ANALIZA PRZECIWRÓWNOLEGŁEGO OBWODU MEMRYSTOROWEGO

The basic purpose of the present paper is to propose an extended investigation and computer analysis of an anti-parallel memristor circuit with two equivalent memristor elements with different initial values of the state variables using a modified Boundary Condition Memristor (BCM) Model and the finite differences method. The memristor circuit is investigated for sinusoidal supply current at different magnitudes – for soft-switching and hard-switching modes, respectively. The influence of the initial values of the state variables on the circuit’s behaviour is presented as well. The equivalent i-v and memristance-flux and the other important relationshipsof the memristor circuit are also analyzed.Podstawowym celem niniejszego artykułu jest zaproponowanie rozszerzonego badania i komputerowej analizy przeciwrównoległego układu memrystorowego z dwoma równoważnymi elementami memrystorowymi o różnych wartościach początkowych zmiennych stanu z wykorzystaniem zmodyfikowanego modelu Boundary Condition Memristor (BCM) i metody różnic skończonych. Obwód memrystorowy jest badany dla sinusoidalnego prądu zasilania o różnych wielkościach – odpowiednio dla trybów miękkiego przełączania i twardego przełączania. Przedstawiono również wpływ wartości początkowych zmiennych stanu na zachowanie obwodu. Analizowane są również równoważne charakterystyki prądowo-napięciowe zależność między memrystancją i strumieniem magnetycznym oraz inne ważne cechy obwodu memrystora

ZAAWANSOWANY MODEL MEMRYSTORA ZE MODYFIKOWANYM OKNEM BIOLEK ORAZ EKSPONENTĄ ZALEŻNĄ OD NAPIĘCIA

The main idea of the present research is to propose a new nonlinear ionic drift memristor model suitable for computer simulations of memristor elements for different voltages. For this purpose, a modified Biolek window function with a voltage-dependent exponent is applied. The proposed modified memristor model is based on Biolek model and due to this and to the use of a voltage-dependent positive integer exponent in the modified Biolek window function it has a new improved property - changing the model nonlinearity extent dependent on the integer exponent in accordance with the memristor voltage. Several computer simulations were made for soft-switching and hard-switching modes and also for pseudo-sinusoidal alternating voltage with an exponentially increasing amplitude and the respective basic important time diagrams, state-flux and i-v relationships are established.Główną ideą niniejszej pracy jest zaproponowanie nowego modelu nieliniowego dryfu jonowego, odpowiedniego do komputerowych symulacji elementów memrystorowych dla różnych napięć. W tym celu stosowana jest zmodyfikowana funkcja okna Biolek z wykładnikiem zależnym od napięcia. Zaproponowany zmodyfikowany model memrystora oparty jest na modelu Biolek i dzięki temu oraz zastosowaniu zależnego od napięcia dodatniego współczynnika całkowitego w zmodyfikowanej funkcji okna Biolek ma on nową ulepszoną właściwość - zmieniając nieliniową zależność modelu od wykładnika całkowitego zgodnie z napięciem memrystora. Przeprowadzono kilka symulacji komputerowych dla trybów przełączania miękkiego i twardego, a także dla pseudo-sinusoidalnego napięcia przemiennego z wykładniczo rosnącą amplitudą i ustalono odpowiednie podstawowe wykresy czasowe, i zależności stan-strumień oraz prądowo-napięciowe

A Nonlinear Drift Memristor Model with a Modified Biolek Window Function and Activation Threshold

The main idea of the present research is to propose a new memristor model with a highly nonlinear ionic drift suitable for computer simulations of titanium dioxide memristors for a large region of memristor voltages. For this purpose, a combination of the original Biolek window function and a weighted sinusoidal window function is applied. The new memristor model is based both on the Generalized Boundary Condition Memristor (GBCM) Model and on the Biolek model, but it has an improved property—an increased extent of nonlinearity of the ionic drift due to the additional weighted sinusoidal window function. The modified memristor model proposed here is compared with the Pickett memristor model, which is used here as a reference model. After that, the modified Biolek model is adjusted so that its basic relationships are made almost identical with these of the Pickett model. After several simulations of our new model, it is established that its behavior is similar to the realistic Pickett model but it operates without convergence problems and due to this, it is also appropriate for computer simulations. The modified memristor model proposed here is also compared with the Joglekar memristor model and several advantages of the new model are established

Analysis of temperature influence on titaniumdioxide memristor characteristics at pulse mode

The main goal of this paper is to analyze the temperature influence on memristor parameters and characteristics at impulse mode. A relationship between ionic mobility and temperature is deduced based on experimental data. Then the dependencies between resistances of the memristor in opened and closed states and the temperature are given in analytical and graphical form. The influence of the temperature on memristor characteristics are presented using MATLAB models in pulse mode. At the end some concluding remarks about the inner memristor diffusion are presented

A Simplified Tantalum Oxide Memristor Model, Parameters Estimation and Application in Memory Crossbars

In this paper, an improved and simplified modification of a tantalum oxide memristor model is presented. The proposed model is applied and analyzed in hybrid and passive memory crossbars in LTSPICE environment and is based on the standard Ta2O5 memristor model proposed by Hewlett–Packard. The discussed modified model has several main enhancements—inclusion of a simplified window function, improvement of its effectiveness by the use of a simple expression for the i–v relationship, and replacement of the classical Heaviside step function with a differentiable and flat step-like function. The optimal values of coefficients of the tantalum oxide memristor model are derived by comparison of experimental current–voltage relationships and by using a procedure for parameter estimation. A simplified LTSPICE library model, correspondent to the analyzed tantalum oxide memristor, is created in accordance with the considered mathematical model. The improved and altered Ta2O5 memristor model is tested and simulated in hybrid and passive memory crossbars for a state near to a hard-switching operation. After a comparison of several of the best existing memristor models, the main pros of the proposed memristor model are highlighted—its improved implementation, better operating rate, and good switching properties

Investigation of memristors’ own parasitic parameters and mutual inductances between neighbouring elements of memristor matrix and their influence on the characteristics

The main purpose of this paper is to investigate the influence of the mutual inductance between the memristors of a memory matrix and of the memristor parasitic parameters on their characteristics at impulse mode. The values of the parasitic capacitance and inductance of a memristor are calculated. In the experiments three possible values of the coefficient of magnetic connection between elements are used. The equivalent memristor circuit is analysed in MATLAB environment. The basic effects from the analysis are given. The main result is that the parasitic parameters do not strongly affect the memristor voltage drops at frequencies up to 2 GHz