Hardware implementation of a quasi-resonant bidirectional flyback converter for capacitive loads

This paper presents hardware implementation of a quasi-resonant bi-directional flyback converter (QR-BFC). The design of power stage, control stage and feedback sensing stage is presented specifically for a low power high voltage capacitive load charging and discharging application. The design objective is to achieve faster charge and discharge process with high efficiency, small size and low cost. The converter operates in three modes - charge, discharge and burst mode. Power stage design presents guidelinies for selection of power stage elements of the converter. The control stage design presents implementation of a minimum voltage point (MVP) switching logic of primary and secondary MOSFETs by use of basic logic gates in a low cost CPLD. The isolated feedback sensing design stage presents a resistive capacitive divider circuit for implementation of burst mode voltage regulation. Experimental results are presented with a hardware prototype design.