Digital load current feed-forward control method for a dc-dc converter

This paper describes a new digital feed-forward control method to enhance the dynamic performance of a dc-dc converter. The feed-forward duty ratio is calculated based on the charge balance of the output capacitor using the load current, and it is combined with the output of the digital PED feedback compensator. The feed-forward duty ratio propagates to the consecutive switching cycles during the load transient interval to immediately supply the required energy. The propagation length is decided by comparing the feed-forward duty ratio with the switching period. The performance improvement of the proposed digital control method is experimentally verified on a 200 W buck dc-dc converter.