR1 1 2 R1STP_SSPWLR IC 1 MODEL R1STP_SSPWLR VPWLR NSEG 2 X0 0 YO 0 X1 1 Y1 0 5U X2 1 1 Y2 1 R232 1 R3 0 3 100 END 9 2 SIMPLIS Input File for Example 1 as generated by SiMetrix Chapter 9 Simplis TX Examples TRI Output Sam R1 A time mSecs 10mSecs div 9 3 Waveforms for Example 1 Example 2 3 Phase Rectifier with Resistive Load The circuit for Example 2 is a three phase rectifier with resistive load
150. n frequencies is carried out SIMPLIS FX reports the progress by printing a matrix of numbers which represent the percent complete of the swept frequency analysis For example a screen display such as SMALL SIGNAL FREQUENCY DOMAIN ANALYSIS CONTINUOUS S DOMAIN Elapsed time 0 hr 0 min 6 sec CPU time 0 hr 0 min 4 64 sec Analyzed freq 2 500000000000e 03 Hz means that 52 percent of the small signal frequency domain analyses have been completed and that the excitation frequency has been swept past 2 5 kHz The percent complete shown in the small signal frequency domain analysis is calculated based on the number of expected analyses at discrete excitation frequencies and not based on the CPU time Since a logarithm sweep of 10 points per decade from 250 Hz to 25 kHz is specified in the preceding example there will be a total of 21 analyses starting from 250 Hz and stopping at 25 kHz The analysis at 2 5 kHz is the 11th one in this sequence of analyses Hence if SIMPLIS FX has just finished the analysis at 2 5 kHz the percent complete is reported as 11 21 x 100 52 Chapter 11 Simplis FX The actual CPU time involved in each individual analysis varies As a rule of thumb the CPU time is linearly proportional to the excitation frequency When the excitation frequency is 1 decade or more below the periodic operating frequency computed in the POP analysis SIMPLIS FX is extremely fast When the excitation frequency is close to the
151. n triggering the start of a new switching cycle the next task to be performed is to determine whether the system has reached steady state operation This is accomplished by finding the difference between the values of each capacitor voltage and inductor current at the start and end of the finished transient analysis If the differences are small enough to be negligible for all capacitors and inductors the system is considered to be in steady state operation and the periodic operating point analysis is considered successful and it is stopped If the system is not considered to be in steady state operation the periodic operating point analysis tool applies a proprietary algorithm to predict what the values of the capacitor voltages and inductor currents at the start of a switching cycle ought to be had steady state operation condition been reached After this prediction phase another transient analysis is initiated and the whole algorithm is repeated until either steady state condition has been reached or the maximum iteration limit as set in the POP_ITRMAX option has been reached If the maximum iteration limit is reached an error message similar to the following is either printed on the screen or to an error file and execution of SIMPLIS is halted Chapter 10 Simplis POP PREDICTION TRANSIENT PHASE ANALYSIS PREDICT NEW CAPACITOR VOLTAGES AND REACH NEW INDUCTOR SWITCHING CURRENTS CYCLE PRINT ERROR REACH STEADY
152. name N_WIND k nl nl N1 t nk nk Nk tk where IT is the two character element keyword T for ideal transformers name is the individual name of the device N_WIND is the seven character keyword N_WIND representing the number of windings in the transformer k is a positive integer assigned as the number of windings and can assume any integral value from 2 to 255 inclusively nl is a nonnegative integer to represent the node name of the dotted terminal of winding 1 nl is a nonnegative integer to represent the node name of the undotted terminal of winding 1 Nl is the three character keyword N1 representing the number of turns in winding 1 tl is a positive floating point number assigned as the number of turns in winding 1 For a k winding transformer the node names of each winding and the number of turns in each winding must be specified in this device statement Simple Switches The formats for simple switches are 43 SIMPLIS Reference Manual 44 Sname n n nc nc mname IC CLOSEIOPEN Sname n n cname mname IC CLOSEIOPEN where S is the one character element keyword S for simple switches name is the individual name of the device n is the name of the positive node of the simple switch and is a nonnegative integer n is the name of the negative node of the simple switch and is a nonnegative integer nc is the name of the positive controlling node nc is the name of the negative controll
153. name of a device In addition each of the following conditions must also be satisfied A model name or a subcircuit name must have at least one character D A model or subcircuit name must contain at least one alphabet character 5 The first character in a model or subcircuit name must not be the underscore character _ Chapter 2 Input File Organization Uppercase vs Lowercase SIMPLIS is case sensitive to individual device names For example the following device names are two different inductors La LA However SIMPLIS is not case sensitive to element keywords For example the following names are the same inductor La la because the first character C1 or L is the element keyword for a device name The interpretation of the model names and subcircuit names follows the same interpretation as the operating system of the host If the operating system is case sensitive to file names then SIMPLIS is case sensitive to model names and subcircuit names If the operating system is not case sensitive to file names then SIMPLIS is not case sensitive to model names and subcircuit names For example UNIX operating systems are case sensitive while Windows operating systems are not Integer Entries Some input statements may have fields or parameters which are required to be integers The legal format for an integer entry is d d where is the optional negative sign associated with a negative inte
154. ng Point Analysis As pointed out earlier the periodic operating point analysis must be the first analysis specified in an input file As a result the initial capacitor voltages and initial inductor currents at the start of the periodic operating point analysis are the same as those specified in the device statements and any overriding initial conditions supplied in the INIT statements Then the periodic operating point analysis tool carries out a sequence of time domain transient simulation on the system The actions of the periodic operating point analysis are summarized by the flow chart in Fig 10 3 The transient analysis shown in Fig 10 3 is carried out indefinitely until the start of a new switching cycle is reached or until the value of the time variable has reached the parameter value of the maximum period set in the POP statement If the transient analysis fails to reach a condition to trigger the start of a new switching cycle before 143 SIMPLIS Reference Manual 144 the maximum period is reached an error message similar to the one shown below is either printed on the screen or to an error file After the error message has been printed SIMPLIS aborts its execution Periodic Operating Pt Analysis Reaching a time duration equal to 3 00000e 04 without registering the triggering condition that defines the start of a period Check your circuit and or initial conditions If the transient analysis is able to reach a conditio
155. ng diagram in 4 3 a still applies when LOGIC is set to POS while the switching diagram in 4 3 b still applies when LOGIC is set to NEG When the LEVEL parameter is set to 2 the simple transistor is still modeled by a resistor with a resistance equal to roff when it is in the open state When the simple transistor switch is in the closed state additional secondary states are provided for the simple transistor allowing the modeling of a physical transistor at operating areas where both the voltage across and the current through the transistor are simultaneously substantial For bipolar transistors such operating areas are collectively called the active region For the simple transistor switch the individual states are called ACTIVE SATURATE and REV_BIASED to stand for active region saturation and reversed biased as indicated in 4 6 SIMPLIS internally computes the voltage across and the current through the simple transistor switch to determine the correct secondary state at which the transistor switch should operate Chapter 4 Model Statements nt NGF lg cs t Va NC n a b la 4 REV_BIASED Va Wi R ACTIVE 3 c 4 6 Model for the simple transistor switch for LEVEL 2 a A simple transistor switch controlled by a control signal cs t b The i Q vs v Q characteristics of a VCQPOS type or ICQPOS type transistor switch c The i Q vs v Q characteristic of a VCQNEG type or ICQNEG type transistor switch
156. ng this time domain transient analysis will be as indicated in fig 10 4 b linearly rising from 1V to 2V during the first second linearly decreasing from 2V to 0 5V during the next second and remaining at 0 5V for the rest of the simulation V VI V 2 1 1 2 3 a vV VI V TIME VARIABLE RESET TO ZERO AT THE END OF A POP ANALYSIS MS Ue eee DA N POP ANALYSIS REGULAR TIME DOMAIN TRANSIENT ANALYSIS b 10 4 a Waveform of a sample piecewise linear voltage source when no periodic operating point analysis is specified and b Waveform of the same voltage source when a periodic operating point analysis is carried out 147 SIMPLIS Reference Manual 148 Periodic Sources Periodic sources are left unchanged during a POP analysis and the time variable is reset to 0 0 at the end of a POP analysis However it is not always true that the source value of a periodic source at the end of a POP analysis will be equal to the value of the same source at t 0 as defined in the input file The reason for this can be seen by examining the following statements in the input file VA 999 0 SAW V1 1 V2 3 FREQ 1K DELAY 0 OFF_UNTIL_DELAY NO VB 998 0 SAW V1 1 V2 3 FREQ 1K DELAY 250U OFF_UNTIL_DELAY NO IDX 555 0 999 997 MX IC 0 MODEL MX COMP RIN 10MEG ROUT 8 HYSTWD 2M VOL 0 VOH 5 VDC 997 0 DC 1 999 POP TRIG_GATE DX TRIG_COND 0_TO_1 MAX_PERIOD 400U If no periodic operating point analysis is carried ou
157. nt as that of threshold is the six character keyword LOGIC is the three character string POS is the three character string NEG If the model type is VCSW the controlling signal cs t for the simple switch is the voltage of a pair of controlling nodes or the branch voltage of a controlling device If the model type is ICSW the controlling signal cs t for the simple switch is the branch current of a controlling device The diagram below defines the state of the simple switch under two operating modes If LOGIC is assigned the value POS the switching of the simple switch is defined by a If LOGIC is assigned the value NEG the switching logic is reversed and the state of the simple switch is then defined by b When a simple switch is in the closed state it is modeled by a linear resistor having a resistance equal to ron between its positive node and negative node When the simple switch is in the open state the resistance of the linear resistor changes to roff Chapter 4 Model Statements switch state ee threshold CLOSED cs t a state threshold _ CLOSED cs t b 4 3 State diagram of the simple switch when the parameter LOGIC is assigned a value of a POS or b NEG Simple Transistor Switch Models There are four simple transistor models composed of 1 a set of two voltage controlled models designated as VCQPOS and VCQNEG 2 aset of two current controlled models designated as ICQP
158. ntensive the computation of the steady state solution of a switched system is conceptually quite similar to finding the DC operating point of a non switching system under only DC excitations In both cases we are interested in finding the operation of the system in the absence of an external stimulus Since the term Operating Point Analysis has been traditionally and widely used as the name for a DC operating point analysis the name Periodic Operating Point Analysis POP is given to this special algorithm for speeding up the computation of the steady state solution of switched piecewise linear systems that are periodically driven or self oscillating The Periodic Operating Point Analysis tool in SIMPLIS is able to speed up the convergence to the steady state solution of a switched piecewise linear system that is either self oscillating or driven by one or more periodic sources that are commensurate in their periods To invoke such an analysis the user only needs to add a few lines in the input file Statements Relating to POP Analysis on page 136 explains in detail the format of the input statements related to the Periodic Operating Point analysis Synopsis of the Periodic Operating Point Analysis on page 143 explains what happens during a Periodic Operating Point analysis After reading this section a user will understand the internal workings of this analysis tool and as a result will be able to use the analysis tool more produ
159. nts specify three small signal AC sources V1 V2 and I3 with amplitudes equal to 2 1 and 5 units respectively vl 10 AC 2 45 v2 4 0 AC IF 7 9 AC 5 60 The waveforms of these three sources at an analysis frequency of kHz are displayed in 11 1 a The waveforms of these sources at an analysis frequency of 2 kHz are displayed in 11 1 b Since the phase parameter is relative these waveforms have been arbitrarily drawn with V2 having a positive slope zero crossing at t 0 Once the phase of V2 has been arbitrarily chosen the phases of V1 and I3 are fixed at 45 degrees behind and 60 degrees ahead of the phase of V2 respectively Chapter 11 Simplis FX 13 V2 t ms V1 a 11 1 Waveforms for the small signal AC source examples V1 V2 and I3 Sample Waveforms of AC Sources Discrete Domain Tf the discrete domain is used the waveform of a small signal AC source as a function of time is the result of applying an ideal sample and hold process to a sinusoidal waveform This ideal sampling is taken at the beginning of a switching period cycle where the beginning of a switching period cycle is defined through the POP analysis statement The value of a small signal AC source is held constant for the remaining of the switching period cycle until another set of samples is taken at the start of the next switching period cycle The sample device statements shown in Sample Waveforms of AC Sources Continuous Domain on page 16
160. o it Virtual_Earth 4 40k Output Input A 1K R1 9 7a Example 3 Operational Amplifier with Saturation Circuit Diagram VINP VINN 9 7b Example 3 Operational Amplifier with Saturation Piecewise linear Equivalent Circuit Chapter 9 Simplis TX Examples Saturation of an Operational Amplifier PRINT ALL OPTIONS PSP_NPT 1001 TRAN 2m 0 XSU1 2 0 1 opamp V1 3 0 SIN VOFFSET 0 APEAK 1 FREQ 1k TDELAY 0 OFF_UNTIL_DELAY NO DAMP_COEF 0 Ri 1 3 1K R2 2 1 10k SUBCKT opamp 3 4 2 NODE_MAP VINN 2 NODE_MAP VINP 4 NODE_MAP VOUT 3 RIN 4 2 1Meg EOP 10 4 2 1Meg ROUT 3 1 50 R R1 3 0 R1ISTP_SSPWLR IC 1 MODEL R1STP_SSPWLR VPWLR NSEG 3 X0 5 1 YO 1MEG X1 5 0 Y1l 1U X2 5 0 Y2 1U X3 5 1 Y3 1MEG ENDS opamp END 9 8 Input File for Example 3 Input Output Virtual_Earth 0 0 2 0 4 0 6 0 8 1 1 2 1 4 1 6 1 8 2 time mSecs 200pSecs div 9 9 Waveforms for Example 3 123 SIMPLIS Reference Manual Example 4 Unregulated Converter 124 Shown in 9 10 is the schematic of a simple current step up buck converter operating under a fixed frequency control law This converter is not regulated by closed loop control and the duty ratio of the transistor Q1 is determined by comparing the fixed reference voltage of 2 5 V to the output of the triangular function generator The SIMPLIS inpu
161. obe shown at the top right of the schematic 11 3 The result of G j for this converter is shown in fig 11 5 In fig 11 5 the gain cross over occurs at 147 Hz and the phase margin is about 100 degrees Although the phase margin is high indicating the converter is stable as it is there is room for improvement to this design The low cross over frequency means the transient response of this regulated converter would be slow and would take a long time to settle back to the periodic operating equilibrium Moreover a zero should be introduced to the loop gain function to compensate for the pair of complex poles at 3 56 kHz which is caused by the output filter formed by L and C Otherwise the sharp drop in the phase due to the pair of complex poles can have a very detrimental effect on the stability of the system if the cross over frequency is pushed higher Changing the value of R14 will effect the gain cross over frequency and the phase margin of this converter As a matter of fact this converter becomes unstable with a phase margin of 6 degrees when the resistor R14 in the feedback loop is raised to 16 KQ Gain Y1 Phase Y2 Y2 Y1 120 160 7 100 a 3 100 a 40 E oO 2 6 E 80 20 60 oO 40 20 20 40 iu 10u 1002 1m 10m 100m 1 10 100 1k 10k 100k freq Hertz 11 5 Magnitude and Phase of G jo 169 SIMPLIS Reference Manual Index IC 46
162. of the clock input changes from 0 to 1 Similarly a logic 1 to logic 0 transition for the clock input is considered to trigger this type of flip flop if TRIG_COND 1_TO_0 The logic state of each output will not change except at the 81 SIMPLIS Reference Manual 82 triggering moment At the triggering moment the logic state of the normal output Q will follow the logic state of the data input terminal ni1 Data ni2 clock a ni1 O no1 Q o ni2 o x 2 a o nref rout1 no1 vouti rout no2 b 4 15 Clocked Data Flip Flop model a Symbol for a SIMPLIS Clocked Data flip flop b Model for a SIMPLIS Clocked Data flip flop Clocked Toggle Flip Flop MODEL mname CLK_TFF TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG TRIG_COND 0_TO_1 1_TO_0 MODEL mname CLK_TFF TH threshold HYSTWD hystwd VOL vol VOH voh RIN is the six character keyword MODEL is a legal model name as explained in Model Names and Subcircuit Names on page 12 is the seven character keyword CLK_TFF to stand for CLK_TFF type simple logic gates is the three character keyword TH is a floating point number which defines the threshold value of the input voltage in volts which together with hystwd determines the values of the input voltage at which the input states of the exclusive OR gate will be changed from a logic 0 to a logic 1 and vic
163. on on page 86 The following two subsections give a brief outline of how the subcircuits are defined SUBCKT Statement Start of Subcircuit Statement Any statement whose first field matches the keyword SUBCKT starts the definition of a subcircuit The SUBCKT statement is the Start Circuit Statement for a subcircuit The keyword SUBCKT is followed by the name of the subcircuit and a group of node names ENDS Statement End of Subcircuit Statement A statement whose first field matches the keyword ENDS is the end of the subcircuit statement This statement is the End Circuit Statement for a subcircuit The ENDS statement can have two forms In the first form the ENDS keyword is the only field in the statement In the second form the ENDS keyword is followed by the name of a proper subcircuit General Statements Comment Statements See Comment Statements on page 10 and In line Comments on page 11 for an explanation on the use of comments in the input file Device Statements A device statement defines the parameter values of the device and indicates how it is connected to the circuit When a model name or initial condition is required for a device they are also defined in the device statement Device Statements on page 20 provides a detailed description of the syntax of device statements Model Statements The model statement defines the parameters associated with a particular device model Once a model
164. ore the POP statement must appear before the AC statement in the input file If both the time domain transient analysis and the small signal frequency domain analysis are specified in an input file the AC analysis statement for the small signal frequency domain analysis must appear before the TRAN analysis statement for the time domain transient analysis Option Statement Associated with AC Analysis There is one option statement associated with the SIMPLIS FX small signal frequency domain analysis The format of this option statement is OPTIONS FREQ _DOMAIN D where OPTIONS is the eight character keyword OPTIONS indicating this is an option statement FREQ_DOMAINZ is the 12 character keyword FREQ_DOMAIN D is either the character S indicating the continuous domain or the character Z indicating the discrete domain Chapter 11 Simplis FX By default a frequency domain analysis is carried out in the continuous domain The statement OPTIONS FREQ_DOMAIN Z will override the default and instruct SIMPLIS FX to analyze the system using discrete domain techniques If the continuous domain is chosen the waveform of each small signal stimulus will be a continuous sinusoidal function of the time variable If the discrete domain is chosen the waveform of each small signal stimulus as a function of the time variable is equal to the result of applying the sample and hold to a continuous sinusoidal function of the time variab
165. ource value s t for t gt xk is set to s t yk An example of the waveform s t of a piecewise linear source is illustrated in the diagram below s t x1 y1 x5 y5 x0 y0 x4 y4 3 9 Example of the waveform s t of a typical piecewise linear source Mutual Inductances The format for mutual inductance is M Lnamel Lname2 value where M is the one character element keyword M for mutual inductors is the hyphen character C Lname1 is the device name of a linear inductor defined in the current circuit Lname2 is the device name of another linear inductor defined in the current circuit Lnamel and Lname2 must refer to different inductors value is a floating point number assigned as the mutual inductance between the two linear inductors For the schematic shown below the two mutual inductors are defined in the input file as L1 3 1 200U IC 50M L2 4 2 500U IC 0 Chapter 3 Device Statements LA 101 100 1M IC 30U LB 210 17 2M M L1 L2 15U M LA LB 30U IC 10U The mutual inductance between two linear inductors is positive if the polarity dots appear on the positive nodes of both inductors or if the polarity dots appear on the negative nodes of both inductors In the example shown below the mutual inductance between inductors LA and LB is negative because the polarity dot is located at the positive node of LA but the polarity dot is located at the negative node of LB e 4a a o V
166. pecified in the device statement for an S R flip flop is used to initialize the logic output state of the normal output Q When the logic state of the set input is equal to logic 1 the logic state of the normal output Q is set to logic 1 When the logic state of the reset input is equal to logic 1 the logic state of the normal output Q is set to logic 0 The output state of an S R flip flop is supposed to be undefined when the input logic states of the set and reset inputs are both equal to logic 1 For ease of debugging the output state of the S R flip flop as implemented by SIMPLIS will remain unchanged when both input states are equal to logic 1 See 4 12 Chapter 4 Model Statements ni1 no1 O O ni2 no2 O O O nref a rout1 no1 b 4 12 SR Flip Flop model a Symbol for a SIMPLIS S R flip flop b Model for a SIMPLIS S R flip flop Clocked Set Reset Flip Flop MODEL mname CLK_SRFF TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG TRIG_COND 0_TO_1 1_TO_0 where MODEL is the six character keyword MODEL mname is a legal model name as explained in Model Names and Subcircuit Names on page 12 CLK_SRFF is the eight character keyword CLK_SRFF to stand for CLK_SRFF type simple logic gates TH is the three character keyword TH threshold is a floating point number which defines the threshold value of the input voltage in volts which together with hys
167. point number which defines the hysteresis width of the input voltage in volts is the four character keyword VOL is a floating point number representing the low value of the output voltage in volts is the four character keyword VOH is a floating point number which defines the high value of the output voltage in volts and must be larger than vol is the four character keyword RIN is a floating point number which defines the input resistance is the five character keyword ROUT is a floating point number which defines the output resistance in ohms is the six character keyword LOGIC is the three character keyword POS is the three character keyword NEG The output state is equal to the result of the boolean NAND operation applied to the k input states Set Reset Flip Flop Model The format for the Set Reset flip flop model statement is MODEL mname SRFF TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG where MODEL mname SRFF is the six character keyword MODEL is a legal model name as explained in Model Names and Subcircuit Names on page 12 is the four character keyword SRFF to stand for SRFF type 75 SIMPLIS Reference Manual 76 simple logic gates TH is the three character keyword TH threshold is a floating point number which defines the threshold value of the input voltage in volts which together with hystwd determines the values of
168. positive floating point number which defines the hysteresis width of the input voltage in volts is the four character keyword VOL is a floating point number representing the low value of the output voltage in volts is the four character keyword VOH is a floating point number which defines the high value of the output voltage in volts It must be larger than the value of vol is the four character keyword RIN is a floating point number which defines the input resistance is the five character keyword ROUT is a floating point number which defines the output resistance in ohms is the six character keyword LOGIC is the three character keyword POS is the three character keyword NEG 71 SIMPLIS Reference Manual 72 ni1 ni2 no nik nref a rin b 4 11 k Input OR gate model a Symbol for k Input OR gate b Model for k Input OR gate The nodes ni1 and ni2 are the two input nodes Up to a maximum of 9 inputs can be accommodated The actual model implemented in SIMPLIS for a k input OR gate is shown in 4 11 b The output state is equal to the result of the boolean OR operation applied to the k input states NOR Gate Model The format for the NOR Gate model statement is MODEL mname NORk TH threshold HYSTWD hystwd VOL vol VOH voh RIN rin ROUT rout LOGIC POS NEG where MODEL is the six character keyword MODEL mname is a legal model name as explained in Mod
169. pret the three device statements above is that the amplitude of V1 V2 and I3 are 2 1 and 5 infinitesimally small units respectively The excitation of a nonlinear system by sinusoidal inputs with finite amplitudes generates responses not only at the excitation frequency but also at harmonics or subharmonics of the excitation frequency For a true small signal analysis the amplitude of the sinusoidal inputs must be made infinitesimally small so the responses 161 SIMPLIS Reference Manual 162 at the higher harmonics and or the subharmonics are insignificant compared to the response at the excitation frequency This is equivalent to saying that the response of a nonlinear system appears linear when the amplitude of the excitation sources are sufficiently small The same can be said about switching piecewise linear systems Making small signal measurements on a breadboard system in the laboratory presents some practical challenges in choosing the amplitude of the exciting sinusoids Ideally we would like the amplitude of the exciting sinusoids to be as small as possible to avoid the nonlinear effects but the amplitude of these exciting sinusoids cannot be too small If these amplitudes are too small the signal to noise ratio would be low and it will be extremely difficult to get an accurate measurement This is especially true for switching systems which inherently carry large signal noises at the switching frequency and higher harmonics
170. put file provided by the user If syntax errors are detected in the input file error messages are recorded in a file for the user to inspect and correct the errors This feature allows the user to detect and correct errors quickly and efficiently SIMPLIS TX is a two pass time domain simulator In the first pass of a simulation run only the data pertaining to the state of the simulation at the switching instances are saved In the second pass called the Post Simulation Processing run detailed waveform information is reconstructed from the data generated in the first pass At the user interface level these two separate operations are not distinguishable since they are executed automatically by SIMPLIS Thus SIMPLIS appears as a one pass simulator to the user This internal two step simulation technique optimizes the simulation speed and versatility of SIMPLIS SIMPLIS POP Periodic Operating Point is an analysis tool that accelerates the convergence to the steady state solution of switch mode power systems By taking into consideration the variation of the timing of the intracycle intervals of a switch mode system with respect to changes in the state vector the POP analysis tool accurately calculates the steady state solution SIMPLIS FX is a special small signal frequency domain analyzer developed for the analysis of switching power supplies By calculating the circuit s response over a range of frequencies to a small perturbation in the time
171. quency switching system and b Output of the comparator D2 in relationship to the waveform of the voltage V 102 0 Chapter 10 Simplis POP Definition of the Maximum Period Depending on how the triggering gate and triggering condition are defined and depending on the capacitor voltages and inductor currents of the system it is possible that the system either takes a very long time or is never able to reach a condition that triggers the start of a new switching cycle Such a condition can occur at the start of the periodic operating point analysis or in the middle of a periodic operating point analysis Since the triggering condition never occurs one of the time domain transient analyses mentioned in 10 2 1 1 may run forever To avoid such a situation the maximum simulation time for all POP time domain transient analyses is set to the numerical value of the maximum period parameter For example a POP statement such as POP TRIG_GATE D2 TRIG_COND 0_TO_1 MAX_PERIOD 500U instructs SIMPLIS to carry out each of these transient analyses for a maximum duration of 500 microseconds If the simulation time of a POP transient analysis reaches 500 microseconds without triggering the start of a new switching cycle SIMPLIS will print out an error message and exit For a driven system the maximum period should be set to at least three times the expected period For a self oscillating system the maximum period should be set to about 10 times the lon
172. r DELAY_F delay_f TAU_R tau_r TAU_F tau_f Chapter 3 Device Statements voltage sources is the one character element keyword I for independent current sources is the individual name of the device is the name of the positive node and is a nonnegative integer is the name of the negative node and is a nonnegative integer is the three character keyword EXP to signify that this is an aperiodic single shot exponential pulse source is the three character keyword V1 representing the quiescent value of the source is a floating point number assigned as the quiescent value in volts for a voltage source and in amperes for a current source is the three character keyword V2 representing the pulsed value of the source is a floating point number assigned as the pulsed value in volts for a voltage source and in amperes for a current source is the eight character keyword DELAY_R representing the time delay of the rising edge of the source that is the edge of the waveform when it moves from the quiescent value v1 to the pulsed value v2 is a nonnegative floating point number assigned as the time delay of the rising edge in seconds is the eight character keyword DELAY_F representing the time delay of the falling edge of the source that is the edge of the waveform when it moves from v2 to v1 is a nonnegative floating point number assigned as the time delay of the falling edge in seconds an
173. r keyword DEC the three character keyword OCT or the three character keyword LIN n_pt is a positive integer If sweep_type is set to DEC the frequency of analysis will be swept in a logarithmic manner and n_pt represents the number of points per decade in the swept frequency If sweep_type is set to OCT the frequency of analysis will be swept in a logarithmic manner and n_pt represents the number of points per octave in the swept frequency If sweep_type is set to LIN the frequency of analysis is swept in a linear manner and n_pt represents the total number of points in the linear frequency sweep If sweep_type is set to be LIN n_pt must be an integer larger than one start_freq is a positive floating point number representing the starting frequency of the sweep stop_freq is a positive floating point number representing the stopping frequency of the sweep The AC statement can be specified in any one of the three formats shown Just like any other analysis statement the AC statement can only appear within the scope of definition of the main circuit There can be no more than one AC statement in an input file Since the SIMPLIS FX Small Signal Frequency Domain analysis is specifically designed for the small signal analysis of switching piecewise linear systems around its periodic operating point the periodic operating point POP analysis must be carried out before the small signal analysis can be applied Theref
174. ral lines through the line continuation character Chapter 2 Input File Organization Organization of the Input File SIMPLIS supports the concept of a main circuit and subcircuits in the definition of the system to be analyzed A subcircuit can be nested within another subcircuit for up to 20 levels of nesting with the main circuit considered as the first level of nesting Since the definitions for the main circuit and a subcircuit are similar the term general circuit is used here to represent either the main circuit or a subcircuit General Circuit The general circuit is defined by the following statements Start Circuit Statement Comment Statements Device Statements Model Statements Subcircuit Definition Statements Control Statements ST SOY es BR End Circuit Statement Subcircuit Definition Statements defining a subcircuit follow the same pattern of statements outlined here for the general circuit The forms of the Start Circuit Statement and End Circuit Statement depend on whether the general circuit is the main circuit or a subcircuit The forms of the rest of the statements remain the same for both the main circuit and subcircuits Sequence of Statements The scope of definition for a general circuit begins at the Start Circuit Statement and stops at the End Circuit Statement inclusively Statements within the scope of definition of a general circuit can be placed in any sequence without any effect on the reading of
175. refers to the circuit definition which begins with the title statement which is the first line in the input file and ends with the END statement which is the last significant line in the input file Any number of subcircuits can be defined within the main circuit The subcircuits can also be nested within other subcircuits As many as 20 levels of nesting are allowed A typical group of statements defining a subcircuit definition duplicates the following pattern of statements Start Subcircuit Statement Comment Statements Device Statements Model Statements Subcircuit Definitions Control Statements End Subcircuit Statement Obviously the Start Subcircuit Statement and the End Subcircuit Statement must be the first and the last statements respectively in the definition of a subcircuit Between these start and end statements the comment statements device statements model statements subcircuit definitions and control statements can appear in any order or sequence without any effect on the reading of the input file Parent and Child Relationships for Subcircuits When a subcircuit named AAA is defined in a general circuit named BBB then the subcircuit AAA is considered the child of the general circuit BBB and the general circuit BBB is considered the parent of the subcircuit AAA Each subcircuit can 87 SIMPLIS Reference Manual 88 have only one parent and each general circuit can have zero one or more children
176. representing the voltage x axis coordinate of the end of the first linear segment of the piece Chapter 4 Model Statements wise linear resistor and the beginning of the second linear segment of the resistor xl is a floating point number which defines the value of X1 in volts Yl is the keyword Y 1 representing the current y axis coordinate of the end of the first linear segment of the piece wise linear resistor and the beginning of the second linear segment of the resistor yl is a floating point number which defines the value of Y1 in amperes X2 is the keyword X2 representing the voltage x axis coordinate of the end of the second linear segment of the piece wise linear resistor and the beginning of the third linear segment of the resistor x2 is a floating point number which defines the value of X2 in volts Y2 is the keyword Y2 representing the current y axis coordinate of the end of the second linear segment of the piece wise linear resistor and the beginning of the third linear segment of the resistor y2 is a floating point number which defines the value of Y2 in amperes so that the straight line starting at the break point x1 y1 and terminating at the break point x2 y2 forms the second segment of the piecewise linear characteristic and so on Xk is the keyword Xk representing the voltage x axis coordinate of the end of the kth last linear segment of the piece wise linear resistor xk
177. s See Simplis POP on page 135 If you wish to simulate a schematic in exactly the same manner as the Run menu you need to execute the script simplis_run This simulates the currently open schematic The full source for simplis_run can be found on the install CD Running SIMPLIS from a DOS Prompt The version of SIMPLIS supplied with SIMetrix SIMPLIS cannot be run directly from the command DOS prompt SIMPLIS Execution SIMPLIS runs as a separate process but communicates with SIMetrix while it is running to provide information on the progress of the run This progress is displayed in the SIMPLIS Status Window as shown below Ts Tir Tpi Pa iag BC lapurdi Tma ihare Dh mni me tod him i oc Uie Cue i Pim DHe Tad h ian 1 rec ii P Aa A a A ELTA aire toy in A Ama mpri Pa ti 11 i am pe a7 Us iF Ss maaie A Are os logy 3 See ooo ley Fii i ff Gd dani de if bone Mi J1 Fp 0 MON OT oO a a1 at 4 sa af oe ara mario AIi ay ee ice ae ag it m LET AFi Daig FF z Ste Tani dey Ae Aes iology oie See Ta ee aJo See terle ai See mology a afe Daley arl See Tan logy cd abe Tae cee aa Ama TH cay Aii i ee Tee cee aa ba eae oe The message window shows some detail about the progress and is similar to that displayed in earlier versions without the status window display 108 Chapter 7 Running SIMPLIS Aborting a SIMPLIS Run At any point during a simulation run you can abort the simulation Select the
178. s turned on as a debugging aid if a POP analysis fails Sets the maximum number of iterations for the periodic operating point analysis POP_ITRMAX is the eleven character keyword POP_ITRMAX n is a positive integer between and 100 The default value for nis 20 POP_CONVERGENCE value Sets the convergence criteria for the periodic operating point analysis The convergence criteria is satisfied when the relative change in each state variable between the start and end of a switching cycle is less than this parameter POP_CONVERGENCE is the eleven character keyword POP_CONVERGENCE value is a positive floating point number between 1 0e 06 and 1 0e 14 inclusive The default value for n is 1 0e 14 Note During the POP analysis the maximum relative change in the state variables is reported in percentages while the POP_CONVERGENCE parameter is entered in actual value POP_USE_TRAN_SNAPSHOT This option instructs POP to take advantage of the last data point of a previous transient simulation assuming the circuit and the initial conditions remained the same between the two simulation runs Chapter 10 Simplis POP This option does not take on any value It is either turned ON or turned OFF If it is turned ON the POP analysis will use the last data point of a previous transient simulation as the initial condition to start the POP analysis Usually this leads to a faster POP analysis Example OPTIONS POP_US
179. s of deriving the small signal response The algorithm behind SIMPLIS FX is rigorously derived making it accurate and robust For example the analysis frequency is not limited to less than half of the switching frequency Undeniably aliasing is going to be present when a switching system is excited at a frequency over half of the switching frequency In such a situation SIMPLIS FX can accurately compute the response of the system at the excited frequency whether it is below or above the switching frequency Theoretically the small signal frequency analysis algorithm behind SIMPLIS FX is accurate to within 0 5 dB and 1 degree at each analysis frequency from DC to infinity Practically the accuracy of the analysis and the highest analysis frequency that can be applied and still maintain a prescribed accuracy depend on how accurately the physical components are modeled in the switching piecewise linear system If there is a noticeable discrepancy between the measured frequency response in the laboratory and the data generated by SIMPLIS FX you can trust SIMPLIS FX and concentrate on 1 determining that the simulated system represents with reasonable accuracy the system measured in the laboratory 2 improving the device models of any components that you believe have not been adequately modeled and 3 checking the laboratory measurement setup to make sure that the measurements are valid since laboratory measurements of switching systems with
180. s that are generated before the syntax checking of the input file is suspended EMSG_MAX is the nine character keyword EMSG_MAX and k is a positive integer For very severe syntax errors the syntax checking is suspended before the number of error messages reaches this maximum limit The default value for k is 20 95 SIMPLIS Reference Manual EXPAND MAPNODEO PSP_START t1 PSP_END t2 PSP_NPT n POP_ITRMAX n Show the entire circuit after all subcircuit calls have been instantiated The listing of this expanded circuit is shown in the file XXXX Ist where XXXX is the name of the input file The default is not to show the expanded circuit By default node 0 is not allowed to appear as an external node in the definition of a subcircuit and node 0 in a subcircuit is considered the same node as node 0 in the main circuit If MAPNODEO is specified as an option node 0 in a subcircuit would not be considered as the same node as node 0 in the main circuit In such a case node 0 in the subcircuit is appropriately mapped for each subcircuit instantiation and it is allowed to appear as an external node in the subcircuit definition For time domain transient analysis the print variables are generated for time values larger than or equal to the value of t1 PSP_START is the ten character keyword PSP_START and tl is a nonnegative floating point number If this option is not specified the default value for t1 is the time the s
181. s the value of X1 in seconds x1 is larger than or equal to x0 is the keyword Y1 representing the voltage or current y axis coordinate of the end of the first linear segment and the start of the second linear segment is a floating point number which describes the value of Y1 in volts for a voltage source and in amperes for a current source is the keyword X2 representing the time or x axis coordinate of the end of the second linear segment and the start of the third linear segment is a floating point number which defines the value of X2 in seconds x2 is larger than or equal to x1 is the keyword Y2 representing the voltage or current y axis coordinate of the end of the second linear segment and the start of the third linear segment is a floating point number which defines the value of Y2 in volts for a voltage source and in amperes for a current source and so 39 SIMPLIS Reference Manual 40 on The x s and the y s form coordinate pairs in the s t versus plane If the source is described by k piecewise linear segments then k 1 pairs of coordinates are required to define the source from x0 y0 up to xk yk The line segment formed by drawing a straight line from x0 y0 to x y is the first segment describing the source The line segment formed by drawing a straight line from x y to x2 y2 is the second segment describing the source The source value s t for t lt x0 is set to s t y0 The s
182. schematic editor that are useful for running SIMPLIS are also repeated here for convenience Running SIMPLIS on a SiMetrix Schematic 106 You must first enter the schematic in SIMPLIS mode To select SIMPLIS mode from the schematic window select menu FilelSelect Simulator then select SIMPLIS If you have already added some components in SIMetrix mode you may get an incompatibility warning This means that some of the components placed will not work with SIMPLIS These will need to be either replaced with suitable alternatives or re entered When the schematic has been entered select your chosen analysis mode using SimulatorlChoose Analysis You can now run the simulation by pressing F9 or menu Simulator Run Adding Extra Netlist Lines The analysis mode selected using the schematic editor s SimulatorlChoose Analysis menu is stored in text form in the schematic s simulator command window If you wish it is possible to edit this directly Note that the text entered in the simulator command window and the SimulatorlChoose Analysis dialog settings remain synchronized so you can freely switch between the two methods To open the simulator command window select the schematic then press the F11 key It has a toggle action pressing it again will hide it If you have already selected an analysis mode using the Choose Analysis dialog box you will see the simulator controls already present The window has a popup menu selecte
183. t the source values V VA and V VB would be as shown in fig 10 5 a From this diagram the source values V VA and V VB are obviously equal to 1V and 2 5 V respectively at t 0 However at the exit of a successful POP analysis the source value of VA will be found to be equal to 2V rather than 1V The cause of this discrepancy comes from the arbitrary reset of the time variable to zero at the end of the POP analysis To understand this reasoning the reader is referred to fig 10 5 b which shows the waveforms of V VA V VB and the logic output of the gate DX From the input file statements above and from fig 10 5 b the start of a switching cycle is seen to occur at time instants when V VA is rising and equal to 2V Since each of the invisible transient analyses carried out in the periodic operating point analysis is terminated at the start of a new switching cycle the source value V VA must be at 2V at the end of the POP analysis Similarly the source value V VB is equal to 1 5 V rather than 2 5V at the end of the POP analysis Chapter 10 Simplis POP 1 i H t s logic output i o 2 h of DX a treset to zero UU SU UU 2 4 POP ANALYSIS REGULAR TIME DOMAIN b TRANSIENT ANALYSIS 10 5 a Waveforms of two periodic sawtooth voltage sources VA and VB when no periodic operating point analysis is carried out and b Waveform of the same voltage source when a periodic operating point analysis is carr
184. t file describing this converter is shown in 9 11 Since the transistor Q1 is driven to behave like a controlled switch it is modeled by a simple transistor switch with the LEVEL parameter set to 1 For the rest of the power stage of this converter the diode is modeled by the piecewise linear resistor R1 R R1 in the input file the energy storage inductor by ideal inductance L and winding resistance RX the output capacitor by ideal capacitor C and equivalent series resistance RC and the load by the resistance RL The current through the inductor L is initialized to a value of zero at the start of the simulation to represent operation of the converter in the discontinuous mmf mode Waveforms obtained from this simulation are displayed in 9 12 Output A 100 RC 50m a u2 A 2 5 a Drive e VREF V_TRI 9 10 Unregulated Converter Chapter 9 Simplis TX Examples Fixed Frequency Unregulated Current Step Up Converter PRINT ALL OPTIONS PSP_NPT 201 TRAN 50u 0 X U2 6 0 8 9 SIMPLIS_COMP 1 V_TRI 9 0 TRI V1 0 V2 5 FREQ 100k DRATIO 500m DELAY 0 OFF_UNTIL_DELAY NO VREF 8 0 2 5 C 5 7 50u IC 28 L 4 5 20u IC 0 VI 2 0 40 RC 7 0 50m RL 5 0 100 Q1 2 3 6 0 QISTP_VCQ IC CLOSE MODEL Q1 TP_VCQ VCQPOS VSAT 700m RSAT 100m ROFF 10Meg GAIN 10 TH 2 5 HYSTWD 100u LOGIC POS LEVEL 1 IR R1 0 3 RISTP_SSPWLR IC 1 MODEL R1S TP_SSPWLR VPWLR NSEG 2 X0 0 YO 0 X1 0 7 Y1 10U X2 0 8 Y2 1 000
185. tate of D1 and the voltage of source V1 The figure shows that the output of D1 will have a logic to logic 0 transition whenever the voltage of V1 is decreasing and equal to 1 001 V If there are multiple periodic sources driving the system the periodic operating point analysis tool can be applied only if these sources are commensurate in their periods In this case the switching cycle should be defined with a period equal to the least common multiple of the periods of all periodic sources Chapter 10 Simplis POP Comparator D1 Triangular Source V1 m V 1 0 V esses saas 1 003 eskasa ss 1 001 b 10 1 a A periodic triangular source a battery and a comparator used to define the start of a switching cycle and b Output of the comparator in relationship to the differential voltage V 1 0 Definition of the Start of A Switching Cycle for a Self Oscillating System In the case of a self oscillating system the start of a switching cycle should be defined to coincide with a major switching event such as the on off switching of the main power transistors s of a self oscillating converter Fig 10 2 a shows a small section of a hypothetical self oscillating switching system The main switching transistor Q1 is controlled by the control unit U1 through the base drive circuit B1 The output level of UL is equal to 12 V and 0 V respectively when it is trying to switch
186. tate of this gate is logic 1 use of the 0 and 1 are mutually exclusive The parameters describing the simple logic gates are defined in a model statement Refer to Simple Logic Device Models on page 64 for the explanation of the model statements associated with simple logic gates The initial output state of the logic gate is used by SIMPLIS as a suggestion 47 SIMPLIS Reference Manual 48 The model types and the associated simple logic gates are summarized in the table below Model Type Gate Type Num Inputs Num Outputs INV Inverter 1 1 COMP Comparator 2 1 XOR Exclusive OR gate 2 1 ORk k input OR gate k 1 2 lt k lt 9 NORk k input NOR gate k 1 2 lt k lt 9 ANDk k input AND gate k 1 2 lt k lt 9 NANDk k input NANDk gate k 1 2 lt k lt 9 SRFF Set Reset Flip Flop 2 2 CLK_SRFF Clocked Set Reset Flip Flop 3 2 CLK_JKFF Clocked JK Flip Flop 3 2 CLK_DFF Clocked D Flip Flop 2 2 CLK_TFF Clocked Toggle Flip Flop 2 2 LATCH Latch 2 1 SIMPLIS Digital Model Types Subcircuit Calls Instantiation The format for a subcircuit call is Xname nl n2 nn sname where X is the one character element keyword X for the subcircuit call instantiation name is the individual name of the device nl is a nonnegative integer to represent the name of the first node of this device n2 is a nonnegative integer to represent the name of the second node of this device nn is the nonnegative integer representing the nth
187. tch when the parameter LEVEL is assigned a value above 1 Its value is ignored when LEVEL is assigned a value of 1 is the three character keyword TH is a floating point number which defines the threshold value of the controlling signal Together with hystwd it determines the values at which the transistor switch will be changed from an OPEN state to a CLOSE state and vice versa It is measured in volts for VCQPOS and VCQNEG type switches and measured in amperes for ICQPOS and ICQNEG type switches is the seven character keyword HYSTWD is a positive floating point number which defines the hysteresis width of the controlling signal It has the same unit of measurement as that of threshold is the six character keyword LOGIC is the three character keyword POS is the three character keyword NEG is the six character keyword LEVEL is the integer 1 is the integer 2 If the model type is VCQPOS or VCQNEG the controlling signal cs t for the simple transistor switch is the voltage of a pair of controlling nodes or the branch voltage of a controlling device If the model type is ICQPOS or ICQNEG the controlling signal cs t for the simple transistor switch is the branch current of a controlling device For model types VCQPOS and ICQPOS the voltage across the transistor switch measured as the voltage of the positive node with respect to the voltage of the negative node assumes nonnegative values under normal operation like
188. te of the data input terminal 84 Chapter 4 Model Statements rin rin O nref rout no1 vout1 nref b 4 17 Latch model a Symbol for a SIMPLIS Latch b Model for a SIMPLIS Latch 85 SIMPLIS Reference Manual Chapter 5 Subcircuit Definition Overview 86 The basic device elements supported by SIMPLIS linear resistors linear inductors and capacitors independent voltage and current sources mutual inductances four types of linear controlled sources ideal transformers simple switches and simple transistor switches PWL resistors PWL inductors and capacitors and simple logic gates are very versatile and they can be used as building blocks to model a wide spectrum of electronic devices and circuits For example an NPN bipolar transistor can be modeled by a piecewise linear Ebers Moll model by using piecewise linear resistors for the junction diodes and two current controlled current sources to model the current conduction In addition three linear resistors can be inserted to model the contact resistances as shown in 5 1 The physical transistor shown in 5 1 a has three nodes while the corresponding model in 5 1 b has six nodes corresponding to the three terminals of the physical transistor and three internal nodes If the physical transistor in 5 1 a appears only once in the entire circuit then the model circuit in 5 1 b can be entered and defined in the input file as is If
189. te signal present E1 accomplishes this by having its output equal to 500 V whenever the output of U2 reaches 5 V 131 SIMPLIS Reference Manual The variables of interest are the input voltage V VI the signal voltage V VS the current I L1 through the inductor and the voltage V SCR across the SCR A differential voltage probe has been added to plot the latter The waveforms associated with these variables as obtained from the simulation are shown in fig 9 23 VS SCR is a hierarchical block Select then press cntrl E to see underlying schematic 9 20 Example 7 A silicon controlled rectifier with series R L load gt U3 2 500001 V5 ened R2 9 21 Piecewise linear model of the SCR in terms of SIMPLIS elements 132 Chapter 9 Simplis TX Examples Sine Wave Driving A R L Load Through A SCR PRINT ALL OPTIONS PSP_NPT 201 TRAN 20m 0 VS 1 0 PUL V1 0 V2 1 FREQ 100 T_RISE 0 T_FALL 0 PWIDTH 400u DELAY 1 1m OFF_UNTIL_DELAY NO XSSCR 4 2 3 scrl L1 3 5 25m IC 0 E Probe2 TP_DIFFPRB 6 0 4 3 1 RL 5 0 40 G13 2101m SUBCKT sori 12 11 10 NODE_MAP A 12 NODE_MAP G 11 NODE_MAP K 10 X U3 2 5 10 1 4 SIMPLIS_SRFF 1 v5 4 7 2 500001 x U1 1 10 11 3 SIMPLIS_COMP 2 H1 7 9 VHISTP_CCVS 1 VHISTP_CCVS 8 10 0 El 9 10 1 10 100 VTH 3 10 2 5 RSR2 6 8 R2STP_SSPWLR IC 1 MODEL R2STP_SSPWLR VPWLR NSEG 2 X0 0 YO 0
190. the device model xk is a floating point number which defines the value of Xk Yk is the keyword Yk representing the y axis coordinate of the end of the last linear segment of the device model so that the straight line starting at the break point xk 1 yk 1 and passing through the point xk yk forms the last segment of the piecewise linear characteristic and yk is a floating point number which defines the value of Yk For a PWL inductor the slope of each line segment on the flux linkage vs current plane is the differential inductance of the device in Henries For a PWL capacitor the slope of each line segment on the charge vs voltage plane is the differential capacitance of the device in Farads To ensure that the differential inductance or differential capacitance is positive to reflect the characteristics of realistic devices the following additional restrictions are placed on the values of the coordinate pairs x0 lt x1 lt x2 lt lt xk yO lt yl lt y2 lt lt yk Simple Switch Models SIMPLIS accepts two types of simple switch models 1 model type VCSW for a voltage controlled switch and 2 model type ICSW for a current controlled switch The formats for both of these two model types are MODEL mname mtype RON ron ROFF roff TH threshold HYSTWD hystwd LOGIC POSINEG where MODEL is the six character keyword MODEL mname is a legal model name as explained in Model Names and Subcircuit Names on pa
191. the inherent switching actions SIMPLIS FX is a small signal frequency domain analyzer specifically designed for the analysis of switching piecewise linear systems The analysis is based on the time domain simulation of the switching piecewise linear systems without having to resort to any circuit averaging or derivation of equivalent non switching models Instead of removing the switching actions to derive the small signal frequency domain characteristics SIMPLIS FX includes the switching action in its calculation of the small signal frequency domain characteristics While the computational aspects of SIMPLIS FX may be daunting and tedious the mathematical basis from which it is formulated is very simple First SIMPLIS POP is used to compute the periodic operating point trajectory of a switching piecewise linear system This operating point trajectory represents the large signal equilibrium of the system SIMPLIS FX can then be applied to study the small signal behavior of the system around the large signal equilibrium The small signal frequency domain analysis is actually a sequence of analyses at discrete analysis frequencies At each analysis frequency the procedure of the analysis can be summarized as follows 1 Apply small signal stimuli in the form of voltage current sources to the system under study These small signal stimuli are called the small signal AC sources and their waveforms are time domain sinusoidal At each analysis frequency
192. the input voltage at which the input states of the exclusive OR gate will be changed from a logic 0 to a logic 1 and vice versa HYSTWD is the seven character keyword HYSTWD hystwd is a positive floating point number which defines the hysteresis width of the input voltage in volts VOL is the four character keyword VOL vol is a floating point number representing the low value of the output voltage in volts VOH is the four character keyword VOH voh is a floating point number which defines the high value of the output voltage in volts and must be larger than the value of vol RIN is the four character keyword RIN rin is a floating point number which defines the input resistance ROUT is the five character keyword ROUT rout is a floating point number which defines the output resistance in ohms LOGIC is the six character keyword LOGIC POS is the three character keyword POS NEG is the three character keyword NEG The actual model implemented in SIMPLIS for an S R flip flop is shown in 4 12 b The set and reset input terminals of an S R flip flop are associated with the first and second input nodes respectively defined in the device statement The Q and Q output terminals are associated with the first and second output nodes respectively defined in the device statement The logic state of the output Q is always equal to the logical complement of the logic state of the output Q The initial condition s
193. the model characteristics of all of these devices can be altered at the same location by modifying the model statement which is common to all A typical model statement can be represented by the following example statement MODEL mname mtype param param where MODEL is the six character keyword MODEL mname is a legal model name as explained in Model Names and Subcircuit Names on page 12 A model name must be unique within a general circuit If a name is used as a model name in a general circuit it cannot be used as a subcircuit name in the same general circuit and vice versa mtype is a keyword which stands for one of the model types supported by SIMPLIS The list of device models recognized by SIMPLIS is shown in the table below param is a parameter assignment in the form illustrated in Parameter Assignments on page 21 Chapter 4 Model Statements Model Description Type VCSW Voltage Controlled Simple Switch ICSW Current Controlled Simple Switch VCQPOS Voltage Controlled Simple Transistor Switch VCQNEG ICQPOS Current Controlled Simple Transistor Switch ICQNEG VPWLR Piecewise Linear Resistor IPWLR PWLL Piecewise Linear Inductor PWLC Piecewise Linear Capacitor INV Simple Logic Gate Inverter COMP Simple Logic Gate Comparator XOR Simple Logic Gate Exclusive OR ORk Simple Logic Gate k input OR where k is an integer 2 lt k lt 9 NORk Simple Logic Gate k input NOR where k is an inte
194. time domain via SIMPLIS TX and 2 SIMPLIS POP is able to successfully compute the periodic operating point trajectory of the system For example multiple switch multiple output multiple feedback loop converters are easily handled by SIMPLIS FX because the analysis is constructed for general switching piecewise linear systems without any assumption or restriction placed on the number of switches outputs or feedback loops Some switching power supplies are designed to have very high DC gain to improve the line load regulation of the output voltage s The measurement of the loop gain of these systems cannot be carried out with the loop opened because the high DC gain of the system may drive the opened loop system to operate at a vastly different operating equilibrium from the original closed loop equilibrium Thus the ability to evaluate the loop gain of a switching power supply with the feedback loop closed is very useful The effect of the parasitic elements on the frequency response is usually minimal If it is suspected that a few parasitic elements are significantly affecting the frequency response of the system SIMPLIS FX can be relied upon to verify such a hypothesis SIMPLIS FX can accurately predict the impact that the parasitic elements might have on the frequency response because SIMPLIS FX does not assume the system variables to be slowly varying within one switching period and does not remove the switching actions during the proces
195. tput 9 14 illustrates how an opamp circuit can be modeled by a simple network if the opamp is not driven into saturation More sophisticated models for the operational amplifier can be built upon this basic model The input file describing this converter is shown in 9 15 In this example we are interested in the steady state waveforms of the sawtooth voltage V 11 the voltage V RL across the load and the current I L through the inductor Qi 10m I L ASA Pa Output RX x L RC 40 50m w Rt RL A 10 R11 40k l 50u IC 12 48 F cc C14 l i l ji in IC 274 1u e c1 4 2k 100h 1C 832 277m ne Sawtooth 4 VSAW 25 vreF R12 FE E 10k 9 13 Example 5 Regulated Converter 126 Chapter 9 Simplis TX Examples C14 n IC 274 1u C1 2k R14 10qn IC 832 277m R13 9 14a Error Amplifier Circuit E 9 14b Piecewise linear Equivalent 127 SIMPLIS Reference Manual 128 Regulated Converter PRINT ALL OPTIONS PSP_NPT 201 TRAN 50u 0 X U2 11 13 10 opamp VSAW 12 0 SAW V1 0 V2 5 FREQ 100k DELAY 0 OFF_UNTIL_DELAY NO X U1 6 0 11 12 SIMPLIS_COMP 1 VREF 13 0 2 5 L 4 5 40u IC 0 14 VI 2 0 40 8 10k 0 10k 50m 1 8 5 40k 11 9 100n IC 832 277m 4 10 9 2k 4 9 10 1n IC 274 1u C 7 0 50u IC 12 48 2 3 6 0 Q1STP_VCQ IC OPEN MODEL Q1 TP_VCQ VCQPOS
196. twd 77 SIMPLIS Reference Manual 78 determines the values of the input voltage at which the input states of the exclusive OR gate will be changed from a logic 0 to a logic 1 and vice versa HYSTWD is the seven character keyword HYSTWD hystwd is a positive floating point number which defines the hysteresis width of the input voltage in volts VOL is the four character keyword VOL vol is a floating point number representing the low value of the output voltage in volts VOH is the four character keyword VOH voh is a floating point number which defines the high value of the output voltage in volts and must be larger than vol RIN is the four character keyword RIN rin is a floating point number which defines the input resistance ROUT is the five character keyword ROUT rout is a floating point number which defines the output resistance in ohms LOGIC is the six character keyword LOGIC POS is the three character keyword POS NEG is the three character keyword NEG TRIG_COND is the ten character keyword TRIG_COND 0_TO_1 is the six character keyword 0_TO_1 1_TO_O is the six character keyword 1_TO_0 The actual model implemented in SIMPLIS for a clocked Set Reset flip flop is shown in 4 13 b The first two input nodes in the device statement are the set and reset input terminals while the third input node in the device statement is the clock input terminal If TRIG_COND 0_TO_1 the clocked
197. uit Names on page 12 XOR is the three character keyword XOR to stand for exclusive OR type simple logic gates TH is the three character keyword TH threshold is a floating point number which defines the threshold value of the input voltage in volts Together with hystwd it determines the values of the input voltage at which the input states of the exclusive OR gate will be changed from a logic 0 to a logic 1 and vice versa HYSTWD is the seven character keyword HYSTWD hystwd is a positive floating point number which defines the hysteresis width of the input voltage in volts VOL is the four character keyword VOL vol is a floating point number representing the low value of the output voltage in volts VOH is the four character keyword VOH voh is a floating point number which defines the high value of the output voltage in volts It must be larger than the value of vol RIN is the four character keyword RIN 69 SIMPLIS Reference Manual 70 rin is a floating point number which defines the input resistance in ohms ROUT is the five character keyword ROUT rout is a floating point number which defines the output resistance in ohms LOGIC is the six character keyword LOGIC POS is the three character keyword POS NEG is the three character keyword NEG ni1 no ni2 O nref a rin rout no ni1 r vout ni2 rin nref b 4 10 Exclusive OR gate model a Symbol for exclusive OR gate b
198. ulation assuming the circuit Chapter 6 Control Statements and the initial conditions remained the same between the two simulation runs This option does not take on any value It is either turned ON or turned OFF If it is turned ON the POP analysis will use the last data point of a previous transient simulation as the initial condition to start the POP analysis Usually this leads to a faster POP analysis Example OPTIONS POP_USE_TRAN_SNAPSHOT POP_OUTPUT_CYCLES n POP_SHOWDATA MAX_TOPOLOGY Number of cycles of steady state POP Data to show After a successful POP analysis SIMPLIS will generate the steady state time domain waveforms for an integral number switching cycles If set the option value must be a positive integer between 1 and 16 inclusively If this option is not set it defaults to 5 Example OPTIONS POP_OUTPUT_CYCLES 3 Display POP Data In general this option is turned on as a debugging aid if a Periodic Operating Point POP analysis fails This option does not take on any value It is either turned ON or turned OFF If it is turned ON the progress of the periodic operating point analysis is output and the resulting waveforms may be viewed in the same manner as for the POP cycles To turn this option ON this the line in the following example should be output to the SIMPLIS simulation input deck Example OPTIONS POP_SHOWDATA Maximum number of saved topologies This sets the maximum n
199. umber of topologies that SIMPLIS would save during a simulation run Topologies are saved in a cache for possible reuse to speed up the run This option sets the size of the cache Tf set the option value must be a positive integer between 2 and 65536 inclusively If this option is not set it defaults to 1024 Example 97 SIMPLIS Reference Manual 98 OPTIONS MAX_TOPOLOGY 512 SNAPSHOT_INTVL Minimum duration between snapshots This instructs SIMPLIS SNAPSHOT_NPT NEW_ANALYSIS FREQ DOMAIN to save a snapshot of the internal state of the simulation at intervals no smaller than the option value set for SNAPSHOT_INTVL If set the option value must be a non negative floating point number Engineering prefixes are allowed If this option is not set it defaults to zero If this option is not set or if the option is set to zero SIMPLIS would not save any snapshots at all Example OPTIONS SNAPSHOT_INTVL 10M Maximum number of saved snapshots This sets the maximum number of snapshots that SIMPLIS would save If there is a conflict between the values set for the SNAPSHOT_NPT and SNAPSHOT_INTVL options the value set for the SNAPSHOT_NPT option will override the value set for the SNAPSHOT_INTVL option If set the option value must be a non negative number between 11 and 201 inclusively If this option is not set SIMPLIS will not save any snapshot Example OPTIONS SNAPSHOT_NPT 30 Force new analysis T
200. ven The format of the ENDS statement is defined as ENDS sname where ENDS is the five character keyword ENDS signifying the end of one or more subcircuits sname is the name of a subcircuit whose definition has not been terminated The subcircuit name may be omitted to form the special case of the non specific ENDS statement Subcircuits are normally terminated with a ENDS statement in the ENDS sname or specific form If a subcircuit has not been terminated with this form of ENDS statement the non specific form of the ENDS statement Chapter 5 Subcircuit Definition ENDS will terminate the subcircuit All subcircuits whose definition have not been terminated individually will be terminated in a group by the ENDS statement without a subcircuit name For example in the statements shown in the example below the three subcircuits SUB1 SUB2 and SUB3 are all terminated by the LENDS statement In this example because of the use of the non specific form of the ENDS statement subcircuit SUB 1 is the parent of subcircuit SUB2 which is itself the parent of subcircuit SUB3 The placement of ENDS statements determines the parent child relationships of the subcircuits The line immediately following the LENDS statement is considered to be part of the definition of the parent of subcircuit SUB1 SUBCKT SUB113 RISE 226 AK CI 2 3 1U Ic 1 X1 2 3 SUB2 SUBCKT SUB2 101 103 R2 101 102 1K c2 102 103 1U Ic 1 X2 102 103
201. voltages are 1V and 3V respectively The triggering gate in this example is the comparator D1 shown in the figure Since V1 is periodic the choice of the start of a cycle is arbitrary For example let us use the instant when the source value is decreasing and it is equal to 1 001V as the instant signifying the start of a switching cycle The statements associated with the triangular source the triggering gate and the periodic operating point analysis for this example are V1 1 0 TRI Vl 1 V2 3 FREQ 10K DRATIO 0 98 DELAY 0 OFF_UNTIL_DELAY NO ID1 5 01 2 M1 IC 0 MODEL M1 COMP RIN 10MEG ROUT 8 HYSTWD 2M VOH 5 VOL 0 v2 2 0 DC 1 002 137 SIMPLIS Reference Manual 138 POP TRIG_GATE D1 TRIG_COND 1_TO_0 MAX_PERIOD 300U The model statement states that the output of the comparator is equal to logic 1 whenever the voltage at the non inverting input is 1 mV above that of the inverting input and that the output is equal to logic 0 whenever the voltage at the non inverting input is 1 mv below that of the inverting input Since the voltage at the inverting input of D1 is a DC voltage source of 1 002 V this implies that the output of D1 is equal to logic 1 when the voltage of V1 exceeds 1 003 V and it is equal to logic 0 when the voltage of V1 drops below 1 001 V When the voltage of V1 is between 1 001 V and 1 003 V the output state of D1 remains unchanged The diagram in fig 10 1 b illustrates the relationship between the output s
202. will be of the form DName pinname where pinname will be p for the first pin and n for the second pin I DName pinname Current through a device pin DName is the device name while pinname is either a pin number or mapped pin name If Dname is a subcircuit device and the subcircuit definition includes NODE_MAP statements to map its external nodes to names them those mapped names may be used for pinname For example X11 2 3 SUBI SUBCKT SUB1 100 200 300 NODE_MAP INP 100 NODE_MAP INN 200 NODE_MAP OUT 300 ENDS SUB1 PRINT I X1 INP The above PRINT will instruct SIMPLIS to output the current into pin connected to node of X1 The resulting SIMetrix vector will be called X1 INP V Node1 Node2 Differential voltage from node Node to node Node2 where Node and Node2 are node names in the current circuit V Node1 Voltage from Node to node 0 the ground node This form is allowable only in the main circuit and only if node 0 is present in the main circuit SIMetrix vector name will be Nodel V Xname1 Xname2 DName 102 Branch voltage across the device named DName in the subcircuit referred to as Xname2 in the subcircuit referred to as Xnamel in the current circuit The allowable device is same as Chapter 6 Control Statements those listed for the form of V DName SIMetrix vector name will be Xname1 Xname2 DName I Xname1 Xname2 DName Branch current through the device named DName in the subcircuit referred to
203. witching in a small group of states If the time interval between two switching events is so short to be negligible compared to the actual simulation time variable SIMPLIS aborts the simulation and displays a similar message to the following No advance in the time variable at t 3 1425e 05 sec This example error message means that when the time variable t reaches 3 1425x10 5 sec in the simulation two consecutive switching events have occurred within a time span that is negligible compared to 3 1425x10 5 sec A number is considered to be negligible to another number if it is sixteen orders of magnitude below the larger number Again you should then inspect the input file and appropriate data files generated by SIMPLIS to locate the source of the problem Netlist Preprocessor Overview The netlist preprocessor is actually part of SIMetrix not SIMPLIS However although it can be used with SIMetrix SPICE netlists it was originally developed for use with SIMPLIS and so is documented here The netlist preprocessor provides some additional functionality not provided by the simulator itself These functions are 109 SIMPLIS Reference Manual 110 1 Searches the model library for unresolved subcircuits and adds them to the netlist 2 Evaluates parameterised expressions 3 Builds static subcircuits from parameterised definitions 4 Localizes globally defined subcircuits for SIMPLIS compatibility The parameterization
204. xcitation frequency is monotonically increased from the starting frequency to the stopping frequency this sequence of analyses is usually called the swept AC analysis or AC analysis with swept frequencies The excitation frequency of the first analysis is set to start_freq In each subsequent analysis the excitation frequency is increased according to the sweep_type and n_pt parameters The sequence of analyses is stopped when the excitation frequency exceeds the parameter value of stop_freq At each of the excitation or analysis frequencies periodic small signal stimuli having the same frequency as the analysis frequency are applied to excite the system around its operating point or equilibrium The response of the system at this analysis frequency is then measured The analysis frequencies are defined through an analysis statement and the small signal stimuli are defined through device statements In addition you have the option of analyzing the system in either the continuous domain or the discrete domain by using an option statement AC Analysis Statement The AC analysis statement instructs SIMPLIS to carry out the SIMPLIS FX Small Signal Frequency Domain analysis The format of the AC statement is 157 SIMPLIS Reference Manual 158 AC sweep_type n_pt start_freq stop_freq where AC is the three character keyword AC standing for small signal frequency domain analysis sweep_type is either the three characte
205. y Chapter 3 Device Statements is the three character keyword PUL to signify that this is a rectangular pulse source is the three character keyword V1 representing the source at the start of a normal cycle is a floating point number assigned as the value of V1 in volts for a voltage source and the value of V1 in amperes for a current source is the three character keyword V2 representing the source at the end of a normal cycle is a floating point number assigned as the value of V2 in volts for a voltage source and the value of V2 in amperes for a current source is the five character keyword FREQ is a positive floating point number assigned as the frequency of this source in hertz is the seven character keyword DRATIO is a dimensionless floating point number between 0 0 and 1 0 exclusively assigned as the value of DRATIO is the six character keyword DELAY is a floating point number assigned as the value of DELAY in seconds OFF_UNTIL_DELAY YES NO is the sixteen character keyword OFF_UNTIL_DELAY is the three character keyword YES is the two character keyword NO The source function s t for t gt delay is defined as follows s H v2 s t v s s t T where T tl for delay lt t lt delay t1 for delay t1 lt t lt delay T for delay T lt t 1 freq T is defined as the period of the waveform DRATIO T t1 is the duration in a period of the w
206. y is defined as follows s H v1 v2 v1 t delay t1 for delay lt t lt delay t1 s t v2 v1 v2 t delay t1 T t1 for delay t1 lt t lt delay T and s H s t T for delay T lt t where T 1 freq is defined as the period of the waveform tl DRATIO T is the duration in a period of the waveform where the source value is moving from the value of v to the value of v2 The source function s t for t lt delay is defined as follows 27 SIMPLIS Reference Manual 28 s t s t T for 0 lt t lt delay and OFF_UNTIL_DELAY NO and s t v1 for 0 lt t lt delay and OFF_UNTIL_DELAY YES Again whether the delay is positive or negative the time domain transient analysis performed by the simulation always starts with the time variable set equal to 0 0 The diagram below shows the waveform s t of a typical triangular source For t lt delay and OFF_UNTIL_DELAY YES the waveform s t is shown in bold dashed line For t lt delay and OFF_UNTIL_DELAY NO the waveform s t is shown in heavy gray line s t T 1 freq T v2 is ap v1 lea jp t1 t1 dratio T 3 3 Waveform s t of a triangular source Square Wave Sources The formats for independent square wave voltage and current sources are Vname n n SQU Vil vl V2 v2 FREQ freq DELAY delay OFF_UNTIL_DELAY YESINO and Iname n n SQU Vl vl V2 v2 FREQ freqg DELAY delay OFF_UNTIL_DELAY YESINO where Vv

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