Integrated low ripple, high frequency power efficient hysteretic controller for dc-dc converters

摘要

The present invention relates to a method of improving power efficiency in a converter circuit at low load currents. The method comprises the steps of monitoring a load current of the converter circuit and adjusting a natural frequency of the converter circuit based on the load current. Such an adjustment of the natural frequency results in a reduction in switching losses at low load currents, thereby improving the power efficiency associated therewith. The present invention also relates to a circuit for improving a power efficiency in a dc-dc converter. The circuit comprises a converter circuit and a comparator circuit coupled to an input of the converter circuit. The dc-dc converter also comprises a feedback circuit coupled between an input and an output of the comparator circuit; the feedback circuit is operable to alter a trip frequency of the comparator circuit as a function of a load current at an output of the converter circuit, thereby decreasing switching losses at low load currents and improving the power efficiency associated therewith.