An RF Energy Harvesting Power Management Circuit with Timing Detection

This study presents an RF energy harvesting power management circuit for battery-less wireless sensor devices. The proposed circuit generates the power supply and activates main circuits at proper timing such as the beginning of communication. To detect the timing, the proposed circuit adopts an RF signal detector that reuses the RF energy harvester for the reduction of the input power loss and area. The fabricated circuit in 180-nm Si CMOS process demonstrates the RF signal detector senses the proper timing without the degradation of the charge efficiency. The total power consumption in charge phase achieves less than 124nW.