Patent ID: 7064527

Claim:
A transition mode operating device for the correction of the power factor in switching power supply units, comprising: a converter for receiving an input voltage and providing a regulated output voltage, including a power transistor, an inductor arranged between the rectifier circuit and a non-drivable terminal of said power transistor and an auxiliary winding of said inductor; and a control device coupled to said converter including first means for receiving a first signal proportional to said regulated output voltage and a reference signal for generating error signal, a multiplier for receiving said error signalk a driving circuit for receiving a second signal from said multiplier to determine the on time period and the off time period of said power transistor, and second means coupled to said auxiliary winding of the inductor for generating a third signal proportional to the input voltage during the on time of said power transistor and a fourth signal representative of the current flowing through said power transistor, said third signal being received by said multiplier for generating the second signal and said fourth signal being received by said driving circuit.