Switched-Inductor Multiple-I/O Power Supplies: MOSFET Selection and Cross Conduction

Switched-inductor power supplies are valued for their high efficiency despite the bulkiness of off-chip inductors. To enhance power density, single-inductor topologies are favored. However, single-inductor multiple-input/multiple-output power supplies (SL-MI/O) present unique design challenges that haven't been sufficiently explored. To assist designers with MOSFET selection, which is non-trivial in SL-MI/Os, an intuitive metric called the Favorability Index (FNP) is introduced. The paper also discusses methods that can be employed to mitigate unwanted turn-on of switches shorting inputs/outputs (cross conduction). Furthermore, a two-transistor selector topology is recommended to block cross conduction with lower impact on efficiency.