Novel control method for multiphase low-voltage high-current fast-transient VRMs

High-current high-density multiphase DC-DC converters controllers require high performance current sharing functionality in order to keep almost equal division of the load current between the phases at all load conditions while retaining voltage regulation. Usually, this functionality adds complexity to the closed loop controller design and it is only accurate at full load condition. Moreover, the available current sharing methods regulate the current in each phase by controlling the ON time of the switches, which forces the current sharing functionality to be dependent on the control method being used. In this paper, a simple and effective current sharing method that is independent of the regulation control method being used is presented. The presented method is applied to a voltage-mode hysteretic-controlled multiphase DC-DC converter for the next generation of microprocessors and communication devices that requires high-density high-current fast transient and low output voltage deviation converters. Simulation and experimental results verified the proposes current sharing method.