Stability and Compensation: Simple Average Model

Abstract

A pole-zero cancellation method is presented to compensate switching power converters. The method models the plant as a single pole model and the error amplifier with a zero and high frequency pole.  The pole-zero cancellation matches the plant’s pole with an error amplifier zero and cancels the ESR zero with a high-frequency pole. This produces a clean 0 dB crossover at 20 dB/decade for stable operation. The approach is quick and predictable, requiring only basic calculations from known component values. It avoids complex modeling by treating all downstream circuitry as a single voltage-controlled current source. The method is well suited for early-stage design, quick prototypes, or educational purposes.