A switching power supply of 99% power factor by the dither rectifier

The authors present a current waveform improvement method, based on the dither effect normally used in the linearization of nonlinear functions. The proposed circuit utilizes this principle to linearize the dead-zone characteristic which is present in the input of capacitor input rectifiers. The principal characteristics of this method are its simple composition and, more importantly, that it avoids the need for current control. The same switching device realizes the input current waveform improvement and the high frequency inverting output. The experimental circuit achieved over 99% input power factor and current distortion below 9%