A simplified charge balance control for better unloading response

In this paper, a novel control strategy is presented which is capable of controlling a 12V-1.5V main Buck converter and an auxiliary converter to achieve significantly improved unloading response performance. While the charge balance controller minimizes the settling time of the main Buck converter, the auxiliary circuit is controlled in boundary conduction mode for a predictable pattern of auxiliary switching to reduce the output overshoot. Therefore, the reliability and dynamic performance of the entire system is significantly enhanced. Compared with existing technologies, the proposed BCM auxiliary switching strategy achieves improved output voltage overshoot and reduced auxiliary power losses at the same time. Furthermore, numerical analysis of the improved output voltage overshoot has been conducted for a design guideline. Finally, simulation and experimental results are provided to verify the proposed scheme on a 12V-1.5V 10A Buck converter prototype.