Miniaturised LED drivers for automotive lighting

Melexis has extended its LIN RGB family with the MLX81123. Built on the success of its predecessor, it provides cost-effective performance and reliability in a small package. Using a new supply chain boosts competitiveness and ensures business continuity for its customers.

Ambient LED lighting is now a key design element for automotive manufacturers, improving the end-user's experience and helping OEMs provide striking visual distinction. With well-known OEMs using ambient lighting extensively across their latest models, maintaining a reliable supply chain is essential.

As a successor to the company's popular MLX81113, the new third-generation MLX81123 offers a SOIC8 and a small DFN-8 3mm x 3mm packaging. This miniaturisation allows the use of light in any location of the car, whereas before, there were limitations due to space constraints. Manufactured using cutting-edge SOI technology, the device's miniaturisation provides increased ICs per wafer. This advancement results in one of the smallest RGB LIN IC controllers on the market and a notable increase in production output volume – ready to fulfil the demands of the growing automotive ambient lighting market.

With common software design and pin-to-pin compatibility (SOIC 8) with its predecessor, it delivers effortless integration into existing designs. Replacement of current MLX81113 chips with the new device is often possible without a full development cycle.

The device delivers RGB according to LIN 2. x and SAE J2602. For safety applications, it supports system integration up to ASIL B under ISO 26262.

The advanced 16-bit MCU has 2KB RAM, 32KB of application-usable flash, and a system ROM with a bootloader and LIN driver. A built-in 512 B EEPROM provides for effective configuration, such as LED calibration coefficients, which are required to ensure uniform cabin brightness and colour representation.

The device's LIN system includes a transceiver and protocol handler, enabling a seamless connection between RGB ambient modules and the vehicle's pre-existing LIN network. Featuring four high-voltage I/O with free configurable current sources (up to 60mA), the device can support RGB and white LEDs from a wide range of suppliers, allowing for greater procurement flexibility. The IC's independent 16-bit PWM output provides precise colour and brightness control of any connected LEDs, fulfilling the demands of various vehicle ambient applications such as door trim, accent, and interior cabin lights.

In sleep mode, the device displays a typical standby current consumption of just 25µA and features a 28V jump start and battery monitoring with over and under-voltage detection. The operating temperature is a wide -40C to +125C with a built-in temperature sensor for thermal monitoring, ideal for even the most demanding automotive environments.

"Ambient lighting transitioned from an aesthetic option in high-end vehicles to a fundamental automotive feature, providing a new landscape for customisation and visual differentiation. This creates additional demand for automotive LED controllers," said Michael Bender, product line manager of Embedded Lighting at Melexis. "Our second generation LIN RGB IC controllers have seen incredible success. The third generation MLX81123 takes existing strengths, miniaturises the solution and adds production capabilities. We deliver an unrivalled feature set at a price point that enables a roll-out across vehicle ranges from luxury to entry-level models."