Efficient capacitance sensing for wireless health monitoring systems

Efficient capacitance sensing for wireless health monitoring systems. IIUM Engineering Journal, 17 (2). pp. 21-29. ISSN 1511-788X (2016)



Abstract

This paper presents a low power capacitance to voltage converter (CVC) circuit using two differential amplifier circuits, two Schottky rectifier diodes constructed in a symmetrical manner and combined with instrumentation amplifier circuits. The differential capacitance to voltage simulation work has been realized with inexpensive discrete components. Energy from a combination of solar, vibration and heat sources is expected to charge the capacitance circuit. A constant DC voltage of 3V has been used to power the CVC circuit in this work. Simulation has shown that the converter circuit consumes 3.9mW of total power, and operates at 40kHz using a 400mV excitation signal. The circuit is able to detect changes of capacitance from 4–12.5pF using a reference capacitance of 5pF. A sensitivity of 0.132mV for 1fF capacitance change has been observed in the circuit. Using discrete components with same component values as in previous work, this circuit has shown more sensitivity in capacitance detection with less power consumption.

Item Type: Article
Keywords: Energy harvester, Differential capacitance sensing, Capacitance measurement system, Health monitoring system
Taxonomy: By Subject > College of Engineering > Electrical Engineering > Communication
By Subject > College of Engineering > Electrical Engineering > Power
Local Content Hub: Subjects > College of Engineering
Depositing User: Eza Eliana Abdul Wahid
Date Deposited: 29 Dec 2022 09:26
Last Modified: 29 Dec 2022 09:26
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