Dalibor Biolek

SPICE modeling of memristive, memcapacitative and meminductive systems

A methodology of SPICE modeling of general memristive, memcapacitative, and meminductive systems is proposed and their special cases such as memristors (MR), memcapacitors (MC), and meminductors (ML) are given. These elements are included alongside the conventional R, C, and L elements in a proposed constellation, which generalizes the hitherto approach when the memristor is regarded as a fourth missing passive element. It is shown that the memristor, designed in HP laboratories, can be modeled as a first-order memristive system with nonlinear dependence of the time derivative of the state variable on this variable and on the current flowing through. The outputs of SPICE analyses are consistent with the hitherto published results.

Realization of electronically tunable voltage-mode/current-mode quadrature sinusoidal oscillator using ZC-CG-CDBA

This paper presents a first of its kind canonic realization of active RC (ARC) sinusoidal oscillator with non-interactive/independent tuning laws, which simultaneously provides buffered quadrature voltage outputs and explicit quadrature current outputs. The proposed circuit is created using a new active building block, namely the Z-copy controlled-gain current differencing buffered amplifier (ZC-CG-CDBA). The circuit uses three resistors and two grounded capacitors, and provides independent/non-interactive control of the condition of oscillation (CO) and the frequency of oscillation (FO) by means of different resistors. Other advantageous features of the circuit are the inherent electronic tunability of the FO via controlling current gains of the active elements and the suitability to be employed as a low-frequency oscillator. A non-ideal analysis of the circuit is carried out and experimental results verifying the workability of the proposed circuit are included.

Grounded capacitor current mode single resistance-controlled oscillator using single modified current differencing transconductance amplifier

This study proposes a current mode canonical single resistance-controlled oscillator (SRCO) circuit based on a single modified current differencing transconductance amplifier. The circuit employs grounded capacitors and provides a current output with high output impedance. The proposed circuit also enables orthogonal control of frequency and oscillation condition. The performance of the proposed SRCO is verified by means of simulation program with integrated circuit emphasis (SPICE) simulations, on-chip experiments and measurements.

Z Copy-Controlled Gain-Current Differencing Buffered Amplifier and its applications

The Z Copy-Controlled Gain-Current Differencing Buffered Amplifier (ZC-CG-CDBA) is introduced in the paper. In addition to the well-known CDBA, the input Current Differencing Unit (CDU) is modified and completed by special circuits. Analogously to the conventional CDBA, the z terminal is internally connected to the input of voltage buffer. The current gain from the difference input p, n to the output z can be controlled electronically or by an external device. In addition, an independent high-impedance output zc is available, providing difference current Ip−In. In the paper, the extension of application range of the ZC-CG-CDBA compared with the conventional CDBA is referred to. The novel circuit element is assembled from commercial integrated circuits and its principle is verified experimentally on a universal second-order filter. Copyright

Mutators simulating memcapacitors and meminductors

Whereas the memristor can be emulated via digital potentiometer controlled by a microcontroller, a similar implementation of memcapacitor and meminductor is problematic. The paper describes a synthesis of mutators which transform the emulated memristor into memcapacitor and meminductor. The transformations preserve the unambiguous constitutive relations of these elements, which are derived from the constitutive relation of the memristor. An example of the circuit configuration and the simulation results are demonstrated.

High-output-impedance current-mode multiphase sinusoidal oscillator employing current differencing transconductance amplifier-based allpass filters

This article presents a multiphase sinusoidal oscillator using current differencing transconductance amplifier (CDTA)-based allpass filters. The oscillation condition and oscillation frequency can be orthogonally controlled. The proposed circuit provides 2n – phase signals (n≥2) that are equally spaced in phase and of equal amplitude. The circuit requires one CDTA, two resistors and one capacitor for each phase and no additional current amplifier. Owing to high-output impedances, the proposed circuit enables easy cascading in current-mode configurations. The effects of the nonidealities of the CDTA-allpass sections were also studied. The results of PSpice simulations are presented, demonstrating their consistency with theoretical assumptions.

Computation of the Area of Memristor Pinched Hysteresis Loop

It is well known that the memristor driven by a periodical voltage or current exhibits pinched v - i hysteresis loop. A novel finding is published in this brief, namely, that the area within the loop is directly related to the value of action potential, which was introduced by Leon Chua in his original work from 1971.

The Art of Finding Accurate Memristor Model Solutions

One of the main issues preventing a large-scale exploration of the full potential of memristors in electrical circuits lies in the convergence issues and numerical errors encountered in the computer-aided integration of the differential algebraic equation set governing the peculiar dynamical behavior of these nonlinear two-terminal electrical components. In most cases the complexity of this equation set prevents an analytical derivation of closed-form state solutions. Therefore the investigation of the nonlinear dynamics of memristors and circuits based upon them relies on software-based integration of the mathematical equations. In this paper, we highlight solution accuracy issues which may arise from an improper numerical integration of the equations, and then propose techniques addressing the problems properly. These guidelines represent a useful guide to engineers interested in the numerical analysis of memristor models.

Fully Balanced Voltage Differencing Buffered Amplifier and its applications

An active circuit element, namely Fully Balanced Voltage Differencing Buffered Amplifier (FB-VDBA), is introduced. Its input stage is composed of a fully-differential operational transconductance amplifier (OTA). Voltage buffer is connected to each OTA output. Several applications are proposed which demonstrate the elements versatility. The results of SPICE simulation and measurements on experimental specimen are included.

Some fingerprints of ideal memristors

Since there are many possible types of nonlinear charge-flux constitutive relations of ideal memristors, such elements can manifest various behavior, and the identification of typical memristor fingerprints from the measured data or simulator outputs can be difficult in some cases. The aim of this paper is to reveal several fingerprints of ideal memristors, which extend the repertoire of hitherto published and currently well-known memristor fingerprints. These results can be useful for a clear and fast identification of a system behavior that violates the principles of the operation of ideal memristors.