Load-interactive steered-inductor dc-dc converter with minimized output filter capacitance

Abstract

The paper introduces a concept of load-interactive digitally controlled point-of-load (POL) dc-dc converters where the size of the output filter capacitor can be minimized based on the enhanced load-related communication between the digital load and the converter controller. Based on the information about upcoming load changes, the inductor current of the dc-dc converter is adjusted such that the converter output current matches the new load, thus minimizing the energy storage requirements for the output filter capacitor. The effectiveness of this approach is verified on a digitally controlled 3.3 V/ 30 W experimental prototype, where the dc-dc converter is a steered-inductor non-inverting buck-boost. Transient response results show that, compared to standard converters with near-time optimal control, the new system has about three times smaller voltage deviation, allowing for a proportionally significant reduction in the output capacitor size.