Modeling and analysis of digital current-mode controlled single-inductor dual-output DC-DC converter with different PWM modulation modes

Current-mode control is extensively used in dc-dc converters as the merits of fast transient performance, simple control loop, and elimination of right-half-plane zeros for boost-type dc-dc converters. In single-inductor multiple-output (SIMO) dc-dc converter, the inductor current would present different trends under different circuit parameters. Therefore, the control logic changes for different inductor current trends, and the corresponding modulations are absolutely different. In this paper, a digital current-mode control technology for SIMO dc-dc converter is proposed to expend the convenience of current-mode control with different inductor trends. Choosing continuous conduction mode (CCM) single-inductor dual-output (SIDO) dc-dc converter as the research object, the principles are analyzed under different pulse width modulation modes, and the corresponding control algorithms are derived. Moreover, the discrete iterative map model is established to analyze the stability of input and output voltages varying. The results show that not only the digital current-mode controlled SIDO buck converter has fast load transient response and small cross-regulation but also the input and output voltages will not affect the stability in the leading edge modulation, which is different from the corresponding analog current-mode control technology. Finally, the experimental results verify the correctness of the theoretical analysis. A digital current-mode control technology for SIMO dc-dc converter is proposed in this paper to expend the convenience of current-mode control with different inductor trends. The results show that not only the digital current-mode controlled SIDO buck converter have a fast load transient response and small cross-regulation but also the input and output voltages will not affect the stability in the leading edge modulation, which is different from the corresponding analog current-mode control technology. image