| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply having a smoothing capacitor on the primary side where an AC input current is soft-switched to have a sine wave. SOLUTION: Primary windings N2 and N1 of a first transformer T1, a primary winding N21 of a second transformer T2, and a switching element M1 are connected in series between positive and negative electrodes of a rectification circuit DB of an AC power supply. A resonance capacitor C1 is connected between the negative electrode of the rectification circuit DB and the joint of the pimary winding N1 of the first transformer T1 and the primary winding N21 of the second transformer T2, and a smoothing capacitor C2 on the primary side is connected between the negative electrode of the rectification circuit DB and the joint of the primary windings N2 and N1 of the first transformer T1. COPYRIGHT: (C)2006,JPO&NCIPI
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