This reference design details how to drive a string of matrix LED headlights, measure the temperature of the LEDs and implement support for thermal foldback which reduces the current in the LEDs as the LED temperature rises to prevent damage to the LEDs. The design uses temperature sensing instead of negative temperature coefficient (NTC) thermistors in order to reduce the number of components, number of physical wires and reduce the number of pins used on the microcontroller. TIDA-01381 should be interfaced with a microcontroller to do the thermal foldback current derating of the LEDs. The input stage of the design includes electromagnetic interference (EMI) and electromagnetic compatibility (EMC) filters and can be directly supplied by a car battery.
Features
- Multiple-channel temperature sensing
- Efficiency-optimized design
- Operation through cold crank
- Load-dump tolerant
- Reverse battery protection
- Thermal foldback