Bifurcation and Lyapunov Exponent Analysis of Valley-Current-Mode SIDO-Buck Converter

Lyapunov exponent and bifurcation diagram are two effective methods to study stability of DC-DC converters. In this paper, the stability of single inductor dual outputs (SIDO) buck converter working in valley-current-mode (VCM) is studied. First, the operation principle, current borderline of the converter's inductor and the unified discrete-iterative model of the VCM SIDO-buck converter are presented. Based on that, the dynamic behaviors and Lyapunov exponent of this studied converter with variation of input voltage are emphatically studied based on the established discrete-iterative model. Furthermore, the stability criteria of input voltage are obtained. Finally, simulation result is presented to verify the theoretical analysis result on bifurcations.