Transient Analysis of Energy Harvester for UHF Wireless Applications

In this letter, a detailed transient analysis is performed on a modified Dickson charge pump (CP) circuit, widely used as an energy harvester in radio frequency identification (RFID) and wireless sensor tags at ultrahigh frequency (UHF). An analytical model was developed and experimentally validated to capture the transient response of a multistage CP circuit at arbitrary capacitive and resistive load. The detailed analysis addresses the effect of stage number and matching network on steady-state dc voltage, efficiency, and charging rise time. The analysis shows that the steady-state voltage varies in proportionate to √(n) and the rise time varies in proportionate to n at no load condition, where n is the number of stages.