WIXLIB

NCV7694PINS DESCRIPTIONFLASHOpen Load condition, if the when FB voltage will be belowthreshold for longer than blanking time. It is not allowed toput external voltage higher than 0.19 V on the FB pin whenthe device is not active. The voltage on the FB pin has to bebelow 0.19 V during VS supply ramp up while FLASHPWM signal is already present.Flash Input pin is compatible with 1.8 V / 2.8 V logic ofthe ON Semiconductor image sensors. Internal pull downresistor is implemented to prevent unwanted switch on.Based on the RETL and RFRL resistors, the maximum TONFLASH time which can be propagated to the output is 6 msand minimum TOFF time, which will can be set, is typically8 ms. The NCV7694 can be used as companion device for60 Hz camera sensors in full FLASH TON range or 120 Hzwith limited TON range.GATEThe NCV7694 can drive MOSFET transistors withminimum GATE voltage of 4.5 V. The preferred mosfettransistor is NVTFS5C478NL.DIAGRETL and RFRLOpen Drain DIAG pin can be connected with pull upresistor to MCU which will be informed about a fault in caseof Open Load, Short to VSTRING or Short to Ground of theLEDs. Diagnostic pin can be connected to the Enable pin ofthe DC/DC converter. The output VSTRING voltage will bedisconnected and user and devices are protected againstdamages. The NCV7694 driver can also inform the systemwhile FLASH pulse is too long or is send too frequent. TheOpen Load and Short circuit detections of the RETL, RFRLtiming resistors are reported on the DIAG pin as well as theThermal Shutdown Flag and Under Voltage status on the VSsupply.To reduce thermal retina hazard and thermal injury risk ofthe cornea, the safety turn off function is implemented.External RETL and RFRL resistor defines maximumexposure time and maximum frame rate. The maximumtimes are calculated using resistor values of the RETL andRFRL resistors divided by KFRL or KETL coefficients. If theFLASH pulse is permanently HIGH, the output pulse isbeing activated only after FRL timer expire and during theallowed ETL time period.Short and Open on the RETL and RFRLTo be able detect the defect on the external resistors theOpen Load and Short to Ground detections are implementedin the NCV7694. If the resistor value will be below 750 W,short to ground will be detected. If the resistor valuebecomes higher than 17.5 kW, Open Load is detected.As soon as a fault condition is detected, then after a shortfilter time the driver is switched off and fault on the DIAGpin is reportedDETDetection pin is sensing the voltage at the cathode of theLEDs. The voltage on DET pin during the FLASH ONperiod should be in range from VSGth (0.35 V) to VSVth(VSTRING – 1.22 V). Below 0.35 V the device will detectShort to ground and above VSTRING minus 1.22 V the devicewill detect Short LEDs to VSTRING.In case of DET pin is disconnected, device will go intofault because internal pull up to VSTRING is implemented.Short to ground can be detected only when output is notactivated.VSTRINGHigh voltage input pin sense the voltage on the top of theLEDs and enable the Open Load and Short diagnostic assoon as the voltage exceed the threshold VSTRth 2.2 V. IfDC/DC converter is not used, the VSTRING voltage has tobe connected to the VS pin. If the LED diagnostic is notrequired, then the VSTRING pin has to be grounded.FBA feedback loop regulates the current through the externalLEDs. The voltage across the external sense resistor isregulated to the 300 mV typ. Using FB pin can be detectedwww.onsemi.com8

NCV7694DETAILED OPERATING DESCRIPTIONUnder Voltage Lockoutshort filter time the driver is switched off and fault on theDIAG pin is reported.Under voltage Lockout feature is used to protect againstan abnormal status during startup. When the initial soft startvoltage is greater than 4.5 V (typ) the device starts to beactive. Below this threshold the GATE output pin is pulledlow to ground to prevent opening external N MOStransistor and DIAG pin is pulled low to report.Exceeding the Flash PulseIf the duration of the FLASH pulse exceeds thepre defined timing or the FLASH pulse repetition is toofrequent, the GATE of the transistor is switched off. Thelimitation of the FLASH pulses is also reported on the DIAGpin. The first FLASH pulse after power on reset should bedelayed longer than FRL period, otherwise the FLASHpulse will be limited and DIAG pin will report a fault untilFRL counter expires.Thermal ShutdownThe thermal shutdown circuit checks the internal junctiontemperature of the device. When the internal temperaturerises above the Thermal shutdown threshold, then after awww.onsemi.com9

NCV7694Open Load DetectionV BATVDD MCUV STRINGDC /DCNCV898031ENC1R220 osuretimeGATEFBR ETLVFB 150 mVR1R FRLR4Definemaxfrequency VSTRthOpen LoadFLASH HighFLASHVSGNDFigure 5. Open Load Detection Circuitapproximately 2 ms to re activate the DC/DC VSTRINGvoltage of the converter. With typical FRL setting, the driverwill be ready to perform the diagnostic on the next FLASHpulse.If the ENable of the DC/DC converter is not driven byNCV7694, the Open Load is reported to the DIAG pin.Diagnostic is not active when VSTRING VSTRth. The firstFLASH pulse will not be detected when driver is going to berecovered from a Short to GND fault because the DC/DCconverter in not fully active.When Open Load fault is introduced duringFLASH High and VSTRING VSTRth, the 22 ms blankingtime eliminate the false faults. When blanking time expires,the NCV7694 immediately report a fault on the DIAG pin.The output GATE pin remains active. The DIAG pin isrecovered with the falling edge on the FLASH pin or afterETL counter is expired.If EN pin of the DC/DC converter is connected to theDIAG output, the Open Load causes switching OFF theVSTRING voltage. The DIAG pin is recovered as soon asFLASH pin goes low or ELT counter expired. It will takewww.onsemi.com10

NCV7694OPEN LOAD BEHAVIORConditions: VS powered, DC /DC used, EN connected to the DIAG pinVSTRINGOpen Load presentVSTRthVGATEFLASHinputVDET2.2 VVDIAGt OLBlankt DC ENt DC ENt DC EN 1.5 ms activation delay of the DC/DCFLASH isFault is presentV STRING is notpropagatedand detectedsufficient, Opento the outputLED is OFFLoad isn’t detectedFigure 6. Timing of the Open Load Behaviorwww.onsemi.com11

NCV7694Short to Groundoutput diagnostic pin can be connected directly to the Enableof the DC/DC converter. In case of fault, the DC/DCconverter is automatically disabled after blanking times.In case of short to ground, huge amount of current ispassing through the LEDs. To protect the LEDs and Humaneyes, the safety mechanism can be implemented. The DIAGV BATVDD MCUENV STRINGDC / DCNCV898031C1R220 kWHigh LED currentVSVSTRFLASH LowDIAGDET V DET 350 mVFLASHDIAGGATENCV7694FBR ETLR3DefinemaxexposuretimeR1R FRLR4DefinemaxfrequencyShort DETpin to GroundFLASHGNDFigure 7. Short to Ground Detection Circuitinput pin. (The next FLASH pulse will not be propagated tothe output, because the DC/DC converter is not activated).The microprocessor can distinguish between Short toGND and Open Load during FLASH Low. If the DIAG pinremains low during FLASH Low, the Short to Ground wasdetected and it is not recommended to not turn ON theVSTRING voltage.When Short to Ground is introduced duringVSTRING VSTRth and FLASH is low, the 10 ms blankingtime eliminate the false faults. When blanking time expires,the NCV7694 immediately report a fault on the DIAG pinwhich leads to the switching OFF the VSTRING voltage toprotect the LEDs. The output GATE pin remains active. Thedevice is recovered with next rising edge on the FLASHwww.onsemi.com12

NCV7694BEHAVIOR OF THE SHORT TO GNDConditions: VS powered, DC /DC used, EN connected to the DIAG pinV STRINGShort to GNDV STRthV DETV GATEFLASHinput(VSTRING – VF)2.2Vt SGBlankV DIAGt SGBlankt DC ENt DC ENt DC EN 1.5 ms activation delay of the DC/DCFLASH isFault is presentV STRING is notpropagatedand detectedsufficient, Opento the outputLEDs are OFFLoad isn’t detected*) DIAG latched until next FLASH rising edgeFigure 8. Timing of the Short to GND Behaviorwww.onsemi.com13

NCV7694Short to VSVBATVDD MCUVSTRINGDC / DCNCV898031ENC1R220 kWVSV STRING V STRthVSTRFLASH HighVDET (V STRING – retimeGATE GATENCV7694GNDFigure 9. Short to VSTRING Detection CircuitWhen Short Cathode of the LEDs to VSTRING voltage isintroduced during the FLASH High andVSTRING VSTRth, the 10 ms blanking time eliminate thefalse faults. When the blanking time expires, the NCV7694immediately switch OFF the GATE output to protect theexternal transistor against high power dissipation. TheDIAG pin will report a fault which will lead to switchingOFF the DC/DC VSTRING voltage if the DIAG pin isconnected to the Enable of the DC/DC converter. The faultis latched during the FLASH signal is high or until ETLcounter expires. The device will be recovered only with nextfalling edge on the FLASH or when the ETL counter isexpired.The diagnostic is not active when VSTRING VSTRth oralso during FLASH Low.www.onsemi.com14

NCV7694Behavior of the Short to VSTRING:Conditions: VS powered, DC /DC used, EN connected to the DIAG pinV STRINGShort to V STRINGt DC ENV STRthFLASHinputV DET2.2VV GATEt SCBlankV DIAGt SCBlankFLASH isFault is presentFault is presentpropagatedand detectedGATE is ON duringto the outputLED is OFFblanking time onlyFigure 10. Timing of the Short to VSTRING Behaviorwww.onsemi.com15

NCV7694Overview of the FaultsFLASH OFFOFFONVSTRINGLEDsare OFFVSTRNormalOperationGATELEDsare ONVSTRING – VF RINGVSTRINGLEDsare OFFLEDsare OFFVSTRDET PULL UPVSTR VSTRINGDET VSTRINGDETGATEdisabledGATEFB VSTRING 0VenabledFB 0V 0.0mVR1R1UnrecognizableVSTRDET PULL UPONVSTRINGHigh ILEDShort toGroundVSTRINGDET0VGATELEDs arestressedDC/DC RINGHigh ILEDOFFDET 0.35 Vor FB 150mV0.0mV 0.0mVR1R1Fault is latcheduntil next risingDET 0.35 VOFFShort toVSTRINGVSTRINGDETLEDsare 300 mVONR1R1DET (VSTRING – 1.22 V)UnrecognizableFigure 11. Overview of the Faultswww.onsemi.com16MOSFET isstressedDC/DC candisableVSTRINGVSTRDETdisabledFBSame asOpen LoadconditionDET 0.35 Vor FB 150 mVONVSTRINGVSTRDET PULL UPLEDs arestressedDC/DC candisableVSTRINGenabledFBHigh PD(N MOS)OpenLoadVSTRINGVSTRdisabledFBVSTRING VSTRthVSTRINGDET VSTRINGDETDET PULL UPONVSTRING VSTRthVSTRING

MECHANICAL CASE OUTLINEPACKAGE DIMENSIONSDFNW10, 3x3, 0.5PCASE 507AGISSUE B1SCALE 2:1DATE 14 APR 2020GENERICMARKING DIAGRAM*1XXXXXXXXXXALYWGGXXXXX Specific Device CodeA Assembly LocationL Wafer LotY YearW Work WeekG Pb Free Package(Note: Microdot may be in either location)*This information is generic. Please refer todevice data sheet for actual part marking.Pb Free indicator, “G” or microdot “ G”,may or may not be present. Some productsmay not follow the Generic Marking.DOCUMENT NUMBER:DESCRIPTION:98AON73716GDFNW10, 3x3, 0.5PElectronic versions are uncontrolled except when accessed directly from the Document Repository.Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red.PAGE 1 OF 1ON Semiconductor andare trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regardingthe suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specificallydisclaims any and all liability, including without limitation special, consequential or incidental damages. ON Semiconductor does not convey any license under its patent rights nor therights of others. Semiconductor Components Industries, LLC, 2018www.onsemi.com

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REMC2 Optional EMC shield resistor for DET pin 1000 REMC3 Optional EMC shield resistor for GATE pin 200 REMC4 Optional EMC shield resistor for FB pin 750 (Note 1) Optional EMC serial resistor shall be used in case if the LEDs are detached far away from the NCV7694 device. The resistors improves the EMC susceptibility of the application.