| 摘要 |
PROBLEM TO BE SOLVED: To realize the dimensional reduction, cost reduction, the conversion gain improvement and noise suppression of an apparatus while a high input power factor is maintained. SOLUTION: This switching power supply apparatus has 1st and 2nd transformers 3 and 2 having respective primary windings and secondary windings, two rectifier circuits rectifying an AC input voltage VAC to generate ripple voltages VR, a smoothing circuit 13 smoothing the ripple voltage generated by one rectifier circuit (11 and 12) to generate a DC voltage VDC, and a switching device 4. A series circuit comprising the primary winding 3a of the 1st transformer 3 and the switching device 4 is connected between the positive polarity output terminal and negative polarity output terminal of the other rectifier circuit 21, and the primary winding 2a of the 2nd transformer 2 is connected between the smoothing circuit 13 and the positive polarity output terminal of the other rectifier circuit 21. By turning on/off the switching device 4, voltages induced in the respective secondary windings 2a and 3a of both the transformers 2 and 3 are rectified and synthesized to generate an output voltage V0.
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