Patent ID: 6671194
Filing Date: 2003-12-30
Classification: H02M,Y02B

Abstract:
A switching power supply unit comprising:a main rectifying and smoothing circuit which rectifies and smooths alternating current power supply input; a main converting circuit connected to the main rectifying and smoothing circuit; a main converting transformer to which the switched output provided by the main converting circuit is supplied; a main output circuit which rectifies and smooths the output from the main converting transformer and obtains main output; a sub rectifying and smoothing circuit which rectifies and smooths the alternating current power supply input; a sub converting circuit connected to the sub rectifying and smoothing circuit; a sub converting transformer to which the switched output provided by the sub converting circuit is supplied; a stand-by output circuit which rectifies and smooths the output from the sub converting transformer and obtains stand-by output; and a back-up circuit which supplies direct current output obtained by the main rectifying and smoothing circuit to the sub converting circuit.