Differential capacitive sensing circuit for a multi-electrode capacitive force sensor

Brookhuis, R.A.; Lammerink, Theodorus S.J.; Wiegerink, Remco J.

doi:10.1016/j.sna.2015.08.020

Cited by 29 publications

(19 citation statements)

References 39 publications

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“…This means that the holding path cannot accurately keep the stable output due to large holding error. As a result, the stable output of the OSSA amplifier is still at a deteriorated level as described by the equation (8).…”

Section: A Holding Errormentioning

confidence: 99%

“…In order to read out the differential capacitive sensor, an AC excitation is needed. The most popular AC excitations are sine excitation and rectangular excitation [8], [9]. The sine excitation is able to measure resistance, capacitance and inductance at the same time [9].…”

Section: Introductionmentioning

confidence: 99%

“…The sine excitation is able to measure resistance, capacitance and inductance at the same time [9]. However, if the capacitance is the only parameter to be measured, rectangular excitation is a better choice for cost efficiency [8].…”

Section: Introductionmentioning

confidence: 99%

“…where is the deterioration factor. Compared to the ideal output in the equation 3, the equation (8) indicates that the 1/A error decreases the output. And a much more important fact is that the 1/A error has deteriorated by a coefficient .…”

Section: Introductionmentioning

confidence: 99%

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Oversampling Successive Approximation Technique for MEMS Differential Capacitive Sensor

Zhong

Lai

2018

IEEE J. Solid-State Circuits

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This paper proposed an over sampling successive approximation (OSSA) technique to build switched-capacitor capacitance-to-voltage convertor (SC-CVC) for readout circuit of MEMS differential capacitive sensor. The readout circuit employing the OSSA technique has significantly improved resistance to common-mode parasitic capacitance of the input terminal of the readout circuit. In the OSSA readout circuit, there are 5 main nonideal characteristics: holding error, recovery degradation, increment degradation, rise-edge degradation and charge injection which reduce the accuracy and the settling time of the circuit. These problems are explained in detail and their solutions are given in the paper. The OSSA readout circuit is fabricated in a commercial 0.18um BCD process. To show the improvement evidently, a reported traditional readout circuit is also reproduced and fabricated using the same process. Compared with the traditional readout circuit, the proposed readout circuit reduces the affect of common-mode parasitic capacitance on the accuracy of SC-CVC by more than 23.8 dB, reduces power dissipation by 69.3%, and reduces die area by 50%.

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Section: A Holding Errormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Oversampling Successive Approximation Technique for MEMS Differential Capacitive Sensor

Zhong

Lai

2018

IEEE J. Solid-State Circuits

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“…On the other hand, PWM-based solutions are synchronous circuit needing a clock line to synchronize the interfacing operation, while their measurement time and resolution are typically independent from the sensor capacitance. These kinds of interface solutions, typically showing straightforward architectures with a high tolerance to common-mode noise/disturbs and to parasitic components as well as to supply voltage drifts, allows for covering wide capacitive variation ranges and can also be combined with a digital system to easily measure the time intervals (e.g., through counters) [25][26][27][28][29][30][31][32][33][34]. Recently, also mixed-signal and digital sensor systems are becoming prevalent, so that new topologies of sensor conditioning circuits have been also introduced.…”

Section: Introductionmentioning

confidence: 99%

A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors

2019

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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.

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Porous Dielectric Elastomer Based Flexible Multiaxial Tactile Sensor for Dexterous Robotic or Prosthetic Hands

Ham

Huh

Kim

et al. 2022

Adv Materials Technologies

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This article presents a lightweight, flexible, multiaxial, and multimodal capacitive tactile sensing design for robotic or prosthetic hand manipulation. The sensor conforms readily to curved surfaces, which wrap around the back and sides of a finger. With a microstructured porous dielectric material, the sensor has a desirable combination of a wide dynamic range with high resolution (0.5–500 kPa in the normal direction). Each taxel measures a combination of normal, shear, and torsional stresses. The capacitive sensor uses active shielding to reduce sensitivity to electromagnetic interference and when contacting a variety of materials with different conductivity and dielectric constants—including soft, wet materials such as tofu or gelatin. By dynamically changing the combinations of electrodes sampled, the sensor can also provide dynamic tactile information at frequencies over 100 Hz. With this combination of capabilities, the sensor is demonstrated for detecting changes in grasp force, and events such as making or breaking contact and the onset of linear or torsional sliding. This work presents the design and characterization of the sensor and demonstrates it in tasks such as handling fragile food items.

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Differential capacitive sensing circuit for a multi-electrode capacitive force sensor

Cited by 29 publications

References 39 publications

Oversampling Successive Approximation Technique for MEMS Differential Capacitive Sensor

Oversampling Successive Approximation Technique for MEMS Differential Capacitive Sensor

A Capacitance-to-Time Converter-Based Electronic Interface for Differential Capacitive Sensors

Porous Dielectric Elastomer Based Flexible Multiaxial Tactile Sensor for Dexterous Robotic or Prosthetic Hands

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