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- Depari, A., et al.
(författare)
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Simple and power efficient interface for AC-excited differential sensors
- 2020
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Ingår i: Proceedings. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728144603
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Konferensbidrag (refereegranskat)abstract
- Capacitive sensors are low-cost and robust devices that can be easily scaled to very small sizes, thus making them suitable for implementation as a micro electro-mechanical system (MEMS). Differential arrangements of the sensors are also available, providing improved rejection of common mode interference. Due to their nature, an AC (sinusoidal) excitation signal is usually adopted. Various types of front-end circuits have been proposed in the past, exploiting different techniques such as conversion of capacitance to current or frequency or analog-to-digital conversion and adopting different approaches, such as full analog or full digital architectures. This paper proposes a digital and microcontroller-based system for AC-excited differential sensors aiming at minimizing cost and power needs, in sight of future large volume applications as for Internet of Things (IoT) paradigm. A proof of concept implementation has been realized and experimentally validated, obtaining a relative error in the measurand estimation on the order of 1%, when the parasitic effects can be neglected. © 2020 IEEE.
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| 2. |
- Sisinni, Emiliano, et al.
(författare)
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Full-Analog Parasitic Capacitance Compensation for AC-Excited Differential Sensors
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 69:8, s. 5890-5899
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Tidskriftsartikel (refereegranskat)abstract
- Capacitive sensors are popular, especially due to the possibility to be integrated together with the readout circuit. In particular, differential implementations are intrinsically insensitive to common-mode noise. Unfortunately, stray capacitances can significantly alter the sensor output value, worsening the performance. This article proposes a novel solution based on an autotuning feedback loop to compensate for parasitic effects, thus preserving measurement performance. In particular, a voltage-controlled negative impedance converter is driven by a feedback loop, in order to control the current flowing in the sensor. The proposed solution can work with the both linear and hyperbolic type of sensors and with any voltage-mode sensor interfaces. An experimental setup, comprising the proposed compensating circuit, a De-Sauty bridge-based sensor front end and an emulated sensor, has been arranged to evaluate obtainable performance. Results show that the linearity error is decreased from more than 10%, without compensation, to less than 1%, when the proposed system is applied. © 1963-2012 IEEE.
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