Simple current sharing control based on differential-mode transformer

A simple current sharing control technique for the switching power supply is presented herein, which is based on the concept of the differential-mode transformer. This current-sharing structure is very simple as well as makes the efficiency relatively high at light load, and this is quite suitable for industrial applications with standby power considered. In addition, a synchronously-rectified (SR) switch is used to further upgrade the efficiency, and to couple output inductors in co-polarity is utilized to decrease the inductor current ripples. In this paper, the detailed basic operating principles focusing on the number of phases not equal to the power of two, together with mathematical derivations, are firstly described, and secondly some experimental results are provided to verify the proposed control strategy.