A high-performance accelerometer with a fifth-order sigma–delta modulator

A novel microelectromechanical system (MEMS) for the measurement of acceleration is presented. It combines a new mechanical structure consisting of two masses with a novel readout principle. The differential-mode displacement of the two proof masses corresponds to the applied acceleration and is embedded in a force-feedback loop. A new readout circuit is presented to give a readout proportional to this differential-mode. In addition, this new readout circuit has a control mechanism to operate the commonmode displacement of this dual-mass structure at the pull-in point. This increases the mechanical and electrical sensitivity.As a proof of concept, a prototype was designed for the complete system. The accuracy of the system is 4.1 µg/ √ Hz, which corresponds to the mechanical noise floor of the mechanical structure.

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“…[13][14][15]. For this, a quantizer is added after the loop filter, before applying the digital feedback.…”

Section: Differential-mode Stabilizationmentioning

confidence: 99%

A virtually floating dual-mass accelerometer

Bock

Woestyn

Raman

et al. 2013

Sensors and Actuators A: Physical

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“…Note that the discretization only applies to the middle part of a hypercube space while the borders will be described by boundary conditions. The PDE in Section 9.2.4 will be discretized as: Figure 9.1 shows the block diagram of a MEMS accelerometer in fifth-order SDM control loop [10]. Like most conventional modelling approaches, the micromechanical sensing element is modelled as a second-order spring damping system:…”

Section: Translation To Vhdl-ams 10761mentioning

confidence: 99%

“…The electrostatic feedback force is generated by a DAC. Such a SDM control loop has the advantages of increased dynamic range, linearity and bandwidth [10] thus it has attracted great research interests.…”

Section: Mz T Cz T Kz T F T ( ) ( ) ( ) ( )mentioning

confidence: 99%

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An Extension to VHDL-AMS for AMS Systems with Partial Differential Equations

Wang

Zhao

Kázmierski

2008

Embedded Systems Specification and Design Languages

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This paper proposes VHDL-AMS syntax extensions that enable descriptions of AMS systems with partial differential equations. We named the extended language VHDL-AMSP. An important specific need for such extensions arises from the well known MEMS modelling difficulties where complex digital and analogue electronics interfaces with distributed mechanical systems. The new syntax allows descriptions of new VHDL-AMS objects, such as partial quantities, spatial coordinates and boundary conditions. Pending the development of a new standard, a suitable pre-processor has been developed to convert VHDL-AMSP into the existing VHDL-AMS 1076.1 standard automatically. The pre-processor allows development of models with partial differential equations using currently available simulators. As an example, a VHDL-AMSP description for the sensing element of a MEMS accelerometer is presented, converted to VHDL-AMS 1076.1 and simulated in SystemVision.

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“…With the increasing requirement for sensitivity and low noise, the basic approach has been to develop higher order Σ∆ modulators, with an integrated EM (Electro Mechanical) Sensor in the loop, with 5 th order systems providing excellent Signal to Noise ratio and overall performance [3,4]. In spite of these efforts, it has become necessary to provide advanced optimization tools [5] to establish the correct Σ∆ design parameters to ensure stability.…”

Section: Introductionmentioning

confidence: 99%

Fully differential electro-mechanical phase locked loop sensor circuit

Rudolf

Wilson

et al. 2013

Sensors and Actuators A: Physical

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Embedding a micro-machined sensing element in a closed loop, force feedback system is a technique commonly used to realise high performance MEMS (micro-electro-mechanical systems) sensors due to the advantages of better linearity, increased dynamic range and reduced parameter sensitivity.Electro-mechanical Sigma Delta modulators (EMΣ∆) have been proposed for this reason and high order loops have been shown to enjoy a good signal to noise ratio (SNR) of more than 100dB. It is also well known that achieving stability in high order EMΣ∆s is a challenging task and in practice stability can be lost with large input signals or due to non-ideal effects in the circuits implemented. In this work we propose a novel differential frequency domain technique for closed loop control of micro-machined sensors. This method, called the electro-mechanical phase locked loop (EMPLL), uses a differential electro-mechanical phase locked loop to control and measure the deflection of micro-machined sensors. We believe that EMPLLs have the potential to have significant advantages over EMΣ∆s for high performance MEMS sensors. Preliminary research suggests that this novel approach will

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A high-performance accelerometer with a fifth-order sigma–delta modulator

Cited by 68 publications

References 14 publications

A virtually floating dual-mass accelerometer

A virtually floating dual-mass accelerometer

An Extension to VHDL-AMS for AMS Systems with Partial Differential Equations

Fully differential electro-mechanical phase locked loop sensor circuit

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