Buck Converter with a Variable Number of Predictive Current Distributing Method

Abstract

This paper reports that the converter efficiency can be achieved by dynamically changing the number of active phases depending on the load. We provide solution related to the transient response of the converter when the number of active phases is changed. The problem arises because the current in the individual phases of the interleaved Buck converter will not be equal immediately after the controller has changed the number of active phases. The current equalisation scheme relies on the measurement of the output current and the knowledge of a few converter parameters and it does not require a measurement of the current in each phase. A digital PWM modulator has been designed that allows the current equalisation scheme to work. Simulations and measurements for a four phase interleaved Buck converter are presented in this paper.