Digital Time-Optimal Phase Shedding in Multiphase Buck Converters

This letter proposes a time-optimal digital controller for the phase shedding (PS) in multiphase buck converters. PS is an established technique to improve the efficiency of multiphase converters at light load by changing the active number of phases depending on the load-current level. In order to minimize the output-voltage deviation and the transient time during PS, a minimum time algorithm is investigated. The proposed technique is insensitive to the power stage parameters, as its operation relies only on a feedforward action, depending on the steady-state duty cycle and the number of phases to be turned on or turned off. The proposed approach is validated through experimental tests on a synchronous buck converter.