Effect of Circuit Parameters on the Stability and Boundaries of Peak Current Mode Single-Inductor Dual-Output Buck Converters
Peak current mode (PCM) control has been widely used for the control of switching dc–dc converters due to its excellent transient performance. With the development of single-inductor dual-output (SIDO) dc–dc converters, PCM control technique is introduced to the control of SIDO dc–dc converters. Conventional PCM buck converter has only one reference current, with two inductor current borderlines are used to divide the operation modes of inductor current. However, PCM SIDO buck converter has more inductor current borderlines as it has one more reference current than that of PCM buck converter. In this paper, inductor current borderlines of PCM SIDO buck converter are investigated, and unified discrete iterative model of PCM SIDO buck converter is established. The effect of the difference of reference currents, initial inductor current and input voltage on the stability of PCM SIDO buck converter has been discussed by using bifurcation diagrams. The study results show that the stability of PCM SIDO buck converter is sensitive to the difference of reference currents, initial inductor current and input voltage. The stability boundary of the difference of reference currents, stability region of initial inductor current, and stability boundary of input voltage are derived. Lyapunov exponent and experimental results are carried out to verify the theoretical analysis results.