Analysis and Design of Voltage Regulator with Adaptive FET Modulation To Improve Efficiency

This paper presents a load adaptive voltage regulator that achieves high efficiency extended to light and heavy load regions. The presented method is named as "Adaptive FET Modulation" (AFM) since multiple FETs with different specifications are paralleled such that the number of driven FETs and their respective gate driving voltage are adaptive to load current. The capability of adaptive modulation of FETs\´ parasitic charges and resistances along with adaptive gate driving voltage allows achieving the best FET optimization over a wide load range. AFM operates at a fixed switching frequency for almost the whole load range, therefore it has no effect on the conventional buck operation and its dynamic performance, and is simple to implement. In this paper, the concept, design, analysis and experimental results of the proposed AFM are presented.