A Capacitive Pressure Sensor Interface IC with Wireless Power and Data Transfer
Auckland Bioengineering Institute, The University of Auckland, Auckland 1010, New Zealand
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Micromachines 2020, 11(10), 897; https://doi.org/10.3390/mi11100897
Received: 12 September 2020
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Revised: 25 September 2020
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Accepted: 25 September 2020
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Published: 27 September 2020
(This article belongs to the Special Issue Power Electronics and Sensors)
This paper presents a capacitive pressure sensor interface circuit design in 180 nm XH018 CMOS technology for an implantable capacitive pressure sensor, which has a wireless power supply and wireless data transfer function. It integrates full-bridge rectifiers, shorting control switches, low-dropout regulators, bandgap references, analog front end, single slope analog to digital converter (ADC), I2C, and an RC oscillator. The low-dropout regulators regulate the wireless power supply coming from the rectifier and provide a stable and accurate 1.8 V DC voltage to other blocks. The capacitance of the pressure sensor is sampled to a discrete voltage by the analog front end. The single slope ADC converts the discrete voltage into 11 bits of digital data, which is then converted into 1 kbps serial data out by the I2C block. The “1” of serial data is modulated to a 500 kHz digital signal that is used to control the shorting switch for wireless data transfer via inductive back scatter. This capacitive pressure sensor interface IC has a resolution of 0.98 mmHg (1.4 fF), average total power consumption of 7.8 mW, and ±3.2% accuracy at the worst case under a −20 to 80 °C temperature range, which improves to ±0.86% when operated between 20 and 60 °C.
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Keywords:
AFE; ADC; BGR; LDO; oscillator; rectifier; SC sampling; SC op-amp
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MDPI and ACS Style
Zhang, C.; Gallichan, R.; Budgett, D.M.; McCormick, D. A Capacitive Pressure Sensor Interface IC with Wireless Power and Data Transfer. Micromachines 2020, 11, 897. https://doi.org/10.3390/mi11100897
AMA Style
Zhang C, Gallichan R, Budgett DM, McCormick D. A Capacitive Pressure Sensor Interface IC with Wireless Power and Data Transfer. Micromachines. 2020; 11(10):897. https://doi.org/10.3390/mi11100897
Chicago/Turabian StyleZhang, Chaoping, Robert Gallichan, David M. Budgett, and Daniel McCormick. 2020. "A Capacitive Pressure Sensor Interface IC with Wireless Power and Data Transfer" Micromachines 11, no. 10: 897. https://doi.org/10.3390/mi11100897
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