| 摘要 |
PURPOSE:To control load voltage constant, by applying voltage from an auxiliary winding of a transformer through a capacitor between gate and source of a FET and regulating current for charging/discharging a capacitor. CONSTITUTION:A D.C power source 1 is connected through a FET15 to the main winding of a transformer 16. Voltage across secondary winding of the transformer 16 is rectified 17 and smoothed 18 so as to feed DC voltage to a load 25. An auxiliary winding is connected through a capacitor 14 to the gate terminal(G) of the FET15, Power source for feeding charging current to the gate terminal is constituted with a diode 4, resistors 2-3 and a chemical capacitor 5, and connected through a diode 11 to a transistor 12 in order to discharge the gate voltage. Consequently, when the gate voltage of the FET15 reaches to threshold voltage and turns ON or OFF, the gate voltage is positive fed back and passed in short time.
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