A novel low-cost capacitive-sensor interface

This paper describes the design of a new capacitive sensor interface. The interface is based on the use of a novel type of oscillator whose frequency is insensitive to low- and high-frequency interfering signals by the application of a third order high-pass filter and special dither techniques. The...

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Bibliographic Details
Published in:IEEE transactions on instrumentation and measurement 1996-04, Vol.45 (2), p.536-540
Main Authors: Van Der Goes, F.M.L., Meijer, G.C.M.
Format: Article
Language:English
Subjects:
Applied sciences
Capacitance measurement
Capacitive sensors
Capacitors
Circuit properties
Circuit stability
Electric, optical and optoelectronic circuits
Electronic circuits
Electronics
Exact sciences and technology
Filters
Frequency
Integrated circuit measurements
Oscillators
Parasitic capacitance
Switching, multiplexing, switched capacity circuits
Temperature distribution
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Summary:This paper describes the design of a new capacitive sensor interface. The interface is based on the use of a novel type of oscillator whose frequency is insensitive to low- and high-frequency interfering signals by the application of a third order high-pass filter and special dither techniques. The fully integrated 0.7 /spl mu/m CMOS circuit shows an inaccuracy of less than 100 aF with respect to a 2 pF reference capacitor over a -30/spl deg/ to +70/spl deg/C temperature range. The applied measurement concept guarantees high stability, high accuracy and a negligible influence of parasitic capacitances without the need for calibration.
ISSN:0018-9456
1557-9662
DOI:10.1109/19.492782