Wolfspeed, Inc.
HIGH RELIABILITY AC LOAD SWITCHING CIRCUIT

Abstract:

A high reliability AC load switching circuit is disclosed. In some embodiments, the AC load switching circuit includes a high-speed switch connected between the load and the voltage source, a cutoff switch connected between the load and the voltage source in parallel with the high-speed switch, and a level detector connected to the voltage source and to a control input of the high-speed switch. The high-speed switch may be a solid-state switch, for example, a TRIAC or a bidirectional switch, and the cutoff switch may be an electromechanical switch, for example, a relay. In some embodiments a snubber is connected in parallel with a solid-state switch. In some embodiments a microcontroller is connected to an electromechanical switch and the level detector. In some embodiments, both a first cutoff switch and a second cutoff switch are used.