Patent ID: 8456872
Filing Date: 2013-06-04
Classification: H02M

Abstract:
1. A switching power supply, comprising: a switching unit; a driving signal generator for providing a driving signal, the driving signal comprising a plurality of acting voltage parts, the plurality of acting voltage parts being used to turn on the switching unit, each of the acting voltage parts being one of a high level voltage and a low level voltage; and a control circuit coupled between the driving signal generator and the switching unit; wherein the control circuit turns off the switching unit when a duration of one of the plurality of acting voltage parts is longer than a preset time period, the switching unit comprises a metal oxide semiconductor field effect transistor (MOSFET), the switching power supply further comprises a primary power supply connected to the drain of the MOSFET, the control circuit further comprises a first resistor and a second resistor, the capacitor is connected between the driving signal generator and the gate of the MOSFET, a terminal of the first resistor is connected to the gate of the MOSFET, the other terminal of the first resistor is connected to a terminal of the second resistor and the source of the MOSFET, the other terminal of the second resistor is grounded.