Pathways to mm-scale DC-DC converters: Trends, opportunities, and limitations

Despite ongoing advances in semiconductor technologies, power conversion circuits and subcomponents remain a major bottleneck in a variety of performance and embedded computing applications. This paper reviews and discusses some of the fundamental tradeoffs and future prospects for high-density passive components, active devices, and circuit architectures that show promise in the direction of monolithic or mm-scale power conversion. These trends are unified in a minimum power loss figure of merit (FOM) that can be used to compare DC-DC converters under various constraints on passive components (area, energy storage, and/or volume). The paper highlights switched-capacitor and hybrid-resonant converters and outlines important trends and tradeoffs that relate to active- and passive-component utilization and conversion ratio.