| 摘要 |
PROBLEM TO BE SOLVED: To make a field-effect transistor treatable as a two-terminal element with respect to a rectifier circuit and a synchronous rectifier circuit and, at the same time, to improve the efficiency of the synchronous rectifier circuit. SOLUTION: A rectifier circuit is constituted in such a way that a field-effect transistor Q0 is connected in series with the primary winding n1 of a current transformer CT, and that an input voltage Vp is impressed upon them. Then the secondary winding n2 of the transformer CT is connected to the gate of the transistor Q0 and a transistor Tr1 which short-circuits the gate and source of the transistor Q0 to each other is provided. Therefore, the transistor Q0 can be turned off quickly by short-circuiting the gate and source of the transistor Q0 to each other, by turning on the transistor Q0 with the voltage induced in the secondary winding n2 of the transformer CT when the input voltage Vp is impressed, or turning on the transistor Tr1 with the voltage induced in the winding n2 of the transformer Ct when the input voltage Vp is turned off. This rectifier circuit is used on the flywheel side of a synchronous rectifier circuit.
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