Melexis Integrates On-Chip DC/DC Power to Simplify LIN RGB Automotive Lighting

Lighting has become a key element of modern automotive design. Across both interior and exterior domains, OEMs are increasing the number of lighting deployments to support new functionality, personalization, and brand differentiation. However, physical, efficiency, and thermal constraints are becoming more severe as more electronics are deployed deeper within the vehicle. In conventional architectures, supplying LEDs via external DC/DC converters increases heat generation, component count, and layout complexity, making it harder to meet these constraints at scale.

The 18-channel MLX81119 addresses this challenge by integrating a 1 A DC/DC converter that generates an optimized local LED supply voltage, programmable between 2.5 V and 6 V. Rather than dissipating excess voltage as heat, the device dynamically adapts the LED supply to the active color mix and operating conditions, significantly reducing power losses and thermal stress. This level of voltage optimization is not achievable with fixed external DC/DC converter solutions.

With 18 low-side current sources configurable up to 60 mA and independent 16-bit PWM control, the MLX81119 supports up to six RGB LEDs per device, enabling smooth color transitions and advanced lighting animations. Built-in direct and indirect temperature sensing allows active compensation across all channels, maintaining stable color points over the full automotive temperature range.

Building on the proven MLX81118 architecture, the MLX81119 integrates a complete LIN system, including transceiver and protocol handler, fully compliant with LIN 2.x and SAE J2602. Developed according to ISO 26262, the device supports up to ASIL B implementations depending on the system safety concept, making it suitable for functional safety-relevant interior and exterior lighting applications.

The integration of the DC/DC converter dramatically simplifies the external power stage. The MLX81119 operates with as few as two capacitors and a single inductor, eliminating the need for a separate DC/DC controller and associated passives. This reduction in component count and PCB area enables more compact lighting modules and eases integration in space-constrained locations. In addition, the device can be configured as a LIN-controlled power and I/O extension, using its 18 channels to support auxiliary loads or distributed functions within a module.

LED control is managed by Melexis’ 16-bit microcontroller. The integrated memory subsystem includes 32 KB of Flash and 4 KB of RAM to support the application, LED calibration coefficients, and additional system data. The compact device comes in a 5 mm × 5 mm QFN32 package, operates from a 5.5 V to 28 V supply, and includes diagnostic capabilities such as overcurrent detection, short current protection, and overtemperature.

“With the MLX81119, we have created a solution that directly addresses the constraints facing modern automotive lighting designs,” said Michael Bender, Product Line Director at Melexis. “By integrating the DC/DC converter and dynamically adapting the LED supply voltage, engineers can simplify their designs, improve system efficiency, and scale lighting architectures without adding complexity.”

The MLX81119 is available now. For more information, please visit melexis.com/MLX81119