A 400 W flyback converter

Abstract

It is demonstrated that it is possible to manufacture a very compact high-power switch-mode power supply based on the flyback technique using standard components, with no sacrifice in performance and operation at 80 kHz. A superior flyback converter can be designed on the basis of the following criteria: (1) choosing a pulse ratio to optimize the switching transistor/diode; (2) assuring low leakage inductance in the transformer and a way of taking care of the energy stored in it; (3) choosing a turns ratio in the transformer that will ensure a low leakage inductance and low output ripple; (4) choosing the airgap and number of turns depending on transformer and output voltage; (5) always having one higher-frequency secondary winding (tightly coupled to the primary) and one 'lower frequency' winding for the main part of the current; and (6) tuning the leakage inductance to maximum efficiency.<>