Analysis and Comparison of Hybrid-Resonant Switched-Capacitor DC-DC Converters With Passive Component Size Constraints

This article explores the merits of a variety of hybrid-resonant switched-capacitor (SC) dc-dc converters under strict size constraints on passive components (flying capacitors and inductors). Topologies are compared using a "minimum power loss" figure of merit (FOM) that captures conduction- and frequency-dependent losses in active semiconductor devices and losses related to passive components as they scale with size and relative voltage rating. Similar to past work on pure SC converters, the method leverages a charge-multiplier approach and is used to show the impact of area or volume constraints on inductors and capacitors. Building on past work, considerations for treating both "direct-" and "indirect-" conversion architectures are provided, as well as treatment of converters that require multiple inductors. Common topologies are compared using the generalized FOM under different scaling scenarios; general trends are validated using an experimental prototype.