| 摘要 |
PURPOSE:To prevent a control input signal circuit from malfunctioning effectively by providing this control input signal circuit with a voltage converter circuit which boosts a control input signal voltage up to a constant voltage and a malfunction preventive circuit which forms the gate-cathode short circuit when a thyristor is OFF. CONSTITUTION:Control input signal voltage V1 inputted between input terminals 1 and 2 is boosted by voltage converter circuit 5 up to constant voltage V2. This voltage V2 turns thyristor 8 ON to ignite gate turn-off thyristor CTO14, and consequently CTO14 is ON while thyristor 8 stays ON. When input control signal voltage V1 disappears, thyristor 8 is ignited to place CTO14 in an OFF state and thyristor 8 remains OFF until a following ON signal is applied between input terminals 1 and 2. Therefore, switching operation is possible by the control input signal voltage and malfunction due to a DC circuit can be prevented effectively. |
