Nanowatt Circuit Technology for an Ultrasmall Wireless Sensor Node with Energy Harvester

摘要

This article describes an ultrasmall wireless sensor node (WSN) that is powered by an energy harvester. The small WSNs can be mounted on any kind of object without increasing their volume, and the energy harvester provides power without having to worry about battery life. However, it is difficult to achieve a WSN that is both ultrasmall and yet still has sufficient power; the smaller the energy harvester is, the less power it generates. We have developed two nanowatt circuit techniques to address this issue. One is a sensing circuit that converts signals with vibration energy. The other is a wireless circuit that uses a quick startup ring oscillator and pulse modulation with an intermittent-driving radio frequency circuit.