LIN LED drivers update automotive ambient lighting

December 19, 2016 // By Graham Prophet
Melexis (Tessenderlo, Belgium) has added single-chip drivers for automotive ambient lighting. Configurable LIN (local interconnect network) slave LED driver ICs deliver the precise control of RGB lighting for ‘personalized’ cabin interiors.

LIN 2.x and SAE J2602 compliant, the single-channel MLX81112 and dual-channel MLX81115 provide a low-BOM solution to driving LEDs via constant current sources. High levels of integration mean that designers can rationalize LIN RGB module designs by combining a single mixed-signal chip with fewer than half the passive components of alternative solutions, on a single-sided PCB.


Both of the new ICs are built around a 16-bit microcontroller featuring 32 kB of Flash memory with error correcting code. Additional memory resource is provided by a 16 kByte ROM (which contains the necessary RGB mix algorithms and LIN driver), a 2 kByte RAM and a 380 Byte EEPROM. Other on-board functionality comprises a 10-bit analogue-to-digital converter (with integrated pre-divider), a LIN protocol controller, a LIN transceiver, four configurable constant current outputs and four 16-bit PWM outputs. A 24 MHz RC-based clock oscillator ensures accurate timing while a voltage regulator is provided for power management.


Melexis RGB slave controllers ensure consistent ambient lighting performance across variations in voltage, temperature and LED characteristics. Each device exhibits robust EMC/ESD characteristics, can accommodate a wide voltage input range (from 6V to 18V) and draws very little standby current (20 μA typically). Operational temperature range is from -40°C to 125°C with over-temperature shutdown and load dump protection. Temperature and battery monitoring capabilities are also provided. The MLX81112 is supplied in 8-pin SOIC package, while the MLX81115 comes in a 12-pin DFN package.


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