NanoWattch: A Self-Powered 3-nW RISC-V SoC Operable from 160mV Photovoltaic Input with Integrated Temperature Sensing and Adaptive Performance Scaling

Abstract

This work presents NanoWattch, a self-powered SoC in 65-nm CMOS with integrated temperature sensing for miniaturized IoT applications. NanoWattch can cold-start and sustain operation directly from ambient light with a photovoltaic input as low as 160mV. A performance-scalable RISC-V processor with 6kB SRAM and DVFS subsystem enable system power consumption to continuously adapt to ambient energy conditions down to a minimum total system power of 3nW to provide always-on operation in a mm-scale form factor.