Fault detection in a LED bias circuit

摘要

A bias circuit for preventing excessive emission from light emitting diodes includes a switch connected to power. A light emitting diode connects to the switch output. Two bias current legs, electrically connected in parallel, interpose the light emitting diode and ground. A fault comparator connects to the bias current legs and a logic OR gate. Four fault comparators can be implemented, each detecting a unique fault condition. The logic OR gate has an output connected to the input of the switch.