A practical control strategy to improve unloading transient response performance for buck converters

In this paper, a practical control strategy is presented which is capable of controlling a 12V-1.5V Buck converter and an auxiliary converter to achieve significantly improved unloading response performance. The auxiliary circuit is controlled by peak current mode method for a predictable number of auxiliary switching, while the charge balance controller minimizes the settling time of the Buck converter. In the proposed strategy, a good tradeoff has been made (between the trends to further suppress the voltage overshoot and reduce the power loss). Furthermore, analysis of the auxiliary circuit power loss and the improved output voltage overshoot has been conducted as a design guideline. Finally, simulation and experimental results are provided to verify the proposed scheme on a 12V-1.5V 10A Buck converter prototype.