| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit for reducing a switching loss in a rectifying FET, and stably and surely operating the rectifying FET regardless of a load voltage. SOLUTION: The power supply circuit is provided with a switching semiconductor element, its control circuit, first and second rectifying elements connected to a secondary winding in a transformer, and a drive circuit. The first rectifying element comprises a field effect transistor for operating as the rectifying FET. The drive circuit drives the rectifying FET, and comprises a third winding in the transformer, a rectifying circuit connected to the third winding, and an inductor and an impedance element connected to an output terminal of the rectifying circuit. The power supply circuit quickly discharges a charge in a gate capacitance of the rectifying FET by discharging energy accumulated in the inductor through the rectifying circuit. COPYRIGHT: (C)2007,JPO&INPIT
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