| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply for improving efficiency and a power factor so as to overcome the problem that multiple conversions between of AC→DC→AC→DC→AC→DC and the like causes the degradation of efficiency, even if the power factor is improved by adding a power factor for improving a circuit to an AC adapter used for a digital electronic device such as a personal computer in which a high-frequency current generated by a capacitor input rectification interferes with the supply of power. SOLUTION: The power factor is improved by the stoppage of smoothing a capacitor input, and conversion efficiency is prevented from degrading by determining a time during a high full-wave rectified voltage and inhibiting power conversion during a time of a low voltage. Efficiency can be improved from 84% to 89%. The power factor can be improved from 0.55 to 0.91. A capacitor for maintaining a voltage during an outage becomes small, since an applied voltage is is stable and low. COPYRIGHT: (C)2006,JPO&NCIPI
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