Modeling of the Control Behavior of Current-Mode Constant On-Time Boost Converters

A constant on-time (COT) controller for dc converters has received much attention recently because of its unique feature of high light-load conversion efficiency. In this paper, a control model is developed for the boost converters with the current-mode COT controller. Models are developed for predicting the loop stability and the step-load transient response. Based on the model, a compensation design is proposed to achieve desired stability margin and step-load transient response. Simulations and experiments are used to verify the model.