Control design for multiphase synchronous buck converters based on exact constant resistive output impedance

Abstract

This paper describes a control design methodology based on output impedance analysis for multiphase synchronous buck converters. This design leads to an optimal output voltage transient response. Two design alternatives are proposed. The first alternative uses an equivalent single-phase converter to design the control parameters. This approximation is valid as long as the deviations between the phases of the converter are within the usual tolerance limits. The second one achieves exact constant resistive output impedance regardless of the differences that exist between the phases. Simulation and experimental results are reported in order to validate the two design approaches.