Initialization of the BIMBO self-test method using binary inputs and outputs

International audienceThis 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

Modelling of nonlinear circular plates using modal analysis: simulation and model validation

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

Estimation quality of a weighted least-square parameter estimation method based on binay observations

International audienceIn this paper, we investigate the quality of a weighted leastsquare (WLS) parameter estimation method based on binary observations when only a finite number of samples are available. An upper bound of the number of samples that are necessary for identifying system with a given accuracy is theoretically derived. The accuracy is defined in the sense of correlation coefficient between the system parameters and our estimated system parameters. Furthermore, we compare theoretical results with simulations in order to study the validity of the results practically

Analysis of a MEMS-based ring oscillator

International audienceThis work introduces a MEMS oscillator composed exclusively of mechanical switches as logic components. The electromechanical model of the system is developed and the conditions for a periodic response are established

Electrostatically-induced modal crosstalk phenomena in resonant MEMS sensors

International audienceThe aim of this paper is to introduce an explanation for the amplitude saturation and inhibition phenomena in resonant MEMS pressure sensors, via the electrostatic coupling of two resonance modes. Our analysis and experimental results reveal that these phenomena may be ubiquitous in electrostatic resonant MEMS sensors

Theoretical study of a self-sustained CMOS-integrated nano-oscillator

Over the last ten years, the progress of Nanoelectromechanical systems (NEMS) fabrication has opened new possibilities for the use of NEMS as high-performance, low-cost, compact sensors [1]. In NEMS resonators-based sensors, the resonant frequency depends upon the physical parameter to be measured [2]. To track dynamically the time-varying resonant frequency of the NEMS, one approach consists in embedding the NEMS in a self-oscillating loop so that it oscillates at its resonant frequency. The resonator chosen in this study uses electrostatic actuation and capacitive detection. This has the advantage of having a relatively simple implementation and good transduction efficiency. Furthermore, this actuation/detection scheme makes possible the monolithical integration of the NEMS resonator with a dedicated CMOS circuit. Co-integrated sensors have higher signalto-noise ratios since parasitic capacitances are drastically reduced. Examples of cointegrated NEMS resonators are presented in [3-5]. The main contribution of this work is the design of a NEMS/CMOS oscillator (NEMS as resonant element, CMOS circuit as sustaining amplifier) with a very simple amplifying circuit based on a single active transistor. The design of the electronics and the oscillator steady-state response are theoretically studied. The micro/nanomechanical resonator is described in section 2, the oscillation conditions and the CMOS sustaining amplifier are respectively analyzed in sections 3 and 4. Finally, the steady-state regime of the oscillator is determined by using a describing function method in section 5

Synchronized State in Networks of Digital Phase-Locked Loops

International audienceClock distribution networks of synchronized oscillators are an alternative approach to classical tree-like clock distribution methods. Each node of the network may consist of a phase-locked loop (PLL) trying to match the phase of its neighbors. Then a network of independent oscillators takes the place of the centralized clock source, providing separate clock signals to the physically distant parts of the system. In the discrete case, the digital filter is necessarily operated asynchronously: each operation is triggered by a rising edge of the locally-generated clock, the frequency and phase of which vary as the whole system tries to synchronize. The locking behavior, the synchronous state and the stability conditions of such a system are analyzed. Similarly, the synchronization of an autonomous network of two self-sampled PLLs is studied. Surprisingly, its analysis is much simpler than that of the single PLL

High Resolution Micro-Pirani Pressure Sensor Gauge with Transient Response Processing

International audienceA micro-Pirani pressure sensor which acts as a pressure dependent thermo-resistance gauge is traditionally exploited using a steady state resistance measurement. However any signal variation occurs over a constant voltage bias due to the initial resistance of the device which affects the sensor's sensitivity. Our work shows for the first time an experimental investigation of a micro-Pirani gauge based on its dynamical behavior when heated by a current step. Such a processing does magnify the pressure dependence of the gauge's signal in eliminating the initial resistance influences on the measurement. Furthermore, a first order low pass filter step response identification of the experimental transient signal strongly reduces the thermal noise influence on the measurement. The heating step, the recording of the time dependent signal and its post-processing can be easily achieved by a small-size controller. The proposed system provides a substantial enhancement of the micro-Pirani pressure sensor performance

Design and VHDL Modeling of All-Digital PLLs

International audienceIn this paper, a VHDL model of a second-order alldigital phase-locked loop (ADPLL) based on bang-bang phase detectors is presented. The developed ADPLL is destined to be a part of a distributed clock generators based on networks of the ADPLL. The paper presents an original model and architecture of a digital multi-bit phase-frequency detector (PFD), and describes in details the VHDL modeling of metastability issues related with asynchronous operation of the digital PFD. This particular architecture of the digital PHD is required by the synchronised operation of the ADPLL network in the context of distributed clock generator. The whole ADPLL model have been validated by purely behavioral (VHDL) and mixed simulation, in which the digital PFD detector was represented by its transistorlevel model