Stability analysis and compensation of a boost regulator with two-loop control

Abstract

A describing-function approach to characterize analytically the frequency response and to design accordingly the feedback compensation of a staggered-phase boost regulator with two-loop control is presented. It is concluded analytically that the uncompensated major loop gain has a sig nificant frequency range where magnitude is inversely proportional to the square of frequency and where phase lag is approximately 180 degrees, so required phase-lead feedback compensation is designed. A comparison between computed and measured loop gains of the compensated major loop gain confirms the analytical model.