US Patent 7375991 Power control device

Provided is a power control device comprising; a power input portion to which an alternating current is supplied; a plurality of diodes for rectifying a power supplied from the power input portion; a first capacitor unit and a second capacitor unit for charging/discharging a power rectified in the diode to provide a smoothed voltage output; and a switching means to change a voltage supplied in the first capacitor and the second capacitor during the main/sub periods in compliance with a voltage level of a power applied in the power input portion.