A New Circuit Design Framework for IoT Devices: Charge-Recycling with Wireless Power Harvesting

Limited energy is a significant challenge for IoT devices since frequent battery replacement is not feasible. Various energy harvesting techniques have been previously proposed to alleviate this challenge. A new circuit design technique is developed in this paper to significantly enhance the power efficiency of existing wireless energy harvesting methods. Contrary to the traditional approach, the rectification and regulation blocks are eliminated and the harvested signal is directly used to power the IoT device by leveraging charge-recycling circuit theory. In addition to higher energy-efficiency, the proposed approach also reduces the form factor and therefore lowers the cost of an IoT device. The methodology is evaluated using a 45 nm CMOS technology, demonstrating approximately five times reduction in power consumption compared to the traditional approach.