Power Management for Energy Harvesting in IoT – A Brief Review of Requirements and Innovations

The Internet of Things (IoT) requires billions of wireless sensor network (WSN) nodes that rely on energy harvesting from ambient sources to recharge their limited-capacity batteries and achieve energy-autonomous operation. However, IoT is an evolving field with a vast number of applications that utilize different standards and protocols. Hence, power specifications for energy harvesting and WSN power management circuits vary and it can be difficult for circuit designers and researchers to identify the appropriate power specifications to target in their designs. This paper presents a brief guide on ambient power levels available for harvesting in low-power IoT applications as well as the power levels consumed by WSNs in various IoT communication protocols. It also presents a short review of various innovations in power management for low-power WSNs that enable harvesting with high power conversion efficiency. This work can be used as a resource by circuit designers researching power management for energy-harvested WSN nodes.