Patent ID: 7577003
Filing Date: 2009-08-18
Classification: H02M

Abstract:
1. A switching power source comprising: a switching element being connected in series with a primary winding of a transformer connected to a DC power source; a first rectifying/smoothing circuit configured to rectify and smooth AC power induced by a secondary winding of the transformer; a second rectifying/smoothing circuit configured to rectify and smooth AC power induced by an auxiliary winding of the transformer and to provide an internal power source; an output detection circuit configured to detect an output voltage that is provided from the first rectifying/smoothing circuit to a load; and a control circuit configured to control an ON-period of a pulse signal supplied to the switching element according to a feedback voltage from the output detection circuit, the control circuit including, the control circuit controls the ON-period of the pulse signal supplied to the switching element according to a resultant feedback voltage provided by a feedback voltage superpose circuit.