Condition for Suppressing Subharmonic Oscillation in Digital Peak Current-Mode Multi-Cycle Controlled Converters

Abstract

Peak current-mode control is a control algorithm for switched-mode power supplies (SMPSs) that is characterized by high-speed response and high-stability. Currently, a method of implementing peak current-mode control in a digital controller has been proposed however, there is a limit to increasing the switching frequency. Therefore, in a previous study, we proposed a method that enables high-frequency switching by applying a control method called multi-cycle control, which applies the same ON duty ratio over multiple switching cycles to the existing method. Furthermore, in peak current-mode control, an unstable phenomenon called subharmonic oscillation occurs, which is problematic. Generally, this problem is solved by slope compensation however, it cannot be applied to multi-cycle control. Therefore, in previous work, we derived the condition to suppress subharmonic oscillation by designing parameters of multi-cycle control. In this study, we verified the above-mentioned conditions using a real-circuit.