Adaptive output current feedforward control in VR applications

A method for adapting the gain of an output current feedforward path in voltage regulation (VR) applications is presented. For regulators using adaptive voltage positioning, output current feedforward can improve the dynamic response to fast load transients. However, the feedforward path depends on parameters of the power train that are not known with precision. By analyzing the error voltage and finding its correlation with the parameter error, a gradient algorithm is derived that makes the parameter error vanish and minimizes the voltage error. The algorithm was verified with simulations and experiments on a four-phase prototype VR board with an field programmable gate array-based digital control implementation.