With the growing demand for animation in automotive lighting, LEDs must be controlled independently. Thus, LED drivers with digital interfaces are crucial to drive pixel-controlled lighting applications effectively. In exterior lighting, multiple lamp functions are generally located on different PCB boards with off-board wires connected. It is challenging for a conventional single-ended interface to satisfy the strict EMC requirements. Using an industrial-standard CAN physical layer, the UART-based FlexWire interface of the Texas Instruments TPS929240-Q1 readily achieves long-distance off-board communication without impacting EMC.
The 24-channel, 40V high-side LED driver controls the 8-bit output current and 12-bit PWM duty cycles. The device fulfils multiple regulation conditions with LED open-circuit, short-to-ground, and single LED short-circuit diagnostics. A configurable watchdog also automatically sets FAIL-SAFE states when the MCU connection is lost, and with programmable EEPROM, the device can flexibly be set for various application scenarios.