| 摘要 |
PURPOSE:To improve the performance of function of a self-extinguishing type thyristor with a simple circuit configuration by connecting the gate of an SCR through a switch to the feedback side of a load, and commutating part of cathode current of the SCR to the gate current by closing the switch at the extinguishing time. CONSTITUTION:When a turn-OFF switch 9 is closed in the state that a turn-ON switch 8 is opened, the gate voltage of a self-extinguishing type SCR 1 is lowered in the voltage applied to a load 3 as compared with the cathode voltage. Then, a load current IL is operated as a gate reverse current IGO flowed through a circuit (a), thereby extinguishing the SCR 1. Simultaneously, charging current IC is flowed via a closing circuit of a main power source 2, the SCR 1, a capacitor 12' and an OFF switch 9 in the condenser 12', and which can be abruptly charged. When the SCR 1 is turned OFF, the load current IL charges the snubber condenser. Accordingly, the cathode voltage of the SCR 1 gradually decreases to become zero. |
