CMOS differential-capacitance-to-frequency converter utilising repetitive charge integration and charge conservation

Lee, H.; Woo, Jong-Kwan; Kim, S.

doi:10.1049/el.2010.3416

Cited by 18 publications

(5 citation statements)

References 2 publications

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“…In signal conditioning, differential pickoff has better common-mode rejection of interferences over single-ended arrangements. Many readout circuits inherently have differential architectures for capacitance pickoff [40,41,42,43,44]. The configuration of actuation electrodes for a wineglass resonator in [45] is similar to Configuration B.…”

Section: Modal Equivalent Forcementioning

confidence: 99%

A Lumped Mass Model for Circular Micro-Resonators in Coriolis Vibratory Gyroscopes

et al. 2019

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Coriolis vibratory gyroscopes (CVGs) with circular micro-resonators, such as hemispherical, ring, and disk resonators, exhibit excellent performances and have extraordinary potential. This paper discusses a generalized lumped mass model for both 3D and planar circular micro-resonators, establishing the relationship between the modal effective mass, the modal equivalent force, and the point displacement of the resonator. The point displacement description of a continuous circular resonator’s motion is defined from the view of capacitance measurement. The modal effective mass is, consequently, determined by the kinetic and the potential energy of the structure and is computed with numerical simulations. Moreover, the modal equivalent force, which can be theoretically calculated for any configuration of discrete electrodes, is deduced by using the concept of force density and the force distribution function. By utilizing the lumped mass model in this paper, the stiffness softening, the mode tuning, and the quadrature correction of the micro-resonators are investigated in detail. The theoretical model is verified by both the finite element method (FEM) and the experiments.

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Section: Modal Equivalent Forcementioning

confidence: 99%

A Lumped Mass Model for Circular Micro-Resonators in Coriolis Vibratory Gyroscopes

et al. 2019

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“…However, a lot of methods are applicable to only single element capacitive sensors [7]- [9]. The circuit that converts the difference between two capacitances into an output frequency has been proposed to date [10].…”

Section: Ca+cbmentioning

confidence: 99%

“…camp' The time intervals tl' and t2' including Vos.comp are given by (9) respectivery. As a result, the output N' is given by (10) and then is equal to the ideal output N.…”

Section: The Offset Voltages Of the Op-amp And Comparatormentioning

confidence: 99%

A switched-capacitor differential-capacitance-to-time converter for capacitive sensors

Ogawa

2011

2011 IEEE 54th International Midwest Symposium on Circuits and Systems (MWSCAS)

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A high-accuracy and low-power consumption switched-capacitor (SC) differential-capacitance-to-time converter (DCTC) is presented for high-accuracy ratio metric operation of capacitive sensors. This circuit does not require additional capacitors and component matching. Performances of the proposed circuit are simulated by HSPICE using a 0.35 J.l.m n-well CMOS process parameter. Simulated results have demonstrated that the capacitance difference can be linearly converted to time. A prototype circuit built using discrete components has confirmed the principles of operation.

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“…The need for complex solutions appears in the context of required added features, e.g., self-calibration, temperature compensation, self-testing, and analog-to-digital conversion. Many different approaches and methods have been introduced for high sensitivity capacitive readout circuits: capacitance-to-voltage converters (CVC) [4]- [9], capacitance-to-frequency converters (CFC) [10], capacitance-to-duty-cycle converters [11], [12] and capacitance-to-phase-shift converters (CPC) [13]. Each of these principles can be implemented through multiple circuit techniques.…”

Section: Introductionmentioning

confidence: 99%

Weakly-Coupled Resonators in Capacitive Readout Circuits

Hafizi-Moori

Cretu

2015

IEEE Trans. Circuits Syst. I

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Low energy consumption and wide operating temperature range of capacitors made them common in sensor designs, e.g., MEMS accelerometers, and hence increased the popularity of capacitive readout circuits. Their main challenges, in either discrete or integrated implementations, are sensitivity, noise, energy consumption, and parasitic components at the analog front end. Compared to conventional "frequency-shift monitoring" which is one of the most accurate and common methods for capacitance measurements, weakly-coupled resonators (well-known in mechanical systems) can offer up to three orders of magnitude increase in sensitivity. Therefore, this concept has been recently applied to the design of micromechanical sensors, e.g., for sensitive mass sensing. This paper applies, for the first time in the electrical domain, the concept of monitoring the eigenstates variations in weakly-coupled resonators as a generic readout circuit technique for measuring very small capacitance changes. The outstanding sensitivity of this method is verified analytically and demonstrated using both extensive circuit simulations and experimental measurements.

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CMOS differential-capacitance-to-frequency converter utilising repetitive charge integration and charge conservation

Cited by 18 publications

References 2 publications

A Lumped Mass Model for Circular Micro-Resonators in Coriolis Vibratory Gyroscopes

A Lumped Mass Model for Circular Micro-Resonators in Coriolis Vibratory Gyroscopes

A switched-capacitor differential-capacitance-to-time converter for capacitive sensors

Weakly-Coupled Resonators in Capacitive Readout Circuits

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