SWITCHING REGULATOR

PURPOSE:To prevent a noise from generating and to reduce the cost by winding a control winding for detecting the variation in the output from an inverter in a transformer of a switching regulator. CONSTITUTION:A switching regulator sequentially couples a chopper circuit 33 and a self-excited inverter 34 with a DC power source 1, and supplies a DC voltage through the secondary winding of an inverter transformer 2 to a load 10. The winding 35 of the transformer 2 is coupled through a waveform shaper 36 with one input side of a pulse width converter 37, and a reference voltage circuit 38 is coupled with the other input side. This pulse width converter 37 controls the chopper 33 through a drive circuit 39. Thus, the chopper 33 is turned ON, the transistors of the inverter 34 are alternately turned ON and OFF. The detection waveforms of the ON and FF are compared with a reference waveform to control the opening and closing time of the chopper 33 through a pulse width conversion drive circuit 39.