Design and implementation of Current mode controlled multiple output flyback converter for military applications

Abstract

This paper is aimed at the design and implementation of a high frequency, multiple output, and miniaturized converter for military applications. The implementation is done using the flyback topology in order to make the converter module compact. The proposed converter design illustrates how to achieve better line, load and cross regulations using post regulators. The converter is operated at a switching frequency of 400 KHz using UC1843 PWM Controller. A separate output bias winding is used for converter loop feedback. Primary side Current mode control scheme is attained by comparing input current with bias winding output to modulate the width of the pulses generated from PWM circuit. The converter is validated with an experimental setup which delivers three outputs with desired efficiency of 70%. A delay circuit is employed to maintain the time delay between the outputs. The flyback converter design is equipped with start-up series pass regulator circuit, inrush current limiting circuit, under voltage as well as over current protection circuits.