| 摘要 |
PURPOSE:To simplify an insulation between a main circuit and a control circuit by a method wherein an LC resonance circuit is connected to a gate and an auxiliary optical thyristor AOTh is connected to the gate. CONSTITUTION:When AOTh1 is turned ON with a pulse signal on AOTh1, an anode voltage on a thyristor GTO is applied through the AOTh1 to charge a capacitance C and when it exceeds a control voltage on Zenor diode ZD, a gate current is applied to GTO to turn ON the GTO. In this case, the potential on the gate and chthode is retained at the same level substantially and the AOTh1 extinguishes by itself. Subsequently, the AOTh2 is turned ON with a pulse from LED2, the charge of the C is applied through the AOTh1 to a reactor L and the counter resonance current becomes an extinction current of GTO to perform an extinction for the GTO. According to such a constitution, the AOTh has a reduced current capacitance, further since the C and L don't perform a direct communication for main circuit current, the ATOh also can be operated at a considerably small capacitance, at a high speed and the insulation between the main circuit and control circuit can be achieved very easily. |
