Analysis and optimal design of self- oscillating dc-to-dc converters

A general and exact analysis is presented for a class of selfoscillating dc-to-dc converters which can be modeled by a single-loop nonlinear feedback system. The nonlinearity is assumed to be a hysteresis characteristic; however, it is not required to have odd symmetry. A set of equations is obtained which govern the switching frequency, duty cycle, dc error, and peak-to-peak ripple. Based on these equations, it is possible to predict the general performance and inherent limitations of various circuit configurations. An optimal design procedure for these circuits with respect to a quadratic performance index is suggested. Measured data from several voltage-regulator circuits verify the model chosen and its analysis.