Efficient power management circuit for RF energy harvesting with 74.27% efficiency at 623nW available power

This paper presents a power management circuit for RF energy harvesting. Rectenna characteristics show that it gives maximum available power for a particular range of load resistance for different power received by the antenna. Therefore to harvest maximum available power, DC-DC boost converter is designed so that its input resistance is always equal to that particular range of load resistance of the rectenna, irrespective of the power received by the antenna. Synchronous rectification technique is also applied to increase the efficiency of the converter. The entire circuit is designed, optimized and simulated in 180nm mixed-mode CMOS technology. Post layout simulation results are presented for -19, -20 and -22dBm power received by the antenna at 950 MHz. Maximum efficiency of the boost converter is 87.70% for 2.4 μW and 74.27% for 623 nW power available at the input of the boost converter.