| 摘要 |
PROBLEM TO BE SOLVED: To provide a power conversion circuit that can prevent an on-pulse width from excessively being expanded with respect to an input voltage which is abruptly changed when the input voltage of a power conversion circuit is abruptly changed, and thereby can prevent the saturation of a transformer and an excessive rise of an output voltage. SOLUTION: The power conversion circuit includes a capacitor which charges an electric charge corresponding to a voltage at the secondary side of the transformer, a second switch element which short-circuits the capacitor, a comparator which detects that both-end voltages of the capacitor have become higher than a prescribed reference voltage, a pulse-width control means which limits the pulse width of an on-pulse by turning off a first switch element when both-end voltages of the capacitor become higher than the prescribed reference voltage, and a control circuit which turns on the second switch element while the first switch element is turned off by turning off the first switch element when the comparator detects that both-end voltages of the capacitor have become higher than the prescribed reference voltage. COPYRIGHT: (C)2011,JPO&INPIT
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