NCP5603GEVB Manual
Contents
1. converter will translate to almost 2 W of input power Consequently some 400 mW will be dissipated as heat into the silicon and according to the NCP5603 data sheet the chip temperature will increase by Roya x Pin 85 x 0 4 34 AC Such a temperature increase is acceptable since even under the worst case 85 C ambient temperature the junction will be below the maximum rating defined for this chip However we must take into account the low battery Situation in this case the efficiency of the converter can decrease and we end up with 60 efficiency yielding almost 54 AC temperature increases At this point the silicon can rise above 125 C under extreme high ambient temperature and the global long term reliability of the chip will be impaired This can be avoided by either reducing the thermal resistance using a heatsink by means of the PCB layer or by ensuring the duty cycle is short enough to properly cool off the chip between pulses Generally speaking the High Intensity LED are power limited and care must be observed to avoid any thermal run out during normal operation This is particularly true for the flash mode in which as depicted above nearly 1 6 W are dissipated into the LED junctions Because the junction to ambient thermal resistance is limited by the packaging of the LED a good thermal contact to a dedicated layer on the printed board is essential The LWW5SSG specifications give a maximum 9 C W junction to ca2. 603MNR2G No Yes Pump Dual Schmitt TSOP 6 ON Semiconductor NL27WZ14DTT1G Trigger Inverter Dual Retriggable SOIC 16 ON Semiconductor MC14538BDG One Shot R3 R4 R5 Resistor CRCW08051030JNEA R1 0 R9 J1 1 Banana Socket NA PLUG 4 Deltron 571 0500 Yes Yes Components J2 1 Banana Socket NA PLUG_4MM Deltron 571 0100 Yes Yes Components D1 D2 D3 4 LW Y87S White NA NA OSRAM_LED Osram Q65110A1709 Yes Yes D4 LED HYPER MINI OSRAM LED Osram Q65110A2364 TOPLED KEZ TP2 Test Point Point NA TEST_POINT POINT Keystone 5006 52 53 54 3 Manual Switch SIP3 09 03290 01 http onsemi com 7 NCP5603GEVB ON Semiconductor and W are registered trademarks of Semiconductor Components Industries LLC SCILLC SCILLC owns the rights to a number of patents trademarks copyrights trade secrets and other intellectual property A listing of SCILLC s product patent coverage may be accessed at www onsemi com site pdf Patent Marking pdf SCILLC reserves the right to make changes without further notice to any products herein SCILLC makes no warranty representation or guarantee regarding the suitability of its products for any particular purpose nor does SCILLC assume any liability arising out of the application or use of any product or circuit and specifically disclaims any and all liability including without limitation special consequential or incidental damages Typical parameters which may be provided in SCILLC data sheets an
3. NCP5603GEVB High Efficiency Charge Pump Converter White LED Driver Evaluation Board User s Manual Abstract This evaluation board describes a multi functional system capable of generating and controlling the power needed to utilized three features available in modern cellular phones In addition to larger displays with full color capability flash and torch features have now been added to support the embedded camera and the night path finder These features are made possible by using an ultra bright LED powered by standard battery cells Basic Circuit Description Since the LED have a forward drop voltage ranging from 3V to 4 5 V depending upon the forward current a straightforward connection to a standard battery is not feasible as depicted Figure 2 A boost structure must be used to make the power supply voltage compatible with the LED ON Semiconductor http onsemi com EVAL BOARD USER S MANUAL On the other hand combining three functions in the same system creates a special case since the converter must be capable of driving the wide current load needed for the different functions The typical currents used to drive the LED summarized in Table 1 range from a low 1 mA to 350 mA when the flash is activated Moreover unlike the xenon photo flash the LED system must have a relatively long pulse of light to properly illuminate the scene Typically a xenon pulse has a 1 ms flash duration the LED system being in
4. ation board can operate with either an external sure the polarity is properly respected power supply or with two dry cell 1 5 V AA type and 3 Toggle switch S4 to turn on the system battery The mechanical switch S4 is used to select one of the System Operation two power sources The system is not designed to run the two 4 Select the Output Voltage 4 5 V or 5 0 V by power sources simultaneously and such connection must be toggling the switch S3 B1 avoided 5 Select the operating frequency 260 kHz or Using an External Power Supply 630 kHz by toggling the switch S2 FSEL 1 Select a DC power supply with 500 mA output Note turn system off before switching frequency current capability minimum adjust the output 6 Select the Normal or PWM mode by toggling the voltage to 3 60 V switch S1 A RED LED turns On when the PWM 2 Connect the positive wire to the RED socket mode is activated The brightness of the LED if connect the negative wire to the BLACK socket necessary can be adjusted when the PWM mode 3 Toggle switch S4 to turn on the system is activated by means of the potentiometer P1 Using Dry Cell Battery 1 Make sure no external power supply is attached to the RED and BLACK sockets Table 3 BILL OF MATERIALS FOR THE NCP5603 EVALUATION BOARD Manufacturer Substitution RoHS Designator Qty Description Value Tolerance Footprint Manufacturer Part Number Allowed Compliant U1 1 NCP5603 Charge NA NA QFN10 ON Semiconductor NCP5
5. d or specifications can and do vary in different applications and actual performance may vary over time All operating parameters including Typicals must be validated for each customer application by customer s technical experts SCILLC does not convey any license under its patent rights nor the rights of others SCILLC products are not designed intended or authorized for use as components in systems intended for surgical implant into the body or other applications intended to support or sustain life or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application Buyer shall indemnify and hold SCILLC and its officers employees subsidiaries affiliates and distributors harmless against all claims costs damages and expenses and reasonable attorney fees arising out of directly or indirectly any claim of personal injury or death associated with such unintended or unauthorized use even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part SCILLC is an Equal Opportunity Affirmative Action Employer This literature is subject to all applicable copyright laws and is not for resale in any manner PUBLICATION ORDERING INFORMATION LITERATURE FULFILLMENT N American Technical Support 800 282 9855 Toll Free ON Semiconductor Website ww
6. ion the RESET of USA is released and the EN pin is clocked High Low by the clock generated by U2A U2B Simultaneously diode LED D7 turns ON to identify the PWM mode of operation The duty cycle of the USA Q output is manually adjusted by potentiometer P1 to set the brightness of the four associated LED The efficiency of the system has been evaluated at room temperature see Table 2 the results being fully within the NCP5603 data sheet specifications esov mom sv ram em v sov im sev wsm em nen sov woma sov erama em m t The inrush current is internally limited by the chip as depicted Figure 7 and no uncontrolled current takes place when the system starts up from scratch Load 66mA Vhat 350V 100mA Figure 7 Typical Startup Timing With a startup time well below 1 ms from zero to full Vout see Figure 7 the NCP5603 is fast enough to accommodate a flash application as shown in the demo board Load 66mA Vhat 350Yv 200 C 22 000 h4 100mA Figure 8 Typical Digital Dimming Although there is no dedicated pin the LED brightness can be dimmed by means of the EN digital control The waveform captured in Figure 8 illustrate this behavior the PWM being intentionally arranged out of the audio band for a portable system http onsemi com 6 NCP5603GEVB TEST PROCEDURE Test Conditions 2 Insert two 1 5 V AA type cell in the holder Make The evalu
7. se thermal resistance capable of limiting the temperature of the silicon to the 100 C maximum specified in the OSRAM data sheet After dissipating 1 6 W the maximum thermal to air resistance acceptable by the chip can be calculated as LE LE R Paa chip 100 85 _ 937C W 1 6 Since the Royc is 9 C W it is practically impossible to achieve a 0 38 C W case to ambient thermal resistance and the only alternative is to limit the operating ambient temperature Assuming 25 C W In this case the case to ambient thermal resistance is 25 9 16 C W a value more realistic although not so easy to achieve with a room limited PCB NCP3603 operates without special treatment in terms of thermal sinking and a simple copper flag is built underneath the QFN package as depicted Figure 6 The schematic of the multiple application Figure 3 illustrates the three functions Tamb 60 C then Reja 100 60 1 6 e Backlight four LED in parallel dimming capability e Torch one LED no output adjustment e Flash one power LED pulse width adjustable http onsemi com 3 NCP5603GEVB C3 TP2 Q 1 bz Hr 1 0 uF 16 V ISENSE gt GND LW67C 82 Q C2 c CH LO A O DZ S3 GND O R4 Vsel 9 S2 GND IER R5 Fsel 10k O O m mi O a GND c 4 7 uF 16 V D Lo A P1 Ge mo OF x O lt mo 200 kA R3 HER ers pr a0 S fat Te Adjus
8. t PWM 10k 2 10 k C8 o C6 S Y S4 T POVER 100 100 nF V GND NL27WZ14 E 3316 Auen 11 1 5k Q E R 3 2 m S 5 100k NL27WZ14 PWM E 2 73 Q Q 2 4 GND br z GND 7 GROUND Figure 3 NCP5603G Evaluation Board Schematic http onsemi com 4 NCP5603GEVB 4000 milo n Semiconductor Figure 4 Top Layer 100 T 2404077 201 WH 204 100 9 2 J WR RE O lout Sense select Ouiput Voltage select Operating Frequency NCPS603 DEMO BOARD W2 0 Figure 5 Bottom Layer Battery cell 1 5V AA Battery ced15Y AA Adjust PWM Figure 6 Silk Layer Top View http onsemi com 5 2650 mil Select Power Source External Power Supply connections 5 Normal PWM NCP5603GEVB The system is powered by two AA cells in series assembled in a standard battery holder the operating mode being selected by the S1 S5 and S6 switches Since the total current is limited by the DC DC converter the backlights LEDs are automatically deactivated when either the Torch or the Flash are selected Moreover the Flash is not available while the Torch is running An extra feature backlight dimming is provided by switch S1 is associated with potentiometer P1 When the switch is connected to ground the NCP5603 enabling pin EN is high and the brightness is maximized When the Table 2 EVALUATION BOARD EFFICIENCY switch S1 is flipped to the Vcc posit
9. the 100 ms to 200 ms range Consequently the converter must be designed to support such a large demand High powered LED capable to sustaining up to 800 mA are under development and drivers for these devices should be available within a few months CNE 20954 BEI VA di Ob d H 2 Figure 1 NCP5603GEVB Semiconductor Components Industries LLC 2012 October 2012 Rev 0 Publication Order Number EVBUM2140 D NCP5603GEVB Battery Voltage F Capacity TA 20 C OSRAM LWY87S 10 mA 3 8 V 100 1 0 TT x o o ee aena R I NICHIA NECVVB205 020 mA 4 0 V 70 s E 0685082 60 3 50 Vout Li ion 40 3 7 N R 2 M 5 Vout V MB JUNE 2004 Figure 2 Typical Lithium lon Battery Voltage and White LED Table 1 WHITE LED TYPICAL APPLICATIONS Pt e ESTI E S auer osm x osam wss xn omzev o sos DIETA 50 fumed http onsemi com 2 NCP5603GEVB Along with the amount of current the converter provides it is worthwhile to note the thermal behavior of both the silicon and the power LED According to the OSRAM s data sheet the Dragon LED LWWS5SG should have a maximum 4 5 V forward drop with 350 mA current The power absorbed by the load will be 1 57 W and assuming a 75 efficiency of the DC DC
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