A power light activated silicon switch

For high voltage power applications where large numbers of silicon pnpn devices are to be operated in series there are two very important advantages to be gained over conventional, electrically gated thyristors using a two-terminal pnpn power switch that utilizes direct optical gating. Such a device is reported here rated at 600V and 40A designed for triggering by GaAs emission in the range 8400 to 9000Å This device provides inherently the electrical isolation of the gate needed for series operation. The relatively large area turned on by the light provides turn-on in hundreds of nanoseconds and di/dt ratings an order of magnitude higher than those of conventional thyristors. Fabrication and encapsulation techniques and test results are reported. Studies of high speed, synchronous triggering of a number of switches using single GaAs sources and fiber optic couplings are discussed.