Patent ID: 7385380
Filing Date: 2008-06-10
Classification: H02M

Abstract:
1. A switching power supply apparatus for performing a switching control of a power semiconductor element that flows current to an inductor and converting input voltage into specified output voltage, comprising a current sensing circuit wherein a feedback loop is structured by use of a single power supply operational amplifier that operates with positive voltage so that voltage of the same potential as that of source voltage or emitter voltage of the power semiconductor element should be applied to a node that connects a current sensing semiconductor element to which the power semiconductor element is connected with drain terminals thereof or collector terminals thereof, and a current sensing resister that is connected to source terminal or emitter terminal of the current sensing semiconductor element, wherein a first capacitor is arranged at the input terminal at one side of the single power supply operational amplifier, and current sensing signals are output on the basis of signals occurring in the current sensing resister.