| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply device enabled in zero-volt switching, and attained in the reduction of the cost of the device as a whole and the reduction of a size. SOLUTION: The switching power supply device is characterized by comprising: a DC power supply Vin; an output transformer T having primary windings Np1, Np2, secondary windings Ns1, Ns2 and a tertiary winding Nr; a series circuit composed of the second primary winding and a first switch element Q1; a series circuit composed of the first primary winding connected between terminals of the switch element and a first capacitor C1; a series circuit composed of a second switch element Q2 connected between terminals of the first primary winding and a second capacitor C2; a series circuit composed of a first rectifying element D1 and the first secondary winding; a series circuit arranged in parallel with the former series circuit and composed of a second rectifying element D2 and the second secondary winding; a series circuit composed of the tertiary winding connected to one end of the second secondary winding that constitutes the former series circuit; and a smoothing capacitor Co. COPYRIGHT: (C)2007,JPO&INPIT
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