| 摘要 |
<P>PROBLEM TO BE SOLVED: To enhance power conversion efficiency as a power supply circuit having a power factor improving function while decreasing the number of circuit components by putting a voltage resonance converter with a secondary series resonance circuit to practical use. <P>SOLUTION: Coupling factor k of a power isolation transformer PIT is set at 0.7 or thereabout, and abnormal operation where a current flows through a switching element at a timing before ending the off interval thereof is eliminated during middle load. A power factor improving circuit for regenerating switching output current obtained in the primary winding N1 of the power isolation transformer PIT as power and feeding it back to a rectified current path into which a switching diode D1 is inserted, and a clamp circuit for reducing withstand voltage of the switching element are also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT |
