Automotive ambient lighting solution features LIN LED drivers

Fully LIN 2.x and SAE J2602 compliant, the single-channel MLX81112 and dual-channel MLX81115 provide a robust and reliable low-BOM solution to driving LEDs via constant current sources.

High levels of integration mean that designers can rationalise LIN RGB module designs by combining a single mixed-signal chip with less than half the passive components compared to competing solutions. This facilitates a major reduction in board real estate and allows the whole system to be implemented with a single-sided PCB.

Both of the new ICs are built around a 16-bit microcontroller featuring 32kB of Flash memory with error correcting code. Additional memory resource is provided by a 16kByte ROM (which contains the necessary RGB mix algorithms and LIN driver), a 2kByte RAM and a 380Byte EEPROM.

Other on-board functionality comprises a 10-bit analog-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 24MHz RC-based clock oscillator ensures accurate timing while a voltage regulator is provided for power management.

The new 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 (20μA typically).

Operational temperature range is from -40°C to 125°C with over-temperature shutdown and load dump protection mechanisms enhancing ongoing reliability. 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.

“Whether for style, security or the ability to personalise the driving environment, ambient lighting is an increasingly important feature for today’s car drivers,” states Michael Bender, product line manager for In-Vehicle Networking at Melexis.

“Melexis continues to lead the field in mixed-signal solutions for automotive applications offering integrated, single-chip LIN slave solutions for ambient lighting designs. With this latest generation, we can help designers to further reduce board space, component count and cost and open up greater opportunities for vehicle manufacturers to benefit from LIN-based ambient lighting solutions.”