Quadratic differential and integration technique in V2 control buck converter with small ESR capacitor

This paper proposes a quadratic differential and integration (QDI) technique for the design of buck converters with small equivalent series resistance (ESR) of the output capacitor. The QDI circuit not only further removes the dependence of ESR in the V² control but also achieves a fast transient response with small load transient voltage variation. The experimental results show the output voltage can have voltage ripple about 30 mV and recovery time of 20 mus in case of 300 mA load current variation.