| 摘要 |
PURPOSE:To prevent a rush current due to a power thermistor without loss of the efficiency of a switching regulator by charging a smoothing condenser of the primary side of an inverter transformer and then shortcircuiting the thermistor. CONSTITUTION:A triac TRA is connected in parallel with a thermistor TH for preventing a rush current. The gate of the triac TRA is connected to the other winding of a transformer T1 for an inverter. Immediately after the main switch S1 is closed, the triac TRA is turned OFF. When the smoothing condenser C1 of the transformer T1 is charged to some degree, the primary winding of the transformer T1 is turned ON or OFF by a switching transistor Q1, a voltage is presented in the other winding. Accordingly, the triac TRA becomes conductive. |
