| 摘要 |
PURPOSE:To prevent inrush of an on-signal in a turn-off period, and to elevate reliability of a circuit, by connecting a thyristor having a turn-on period synchronizing with a gate turn-off signal, between the gate of a gate turn-off thyristor and the gate turn-on and off circuit. CONSTITUTION:A gate circuit is constituted of a gate turn-on circuit 2A, a gate turn-off circuit 2B and a gate turn-off thyristor 1, and a parallel circuit consisting of a thyristor 8 and a diode 9 is connected between a parallel connecting point of the on-circuit 2A and the off-circuit 2B, and the thyristor 1. Also, the gate of the thyristor 8 is connected to the base of a transistor 5A of the on-circuit 2A through a transformer 10 and 11. Subsequently, a gate signal synchronizing with a turn-on signal of the thyristor 1 is supplied to the thyristor 8 through the transistors 10, 11, is made to conduct only in the on-period of the thyristor 1, and in case of off, it is turned off by applying reverse voltage due to a forward voltage drop of the diode 9, and a current of the on-signal of the thyristor 1 is obstructed. |
