NCV7691RCLV1GEVB User Manual
Contents
1. kas ee e cam m o lt C iz el ai a 5 m Y rol v 177 LEDI3R LED23R LED33R Thermal fold back circuitry LED11 5 3 pars MM MM Am LED31H LEDA wa e g LED12H LEp22 PG LED32H LED4 2 g Na ped Mich ia D a IIa m vm m s o ml m LEDS2R vw ma x git lt Pi Ce a RN rp Tm is lt PE 1 u m r Po Loro M LED82R 2 ajar pe w po ae medi wez aa Lj a kr a PN JE ri c Kam ie tet jii m J L a ree A 5 Fa F OPENI A UPENZ OPENA E P UP GND1 Tits ee URH hs Nd ah i Ip lem MEJE Mu P pa S Pv i IN DI d iy n TIS DS Ta NT KS NCV7691 The LEDs current is defined by Rx1 resistors By default it is set to 100 mA but may be changed using following formula e With no thermal fold back NTC pin grounded pin FB Regulation Voltage _ 0 15 ILED liED e With thermal fold back circuitry on NTC pin VNTC 1 5 0 15 R1 z 10 Irgp 10 Irgp LED 2 s ne oaz psa bi t T LEDSIR M pi U E E E m Na s a Sum if 2 ns ra recuse _ ra ea T i E eb 4 4 e v NI m lt 4 LED52HL pi LEDE2H rh L Enea Ba AX acy a xi ik C3 V2 ET EJ SHORTE se SHORT7 Zext LEDsg x ext LEDsy x EVB_RLC PA 3 SHORTS sHorte zext LEDspi ui sext LEDS e Pox 31 10 2014 NCU 691 aM 0 jo 8 2 SIG ro nim Gag HR ne m EIN wo2. Shorting terminals by the jumper emulates short LED condition OR SMD Mma terminal for external LEDs Colt Cols Connector Type Description Function FB FB1 FB5 Test Point String 5 NPN emitter feedback resistor Control diagnostic functions Pin 1 GND Pin 2 PWM input 10k pull up to VS Ji SMD Header Pin 3 Error signal active low pull up to VS through LED and 10k Pin 4 FLTS pin of NCV7691 Pin 5 Alternative pull up input for the error signal if used remove RQ Getting Started The board is supplied through a standard 5 5 x 2 1 mm DC connector Nominal supply voltage ranges from 7 to 18 V Below 7V the current through the LEDs starts decreasing For battery voltage above 18V the LED current is reduced by the over voltage fold back to reduce the power dissipation The thermal fold back circuitry ensures the board temperature remains within the safe range see following chapter for details Two jumpers in each string emulate LEDs short or opening By default OPEN jumper is closed while SHORT terminals are not shorted Alternatively external LEDs may be connected through SHORT header while on board LEDs are disconnected 7 to 18 V 2 1 mm DC paa 1 LED31 R 4 US _ i SHORT3 SHORT4 SHORTI 4 snHort2 N zm ext LEDs LN a mi t E t LEDsp 7ex LEDsg rex sa ead LEDI x noo di 9 a 11 1 mm mi AM aa zext LEDsk m censo di o Lo SAN
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5. NCV7691 includes Open Load Detection feature When the LED is open the control loop tries to increase the BASE current to reach 152 mV on the FB pin As the BASE current is limited to typ 25 mA the FB voltage drops below the target level When the FB voltage decreases below the Open Load Detection FB Threshold typ 75 mA an open load is detected after a period defined by a capacitor connected to the FLTS pin Figure 5 demonstrates an open load situation on two string application V FB lt 75 mV gt 1 gt FLTS current source active gt LEDs off Figure 6 Open load detection principle In multi string applications with high beta transistors the feedback voltage from individual strings is averaged so one defective LED string does not always lead to the open load detection One of the ways to improve the open load detection capability is more precise external BASE current limitation An example of the circuit with one extra resistor and PNP bipolar is shown in Figure 6 V FB lt 75 mV gt gt FLTS current source active gt BC856 gt LEDsoff Figure 7 Improved open load detection for 8 strings Short LED diagnostics NCV7691 contains a LED string short detection based on LED string voltage measurement pin SC In case the voltage difference between the VS and SC pins drops below typ 2 V Figure 7 the BASE is switched off and FLTS current source is active to flag an error In multi strin
6. l1 P i k 1 2 N 1 1 0 u 08 0 6 N 0 4 0 2 0 0 40 20 O 20 40 60 SO 100 120 Tpcb C Figure 12 NTC voltage vs board temperature VS 12V If the thermal fold back feature is not required components R3 R4 R6 ZD1 and PTC do not need to be assembled and NTC pin should be tied to GND directly or via R5 EMC recommendations If extensive EMC immunity level is required Cx1 C3 and C4 capacitors can improve the EMC performance Using C3 is usually sufficient against disturbances from the supply line Capacitors Cx1 and C4 may further improve the performance esp in the setups with external off board LEDs http onsemi com 7 Preliminary Information PCB Drawings Assembly Drawings LED Rag lt lt lt IE lt lt Wa LED2IR fig LEDSIRM RR LEDAIR a Mi LEDGIR a LEDZIR Ma M N o ed m en po w m NO N o 5 N o lt e m asi mile Figure 13 NCV7691 RCL EVB PCB Top Assembly Drawing Red LEDs Option A CD NCU7691_EUB_RLC_U2 Mm i T 31 10 2014 d m 880 mil gt lt ys 880 mil gt 6180 mil Figure 14 NCV7691 DRL EVB PCB Top Assembly Drawing White LEDs Option B Composite Drawings Figure 15 NCV7691 RCL DRL EVB PCB Top Composite Drawing http onsemi com 8 Preliminary Information Figure 16 NCV7691 RCL DRL EVB PCB Bottom Composite Drawi
7. Preliminary Information NCV7691RCLEVB NCV7691 8 channel Rear Combo Daylight Running Light Evaluation Board User s Manual ON Semiconductor http onsemi com Prepared by Onde Kupeik EVAL BOARD USER S MANUAL Updated by Ladislav Ba ant ON Semiconductor Introduction The evaluation board demonstrates rear combination daylight running light RCL DRL solution with up to eight LED string The board regulates constant current of 100 mA 68 to 150 mA through each on board LED string consisting of three red or two white LEDs in the wide range of the supply voltage The current is reduced for the board temperature above 90 C The board is designed in order to provide good cooling of the active components with no extra cost Additionally a heat sink may be mounted on the bottom side of the board to improve the thermal capability of the board In case of LEDs short or opening the current sources are disabled and the fault may be detected by the ECU diagnostics On board LEDs may be easily replaced by external ones Evaluation Board Features e Wide range of supply voltage 7 to 40 V e Eight LED strings with on board red or white LEDs RCL DRL e Nominal LED current 100 mA 150 mA max e Over temperature current fold back protection e OPEN jumper in each string allowing LEDs disconnection e SHORT jumper in each string for short emulation or connection of the external LEDs e Led short circuit and open load emulati
8. V 10 pasn aq Keri po pue IXO UI o 4SVH gt IS O co H9ISVA Isa pe quiesse jou ar JLA pue OY PA CA IAZ pannbal jou st x eq p o euu eseo ug MXGTI pue A Ixq T perquiesse ITTANIM xz TAA MEXITI NIXOTI p lqtut sse GTI ped XE TOM SNOLLdO ATAINASSV pei euuoo zs poi euoosip S pajqesip mdmo SLTA X MZSaTI panauossip zs pai euuoo s monedo peo ZS IS dens x AMIN xoeq p 9J 21n3e rodur T AND x ssaa 3 DILLAFZEWN gt 3044V Gg34O LINSV J0THN 44MO LNSV 3S6 OLF T9VS6GVIO96SH XT31 pay xe CAT ANIM XZ SA pa qurasse jou po pue AND ONO QND ND ONO CONO dNLY AdNLY Jos JU LINDO tO cI IGN5 ENAIT TA9S8IH AIND USI c ITA 169LAON AND UND 301 E 18 1SSA i84 o4 7 osjo JO e perquiesse jou 119 9 a58 AND 010 ANO JI ITI IS sqaTixe Tw H9ISV8 gt LINOHS IN3dO na OTLLOOPSSTASN M00 p l5 uuo3 ST A S ISLI UL nea tel TIK za L 63 A qurasse jou op T x paa 1o T NOI k imejap Aq pasn YO Ni TIGITE Armunn ssjnd uonisuen saaoidun y t ATIGTI ANO MIITTIM an x x NOOI 92 5 d0J1V dHWO LNSV 30 TIN JHMO LINSV V SA ELEOOPVAN V CAT pear xe GAT AM XZ SA la GA ic Board Schemat ion NCV7691 RCL DRL Evaluat Figure 2 I com onsemi http Preliminary Information Table 3 Interface Function Description Connector Name VBAT OPEN1 8 SHORT 1 8 2 1 mm DC supply Supply battery input SMD Jumper Removing the jumper emulates open LED condition
9. circuitry output voltage is given by R4 and R5 while for high temperatures the reference voltage drops rapidly Figure 9 R6 ensures the voltage on NTC input does not fall below the NTC Detection Level max 300 mV at high temperature which would result into a switch over to the internal voltage reference of NCV7691 http onsemi com Preliminary Information 4 3 V 4 3 V ba TsTsense m PTC 470R to NTC pin to NTC pin R5 V NTC hasto be gt 0 3 V 51k Figure 10 Thermal fold back circuitry at low high temperature The optimal Zener voltage in terms of the temperature independency is usually between 4 and 5 V At the same time it should be as low as possible to allow a low battery operation 4V7 Zener diode is recommended as a good tradeoff Because of lower bias current lt 1 mA and impedance of the Zener the reference voltage is lower than the nominal one 4 3 V for 4V7 Zener Figure 10 1 7 1 6 NTC V 1 4 HEEFT 1 3 a 6 8 10 12 14 16 18 20 22 24 26 28 VS V Figure 11 NTC voltage vs supply voltage Tpcb z 25 C The sensing temperature PTC parameter has to be chosen carefully with respect to the heat distribution over the board and thermal properties of the power dissipating components For PTC type B59641A95A62 the current fold back reduces the reference voltage on the NTC pin and thus LED current above the board temperature of 90 C Figure 11 1 6 1 4 D 1
10. g applications an OR circuitry e g diodes has to be used to cover all the strings V SC gt VS 2 V gt gt FLTS current source active gt LEDs off Figure 8 Short LED detection principle Thermal considerations of the board As the board dissipation is typ 11 W at 13 8 V battery supply and 100 mA LED current the thermal aspects should be taken into account for the board design The main limitations are LED lifetime vs operating temperature and NPN bipolar maximum junction temperature The board was designed to operate at full current with board temperature of up to 90 C on standard 70 um FR4 PCB substrate and passive cooling without any extra thermal improvements In case higher power dissipation is foreseen a cooling metal profile may be mounted to the bottom side of the board Thermal fold back To the protect power dissipating devices on the board LEDs NPN bipolar transistor a circuit reducing LED current at high board temperatures is included Figure 8 Temperature pa dependent element to NTC pin RS T lt Tsense 4700 51k T Tsense 15 C 540 kA Figure 9 Thermal fold back circuitry The circuit consists of a voltage reference ZD1 supplied via R3 and temperature dependent resistor divider A thermistor with positive temperature dependency PTC is used for temperature sensing For temperatures below the PTC sensing temperature the thermistor has low resistance typ 470 Q so the
11. ng http onsemi com 9 Preliminary Information REFERENCES 1 ON Semiconductor NCV7691 Product Datasheet Rev 2 January 2015 2 EPCOS PTC thermistors as limit temperature sensors Series B59421 B59641 B59721 March 2014 3 ON Semiconductor BCP56 NPN Silicon Epitaxial Transistor Rev 10 March 2014 http onsemi com 10 Preliminary Information ON Semiconductor and Q are registered trademarks of Semiconductor Components Industries LLC SCILLC 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 and 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 sup
12. on jumpers e Optional external PWM input e Optional Error flagging through indication LED and FLTS output e Positions for optional EMC capacitors e One side components assembly e Passive cooling optional heat sink may be attached to the bottom Semiconductor Components Industries LLC 2015 http onsemi com Publication Order Number May 2015 Rev i2 10 EVBUMXXXX Figure 1 Running NCV7691 Evaluation Board Picture Table 1 Absolute Maximum Ratings Rating Supply Voltage Vbat LED String Current thermally limited PWM FLTS Err Voltage J1 connector Error pin current J1 connector pin 3 Junction Temperature NCV7691 BCP56 Junction Temperature ASMT QRBD AEFOE ASMT QWBF NKLOE Ambient Temperature Table 2 Recommended Board Operating Conditions Rating Supply Voltage Vbat Rated LED string Current VS lt 18 V Tboard lt 90 C Open Load or Short Circuit board consumption VS 14 V Ambient Temperature for rated LED current 68 100 150 mA 40 to 70 C Value Unit Value Unit mA o lon Informat iminary Prel Rear Combo Daylight Running Light Evaluation Board Schematic pe quiesse jou INIS NO Smm 8 I8CHT jes UALM ILGTI jes juaumo 9 19GTI QNO ust xot ANO 501 GND ust NOI T uU 8 1 perquiesse jou Isa csu pajqu sse jou cLa pe quiesse jou cod ANOI 9sdoH ANOT ANOI 182 080 4SVH ILI 4SVH 192 dsVH DS gt DS gt DS SATTIMA H9ISVH SCA TINS
13. port 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 JAPAN ON Semiconductor Japan Customer Focus Center Literature Distribution Center for ON Semiconductor 2 9 1 Kamimeguro Meguro ku Tokyo Japan 153 0051 P O Box 5163 Denver Colorado 80217 USA Phone 81 3 5773 3850 Phone 303 675 2175 or 800 344 3860 Toll Free USA Canada Email r14525 onsemi com Fax 303 675 2176 or 800 344 3867 Toll Free USA Canada Email ONlit hibbertco com ON Semiconductor Website http onsemi com N American Technical Support 800 282 9855 Toll Free USA Canada For additional information please contact your local Sales Representative
14. s Pye Bion BE IC4 o gi TE B A j v NG E INA ie 24 Ng fi s do Hi B x pa O LED42 razu i x r L LEDS3R LEDG3R Positions for optional EMC resistors JB Figure 3 NCV7691 8 channel Evaluation Board Picture Modules control strategy The board is designed to operate in standard One Wire Driver Body ECU and decentralized architecture In the first case both control and diagnosis is done through one supply wire The dimming might be provided through the PWM applied to the High side SmartFET in the body ECU At the same time the SmartFET allows diagnosis of the failure on the LED module open load or short circuit see Figure 3 In case of both LED short and disconnection NCV7691 disables all the NPN bipolars In decentralized operation extra wires are needed for the control and diagnosis Figure 4 For this purpose header J1 is available on the board for easy access to FLTS and PWM functions of NCV7691 http onsemi com Preliminary Information Normal operation LED string open LED string short ECU ECU control control control diagnostics diagnostics diagnostics NCV8460A NCV8460A NCV8460A RCL DRL RCL DRL RCL DRL 8x 100 NCV7691 NCV7691 NCV7691 Figure 4 Centralized One Wire System Diagram LED string open LED string short NCV7691 NCV7691 Figure 5 De centralized System Diagram http onsemi com 5 Preliminary Information Open LED string diagnostics
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