Patent ID: 7042743

Claim:
A switching power supply comprising a power factor correction device and a DC—DC converter coupled to an output of the power factor correction device, wherein the power factor correction device includes: a boost converter including a power transistor and an output terminal; and a control device coupled to the boost converter so as to obtain, from an alternating voltage, a direct regulated voltage at the output terminal of the boost converter, wherein the control device includes: an error amplifier receiving at an inverting terminal a first signal that is proportional to the regulated voltage, and receiving at a non-inverting terminal a reference voltage; at least one capacitor having a first terminal coupled to the inverting terminal of the error amplifier, and a second terminal coupled to an output terminal of the error amplifier; a driving circuit for driving the power transistor of the boost converter, the driving circuit being coupled to the second terminal of the capacitor; an interruption circuit coupled between the output terminal of the error amplifier and the second terminal of the capacitor; and a control circuit for activating the interruption circuit so as to interrupt the connection between the error amplifier and the driving circuit for at least one time period, which is shorter than a time period in which the control device is operative.