Energy-Autonomous MCU Operating in sub-VT Regime with Tightly-Integrated Energy-Harvester : A SoC for IoT smart nodes containing a MCU with minimum-energy point of 2.9pJ/cycle and a harvester with output power range from sub-µW to 4.32mW

Abstract

We describe a SoC achieving zero-net-energy operation by using energy harvesting and sub-threshold design. It consists of a microcontroller for data acquisition, data processing, and communication and an energy harvester unit enabling energy-autonomous operation. The microcontroller built with latch-based design achieves robust operation in a wide frequency range from 5 kHz to 40 MHz with a minimum energy point of 2.9 pJ/cycle @ 0.375V and 21 MHz. With this SoC, the battery lifetime is extended indefinitely thanks to the energy harvesting unit, which is capable to handle output power range from sub-μW to 4.32 mW with peak conversion efficiency of 65%. The tight integration of MCU and harvester enables the development of customized firmware algorithms for energy optimized operation with very diverse energy sources.