| 摘要 |
PROBLEM TO BE SOLVED: To provide an overvoltage protection circuit capable of preventing an overvoltage from being applied to a smoothing capacitor and a load in a power circuit having a means for conducting switching between voltage doubler rectification and full-wave rectification corresponding to the voltage of a commercial AC power supply. SOLUTION: This overvoltage detection/protection circuit 5 includes a MOSFET9 and a MOSFET13 connected in series with a first smoothing capacitor 8 and a second smoothing capacitor 12, respectively, to detect voltages applied to the first smoothing capacitor 8 and the second smoothing capacitor 12 or the load 17. When a voltage of at least a prescribed value is applied, the MOSFET9 and MOSFET13 are turned off so that the first smoothing capacitor 8 and the second smoothing capacitor 12 are separated from the circuit. COPYRIGHT: (C)2004,JPO&NCIPI
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