A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors
In this paper we present an oscillating conditioning circuit, operating a capacitance-to-time conversion, which is suitable for the readout of differential capacitive sensors. The simple architecture, based on a multiple-feedbacks structure that avoids ground noise disturbs and system calibrations,...
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-01-01
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| Series: | Electronics |
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| Online Access: | http://www.mdpi.com/2079-9292/8/1/80 |
| _version_ | 1798039647221186560 |
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| author | Andrea De Marcellis Càndid Reig María-Dolores Cubells-Beltrán |
| author_facet | Andrea De Marcellis Càndid Reig María-Dolores Cubells-Beltrán |
| author_sort | Andrea De Marcellis |
| collection | DOAJ |
| description | In this paper we present an oscillating conditioning circuit, operating a capacitance-to-time conversion, which is suitable for the readout of differential capacitive sensors. The simple architecture, based on a multiple-feedbacks structure that avoids ground noise disturbs and system calibrations, employs only three Operational Amplifiers (OAs) and a mixer implementing a square wave oscillator that provides an AC sensor excitation voltage. It performs a Period Modulation (PM) and a Pulse Width Modulation (PWM) of the output signal proportionally to the sensor differential capacitance values. The sensor variation range and the detection sensitivity can be easily set through the additional resistors. Preliminary PSpice simulation results have shown a good agreement with theoretical calculations as well as a linear response with a high detection sensitivity of differential capacitive sensors having a baseline in the range [2.2 ÷ 180 pF]. Moreover, different experimental measurements have been also performed by implementing the circuit on a laboratory breadboard using commercial discrete components so validating the idea and providing the circuit performances with different kind of differential capacitive sensors achieving detection resolutions of about 0.1 fF in an overall differential capacitive variation range that is equal to ±15.8 pF. The achieved results demonstrate that the proposed interface solution is suitable for on-chip integration with different kinds of differential capacitive sensing devices, such as Micro-Electro-Mechanical-System (MEMS), force/position, and humidity sensors in biomedical and robotics applications. |
| first_indexed | 2024-04-11T21:56:46Z |
| format | Article |
| id | doaj.art-65764e62800e4be281dc00afb8669d99 |
| institution | Directory Open Access Journal |
| issn | 2079-9292 |
| language | English |
| last_indexed | 2024-04-11T21:56:46Z |
| publishDate | 2019-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Electronics |
| spelling | doaj.art-65764e62800e4be281dc00afb8669d992022-12-22T04:01:05ZengMDPI AGElectronics2079-92922019-01-01818010.3390/electronics8010080electronics8010080A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive SensorsAndrea De Marcellis0Càndid Reig1María-Dolores Cubells-Beltrán2Department of Industrial and Information Engineering and Economics, University of L’Aquila, 67100 L’Aquila, ItalyDepartment of Electronic Engineering, University of Valencia, 46100 Burjassot, SpainDepartment of Electronic Engineering, University of Valencia, 46100 Burjassot, SpainIn this paper we present an oscillating conditioning circuit, operating a capacitance-to-time conversion, which is suitable for the readout of differential capacitive sensors. The simple architecture, based on a multiple-feedbacks structure that avoids ground noise disturbs and system calibrations, employs only three Operational Amplifiers (OAs) and a mixer implementing a square wave oscillator that provides an AC sensor excitation voltage. It performs a Period Modulation (PM) and a Pulse Width Modulation (PWM) of the output signal proportionally to the sensor differential capacitance values. The sensor variation range and the detection sensitivity can be easily set through the additional resistors. Preliminary PSpice simulation results have shown a good agreement with theoretical calculations as well as a linear response with a high detection sensitivity of differential capacitive sensors having a baseline in the range [2.2 ÷ 180 pF]. Moreover, different experimental measurements have been also performed by implementing the circuit on a laboratory breadboard using commercial discrete components so validating the idea and providing the circuit performances with different kind of differential capacitive sensors achieving detection resolutions of about 0.1 fF in an overall differential capacitive variation range that is equal to ±15.8 pF. The achieved results demonstrate that the proposed interface solution is suitable for on-chip integration with different kinds of differential capacitive sensing devices, such as Micro-Electro-Mechanical-System (MEMS), force/position, and humidity sensors in biomedical and robotics applications.http://www.mdpi.com/2079-9292/8/1/80PM/PWMcapacitance-to-time conversiondifferential capacitive sensor |
| spellingShingle | Andrea De Marcellis Càndid Reig María-Dolores Cubells-Beltrán A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors Electronics PM/PWM capacitance-to-time conversion differential capacitive sensor |
| title | A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors |
| title_full | A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors |
| title_fullStr | A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors |
| title_full_unstemmed | A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors |
| title_short | A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors |
| title_sort | capacitance to time converter based electronic interface for differential capacitive sensors |
| topic | PM/PWM capacitance-to-time conversion differential capacitive sensor |
| url | http://www.mdpi.com/2079-9292/8/1/80 |
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