| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply capable of reducing the standby power of an electronic apparatus. SOLUTION: The switching power supply is characterized in that a capacitor C1 is inserted to an AC power supply in series; an AC switching element SW is connected in parallel with the capacitor C1; an AC input voltage of the switching power supply is reduced with less loss by the capacitor C1, and fed to an AC input terminal of a rectifying bridge B1 of the switching power supply; and, when a large input is required, the AC input voltage is fed to the AC input terminal of the rectifying bridge B1 of the switching power supply without causing reduction in the AC input voltage by controlling the AC switching element SW into a short-circuit state. Two capacitors C4 and C5 are connected to one pole of an AC input of the rectifying bridge B1 and to the other pole thereof, respectively, and other ends of the two capacitors C4 and C5 are connected to AC input terminals of a different rectifying bridge B2. COPYRIGHT: (C)2004,JPO
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