Unified Discrete-Mapping Model and Dynamical Behavior Analysis of Current-Mode Controlled Single-Inductor Dual-Output DC-DC Converter

Buck type, boost type, and buck-boost type are basic topologies of single-inductor dual-output (SIDO) dc-dc converters. Current-mode controlled SIDO dc-dc converters have three current borders in wide-range parameter variations. According to the change of inductor current which presents five trends of "up-down-down," "up-up-down," "up-down-up," "down-up-down," and "up-down," the corresponding current borders are defined. On this basis, a unified discrete-mapping model of five inductor current trends is established and the boundary equations of system stability and mode shifting are derived in the meantime. The dynamic behaviors with the variations of circuit parameters in different inductor current trends are analyzed in detail by numerical simulation, and theoretical analyses of period-doubling bifurcation and tangent bifurcation are presented to validate the simulation results. The research results indicate that the SIDO dc-dc converter has different bifurcation sequences with the same circuit parameter varying for different inductor current trends. Operating regions of the converter are given in this paper, which provides theoretical guidance in designing current-mode controlled SIDO dc-dc converters. The experimental results are presented to verify the correctness of theoretical analysis and unified discrete-mapping model.