Current-mode control to enhance closed-loop performance of asymmetrical half-bridge dc-to-dc converters

Asymmetrical half-bridge dc-to-dc converters exhibit the fourth-order power stage dynamics. When the conventional voltage-mode control is employed, the fourth-order dynamics impose certain constraints on the feedback compensation design and the result could be poor closed-loop performance. This paper demonstrates that the current-mode control could alleviate the detrimental effects of the power stage dynamics and offer an improvement in the closed-loop performance. The principles, performance, and experimental results of current-mode control are presented in comparison with those of voltage-mode control.