Development of an isolated flyback converter employing boundary-mode operation and magnetic flux sensing feedback

Abstract

This thesis focuses on the marriage of magnetic-flux-sensing feedback and boundary-mode operation in a flyback converter to create a simple, small, low-cost, isolated, and tightly regulated power supply. Although each technique has been implemented before, the marriage of these two concepts is new. The union of these two techniques is powerful in terms of simplifying the overall design. The same signal, the flyback pulse on the bias winding, controls the feedback loop and the turn-on of the switch. In the process of building an isolated power supply, a complete understanding of the benefits and disadvantages of various operational modes along with other design options are explored. The flyback converter was built using discrete parts including op-amps, comparators, and other analog building blocks. The goal was to create a proof of concept board to test the overall effectiveness of the new topology in a simple, quick manner.