| 摘要 |
PURPOSE:To reduce the power of a gate circuit for a gate turn-off thyristor GTO, so that an off-circuit and an on-circuit can be controlled with the same control element at a bundle. CONSTITUTION:When an on-signal is inputted to a photocoupler PC1, a transistor (TR) Q1 turns on and a TRQ2 turns off. Thus, a TRQ3 turns on and an on-gate current flows to a GTO in the path of R10 Q3 GTO gate cathode ground. When the GTO turns on, the TRQ3 turns off and the on-gate current is narrowed. When the input signal to the photocoupler is absent, the TRQ2 turns on and the TRQ3 turns off. When the TRQ3 turns off, a TRQ4 turns on and a gate current flows to a thyristor TH1 to turn on the Th1, and an off-gate current is supplied to the GTO in the path of ground cathode of GTO gate of GTO L1 Th1 to turn off the GTO. |
