Photo switching device having a control circuit with a gate controlled device

摘要

A photo switching device includes first and second terminals respectively coupled to a power source and a load. A bi-directional current routing circuit including a rectifying bridge is connected to the first and second terminals to receive electricity from the first and second terminals and has positive and negative output terminals. A switching/driving circuit is connected between the positive and negative output terminals for selectively conducting an output current of the bi-directional current routing circuit from the positive output terminal to the negative output terminal. The switching/driving circuit includes a silicon controlled switching device having a gate coupled to and controlled by a controlling circuit to switch between open condition and closed condition. The controlling circuit includes a photo detecting device connected to a gate of a gate controlled device. The gate controlled device has an output coupled to and controlling the gate of the silicon controlled switching device.