Active Circuit Elements Research Articles

EXPERIMENTAL ANALYSIS OF POWER SEMICONDUCTOR ELEMENTS USED IN FLYBACK CONVERTERS

Switch-mode power supplies (SMPS) have become very popular lately due to their superior efficiency and compact dimensions as compared to conventional counterparts which contain low-frequency transformers. This efficiency and miniaturization are connected to several factors, including high operating frequencies typically in the kHz to MHz range, the utilization of ferromagnetic materials for inductive coupling, and the incorporation of active switching components to mitigate energy loss via the Joule-Lenz effect. Enhancing SMPS efficiency implies active circuit elements (diodes, transistors, etc.) sizing and arrangements. This paper presents a practical approach by addressing a series of experiments to analyze and compare the performance of different active components. It starts with the analysis of the PWM generator module from the primary and continues with the field-effect transistors and rectifier diodes in the secondary. The asynchronous flyback topology has been chosen to carry out the experiments. By using the same experimental platform, based on the obtained results, the analysis of behavioral differences between the different components has been performed.

Effective Gating in Single-Molecule Junctions through Fano Resonances.

The successful incorporation of molecules as active circuit elements relies on the ability to tune their electronic properties through chemical design. A synthetic strategy that has been used to manipulate and gate circuit conductance involves attaching a pendant substituent along the molecular conduction pathway. However, such a chemical gate has not yet been shown to significantly modify conductance. Here, we report a novel series of triarylmethylium and triangulenium carbocations gated by different substituents coupled to the delocalized conducting orbitals on the molecular backbone through a Fano resonance. By changing the pendant substituents to modulate the position of the Fano resonance and its coupling to the conducting orbitals, we can regulate the junction conductance by a remarkable factor of 450. This work thus provides a new design principle to enable effective chemical gating of single-molecule devices toward effective molecular transistors.

A memristor-based circuit approximation of the Hindmarsh–Rose model

Neuron models exist in different levels of complexity and biological modeling depth. The Hindmarsh–Rose model offers a rich repertoire of neuronal dynamics while being moderately mathematically complex. Existing circuit realizations of this neuron model, however, require a large amount of operational amplifiers due to the model’s quadratic and cubic nonlinearity. In contrast to hardware realizations of simpler neuron models, this leads to a higher power consumption. In this work, the Hindmarsh–Rose model is approximated by an ideal electrical circuit that relies mostly on passive circuit elements and thus reduces the power consumption. For this purpose, we analyze the power flows of an equivalent electrical circuit of the Hindmarsh–Rose model and replace several nonlinear circuit elements by constant ones. Moreover, we approximate the cubic nonlinearity by three memristors in combination with a negative impedance converter. This negative impedance converter represents the only active circuit element required for the complete circuit, leading to an increased energy efficiency compared to the existing circuit realizations. Simulations verify the circuit’s ability to generate spiking and bursting dynamics comparable to the original Hindmarsh–Rose model.Graphic abstract

A new CCII based meminductor emulator circuit and its experimental results

Due to their many advantages, memelements are a prominent research topic among scientists. Nevertheless, creating emulator circuits is necessary because of the issues with memelements availability. In this paper, a new CCII-based meminductor emulator circuit is presented. The circuit is composed of a few active and passive circuit elements. In order to demonstrate the performance of the proposed circuit, we applied to different analysis types such as at different operating frequencies, temperatures, Monte Carlo, worst case analysis and non-volatility test. In addition to the simulation results, the circuit was built using discrete circuit components, experimental results were examined. The proposed meminductor emulator circuit has a variety of significant advantages, including a simple construction, suitability for implementation in discrete circuits, and great performance in the analysis of both simulation and experimental results.

Modulations in electrical properties of sputter deposited vanadium oxide thin films: Implication for electronic device applications

• Optimized growth of polycrystalline VO 2 films on SiO 2 /Si substrates by Sputtering. • Appreciable insulator to metal transition (IMT) observed down to 23 nm film thickness. • Film thickness induce systematic modulation in IMT order and IMT temperature. • Low resistivity (∼10 −2 Ω-cm) achieved for insulator state in 23 and 38 nm films. Engineering electronic properties of VO 2 across its insulator to metal transition enable to design wide range of electronic devices operating with low voltage such as memristor, field effect transistor, and in neuromorphic device as an active circuit element. We investigated the electrical and structural properties of sputter deposited VO 2 thin films grown on SiO 2 /Si substrates. In polycrystalline VO 2 films, we observed appreciable insulator to metal transition (IMT) down to film thickness of 23 nm. Further, thickness dependence study reveals a systematic variation in the IMT order between 30-3000, accompanied by modulation in transition temperature and hysteresis. The genesis of the modulations is attributed to morphological and structural growth dynamics. Significantly, we have attained low values for insulating states (∼10 −2 Ω-cm) in low dimensional thin films (23 and 38 nm), which are desirable for Joule heating driven IMT based VO 2 devices with low voltage switching, as well as for sensing applications.

AUTOGENERATOR PARAMETRIC SENSORS OF THE MAGNETIC FIELD WITH A HALL ELEMENT AND A TWO-COLLECTOR BIPOLAR MAGNETOTRANSISTOR

Self-oscillating parametric magnetic field sensors with a frequency output signal based on transistor structures with negative differential resistance with primary magnetically sensitive Hall elements and a bipolar two-collector magnetically sensitive transistor are proposed, moreover, the primary magnetically sensitive elements also act as active circuit elements. Magnetic field sensors with a frequency output do not require analog-to-digital converters and amplifying devices for further processing of information signals, which reduces the cost of information-measuring equipment, in addition, it is possible to transmit information over a distance when the sensors operate at microwave frequencies. Based on the analysis of physical processes in primary magnetically sensitive elements and self-oscillators, mathematical models of sensors were developed, on the basis of which parametric dependences of the conversion and sensitivity functions were obtained. The obtained functions clearly show the influence of each element of the primary magnetic converters and self-oscillator elements on the output frequency of the sensors in comparison with the calculations of the conversion functions from equivalent device circuits based on the Kirchhoff solution equations. It is shown that the main contribution to the conversion functions is made by a change in the magnetic induction, which causes a change in the negative differential resistance and the equivalent capacitance of the oscillatory circuit of the self-oscillator, which in turn changes the output frequency of the magnetic field sensors. Self-oscillating parametric magnetic field sensors with a frequency output signal can significantly improve the accuracy and sensitivity of measuring magnetic induction, abandon analog-to-digital converters and amplifying devices in the further processing of information signals, they also allow transmitting initial information over a distance when operating at microwave frequencies. The sensitivity of the magnetic field sensors varies from 1.45 kHz/mT to 11.95 kHz/mT when the magnetic induction changes from 0.1 to 120 mT.

Electronically Controllable Memcapacitor Circuit With Experimental Results

The memcapacitor is one of the new memory circuit elements although it is not found on the market as a discrete circuit element. In this study, two simple memcapacitor emulators were developed using active circuit elements. These proposed circuits are both electronically controllable. The relationship between charge and flux depending on different frequencies was obtained for both presented memcapacitor circuits. To demonstrate the experimental response of the circuit, discrete circuit elements were used to build the first proposed circuit on the breadboard. All experimental results showed good agreement with the theoretical analyses.

Implementation of Passive and Active Circuit Elements in Cylindrical Finite-Difference Time-Domain Formulation

The implementation of passive and active linear circuit elements in cylindrical finite-difference time-domain technique (CFDTD) is developed. The updating equations for active element such as a voltage sources and passive elements such as resistors, capacitors and inductors are represented for elements located along one of the cylindrical coordinate’s independent parameters. The analytical solutions for simple circuit configurations are computed and used as a reference to verify and confirm the accuracy of the developed CFDTD formulation and numerical results.

Design of low-voltage and low-power current-mode DTMOS transistor based full-wave/half-wave rectifier

A low-voltage and low-power current mode rectifier based on dynamic threshold MOS (DTMOS) transistor is proposed in this paper. The suggested one input–two output rectifier architecture provides full-wave rectification and half-wave rectification. Full-wave rectifier consists of only 6 MOS transistors (excluding 1 MOS transistor in half-wave rectifier part) and is designed without the necessity of using active and passive circuit elements. The proposed rectifier design is simulated using 0.13 µm IBM CMOS technology parameters. The full-wave rectifier circuit requires ± 0.25 V of supply voltages and consumes only 4.36 nW thanks to employing DTMOS transistor structure.

III-N/Si₃N₄ Integrated Photonics Platform for Blue Wavelengths

In this paper, we report a low-loss photonic integrated circuits (PICs) platform at blue wavelengths of the visible spectral regime. Silicon nitride (SiN) is a popular passive waveguide material due to its fabrication flexibility, CMOS compatibility and spectral transparency in this wavelength regime. For active devices including lasers, gallium nitride (GaN) and its alloys are considered. Several basic building blocks for the development of a complete integrated platform, including blue diode lasers, in-plane- and out-of-plane light couplers, as well as on-and off-chip coupling between these active and passive components are theoretically investigated. The proposed in-plane and out-of-plane architectures operate through edge- and vertical grating couplers (VGCs), respectively. With edge-coupling, large mode-mismatch between the GaN laser diode and SiN waveguide is alleviated through nanotapers on both the active and passive sections and the calculated peak coupling efficiency is achieved to be 74% at a wavelength of 450 nm. We also separately designed efficient VGCs for coupling light from standard, commercial, off-the-shelf fibers to the SiN chip, and edge couplers for fiber-chip coupling, exhibiting coupling efficiencies of 51% and 83%, respectively. For robust on-chip light-coupling between active and passive circuit elements, with relaxed alignment tolerances, two approaches, i.e., flip-chip based hybrid integration and evanescent coupling based heterogeneous integration are studied. Calculated maximum coupling efficiencies of 40% (-4 dB) are achieved for both the hybrid and heterogeneous schemes. The theoretical work performed is an initial step towards demonstrating complex blue PICs which could offer a comprehensive range of photonic functionalities.

Electronic realisation technique for fractional order integrators

In this study, a new method is presented for the realisation of the fractional order integrator. First, integer order approximate methods are analysed, then based on this analysis and using existing successfully applied approximate methods given in the literature, the design of fractional order integrators with active circuit elements is studied. In other words, fractance elements are developed. Operational amplifier is preferred in the design of fractional order integrator. Time responses of fractional order integrator circuits are computed by using Multisim software of National Instruments. Then the results are compared and verified with the results obtained from Matlab.

Photonic-Crystal-Fiber Quantum Probes for High-Resolution Thermal Imaging

All-optical thermometry presents a promising avenue of investigation for sensitive biological and electronic systems, with methods free of radio-frequency interference of particular importance. In this work, an all-optical scanning fiber thermometer is tested and shown to possess $5\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{m}$ spatial and $20\phantom{\rule{0.2em}{0ex}}\mathrm{mK}/\sqrt{\mathrm{Hz}}$ temperature resolution. This probe is then used to generate noncontact scanning thermal images of active circuit elements with microscale thermal features.

Circular Polarization Diversity Implementation for Correlation Reduction in Wideband Low-Cost Multiple-Input-Multiple-Output Antenna

In this paper, a multiple-input-multiple-output (MIMO) antenna featuring circular polarization diversity, and designed on a common coplanar ground is presented. The proposed antenna design utilizes a coplanar waveguide (CPW) feeding technique with three parallel coplanar ground planes, and two feedlines in-between. For circular polarization (CP), quasi-loops are created by etching slots on the outermost ground planes. With this configuration, circular polarization diversity is induced in the MIMO antenna with the left-hand CP (LHCP) from one antenna and the right-hand CP (RHCP) from the other. The total footprint of the antenna radiator is only 0.78λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.55λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> = 0.42λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Experimental results show perfectly overlapping impedance and axial ratio bandwidths of 39.3% (4.5 GHz to 6.7 GHz). In addition, average in-band isolation |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> | ≤ -15 dB without any added complexity or active circuit elements. The peak realized gain of the antenna is 5.8 dBic with broadside radiation pattern in the +zdirection and envelope correlation coefficient (ECC) of 0.005. The antenna is suitable for multiple applications in the C-band that includes WLAN (5 GHz, 5.2 GHz and 5.8 GHz) and WiMAX (5.5 GHz).

Chiral Voltage Propagation and Calibration in a Topolectrical Chern Circuit.

We propose an electric circuit array with topologically protected unidirectional voltage modes at its boundary. Instead of external bias fields or Floquet engineering, we employ negative impedance converters with current inversion (INICs) to accomplish a nonreciprocal, time-reversal symmetry-broken electronic network we call a topolectrical Chern circuit (TCC). The TCC features an admittance bulk gap fully tunable via the resistors used in the INICs, along with a chiral voltage boundary mode reminiscent of the Berry flux monopole present in the admittance band structure. The active circuit elements in the TCC can be calibrated to compensate for dissipative loss.

(Plenary) 4D Printing for Sensors and Energy Applications

Sustained advances in 3D printing techniques have resulted in the emergence of 4D printing that incorporates additional dimension where stimuli-responsive smart materials change the shape of the printed structure. Unlike the 3D printed structures, a 4D printed structure evolves as a function of time. The mechanical and structural properties of a 4D printed structure can be pre-programmed using a combination of material properties and computational modeling. We have shown that it is possible to print structures that are electrically conducting. This electrically conducting structure can be transformed under physical stimuli into an active circuit element. Such circuit elements can be the basis for transferring electrical power using single contact, single conductor concept for powering sensors. Stimuli dependent shape can be used for tuning the electrical resonance of single conductor electrical transmission. This single conductor, single contact power delivery also offers opportunities for imbedded sensors in 3D and 4D printed structures. It is also possible to use similar 4D printed structures for developing tunable structures for target analyte pre-concentrators for enhancing the sensitivity of sensors. These 4D printed structures will have myriads of applications in chemical sensing. Our recent results will be presented. We will also address the challenges and opportunities for their future applications.

Ultra-Low voltage-power DTMOS based full-wave rectifier

In this paper, dynamic threshold MOS (DTMOS) transistor based full-wave rectifier with ultra-low power consumption is presented. The proposed circuit composed of only four NMOS and seven DTMOS transistors when many rectifier circuits consist of passive circuit components such as diodes, resistors and active circuit elements. The layout occupies an active area of 24.6 µm × 65.01 µm and post-layout simulation results performed using Cadence Environment with 0.18 µm TSMC CMOS technology parameters. The rectifier circuit with ±0.2 V DC supply voltages can be operated up to approximately 500 MHz and consumes only 2.83 nW thanks to the DTMOS transistors.

A new ultra low-power, universal OTA-C filter in subthreshold region using bulk-drive technique

In this paper, a new ultra low-power universal OTA-C filter which can properly operate in all modes of operation (voltage, current, trans-resistance and trans-conductance) is presented. However, in order to reduce the power consumption effectively, the proposed circuit uses subthreshold transistors which are biased at Ia=50nA, Ib=150nA. Furthermore, using the bulk-drive technique leads to a reduced power consumption as well as the supply voltage of ±0.3V. Moreover, the grounded capacitors are used to effectively reduce the parasitic effects. However, the result of sensitivity analysis shows that the proposed circuit has a very low sensitivity to the values of active and passive circuit elements such as: trans-conductance (gm) and capacitance (C) values. Furthermore, the proposed circuit uses the minimum number of active elements to effectively reduce the power consumption as well as the chip area. Finally, the proposed filter is designed and simulated in HSPICE using 0.18µm CMOS technology parameters, while HSPICE simulation results have very close agreement with theoretical results obtained from MATLAB, which justifies the design accuracy and low-power performance of the proposed universal filter.

Second Law based definition of passivity/activity of devices

Recently, our efforts to clarify the old question, if a memristor is a passive or active device [1], triggered debates between engineers, who have had advanced definitions of passivity/activity of devices, and physicists with significantly different views about this seemingly simple question. This debate triggered our efforts to test the well-known engineering concepts about passivity/activity in a deeper way, challenging them by statistical physics. It is shown that the advanced engineering definition of passivity/activity of devices is self-contradictory when a thermodynamical system executing Johnson–Nyquist noise is present. A new, statistical physical, self-consistent definition based on the Second Law of Thermodynamics is introduced. It is also shown that, in a system with uniform temperature distribution, any rectifier circuitry that can rectify thermal noise must contain an active circuit element, according to both the engineering and statistical physical definitions.

Optical interaction in active analog circuit elements

This publication introduces (spectral) photon emission (PEM) and electro-optical frequency mapping (EOFM/LVI) measurements to analog circuit elements (simple, cascode and low-voltage current mirrors). Different operating conditions of the devices are probed and the voltage dependence of the signals is analyzed. Results partly show close similarities to optical probing of digital IC's, but also differences in voltage dependence and signal levels due to more complicated voltage and signal distributions along the devices.

A Low-Cost and Portable Apnea Detector for Healthcare System

Objectives: This paper highlights on the development of a simple electronic circuit based low-cost, noninvasive and portable apnea detector for patient care monitoring system. Methods/Statistical Analysis: Apnea indicates the cessation of breathing. In this study, thermistor sensitivity method has been implemented in designing the apnea detector. The resistance of a thermistor changes significantly with temperature. The change of temperature between inhaled and exhaled air (during respiration process) is sensed by the thermistor and corresponding change of thermistor resistance is measured in terms of electrical signal with the help of additional active and passive circuit elements. Findings: The resistance of the thermistor changed by 7 Ohm with increase of temperature of 1 degree centigrade. When the apnea detector is switched on and no exhaled breath is incident on the thermistor, the buzzer associated with the device gives sound to indicate the condition of apnea or absence of breathing. The output voltage of the circuit is found to be 8 Volts at this condition. However, if a subject exhales upon the thermistor, the sound of the buzzers stops to indicate the presence of breathing. During this condition, the output voltage is less than 8 Volts and found to vary from subject to subject. Application/Improvements: The designed apnea detector, being a low-cost and portable device can be implemented in patient care monitoring system.