A Monolithic Resonant Switched-Capacitor Voltage Regulator With Dual-Phase Merged-LC Resonator

Fully integrated voltage regulation, while important for a number of applications, is challenging due to the limitations of on-chip passive components, particularly inductors. This work demonstrates a new direction in passive-component integration through the design and implementation of a silicon-integrated merged-<inline-formula> <tex-math notation="LaTeX">$LC$ </tex-math></inline-formula> resonator, used in a resonant switched-capacitor voltage regulator. The merged-<inline-formula> <tex-math notation="LaTeX">$LC$ </tex-math></inline-formula> resonator combines flying capacitance and inductance into a single structure to reduce ac resistive losses, achieving higher efficiency and power density. The voltage regulator is implemented in a 0.18-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS process and achieves 85.5% efficiency at 0.47 W without off-chip passive components. Light-load efficiency is extended through the use of OFF-time modulation (OTM); the design achieves <40-mV under-/over-shoot during 2–50-mA/4-<inline-formula> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> load transients.

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