Patent ID: 6625044
Filing Date: 2003-09-23
Classification: H02M

Abstract:
A programmed isolating starting system of a switching power supply, which comprises:a filter connected to an input power, which is used to output a DC voltage from the input power; an isolating starting circuit connected to the filter, which has an input end to receive said DC voltage and provides a starting voltage, a program controlling the starting of the isolating starting circuit; a pulse width modulator connected to an output end of the programmed isolating starting circuit, which is used to receive the starting voltage and output a pulse voltage, the program stopping the starting of the isolating starting circuit when the pulse width modulator reaches normal operation; a driving transformer having a secondary end connected to the pulse width modulator, which is used to transfer the pulse voltage into a driving voltage, and output a driving voltage to a primary end of said driving transformer; a power transformer connected to an output end of the filter, which is used to transfer said DC voltage to a working voltage; a first switch connected to the primary end of the driving transformer and a primary end of the power transformer, which is used as a switch of the primary end of the power transformer; a first rectifying filter connected to a secondary end of the power transformer, which is used to rectify and transfer the working voltage into an output voltage; and a feedback compensating circuit having an input end connected to the output end of the DC output voltage and an output end connected to an input end of the pulse width modulator, which is used to stabilize the output voltage.