Effectively Driving LED Arrays with Passive Electric Circuits for Dual Function Automotive Applications

Many LEDs are typically required to source sufficient light for automotive exterior applications. Maintaining even illumination requires the drive current to be well controlled for all the LEDs in an array. This can be challenging in the voltage driven automotive environment when dual level operation is desired, such as for combined stop and tail function. A current source in the form of an LED Driver Module (LDM) can be employed to drive the LED array. However, a passive resistor network may be capable of driving the LED array with a reduction in both cost and complexity when compared to an LDM solution. The advantages and disadvantages of various passive resistor network configurations for dual level operation will be examined.