Influence of Output Capacitance on Buck Converter Compensation Network and Simulation

To study the influence of output capacitance parameters (capacitance, ESR) on loop compensation, a reasonable compensation network was designed to improve the stability and dynamic response performance of DC-DC converters. A small signal model of Buck converter controlled by peak current mode (PCM) and continuous conduction mode (CCM) was constructed to analyze the equivalent power level transfer function from control quantity to output voltage. The influence of output capacitance parameters on compensation network design was analyzed, and the design schemes of compensation networks with different capacitance and ESR were explored using the model. Mathcad software was used to simulate the compensated loop. The results showed that the system’s cross-over frequency and phase margin were 10 kHz (1/20 Fsw) and 70° after compensation, which verified the correctness of the theoretical analysis.