Study On Single-Inductor Multiple-Output Switching Converters

With the rapid development of portable electronic equipmens, multiple output voltages are required more and more for different function modules, which have attracted much attention. The conventional implementation of multiple-output has complicated circle, excessive components and big volume. And importantly, there is serious cross-regulation among the output voltages. Compared with the conventional approaches, the single-inductor multiple-output (SMO) converters, which use a novel time-multiplexing (TM) control scheme, require only a single inductor to realize independent control of each output. The family of single-inductor multiple-output converters saves the magnetical components, weight, size and cost by using only one inductor.Based on the analysis of several conventional techniques of multiple-output, the operating principle of SIMO converters is studied on the single-inductor dual-output (SIDO) Boost converters in this thesis. The SMO converters can be classified into same-type and mixed-type converters. Then the work conditions are studied and simulated on a SIDO Buck converter which operates in critical continuous conduction mode (CCCM), continuous conduction mode (CCM), discontinuous conduction mode (DCM) and pseudo continuous conduction mode (PCCM) respectively.Based on the analysis of SMO converters, a novel control method peak inductor current-differential-mode voltage is presented in this thesis, which avoids the cross-regulation among the output voltages of the SMO converters. The subharmonic oscillation, which maybe caused by the peak inductor current-differential-mode voltage control technique, is studied in this thesis. Slope compensation technique is proposed to eliminate the subharmonic oscillation. Simulation results are performed to verify the proposed control method.