Patent ID: 6862193

Claim:
A power supply apparatus comprising: a transformer having a primary winding, a secondary winding, and a feedback winding; a first switching device for controlling conduction and interruption of a current flowing in said primary winding; a rectifier and smoothing device for rectifying and smoothing a voltage generated in said secondary winding; an error detection device for comparing an output voltage of said rectifier and smoothing device with a reference voltage and for outputting a voltage corresponding to a difference between the output voltage and the reference voltage; a transfer device having a primary side part and a secondary side part and configured to transfer an output from said error detection device from said secondary side part to said primary side part; and a controller for generating an intermittent pulse signal for forcibly reducing a signal level supplied to said transfer device for the period of the pulse being sufficient for stopping oscillation of the power supply apparatus irrespective of a result of the comparison of said error detection device.