Patent ID: 7239120
Filing Date: 2007-07-03
Classification: H02M,Y02B

Abstract:
1. A device for power factor correction in a forced switching power supply unit, the device comprising: a converter; and a control device coupled to the converter so as to obtain from an input alternating mains voltage a direct regulated voltage on an output terminal, wherein the converter comprises a power transistor, the control device comprises an error amplifier having its inverting terminal coupled to a first signal that is proportional to the regulated voltage, and its non-inverting terminal coupled to a reference voltage, a drive circuit for the power transistor is coupled to an output terminal of the error amplifier, the control device further comprises a signal generating circuit for generating a current signal that is representative of the effective input voltage, the current signal being coupled to the inverting terminal of the error amplifier to vary the regulated voltage in reply to variations in the effective input voltage, the signal generating circuit comprises: the converter further comprises a second circuit for rectifying the input voltage, and the first circuit comprises at least one diode and at least one capacitor, the diode having its anode coupled to the second circuit and its cathode coupled to the capacitor.