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-LC resonator, used in a resonant switched-capacitor voltage regulator. The merged-LC 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-μm 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-μs load transients.