Analysis of Pulse Bursting Phenomenon in Constant-On-Time-Controlled Buck Converter

In this paper, the effect of equivalent series resistance (ESR) of an output capacitor on the performance of a constant-on-time (COT)-controlled buck converter is studied, and a pulse bursting phenomenon is revealed. It indicates that the ESR of the output capacitor is one of the key factors causing pulse bursting phenomenon in COT-controlled buck converters, and the critical ESR is derived via time-domain analysis and stability analysis in the s-domain. It is pointed out that, when the ESR of the output capacitor is smaller than the critical ESR, pulse bursting phenomenon occurs; otherwise, it disappears. Simulation and experimental results are provided to verify the theoretical analysis results.