Auxiliary current control for improving unloading transient recovery of buck converter

An auxiliary current control technique is presented to improve the unloading transient response of the buck converter in this paper. The proposed control minimizes the output voltage deviation with minimal efficiency degradation of the auxiliary buck/boost converter. The parasitic components of the output capacitor and load are analyzed to estimate their effect on the load transient response. An implementation of the proposed control circuit was realized by discrete analog integrated circuits, such as operational amplifiers, comparators, logic gates, and their peripheral passive components. The performance and feasibility were experimentally verified by a 15-3.3 V and 400-kHz prototype buck converter applying the proposed control circuit.