A deep trench capacitor based 2:1 and 3:2 reconfigurable on-chip switched capacitor DC-DC converter in 32 nm SOI CMOS

Abstract

On-chip switched capacitor (SC) converters for multicore microprocessor power delivery have the potential to reduce the overall energy consumption of future multicore microprocessor systems by independently regulating the voltage supply of each core. This paper describes an on-chip SC converter that can be reconfigured between a 2:1 and a 3:2 voltage conversion ratio to support a wide output voltage range from a single input supply. Regarding SC converter analysis and modeling, this paper extends an existing state space model framework to include the flying capacitors' parasitic bottom plate capacitors, which for on-chip SC converters significantly influence both the capacitor currents and the converter efficiency. A reconfigurable SC converter that supports an output voltage range of 700mV to 1150mV from a 1.8V input supply is implemented in a 32nm SOI CMOS technology that features the high-density deep trench capacitor. The converter achieves a maximum efficiency of 85.2% at 2.1W/mm2 power density in the 2:1 configuration and a maximum efficiency of 84.1% at 3.2W/mm2 in the 3:2 configuration. © 2014 IEEE.