Current-Mode Control Technology Of Single-inductor Dual-Output Boost Converter

With all output branches sharing one inductor, single-inductor multiple-output (SIMO) DC-DC converter receives much concern in academic and industry, which effectively reduces the number of required cores and the cost. It can be widely applied in many multiple independent voltage supplies, especially in computers, portable devices and LED lighting. Therefore, it is significant to study further.Taking dual outputs as the starting point in this thesis, single-inductor dual-output (SIDO) boost converter is studied firstly, including its working principles, operating characteristics and inductor current trends. The causes and solutions of output cross-regulation are analyzed theoretically. For low voltage output in one sub-converter of SIDO boost converter, the theoretical basis and operating conditions are derived as well. The research results show that under certain circuit parameter condition, SIDO boost converter can output low voltage of one sub-converter, whose theory value can be lowed down to zero. The simulation and experimental results are given to verify the feasibility and correctness of the theoretical research on outputting low voltage in SIDO boost converter.Secondly, the feasible current-mode control technology of SIDO boost converter is proposed for different varying trends of inductor current. With the investigation of single-slope compensation and dual-slope compensation, the stable conditions of current-mode controlled SIDO boost converter are derived. The time-domain simulation model of current-mode controlled SIDO boost converter is established, based on its we analyzed the steady-state performance, transient performance, output cross-regulation, stability, etc. From the simulation, it is found that, comparing to traditional common-mode and difference-mode voltage-mode controlled SIDO boost converter, current-mode controlled SIDO boost converter has improved transient response and reduced output cross-regulation. With the slope compensation added in the current-mode controller, the stability under dual-slope compensation is better than that under single-slope compensation. Through time-domain simulation, the validity of the theoretical analysis on SIDO boost converter under current-mode control is proved.Finally, dynamic model of current-mode controlled SIDO boost converter is established, based on which, its complex nonlinear dynamical behavior is emphatically investigated with variations of circuit parameters. The operating-state regions corresponding to varying two circuit parameters are estimated, as well as the derivation of two boundary equations, where operating-state of current-mode controlled SIDO boost converter can transit from stability to instability, and operating-mode of that can shift from continuous conduction mode (CCM) to discontinuous conduction mode (DCM). The results show that there exist different bifurcation types, operating-states and bifurcation routes in current-mode controlled SIDO boost converter with varing circuit parameters. Time-domain simulation and experiment results confirm the validity of theoretical analysis.