Abstract: We propose a simple analytical model of a metal-oxide-semiconductor field-effect transistor with a lateral resonant gate based on the coupled electromechanical equations, which are self-consistently solved in time. All charge densities according to the mechanical oscillations are evaluated. The only input parameters are the physical characteristics of the device. No extra mathematical parameters are used to fit the experimental results. Theoretical results are in good agreement with the experimental data in static and dynamic operation. Our model is comprehensive and may be suitable for any electromechanical device based on the field-effect transduction.
Abstract: The objective of this work is to extend the linear analysis of Pulsed Digital Oscillators to those topologies having a Finite Impulse Response (FIR) in the feedback loop of the circuit. It will be shown with two specific examples how the overall response of the oscillator can be adjusted to some point by changing the feedback filter, when the resonator presents heavy damping losses. Extensive discrete-time simulations and experimental results obtained with a MEMS cantilever with thermoelectric actuation and piezoresistive position sensing are presented. It will be experimentally shown that the performance of the oscillator is good even below the Nyquist limit
Abstract: A method for simulating the large-displacement actuation of deformable micro-structures is proposed and illustrated in the case of a circular axisymmetric plate. First of all the problem is formulated and its boundary conditions are expressed as functions of the two unknowns, displacements and the Airy stress function. The problem is then split into two parts, each part corresponding to one equation of Von Karman, to which the techniques of modal analysis are applied in order to obtain a set of nonlinear ordinary differential equations. The implementation of the resulting high-level model is then discussed and some simulation results are given, as a basis for comparison
Abstract: This paper presents a digital self-calibration method for microelectromechanical systems (MEMS) using a relay-feedback loop and a set of discrete-time filters. This method is based on the measurement of limit-cycles at the comparator's output, which result from a synchronization phenomenon between the natural frequency of the MEMS and the clock frequency of the discrete-time components. We show how quantized information concerning the MEMS parameters may be extracted from the shape of the limit-cycle, which depends on the characteristics of the MEMS (pulsation, damping, etc.). This digital technique is amplitude-independent, relatively insensitive to noise, and not costly to implement. Details concerning its implementation are discussed, and some simulation and experimental results are given.
Abstract: We describe a method for exciting a micro-mechanical resonator using short pulsed forces. A brief impulse excites the system whenever it passes its position of equilibrium, thus bringing it to oscillate. This actuation strategy is described from a theoretical point of view and a possible application to the case of a resonant accelerometer is presented. Results of the simulation of the entire process, obtained with VHDLâAMS, are given and commented. This actuation scheme offers several advantages: it can be applied to several sorts of excitation techniques; it reduces possible non-linearity problems; such as those associated with electrostatic actuation; it does not require any special design of the oscillating microstructure (as opposed to linear comb-drives solutions). Additionally, the electronic circuitry needed to realize the system is simple and is therefore a good alternative to other techniques for driving MEMS at resonance.
Abstract: A robust closed-loop control and observation methodology for a microbeam electrostatic dynamic shaping using N small separate electrodes is described. After decomposing the displacements vector on the n eigenmodes using the modal analysis, n controllers are designed to control the dynamic coefficients of each mode and deliver the stresses that must be distributed throughout the beam. In a previous work, we considered direct access to non noisy displacement measurements. In this paper, we investigate the capacitive measurement of the local displacements done by each small electrode, which gives a noisy readout. Robust control methodology applied on extended standard model allows the design of n observers associated to n controllers and guarantees a precise shape tracking, free from noise and robust against parameters incertitude.
Abstract: A harvesting microsystem is a heterogeneous component that is to say with at least one element none strictly electric. Several key points have to be taken into account to achieve a design of this kind of system: software-hardware partitioning, multi-physics simulation, 3D integration⦠This article introduces a top down methodology from specifications to layout. After a focus on specificities and needs of autonomous microsystems, the proposed methodology will be used to design an autonomous power generator unit including two micropower sources and their management IC: a RF power receiver and a 1V miniature thermogenerator with a dedicated DC/DC up converter are combined with an manager and charger, and a discharge monitor to manage and store the harvested energy in an above-IC microbattery.Finally, consumption reduction by specified static and dynamic architecture and regulation between load and source will introduce the need of energy optimization algorithm in the proposed methodology.
Abstract: This paper presents an inductive telemetry platform system for the continuous, real-time and simultaneous remote measurement in harsh environment of multiple parameters. Based on an efficient algorithm used for system identification purpose a readout unit for passive telemetric environment is proposed. Tests show promising results at mutual coil distances up to 5 cm.
Abstract: The first front-end CMOS co-integration based on the lateral SGMOSFET presented in this paper demonstrates the benefit of a co-integration approach for NEMS devices. Performance using this device is compared to that obtained with a standalone ASIC. The next step will consist of replacing equivalently the input transistor of the ASIC cascode structure by the SGMOSFET.
Abstract: The paper presents a lateral MOSFET structure with movable gate used to enable the displacement measurement in NEMS devices compatible with "In-IC" integration. The modeling of this novel structure has been performed. Demonstrators have been fabricated based on SON technology and first electrical characteristics have been obtained.
Abstract: An ASIC for an integrated microfluxgate sensor uses pulsed excitation, a 2nd-order DeltaSigma modulator, an LPF and an FIR DAC current generator in a fully-digital field-canceling loop to achieve high linearity over a 120muT DR. A low noise floor of 5nTA/radicHz is measured over a 100Hz BW. This ASIC can be adapted to numerous applications since it is fully programmable. The 9mm2 ASIC consumes 36mW from 3.3V and is fabricated in a 0.35mum CMOS process.
Abstract: This paper presents a control method for initiating and maintaining oscillations of a given amplitude in some nanoelectromechanical device. The control law is based on some nonlinear feedback design and state reconstruction. The achieved performances are illustrated via simulations.
Abstract: This paper deals with the initialization of the BIMBO method, a deterministic identification method based on binary observation, for the (self-) test of integrated electronic and electromechanical systems, such as MEMS. Finding an adequate starting point for the parameter estimation algorithm may be crucial, depending on the chosen model parameterization. We show how this starting point may be obtained using only binary inputs and outputs and a few straightforward calculations. The practical implementation of this method only requires a one-bit digital-to-analog converter (DAC) and a one-bit analog-to-digital converter (ADC). This makes the proposed approach very amenable to integration and leads to no additional cost compared to the BIMBO method. We describe the method from a theoretical point of view, discuss its implementation and illustrate it in some idealized cases.
Abstract: This paper deals with the test of sigma-delta MEMS sensors thanks to BIMBO, an identification method based on binary observations. We show how this method may be used in order to estimate the parameters of the sensing cell and of the associated analog electronics. The principle of the method and its theoretical properties are briefly presented and its pros and cons are discussed. Two approaches for the test of sigma-delta sensors are then presented and compared.
Abstract: In this article we present a complete study of a mechanical nanostructure of the kind of accelerometer. Our models include in particular impact of submicron phenomena such Casimir force considering conductivity of silicon, thickness and roughness of the NEMS. We use these new results to simulate the static and dynamic behavior of on the nano accelerometer like specific design. We fabricated a NEMS demonstrator and performed first electrical measurements that we compared to our model.
Abstract: This paper presents the concept and the design of a new architecture for microfluxgate sensors. An innovative low-pass architecture based on pulsed excitation is presented, with a SigmaDelta-based closed-loop measurement circuit including digital and semi-digital filters. While the total power consumption is reduced to about 20 mW, it also allows a power/resolution tradeoff for a digitally-controlled tunable magnetometer.
Abstract: An original method for estimating the parameters of MEMS sensors is presented. It is based on the measurement of binary oscillations appearing at the system's output when a discrete-time relay feedback is used: the parameters of the system can then be deduced from the shape of these oscillations with a very good accuracy. This method is presented and demonstrated in the case of the identification of some cantilever micro-beams.
Abstract: A method for solving design problems involving coupled-field physics is presented: it is demonstrated in the case of the electrostatic actuation of a deformable micro-mirror. The focus of the present paper is on the inversion of the mechanical problem in the case of a membrane of arbitrary shape, that is, how to compute the ideal pressure distribution on the membrane which corresponds to a given set of displacements.
Abstract: We present a new approach to the simulation of uncertainties in micro-electromechanical systems, based on the same principle as perturbation methods. This approach is valid for large variations of the uncertainties and requires much less simulations than a Monte-Carlo method. An implementation in the case of an electrostatically actuated beam with uncertain stiffness is presented and compared with obtained with Monte-Carlo.
Abstract: This paper presents a self-calibration method for a sigma-delta micro-accelerometer, based on the measurement of limit-cycles at the comparator's output. Some information concerning the sensing cell's parameters may be extracted from the shape of the limit-cycle, which depends on the characteristics of the micro-accelerometer (pulsation, damping, ...). By changing the coefficients of the discrete feedback filter, this information can then be made more accurate. This digital technique can be implemented with ease in the context of sigma-delta sensors. It is amplitude-independent and relatively insensitive to noise. Details concerning the implementation are discussed and some simulation results are given.
