Patent ID: 7576735

Claim:
A power circuit, comprising: a first switch connected to a first end of a capacitor; a first voltage adjuster for selectively outputting through the first switch to the first end of the capacitor an AC voltage and a first DC voltage which is equal to a predetermined value within a range of peak-to-peak voltage of the AC voltage and smaller than the peak voltage; and a second voltage adjuster for outputting a second DC voltage to a second end of the capacitor; and a power output terminal connected to the other end of the capacitor to obtain an output from the capacitor; wherein the second end of the capacitor is connected to a power output terminal for outputting power from the power circuit; during a period from turning-on of power until a predetermined duration has passed, the power circuit switches the first switch to supply the first DC voltage output from the first voltage adjuster for application to the first end of the capacitor, and the power circuit supplies the second DC voltage output from the second voltage adjuster for application to the second end of the capacitor; and after the predetermined duration has passed, the power circuit switches the first switch to change the voltage output from the first voltage adjuster to the AC voltage to supply the AC voltage for application to the first end of the capacitor, and the power circuit supplies the second DC voltage for application to the second end of the capacitor.