Patent ID: 7289340
Filing Date: 2007-10-30
Classification: H02M,Y10S

Abstract:
1. A switching power supply device comprising: a switching power supply circuit having a main switching element, wherein said switching power supply circuit is connected to a pulse oscillation circuit for outputting a pulse signal to said switching power supply circuit; a pulse detection circuit for detecting the pulse signal output from said pulse oscillation circuit to said main switching element; a DC signal level conversion circuit for converting the pulse signal detected by said pulse detection circuit into a DC signal level; a second switching element that is switched by the DC signal level so as to control timing of switching of said main switching element upon detection of the pulse signal supplied from said pulse oscillation circuit; a series capacitor that is connected between an AC power source and said main switching element, wherein the second switching element is in parallel connected to the series capacitor so as to be short-circuited according to the DC signal level, and the second switching element comprises a photo-coupler.