Abdelghani Dendouga

CONTRIBUTION TO THE ANALYSIS AND MODELING OF THE NON-IDEAL EFFECTS OF PIPELINED ADCs USING MATLAB

The present work analyses the non-ideal effects of pipelined analog-to-digital converters (ADCs), also sometimes referred to as pipeline ADCs, including the non-ideal effects in operational amplifiers (op-amps or OAs), switches and sampling circuits. We study these nonlinear effects in pipelined ADCs built using CMOS technology and switched-capacitor (SC) techniques. The proposed improved model of a pipelined ADC includes most of the non-idealities which affect its performance. This model, simulated using MATLAB, can determine the basic blocks specifications that allow the designer to meet given data converter requirements.

Multi-Objective Genetic Algorithm optimization of CMOS operational amplifiers

This work studies the problem of CMOS operational amplifiers (op-amps) optimization. A front Pareto based-MOGA (Multi-Objective Genetic Algorithm) methodology is proposed to optimize the operational amplifier. The proposed approach is used to find the optimal dimensional transistor parameters in order to obtain operational amplifier performances for analog and mixed CMOS-based circuit applications. To evaluate the proposed approach, an example in both time and frequency domains for a two-stage CMOS Operational Transconductance Amplifier (OTA) is presented in 0.18μm process. The simulation results confirm the efficiency of MOGA in determining the device sizes in an analog circuit.

Optimization of TiO2 concentration effect for a chemical humidity sensing mechanism

Purpose – The purpose of this paper is to propose a new approach to optimize the TiO2 concentration on a resistive‐type humidity sensing mechanism (RHSM) based on artificial neural network.Design/methodology/approach – First is the modeling of the sensing mechanism. Using neuronal networks and Matlab environment to accurately express the output of the sensing mechanism, this model thus takes into account the parameter, non‐linearity, hysteresis, temperature and frequency; furthermore, the TiO2 concentration effect on the humidity sensing properties in the model is investigated. In a second step, the Matlab environment is used to create a database for an ideal model for the sensing mechanism, where the response of this ideal model is linear for any above parameters value.Findings – An analytical model for the sensing mechanism “SM” and the ideal model “IM” has been created. The bias matrix and the weights matrix were used to establish the SM model and the IM on performance simulation program with integrate...

Optimization of TiO(2) and PMAPTAC Concentrations of a Chemical Humidity Sensing Mechanism.

This work aims to achieve an optimization of the TiO2 and PMAPTAC concentrations in a chemical resistive-type humidity sensing mechanism (RHSM). Our idea is based primarily on the modeling of the sensing mechanism. This model takes into account the parameters of non-linearity, hysteresis, temperature, frequency, substrate type. Furthermore, we investigated the TiO2 and PMAPTAC effects concentrations on the humidity sensing properties in our model. Secondly, we used the Matlab environment to create a database for an ideal model for the sensing mechanism, where the response of this ideal model is linear for any value of the above parameters. We have done the training to create an analytical model for the sensing mechanism (SM) and the ideal model (IM). After that, the SM and IM models are established on PSPICE simulator, where the output of the first is identical to the output of the RHSM used and the output of the last is the ideal response. Finally a “DIF bloc” was realized to make the difference between the SM output and the IM output, where this difference represents the linearity error, we take the minimum error, to identify the optimal TiO2 and PMAPTAC concentrations. However, a compromise between concentrations, humidity and temperature must be performed. The simulation results show that in low humidity and at temperature more than 25 °C, sample 1 is the best (in alumina substrate). However, the sample 9 represents the best sensor (in PET substrate) predominately for the lowest humidity and temperature.

Parameter determination of Schottky -barrier diode model using genetic algorithm

In this paper, genetic algorithm (GA) has been applied to extract the Schottky-barrier height, ideality factor and series resistance, this new method presents the effect of wide range temperature of Schottky-barrier diode (SBD) model using forward current-voltage (I–V) characteristics, is discussed. The results found was compared with experimental current-voltage data, it has been confirmed that the proposed method can obtain higher parameter precision with better computational efficiency more easily than other methods.

Modeling of op-amp nonlinearities in pipelined ADC

In this paper, we present a behavioral SIMULINK model for the simulation of operational amplifiers (op-amp). The model includes most of the nonlinearities which affect the performance of these circuits, such parameters (noise, finite gain, finite bandwidth, and slew-rate).With the proposed models it is possible to accurately predict with fast simulations the linearity of sample and hold (Stll) circuit and Multiply digital-to-analog (MDAC) circuit that constructed the pipelined ADC.