Patent ID: 7113380
Filing Date: 2006-09-26
Classification: H02H,H02P,Y02P

Abstract:
1. A power supply device having an AC power supply, a rectifier which rectifies power supplied from the AC power supply, and a capacitor which smoothes power rectified by the rectifier, the power supply device comprising: a switching unit; a diode having a cathode connected to the capacitor and an anode connected to the switching unit; an inductor having a first end connected to the rectifier and a second end; a resistor having a first end connected to the capacitor and a second end; a first relay which selectively connects a node between the switching unit and the diode to one of the second end of the inductor and the second end of the resistor; a controller which controls the first relay to connect the node and the second end of the resistor if a voltage applied across the capacitor exceeds a predetermined PFC voltage limit; and a capacitor voltage detector which detects the voltage applied across the capacitor, wherein the controller turns on/off the switching unit if the detected voltage across the capacitor exceeds a predetermined overvoltage region in a state that the first relay connects the node and the second end of the resistor, and wherein the controller controls the first relay to connect the node between the diode and the switching unit and the second end of the inductor if the voltage applied across the capacitor and detected by the capacitor voltage detector becomes lower than the predetermined PFC voltage limit.