LED in automotive rear combination lighting (RCL) is becoming widely used in high end to mid class segment car. This is mainly fuelled by the strong influence of styling and requirement of a compact design. With OEMs competing to provide higher value to the customers such as longer warranty and advanced diagnostic features, the topic of semiconductor integration is becoming significant. Integration is a key to enable small form factor, high robustness and implementation of advanced technical functionality in the LED driver. However, the cost of implementing an integrated driver, if not partitioned effectively, will be much higher than the discrete solution. Therefore, it is important to implement the cost optimization strategy right from the conceptualization of the LED driver integrated device.
In the beginning of this paper, the LED driving concept that is commonly used in the RCL lighting such as linear current sources and switching supply is discussed. The cost-performance trade-offs of different LED driving concepts are evaluated and described in the cost-performance matrix. The paper will further discuss on the various levels of driver integration, investigate a cost-effective partitioning and promote driver modularity design to address a wide range of LED topologies in RCL. Lastly, a PCB thermal simulation has been done to optimize the thermal budget. The approach shows significant advantages in the optimization of PCB board cost, reduction in design iterations and shortened time-to-market.
The LED driver mentioned in this paper refers to the Infineon LITIX™ Basic/Power LED driver to implement the concept of Tail/Stop light in the rear combination light module.