Design of a Passive Near Field Communication Tag with High Power Conversion Efficiency Active Rectifier for Biomedical Applications
Date Issued
2016
Date
2016
Author(s)
Lu, Chi-Huan
Abstract
Wireless power transfer (WPT) system plays an important role for implantable medical devices (IMDs), which are used for disease monitoring, diagnosis and prosthesis. The size and power conversion efficiency are the critical issues of providing enough power and voltage supply without damaging body tissues. Conventionally, a MedRadio band transceiver was integrated into the system for data transmission. However, larger power consumptions and chip size are not suitable for IMDs applications. In this work, a passive NFC tag with high PCE active rectifier is implemented. The inductor coil for NFC antenna is reused for wireless power transfer to reduce the system size. Both turn-on and turn-off delay compensation techniques are used to achieve high power conversion efficiency and voltage conversion ratio under large range of input amplitudes, PVT and process variations. The tag is fabricated in TSMC 0.18-μm CMOS technology. It consumes 72.7 μW with 1.8 V supply for 10% ASK demodulation and clock generation. The PCE is 80.2 ~ 85.7％ and VCR is 82.1 ~ 86.8% at 500 Ω load, and the maximum output power is 30.5 mW.
Subjects
implantable medical devices
Wireless power transfer
Near field communication
active rectifier
Type
thesis