An RF-DC Converter IC With On-Chip Adaptive Impedance Matching and 307-mu W Peak Output Power for Health Monitoring Applications

作者：Liu Zemin^*; Hsu Yu Pin; Fahs Bassem; Hella Mona Mostafa

来源：IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 2018, 26(8): 1565-1574.

DOI：10.1109/TVLSI.2018.2822120

• Adaptive impedance matching
• health monitoring
• high output power
• RF-DC converter
• RF energy harvesting

This paper presents an RF-DC converter integrated circuit (IC) with similar to 307-mu W output power capable of powering individual health monitoring systems. The IC is designed with an on-chip adaptive impedance matching network to accommodate a wide input RF power variation and extend the operating frequency range. The system is composed of an antenna, an adaptive impedance matching network, a three-stage fullwave RF-DC rectifier, and a low-power digital control loop. A 5-bit successive-approximation-register analog-to-digital converter (ADC) is employed to monitor the dc output voltage and tune a 4-bit binary-weighted capacitor array in the matching network through the control loop. The complete system is designed and fabricated in standard 0.13-mu m CMOS technology. The post-simulated power consumption of the 5-bit ADC and digital control loop is 208 and 87 nW, respectively. Measurement results show that the impedance tuning mechanism can extend the optimal frequency range where the efficiency is higher than 80% of its peak value from 150 MHz (800-950 MHz) for the case without tuning to 220 MHz (780 MHz-1 GHz) when the impedance is adjusted using the control loop. The system achieves a measured end-to-end peak efficiency of 29.3% and is able to deliver an output power higher than 300 mu W with an output voltage and current of 1.75 V and 175.4 mu A, respectively. The active chip area is 0.17 mm(2) including the control loop and ADC.

• 出版日期2018-8