A Monolithic 12.7 W/mm2, 92% Peak-Efficiency Switched-Capacitor DC-DC Converter Using CSCR-First Topology

Abstract

This article introduces the continuously scalable conversion-ratio (CSCR)-first topology for monolithic switched-capacitor voltage regulators (SCVRs), substantially improving the performance of CSCR SCVRs for higher input voltages. The topology combines fixed-ratio 2:1 stages together with a CSCR stage to limit the voltage across the CSCR stage while boosting the allowable input voltage higher without relying on stacking capacitors or transistors. Furthermore, by running the fixed-ratio and CSCR stage out of phase, the effectiveness of the CSCR’s intermediate rails and switches is doubled, thus reducing the required transistor footprint. This article discusses a scalable implementation of this technology, leveraging an array-able voltage regulator (VR) core that encompasses the required powertransistors, capacitors, as well as local signal generation circuits, that is then combined with a single centralized controller to meet the current demands of small and large power domains. Measurement results of the VR, realized on Intel 16 technology using high-density metal-insulator-metal (MIM) capacitors, demonstrate the transient performance and reliability of the proposed approach, while showcasing a record 12.7 W/mm2 peak power density for monolithic voltage conversion, and 92% peak efficiency.