Identification and adjustment of the position and attitude for the electrostatic accelerometer's proof mass

Fan, Da Peng; Liu, Yunfeng; Han, Fengtian; Jiang, Dong

doi:10.1016/j.sna.2012.08.037

Cited by 11 publications

(5 citation statements)

References 7 publications

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“…One way to solve this problem is getting the linear result by subtracting a pair of balanced preload forces which are differentially changed on both sides, and realizing the frequency domain separation by modulating the measurand to high frequency [ 35 , 36 , 37 ]. However, there are interactions between sensing and force feedback mode, and if the preload force is above a certain limit, its polarity will reverse, resulting in instability [ 33 , 37 ].…”

Section: System Description and Topology Analysismentioning

confidence: 99%

A ΣΔ Closed-Loop Interface for a MEMS Accelerometer with Digital Built-In Self-Test Function

et al. 2018

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Sigma-delta (ΣΔ) closed-loop operation is the best candidate for realizing the interface circuit of MEMS accelerometers. However, stability and reliability problems are still the main obstacles hindering its further development for high-end applications. In situ self-testing and calibration is an alternative way to solve these problems in the current process condition, and thus, has received a lot of attention in recent years. However, circuit methods for self-testing of ΣΔ closed-loop accelerometers are rarely reported. In this paper, we propose a fifth-order ΣΔ closed-loop interface for a capacitive MEMS accelerometer. The nonlinearity problem of the system is detailed discussed, the source of it is analyzed, and the solutions are given. Furthermore, a built-in self-test (BIST) unit is integrated on-chip for in situ self-testing of the loop distortion. In BIST mode, a digital electrostatic excitation is generated by an on-chip digital resonator, which is also ΣΔ modulated. By single-bit ΣΔ-modulation, the noise and linearity of excitation is effectively improved, and a higher detection level for distortion is easily achieved, as opposed to the physical excitation generated by the motion of laboratory equipment.

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Section: System Description and Topology Analysismentioning

confidence: 99%

A ΣΔ Closed-Loop Interface for a MEMS Accelerometer with Digital Built-In Self-Test Function

et al. 2018

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“…In the static closed loop state, the electrostatic force

F_{e}

balances the sum of other forces on the proof mass [26,27], namely

F_{e} + (K_{m} (x_{0} - x) - m a) = 0

where

x_{0}

is the initial deviation from the zero point of the proof mass when no stress is applied on the feedback beam,

K_{m}

is the stiffness of the feedback beams and m is the mass of the proof mass. Substituting

a = \pm 1 g

into Equations (4) and (5), after subtraction, Equation (6) of the scale factor of the MEMS accelerometer can be obtained as following:

K_{1} = \frac{D_{+ 1 g} - D_{- 1 g}}{2} V_{D D} = \frac{m g d_{0} V_{D D}}{C_{F 0}} \frac{1}{V_{C P}^{2} - 2 V_{C P} V_{M}}

…”

Section: Mems Accelerometer Utilizing Charge Pumpmentioning

confidence: 99%

A Novel Digital Closed Loop MEMS Accelerometer Utilizing a Charge Pump

Chu

Jiang

Chi

et al. 2016

Sensors

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This paper presents a novel digital closed loop microelectromechanical system (MEMS) accelerometer with the architecture and experimental evaluation. The complicated timing diagram or complex power supply in published articles are circumvented by using a charge pump system of adjustable output voltage fabricated in a 2P4M 0.35 µm complementary metal-oxide semiconductor (CMOS) process, therefore making it possible for interface circuits of MEMS accelerometers to be integrated on a single die on a large scale. The output bitstream of the sigma delta modulator is boosted by the charge pump system and then applied on the feedback comb fingers to form electrostatic forces so that the MEMS accelerometer can operate in a closed loop state. Test results agree with the theoretical formula nicely. The nonlinearity of the accelerometer within ±1 g is 0.222% and the long-term stability is about 774 µg.

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“…According to [37], only the low frequency component of V i is taken into account, thus The total electrostatic force F e is calculated as:…”

Section: Sensing Principle Of the Closed-loop Accelerometermentioning

confidence: 99%

Effects of dielectric charging on the output voltage of a capacitive accelerometer

Zhou

et al. 2016

J. Micromech. Microeng.

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Output voltage drifting observed in one typical capacitive microelectromechanical system (MEMS) accelerometer is discussed in this paper. Dielectric charging effect is located as one of the major determinants of this phenomenon through a combination of experimental and theoretical studies. A theoretical model for the electromechanical effects of the dielectric surface charges within the electrode gap is established to analyze the dielectric charge effect on the output voltage. Observations of output voltage drift against time are fitted to this model in order to estimate the possible dielectric layer thickness. Meanwhile, Auger electron spectroscopy is carried out to analyze the electrode surface material composition and confirms a mixture layer of dielectric SiO 2 and Si with a thickness about 5 nm, which is very close to the model estimation. In addition, observation of time-varing output drift in the variable bias voltage experiment indicates the movement of dielectric charge can be controlled by the applied electric field.

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Identification and adjustment of the position and attitude for the electrostatic accelerometer's proof mass

Cited by 11 publications

References 7 publications

A ΣΔ Closed-Loop Interface for a MEMS Accelerometer with Digital Built-In Self-Test Function

A ΣΔ Closed-Loop Interface for a MEMS Accelerometer with Digital Built-In Self-Test Function

A Novel Digital Closed Loop MEMS Accelerometer Utilizing a Charge Pump

Effects of dielectric charging on the output voltage of a capacitive accelerometer

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