Circuit to shunt excess photocurrent in optical receivers

摘要

A clamping circuit for shunting excess photocurrent in an optical receiver is disclosed. In one preferred embodiment, matching transistors are coupled in parallel across the input to an amplifier in the optical receiver. The output of the amplifier is coupled so as to turn the transistors on when the photocurrent reaches a predetermined level, and therefore divert the flow of current away from the input to the amplifier. In another preferred embodiment, a schottky diode circuit is coupled across the input to the amplifier. The schottky is biased so as to conduct, and thereby divert current away from the input of the amplifier, when the photodetector current reaches a predetermined threshold.