Analysis and small-signal modeling of self-oscillating converters with applied switching delay

This paper presents a consistent methodology to assess the effect of variable-frequency operation on the dynamics of DC/DC converters, which are commonly used in power-factor-correction and low-cost battery-charger applications. The self-oscillation is typically implemented using peak-current control in boundary mode operation with a deterministic delay. The modeling is based on the proper derivation of cycle-time and on-time constraints leading to full-order small-signal models predicting accurately the dynamical behavior of a converter. The effect of switching delay is found to be insignificant in the load level of concern both by predictions and experiments.