The objective of the proposed research is to develop, implement, and validate a fast, compact, and power-efficient switched-inductor battery-charging voltage regulator. Power supplies like this are highly demanded, due to the prevalence of micro and portable electronics. However, the state of the art with multiple-inductor, multiplexed single-inductor, or switched-inductor-capacitor hybrid solutions all require trade-offs between efficiency, compactness, and response time during charging. This research seeks to avoid the trade-offs by employing a serial-battery topology, which allows the battery to be placed in series with the output. Additionally, the study develops and validates design guidelines for single-inductor multiple-I/O power supplies for better efficiency. This approach enables the power supply to simultaneously achieve high efficiency, minimal size, and rapid response.