Light triggered thyristor with a MOS amplifying gate: an example of a galvanically insulated high voltage integrated switch

Results for a light-triggered thyristor with an MOS amplifying gate are used to illustrate the concept of functional integration in the framework of high-voltage integrated switches. These devices integrate a thyristor with an MOS amplifying gate, a photodiode, a depletion-mode MOSFET, and a Zener diode. Light-triggered thyristors with an MOS amplifying gate offer interesting electrical characteristics: high blocking voltage, excellent dV/dt immunity, and low on-stage voltage. The high input impedance of the MOS gate allows the power device to be triggered with a very low photocurrent induced by light-emitting-diode illumination. This optical trigger makes it possible to simplify the control circuits and to use these devices for applications in industrial supply networks requiring high galvanic insulation