Quasi-constant-frequency variable off-time control technique for buck-type DC–DC converter

There are two weaknesses in conventional constant off-time controlled buck-type DC-DC converters: which are varied switching frequency and poor output-regulation accuracy. To make the switching frequency immune to the variation of the input voltage and the reference voltage and provide both high output-regulation accuracy and a fast transient response for buck-type DC-DC converters, a new control method, called the quasi-constant-frequency variable off-time control technique, is proposed. Circuit simulation results validate the correctness of the theoretical analysis.