Modeling and design of SR-Buck converter with parallel current mode control method

This paper presents a novel current mode controller for the synchronous rectifier Buck (SR-Buck) converter. In term of the discrete equation, the required duty cycle can be calculated directly with two parallel terms: the current term and the voltage term. Based on the analysis of the proposed algorithm, the small signal model of the closed-loop system is derived, thus a proportional and integral compensation strategy is suggested to achieve fast output voltage control. The resultant control system achieves rapid and precise output voltage regulation for both input voltage and output load changes. Furthermore, the theoretical analysis is confirmed by experimental investigations.