Patent ID: 6686725
Filing Date: 2004-02-03
Classification: G05F,H02M,Y02B

Abstract:
A power supply circuit compensating a power factor, comprising:a voltage filter receiving for an alternating current power which is varying in a certain range, and eliminating and outputting noise contained in the voltage; a rectifier rectifying for the alternating current power outputted from the voltage filter into a direct current power; a voltage sensor and variable resistor for receiving an output signal of the rectifier, recognizing a magnitude of the present input AC voltage and outputting one of different control signals according to a predetermined reference value; a PFC coil of which an end is connected to an output end of the rectifier; a PFC switch having an end grounded and the other end connected to an output end of the PFC coil, which is turned on or off according to an inputted control signal to allow an output voltage of the PFC coil to be transmitted to a device provided at a rear side only during the turned off state; a voltage divider for dividing the voltage if the PFC switch allows the voltage to pass, wherein the rate of the division is dualized according to the control signal of the voltage sensor and variable resistor; a PFC controller for receiving the voltage divided by the voltage divider to compare the voltage with a reference voltage and to control the control signal to be applied to the PFC switch according to a result of the comparison.