LED drivers promise reliable control of automotive exterior LED lighting

February 17, 2015 // By Graham Prophet
Infineon Technologies’ LITIX Basic family of LED drivers is designed for low-power to medium-power automotive exterior lighting applications. The high-integration LED driver family reduces system complexity and improves reliability of turn indicator, tail, stop and reverse LED lights.

By reducing part count and offering more features than discrete design approaches, the LITIX Basic family allows automotive manufacturers to expand the use of brand-specific and safety-enhancing LED light systems. The LITIX Basic family provides precise current control across a wide voltage range. It consists of 15 pin-compatible linear current sources with one to three output channels and current ratings from 60 to 180 mA. In addition to stable and reliable LED brightness, the LITIX Basic family includes versions supporting advanced diagnostic functions directly at the LED’s point of load. This allows car manufacturers to achieve highest light quality.

Today, says Infineon, 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%, 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 offers a scalable portfolio of 15 LED drivers that use the same package footprint. This makes it easy 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 180 mA of individual devices can be realised. 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, centralised diagnosis – meaning that the