| 摘要 |
PROBLEM TO BE SOLVED: To reduce a control range required for switching frequency control and achieve a constitution adapted to a wide range in a power supply circuit for implementing constant voltage control by the switching frequency control and having a power factor improving function. SOLUTION: A coupling resonance circuit based on the magnetic coupling of an insulative converter transformer PIT is formed by providing a primary series resonance circuit for forming a current-resonance converter, and a secondary series resonance circuit formed of at least a secondary winding N2 and a secondary series resonance capacitor C2. The total coupling coefficient of the insulative converter transformer PIT is set so as to acquire the single peak characteristic of the coupling resonance circuit. A circuit configuration is formed so as to insert an inductor into at least one of a primary winding N1 and the secondary winding N2 in series. A power regeneration or voltage feedback power factor improving circuit is provided and improves a power factor. A heavy load is dealt with by generating a secondary DC output voltage Eo from outputs of a plurality of the secondary windings. COPYRIGHT: (C)2006,JPO&NCIPI
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