Multiple Output Switched Capacitor DC-DC Converter with Capacitor Sharing for Sensor-Fusion Platforms

Abstract

In this paper, a multiple output switched capacitor (SC) DC-DC converter with capacitor sharing technique is proposed for event-driven energy-efficient sensor-fusion platforms. The converter is able to convert 1.2V supply voltage to five different output voltages ranging from 0.44V to 2.2V to power different building blocks in the system. A part of the flying capacitor can be shared between five SC cells according to the loading condition to reduce the chip area. With capacitor sharing concept, 36% of on-chip metal-insulator-metal (MIM) capacitor can be reduced. The proposed switched capacitor DC-DC converter is implemented by TSMC 90nm CMOS process. The simulation results show the converter achieves 80% maximum conversion efficiency with less than 20mV output ripple.