Altan, Muhammet Alper; Orman, Kamil; Babacan, Yunus; Yesil, Abdullah

Implementing neuron circuit using memristor can be more effective thanks to some properties of memristor such as nonlinearity. For this reason, many memristor-based neuron circuits have been found in the literature. This study presents a memristor-based floating neuron circuit that exhibits different types of spikes. In the proposed circuit, two classical memristors and one special memristor are utilized. The special memristor is designed to exhibit various pinched hysteresis loops and plays an important role in producing different spike types. The proposed special memristor can also be controlled using only one voltage source. Using memristors, we implemented a neuron circuit which can produce regular spike, bursting spike and fast spike. Also, neuron circuit has a floating structure, and so there is no restriction on using it with other circuit elements. All simulations are implemented in the SPICE simulation program with TSMC 0.18-μm CMOS process parameters.

Gokyildirim, Abdullah; Yesil, Abdullah; Babacan, Yunus

Following the experimental realization of memristors, researchers have focused on memristor-based circuits. Chaotic circuits can be implemented easily using a memristor due to its nonvolatile and nonlinear behavior. This study presents a memristor-based four-dimensional (4D) chaotic oscillator with a line equilibria. A memristor having quadratic memductance was utilized to implement the proposed chaotic oscillator. The 4D chaotic oscillator with quartic nonlinearity was designed as a result of the quadratic memductance. In terms of communication security, random number generation and image and audio encryption, systems with quartic nonlinearity or that are higher-dimensional are better than systems that are lower-dimensional or possess quadratic/cubic nonlinearity. The performance of the proposed chaotic circuit was investigated according to properties such as phase portraits, Jacobian matrices, equilibrium points, Lyapunov exponents and bifurcation analyses. Furthermore, the proposed system is multistable and its solutions tend to appear as twin attractors when initial conditions approach their equilibria. The Lyapunov-based nonlinear controller was constructed for controlling the proposed system having a line equilibria. The effect of the initial conditions on the controlling indicators was also studied. In conclusion, by using discrete circuit elements, the proposed circuit was constructed, and its experimental results demonstrated a good agreement with the simulation results.

Demir, Eyyup; Yesil, Abdullah; Babacan, Yunus; Karacali, Tevhit

In this paper, two simple circuits are presented to emulate both memcapacitor and meminductor circuit elements. The emulation of these components has crucial importance since obtaining these high-order elements from markets is difficult when compared to resistor, capacitor and inductor. For this reason, we proposed Multi-Output Operational Transconductance Amplifier (MO-OTA)-based electronically controllable memcapacitor and meminductor circuits. To operate the MOS transistor as a capacitor, drain and source terminals are connected to each other. The memcapacitor behavior is obtained by driving the connected terminals with suitable voltage values. Only a few active and grounded passive components which are found in markets easily are used to emulate meminductive behavior. Furthermore, all passive elements in the circuit are grounded. All simulation results for memcapacitor and meminductor emulators are obtained successfully when compared to previous studies. For all analyses, MO-OTA is laid using the Cadence Spectre Analog Environment with TSMC 0.18μm process parameters and occupied a layout area of only 86.21μm×34.67μm.

Yesil, Abdullah; Babacan, Yunus

In this paper, we present second generation current-controlled conveyor (CCCII)-based simple memristor circuit which exhibits a hard-switching voltage-current relationship. The proposed memristor circuit contains only single CCCII and single grounded capacitor that are attractive for the integrated circuit designers. The proposed memristor emulator has four main advantages: hard-switching behavior, not utilizing multiplier circuit, biasing current or voltage source (excluding DC current or voltage source), and being free of body effect for all transistors. Cadence Spectre Analog Environment with TSMC 0.18μm process parameters is used for all simulations. The memristive chip occupies only 81.85μm×87.76μm area. All simulation results are presented to demonstrate the performance of the proposed circuit by changing some parameters such as frequency, temperature, DC power supply voltages and process variations. Also, the robust performance of the proposed memristor is confirmed via Monte Carlo simulations. The simulation results for designed memristor are in accordance with theoretical memristive behavior.

Yesil, Abdullah; Babacan, Yunus; Kacar, Flrat

This paper presents a new floating memristor emulator (FME) consisting of only a single current backward transconductance amplifier (CBTA) as the active element and two grounded capacitors. The proposed FME-based on CBTA enjoys some advantages that include minimum active and passive elements without using an analog multiplier circuit and grounded passive elements which are attractive for the integrated circuit. In addition, excluding the DC power supply voltage, it does not use bias voltage and/or bias current. The designed memristor circuit provides incremental and decremental characteristics without changing circuit topology or using a switching mechanism and it is implemented with a minimum of circuit elements. All simulation results for the memristor emulator were obtained as expected when compared with fabricated memristors.