Bringing smart interior lighting to automotive applications

With an increasing number of car manufacturers looking to introduce animated lighting into the cabin, as a way of conveying important driver-assistance prompts and vehicle-status information, current design thinking uses an RGB-LED lightbar to communicate to the driver, through colour coding, colour changing, and blinking sequences.

Key engineering challenges include maintaining consistent colour across all the LEDs in the lightbar, and ensuring they all change together, at the same time. The MLX81116 addresses this through its high-speed communication interface IP, MeLiBu. The MeLiBu controls all individual LEDs separately in the lightbar to produce the lighting effects commanded by the vehicle. The intelligent RGB-LED controller also provides real-time compensation of any LED colour drift caused by environmental changes.

The MeLiBu communication interface leverages the CAN-FD physical layer, which ensures robustness, reliability and high speed (up to 2 Mbit); features that are key requirements for today’s car manufacturers. Support for dedicated optical parameters allows colour-mixing accuracy with a delta UV of 1% to ensure no distinguishable differences between individual LEDs in the lightbar. In addition, intelligent high resolution for temperature-related colour drift helps maintain a consistent and non-distracting user experience under all operating conditions.

The MLX81116 driver IC has an extremely wide dimming range that allows optimal brightness adjustment for daytime and night driving. Meeting automotive ISO 26262 functional safety requirements up to safety integrity level B (ASIL B), the MLX81116 also features low EMI emission and high immunity, thanks to the use of the CAN-FD physical layer, which eases compliance with applicable EMC regulations.