Recent development of the static induction (SI) thyristors

The authors describe two kinds of new SI thyristors. Firstly they introduce a new idea for an anode-emitter-shorted structure for the SI thyristor. The performance of the new anode-emitter-shorted 1200 V-10 A class buried-gate SI thyristor is described compared with the performance of the conventional IGBTs. Secondly, they describe the performance of very low-loss, high-efficiency, planar-gate normally-off type SI thyristors. The performance of the low-power class of the SI thyristors have been improved up to the extent that the switching frequencies can be increased up to a few 100 kHz accompanying with the ultra-low loss capabilities. In fact, the power conversion efficiency of 99% was realized at 100 kHz and even 93% at 1 MHz of the switching frequencies. The 1200 V-5 A class SI thyristors developed have been tested for the application to the quasi-resonant DC-DC converters. The power-loss of the SI thyristor was evaluated as functions of the switching frequency, and the operating temperature. The performance of the ultra-low loss SI thyristors as compared with the power MOSFETs in view of the operating frequencies and the power-loss capabilities, is discussed