| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply circuit in which increase of ripple is suppressed while including an arrangement for improving power factor. SOLUTION: In a complex resonance converter combining a half bridge coupling system current resonance converter and a partial resonance voltage circuit, power factor is improved by a power factor improving circuit 10 of such an arrangement (power regeneration system) as a primary DC resonance current being obtained in a primary DC resonance circuit is regenerated as power and fed back to a smoothing capacitor Ci. Under such an arrangement, flux density of an insulating converter transformer PIT is set at a predetermined level or below so that the rectification operation current of a secondary both wave rectification circuit has continuous mode regardless of load variation thus suppressing increase in ripple on the secondary DC output voltage resulting from power regeneration. Furthermore, lowering and variation of power factor are suppressed by providing a switching diode D2 in place of a high frequency inductor provided in the power factor improving circuit. Power factor is improved furthermore by providing a power factor improving capacitor C30 in addition to a power factor improving capacitor C20. COPYRIGHT: (C)2006,JPO&NCIPI
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