Driver chip reduces LED taillight complexity

February 17, 2015 //By Christoph Hammerschmidt
More functions, higher integration and lower complexity in medium-power LED exterior lighting are the benefits designers can expect from Infineon's new Litix Basic LED driver product family. Automotive OEMs can implement brand-specific features and improve the safety through innovative lighting functions in direction indicators, taillights and stop lights.

The Litix Basic family provides precise current control across a wide voltage range. It consists of 15 pin-compatible linear current sources with 1 to 3 output channels and current ratings from 60 to 180mA. The Litix Basic family includes versions supporting advanced diagnostic functions directly at the LED’s point of load.

Today, the majority of LED rear light designs still use discrete resistor solutions for the control of the LEDs. Apart from higher system cost, this increases the complexity and thus lowers reliability of LED rear light configurations due to the high discrete components count. PCB part counts can be reduced by about 40 percent, with corresponding reduction in risk of failures and savings in both the design and assembly phase, where the automotive industry occasionally has to struggle with poor solder joints.

With the automotive qualified Litix Basic family, Infineon claims to be the first semiconductor supplier to offer such a scalable portfolio of 15 LED drivers that use the same package footprint. This makes it easier to adapt a design for reuse in new LED configurations when requirements change, such as output current or the need for failure detection. With parallel connection of several Litix Basic LED drivers, load currents higher than the 180mA of individual devices can be easily realized. The Litix Basic family features overload and over-temperature protection in all devices including output current reduction, and also a wide supply voltage range of 5.5V to 40V.

For devices with integrated diagnostics, SC (short circuit), OL (open load) or N-1 (diagnostic bus between devices) functionality can be chosen for LED chain failure detection. The Litix Basic drivers are suitable for both, centralized diagnosis – meaning that the failure diagnosis is controlled by the centralized Body Control Module – and also for decentralized diagnosis to enable real-time fault detection. In a decentralized architecture the Litix Basic LED drivers communicate with a microcontroller which can be located within the