单电感双输出Buck变换器的供能模式及输出纹波电压分析

Supply Modes and Output Ripple Voltage of Single-Inductor Dual-Output Buck Converter

由于后级开关的存在,使得单电感双输出(SIDO)Buck变换器的供能模式变得复杂化,为给SIDO Buck变换器的分析设计提供正确的理论指导,该文对SIDO Buck变换器的供能模式进行深入分析。发现变换器工作在连续导电模式(CCM)时存在完全电感供能模式(CISM)和不完全电感供能模式(IISM)两种供能模式,同时变换器工作在断续导电模式(DCM)时也存在两种供能模式:双支路供能模式(DSM)和单支路供能模式(SSM)。该文得到各供能模式的临界电感,推导各供能模式的输出纹波电压解析式,总结出供能模式和输出纹波电压与电感之间的关系,并指出变换器工作在CCM时两条支路输出纹波电压间存在交叉影响。仿真和实验结果验证了理论分析的正确性。

The supply mode of the single-inductor dual-output(SIDO)Buck converter becomes complicates due to the presence of post-stage switch.In order to provide correct theoretical guidance for the analysis and design of SIDO Buck converter,this paper deeply analyzes the supply mode of SIDO Buck converter.It is found that there are two supply modes when the converter works in continuous conduction mode(CCM):complete inductor supply mode(CISM)and incomplete inductor supply mode(IISM).Moreover,when the converter works in discontinuous conduction mode(DCM),there are also two supply modes:dual-branch supply mode(DSM)and single-branch supply mode(SSM).The critical inductance of each supply mode is obtained,and the output ripple voltage(ORV)expression of each supply mode is derived.The relations of inductance with supply mode and ORV are summarized.It is pointed that there is a cross-regulation between the ORV of the two branches when the converter works in CCM.The correctness of theoretical is verified by simulation and experimental results.