| 摘要 |
PURPOSE:To suppress the overcurrent of the power source when closing the power source by controlling the switching circuit when a current higher than a predetermined value is detected in a current detecting circuit. CONSTITUTION:By detecting an input current with the input current detecting circuit 4 CT1 the gate signal of the gate turn-off thyristor GTO1 of a switching circuit 2 is controlled by the control circuit when a current higher than a predetermined value flows, thereby shutting off the thyristor. In next cycle, similar operation is conducted and repeated, and the power source is so closed that a current higher than predetermined value may not flow. If a transistor Q1 is shorted dur to erroneous operation or if a capacitor C1 is shorted, when a large current flows at the input, the input current is detected for short time, thereby interrupting the switching circuit so as to protect the rectifying circuit. |
