Time optimal, parameters-insensitive digital controller for VRM applications with Adaptive Voltage Positioning

A digital control approach is investigated for time-optimal load step response of Voltage Regulation Modules (VRM) equipped with low-ESR ceramic output capacitors. The proposed time-optimal technique is insensitive to the power stage parameters, as its operation does not rely on the knowledge of the output filter inductance or capacitance. The time-optimal response is achieved through a single on/off switching action undertaken as soon as a load transient is detected and automatically incorporates Adaptive Voltage Positioning (AVP) regulation. The proposed robust time-optimal approach is validated through both computer simulations and experimental tests on a synchronous buck converter prototype.