Prediction of Subharmonic Oscillation in SIMO DC-DC Converter with Ordered Power Distributive Control in CCM and Peak Current Mode

This article presents a stability analysis method for single-inductor multiple-output ordered power distributive control (OPDC) DC-DC converters. In OPDC converter, both the output voltage and the load current affect the stability, which may eventually cause subharmonic oscillation. The cross-regulation issue of the OPDC control further increases the complexity compared to a single-output converter. This paper derives the stability judgment equation and proposes an optimal output sequencing strategy for stability consideration. Then, a compensation criteria is derived and compared with the traditional single-output current-mode control. In the end, an equivalent compensation scaling factor K is given to evaluate the effects of the output sequence on the required compensation amplitude.