Variable on-time control scheme to achieve high efficiency for AC/DC border line current mode buck converter

The Buck power factor improvement converter (BPFIC) is much better topology because of having advantages like less inrush current, less voltage gain ratio, gives less voltage output ripple and steps down the voltage even with high input voltage, protection from short circuit and its single active switch operation makes it attractive. However borderline current mode (BCM) operated with fixed on-time control technique (FOCT) results in its low efficiency. The main reason of low efficiency is due to high conduction and switching losses which occur due to high peak and rms inductor current. In this paper, varying on-time control technique (VOCT) has been implemented that reduces the peak value of current which results in improved efficiency. In the proposed research, work is related to BPFIC operating in BCM because BCM has many advantages like no reverse recovery of diode, and zero current turning off the switch. To verify the effectiveness of proposed control technique, comparative analysis is obtained between both the two control techniques using SABER SIMULATOR. It is found that VOCT improves the converter’s efficiency compared to FOCT.