独立充放时序SIDO开关变换器电流型变频控制技术OA北大核心CSTPCD

Single-inductor dual-output(SIDO)switching converters with shared charge and discharge sequence have problems of the large inductor current ripple and cross-regulation between output branches,and the control circuit fails to work normally under the wide range of changes in circuit parameters.To solve these problems,a current-mode variable frequency control(C-VF)technique with an independent charge and discharge sequence was proposed.First,the working principle of the converter in continuous conduction mode(CCM)was specifically described,and the open-loop transfer function of the main circuit was derived.Furthermore,a closed-loop small signal model was constructed,and the closed-loop cross-regulation impedance transfer functions were derived.The cross-regulation characteristics of the converter with different output voltages and load currents were analyzed in detail.Finally,simulation and experimental verification were carried out.The results show that compared with the shared charge and discharge sequence,the C-VF CCM SIDO buck convert with independent charge and discharge sequence reduces the cross-regulation and improves the transient load response performance.When the load voltages of the two branches are different,decreasing the load of one branch can reduce the cross-regulation of this branch to another one.When the output voltages of the two branches are the same,but the loads are different,the branch with heavy loads has small cross-regulation on the branch with light load.