Loop model and quasi limit cycle for digitally controlled switching dc-dc converters

Loop model and controlled object model for digitally controlled switching dc-dc converters are set up in this paper, and buck converters stability for both digital control and analog control are comparatively analyzed based on the proposed models. This paper also discusses the presence of one oscillation, called as quasi limit cycle, caused by one additional switching cycle delay in the digital feedback loop, and three methods to remove it are introduced and studied. Simulation results are provided to verify the correctness of proposed models and the validity of removal methods.