| 摘要 |
PROBLEM TO BE SOLVED: To provide a current resonance switching power circuit capable of preventing an output DC voltage from remaining in an overvoltage state when the switching power circuit is protected from an overvoltage of the output DC voltage. SOLUTION: In this current resonance switching power supply, a pair of switching elements 2a, 2b connected to the DC voltage with a half bridge are alternately turned on and off by a driving circuit 3, and alternating voltage acts on a primary winding 7a of a converter transformer 7 from a junction of the pair of switching elements 2a, 2b through a resonance capacitor 8, and a first and a second synchronous rectifying elements 11a, 11b are respectively connected with the converter transformer 7. An overvoltage detection means 10 for detecting an overvoltage acting on the primary winding 7a and an overvoltage detection means 22 for detecting an overvoltage of the output DC voltage are provided, and when the overvoltage detection means 22 detects the overvoltage, the first and the second synchronous rectifying elements 11a, 11b are in ON-state to make the overcurrent flow through the primary winding 7a. COPYRIGHT: (C)2005,JPO&NCIPI
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