| 摘要 |
PROBLEM TO BE SOLVED: To prevent overvoltage from being applied to a switching element and to attain high power conversion efficiency. SOLUTION: An excitation current, passed through the primary winding 15p of a transformer 15, is subjected to switching control using a switching element 20 for obtaining a desired output voltage on the secondary winding 15s side of the transformer. If an excitation current induced voltage produced at the transformer is superposed on an input direct-current voltage Vin and applied, it is detected, using a comparator 52 as to whether the voltage between the terminals of the switching element 20 exceeds a specified voltage. A switching element 42, comprising a snubber circuit, is brought into conduction to perform clamp operation on the voltage between terminals, only during the period when the voltage between terminals is detected as exceeding the specified voltage.
|
