| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply that improves the use efficiency of a transformer and is adapted to reduction in size, particularly in thickness. SOLUTION: The switching power supply device comprises a rectifying circuit that rectifies an AC voltage; a smoothing capacitor that smoothes an output of the rectifying circuit; and a plurality of transformers to each of which a voltage of the smoothing capacitor is applied by turning on and off the switching circuit, and each of which induces a voltage as an output to a secondary winding. In the switching power supply, each of the transformers comprises a first primary winding that is connected in parallel to each transformer, and a second primary winding that is connected in series to each transformer. The first primary winding, the second primary winding, the switching circuit and the smoothing capacitor are connected in series, and a connecting point of the first primary winding and the second primary winding is connected to the AC voltage via a diode and a first magnetic element. COPYRIGHT: (C)2005,JPO&NCIPI
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