An asymmetric thyristor with self-generated gate-assisted turn-off

Self-generated gate-assisted turn-off relies on the negative charging of a gate condenser by the reverse current of a thyristor. This principle has been extended to asymmetric thyristors operated with an antiparallel diode. In order to have sufficient reverse current, the thyristors were fitted with anode shorts. Turn-off times less than 5 mu s were obtained for a 1000 V-design. The tradeoff between forward voltage drop and turn-off time of asymmetric thyristors is clearly better than for symmetric thyristors and makes them well suited for 20 kHz operation. The anode shorts cause a reduction in the blocking current, a fact that could be used to increase the operating temperature, although this would also mean an increase in turn-off time.<>