NCV7694 Safety Controller for Infra-Red LED Illumination to Complement the Image Sensor for Automotive Applications NCV7694 www.onsemi.com The NCV7694 is a device which can drive a string of infrared LEDs using an external mosfet. The IR LEDs are used to illuminate the surroundings of the image sensor. Since these LEDs can damage the end users eyes, the power feed to the LEDs needs to be turned off during a fault condition. 1 The NCV7694 driver features prevents the IR LEDs from being on DFNW10, 3x3, 0.5P too long due to an inappropriate exposure time or being turned on too CASE 507AG frequently using external resistors. The value of the R resistor ETL defines the maximum T time of the emitted light intensity and the ON MARKING DIAGRAM value of the R resistor defines the maximum frequency of the FRL FLASH signal from the image sensor. NV76 A LED driver with hardware interlocks helps protect the users eyes 940 in cases where the control signal has failed or a fault in the LED power ALYW path has occurred. LED brightness level is easily programmed using an external NV76940 = Specific Device Code resistor in series with the mosfet transistor. A = Assembly Location The device can also detect Open Load, Short Circuit to GND and L = Wafer Lot VS. Faults are reported to the DIAG pin, which can directly disable the Y = Year DC/DC converter to prevent possible damage. W = Work Week The device is available in 10 pin DFN package. = PbFree Package Features Constant Current Output for LED String Drive PIN CONNECTIONS FLASH Input Pin Open LED Diagnostic Detection V VS 1 10 STRING Short LED to GND and VS Detection DIAG 2 9 DET Safety Feature Prevent Being ON too long FLASH 3 GATE 8 Safety Feature Prevent Being ON too frequently R 4 7 FB ETL External Resistor Defining max ON time R 5 GND FRL 6 External Resistor Defining min OFF time Protection against Short to Ground and Open of the External Resistors Top View Detection and Protection Against UnderVoltage and over Temperature ORDERING INFORMATION AECQ100 Qualified and PPAP Capable ASILA safety design, ISO26262 compliant Device Package Shipping 10 Pin Packaging NCV7694MW0R2G DFN10 2500 / Tape & Wettable Flank Package for Enhanced Optical Inspection (PbFree) Reel These are PbFree Devices For information on tape and reel specifications, Applications including part orientation and tape sizes, please InCabin Monitoring Sensor refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D. Infrared Illumination for Automotive Cameras Machine Vision Systems Surveillance Systems Semiconductor Components Industries, LLC, 2020 1 Publication Order Number: February, 2021 Rev. 2 NCV7694/DNCV7694 VS V BAT Supply for MCU and Image Sensor C SUPPLY VDD MCU VDD AR VDD MCU R2 VDD MCU VS VDD AR 20k R EMC1 VSTR 1 k Data interface R EMC2 DET Image Sensor FLASH FLASH 1 k Micro Q1 AR 0135 controller / R EMC3 GATE DIAG 200 DSP NCV7694 REMC4 FB GND Diag detection 750 R ETL Note1: 4x optional ZD R3 R1 GND EMC shield resistors R FRL Define max R4 exposure time GND Define max frequency Note2: Optional Zener diode Figure 1. Application Diagram Powered Directly from Battery V BAT DC /DC Supply for MCU and Image Sensor VString C EN SUPPLY NCV898031 VDD AR VDD MCU VDD MCU C1 R2 VDD MCU VS VDD AR 20k REMC1 VSTR 1 k Data interface R EMC2 Image Sensor FLASH FLASH DET 1 k Micro AR 0135 controller / REMC3 GATE 200 DSP DIAG NCV7694 REMC4 FB GND Diag detection 750 R ETL Note1: 4x optional ZD R3 R1 GND EMC shield resistors R FRL Define max exposure time R4 GND Define max Note2: Optional Zener diode frequency for Mosfet Gate protection Figure 2. Application Diagram using DC/DC RECOMMENDED EXTERNAL COMPONENTS FOR THE APPLICATION DIAGRAM Component Function Min Typ Max Unit C1 Decoupling capacitor 100 nF R1 FB current sense resistor 100 m R2 DIAG pullup resistor 20 k R3 Resistor for Exposure Time Limitation 0.8 15 k R4 Resistor for Frame Rate Limitation 0.8 15 k REMC1 Optional EMC shield resistor for VSTR pin 1000 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 Figure 1 shows an example of the typical output drive if the LEDs are detached far away from the NCV7694 configuration. The current through the external LEDs is device. The resistors improves the EMC susceptibility of the equal to application. I = V / R LEDs FB 1 (Note 2) Optional Zener diode may be used if the VS Where: supply is higher than V voltage of the external transistor. GS V is internal feedback reference = 300 mV FB In case of Open Load on the LEDs, the GATE voltage will R is feedback resistor which set the current go high, the Zener diode will limit the maximum voltage 1 during eventual Open Load condition. www.onsemi.com 2 NVTFS5C478NL NVTFS5C478NL