Use Of Circuits Research Articles

Directly Printable, Non‐Smearable and Stretchable Conductive Ink Enabled by Liquid Metal Microparticles Interstitially Engineered in Highly Entangled Elastomeric Matrix

AbstractLiquid metal or liquid metal microparticles (LMP) based conductive inks, though promising for fabrication of circuits for use in soft and stretchable electronics, are constrained by a few drawbacks such as need for encapsulation, need for sintering to induce conductivity, and smearing. To address these issues, herein, a stretchable conductive composite ink is developed by combining LMPs with carbon black (CB) in highly entangled polysiloxane elastomer. LMP‐dispersed elastomer lacks conductivity because of its non‐percolated network, however, the CB can interconnect LMPs to act as a bridge, thereby imparting conductivity to the elastomer. Due to presence of fluidic LMPs, the LMPs‐dispersed elastomer lies in soft regime with initial conductivity of 5.6 S m−1, aided by the presence of CB in the interstitial spaces between the LMPs. The highly entangled molecular network of the encapsulating elastomer endows the resulting composite with high stretchability (≈286%) and softness (0.648 MPa) and its long pot life enables rheological modulation of the ink to achieve pressure‐driven direct printed non‐smearing traces. The LMPs‐based conductive ink developed in this work is expected to be further utilized in the fabrication of soft robotics and electronic skin and integrated into electronic modules by facile direct 3D printing.

The Design of a Low-Noise, High-Speed Readout-Integrated Circuit for Infrared Focal Plane Arrays

This paper describes the design of a low-noise, high-speed readout-integrated circuit for use in InGaAs infrared focal plane arrays, and analyzes the working principle and noise index of the pixel circuit in detail. The design fully considers the dynamic range, noise, and power consumption of the pixel circuit in which a capacitance transimpedance amplifier structure is adopted as the input stage circuit, and chip fabrication via an XFAB 0.18 µm CMOS process is successfully realized. The ROIC adopts monolithic integration and implements various functions, such as windowing, subsampling, and different integration and readout modes. The ROIC reached an array scale of 32 × 32, a frame rate of 100 Hz, and a readout rate of 20 Mbps with an analog power consumption of less than 52 mW. The measurement results show that the input reference noise can be reduced to 143 e- via the CDS, and the fully customized scheme has certain advantages in the research of high-performance ROICs.

Analysis of Bahrain GP Circuit for Use in MotoGP with Account for Gyroscopic Effect of Wheels on Speed and Lean Angle

Motorcycle racing is an exhilarating and demanding sport that requires riders to master a variety of skills and techniques. Among these, counter-steering and leaning the motorcycle are paramount for achieving efficient and safe cornering. Unfortunately, a significant number of major accidents in motorcycle racing occur during the cornering phase, particularly near sharp corners on racing tracks. To mitigate these risks and ensure rider safety, this research project focuses on the dynamic analysis of the gyroscopic couple effect on motorcycle wheels with the aim of determining the safe angle of heel for more efficient and secure cornering.

Design of Energy-Efficient RFET-Based Exact and Approximate 4:2 Compressors and Multipliers

The ever-increasing demand for low-power and area-efficient circuits for use in battery-powered devices and the CMOS scaling problems have attracted the attention of VLSI designers to beyond-CMOS technologies like Reconfigurable Field-Effect Transistors (RFETs). Improving the efficiency of multipliers is critical as the core component of many applications such as image processing and Machine Learning (ML). This paper proposes a compact and energy-efficient RFET-based architecture for the 4:2 compressor and Dadda multiplier, leveraging transistor-level reconfigurability and multi-input support of the RFET. Moreover, we propose a novel approximate 4:2 compressor based on efficient RFET logic cells to cater to the needs of error-resilient applications. Extensive circuit-level simulations with 14nm germanium nanowire (GeNW) RFET technology show that the proposed RFET-based exact multiplier improves the power consumption and power-delay product (PDP) by 65% and 45%, respectively, compared to the conventional CMOS-based counterpart in 14nm FinFET technology. Besides, we show that utilizing the proposed approximate compressor, the area and PDP of the multiplier reduce by 46% and 42%. The effectiveness of the approximate multiplier is evaluated in the image multiplication, and the average PSNR and SSIM values are 31.39 and 0.87, respectively.

Dipolar Energy as an Electrical Power Source: Dipole Rotation in Solids Enables a New Source for the Triboelectric Generator

Herein, the concept of triboelectric generators using dipolar polarization energy as an electrical power source is introduced. Dipolar polarization energy is stored in dielectric films by rubbing, and is conveyed to external circuits for use during the depolarization process. Pyromellitic dianhydride‐4,4’‐oxydianiline polyimide films are used as a possible candidate for triboelectric generators, where polarization is formed by rubbing owing to the orientational alignment of polar molecular groups. The current–voltage measurements are used to evaluate the equivalent‐circuit parameters of the generator. The current source is 0.07 nA at 30 °C, which is enhanced to 0.13 nA at 110 °C. It is indicated in these results that the depolarization process proceeds in a short time at higher temperatures, causing an increase in the current. Consequently, the maximum power increases from 18 nW (30 °C) to 33 nW (110 °C). The enhancement of the output power at higher temperatures well supports the idea of using dipolar polarization energy as a power source of triboelectric generators.

Piecewise quadratic neuron model: A tool for close-to-biology spiking neuronal network simulation on dedicated hardware.

Spiking neuron models simulate neuronal activities and allow us to analyze and reproduce the information processing of the nervous system. However, ionic-conductance models, which can faithfully reproduce neuronal activities, require a huge computational cost, while integral-firing models, which are computationally inexpensive, have some difficulties in reproducing neuronal activities. Here we propose a Piecewise Quadratic Neuron (PQN) model based on a qualitative modeling approach that aims to reproduce only the key dynamics behind neuronal activities. We demonstrate that PQN models can accurately reproduce the responses of ionic-conductance models of major neuronal classes to stimulus inputs of various magnitudes. In addition, the PQN model is designed to support the efficient implementation on digital arithmetic circuits for use as silicon neurons, and we confirm that the PQN model consumes much fewer circuit resources than the ionic-conductance models. This model intends to serve as a tool for building a large-scale closer-to-biology spiking neural network.

Development of Selenonium PAGs in EUV Lithography toward High Sensitivity Achievement

Extreme ultraviolet (EUV) lithography at 13.5 nm has become an essential technology for the mass production of state-of-the-art semiconductor integrated circuits for use in devices such as smartphones. Chemically amplified resists (CARs) are primarily used for their production, and several performance requirements have to be met to achieve fine patterning. The requirements are known for simultaneous achievement of resolution, low line edge roughness (LER), high sensitivity, and low outgassing. As photoacid generators (PAGs) are ingredients for determine CARs sensitivity, high absorption of EUV light, acceptability of the secondary electron from matrix polymer, and high decomposability (high acid generation efficiency) are required in EUV lithography. Most onium-salt structures that have been proposed for use as EUV PAGs possess a sulfur atom at its center of cation. In this study, we focus on selenonium salts possessing selenium atoms at its center of cation, which exhibit strong absorption of EUV light, and evaluate their utility in EUV lithography.

A 6.78-MHz Burst-Mode Controlled Inductive Wireless Power Transfer System for Biomedical Implants With Back-Channel Communication Eliminated Using Transmitter Q-Factor Detection

This article presents an analysis and design of high-efficiency, 6.78-MHz burst-mode controlled inductive wireless power transfer system (WPT) with no back-channel communication between a transmitter (TX) and a receiver (RX). Power is transmitted in bursts between the TX and the RX, and the duty cycle of the burst is controlled through load modulation to control power flow between the TX and the RX. Extra back-channel traditionally used for TX–RX communication to control power flow is avoided by using inherent load modulation properties of the WPT circuit. It is demonstrated that the quality factor of the TX can be detected to eliminate the back-channel communication. Furthermore, only an extra switch is added in the RX power stage in series with the load to regulate the output voltage. The proposed WPT circuit can regulate output voltage against distance variation of up to 3 cm using 3-cm-diameter TX and RX coils and a load variation from full load to no load. A 330-mW prototype circuit for use in medical implants is designed, built, and tested. The proposed research advances the state-of-the-art WPT systems for use in resource-constrained biomedical implants.

Synthetic memory circuits for stable cell reprogramming in plants.

Plant biotechnology predominantly relies on a restricted set of genetic parts with limited capability to customize spatiotemporal and conditional expression patterns. Synthetic gene circuits have the potential to integrate multiple customizable input signals through a processing unit constructed from biological parts to produce a predictable and programmable output. Here we present a suite of functional recombinase-based gene circuits for use in plants. We first established a range of key gene circuit components compatible with plant cell functionality. We then used these to develop a range of operational logic gates using the identify function (activation) and negation function (repression) in Arabidopsis protoplasts and in vivo, demonstrating their utility for programmable manipulation of transcriptional activity in a complex multicellular organism. Specifically, using recombinases and plant control elements, we activated transgenes in YES, OR and AND gates and repressed them in NOT, NOR and NAND gates; we also implemented the A NIMPLY B gate that combines activation and repression. Through use of genetic recombination, these circuits create stable long-term changes in expression and recording of past stimuli. This highly compact programmable gene circuit platform provides new capabilities for engineering sophisticated transcriptional programs and previously unrealized traits into plants.

Auto-Bias Electrical Variable Capacitor of Reduced Active Component Count and Voltage Stress for 13.56 MHz RF Plasma Process

This article introduces a novel electrical variable capacitor (EVC) circuit for use in the impedance matching circuits employed by 13.56 MHz RF plasma systems. The proposed design employs a turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> / <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> using bias current and voltage condition technology, reducing the number of active components necessary for the EVC to operate. Experiments comparing the proposed EVC to state-of-the-art alternatives confirmed that the proposed design successfully operated with the reduced number of active components. Proposed EVC of automatic bias action by the power semiconductor switch may improve the impedance matching circuits used in high-power and high-frequency RF plasma system.

FPGA Architecture Exploration for DNN Acceleration

Recent years have seen an explosion of machine learning applications implemented on Field-Programmable Gate Arrays (FPGAs) . FPGA vendors and researchers have responded by updating their fabrics to more efficiently implement machine learning accelerators, including innovations such as enhanced Digital Signal Processing (DSP) blocks and hardened systolic arrays. Evaluating architectural proposals is difficult, however, due to the lack of publicly available benchmark circuits. This paper addresses this problem by presenting an open-source benchmark circuit generator that creates realistic DNN-oriented circuits for use in FPGA architecture studies. Unlike previous generators, which create circuits that are agnostic of the underlying FPGA, our circuits explicitly instantiate embedded blocks, allowing for meaningful comparison of recent architectural proposals without the need for a complete inference computer-aided design (CAD) flow. Our circuits are compatible with the VTR CAD suite, allowing for architecture studies that investigate routing congestion and other low-level architectural implications. In addition to addressing the lack of machine learning benchmark circuits, the architecture exploration flow that we propose allows for a more comprehensive evaluation of FPGA architectures than traditional static benchmark suites. We demonstrate this through three case studies which illustrate how realistic benchmark circuits can be generated to target different heterogeneous FPGAs.

Online learning for orientation estimation during translation in an insect ring attractor network

Insect neural systems are a promising source of inspiration for new navigation algorithms, especially on low size, weight, and power platforms. There have been unprecedented recent neuroscience breakthroughs with Drosophila in behavioral and neural imaging experiments as well as the mapping of detailed connectivity of neural structures. General mechanisms for learning orientation in the central complex (CX) of Drosophila have been investigated previously; however, it is unclear how these underlying mechanisms extend to cases where there is translation through an environment (beyond only rotation), which is critical for navigation in robotic systems. Here, we develop a CX neural connectivity-constrained model that performs sensor fusion, as well as unsupervised learning of visual features for path integration; we demonstrate the viability of this circuit for use in robotic systems in simulated and physical environments. Furthermore, we propose a theoretical understanding of how distributed online unsupervised network weight modification can be leveraged for learning in a trajectory through an environment by minimizing orientation estimation error. Overall, our results may enable a new class of CX-derived low power robotic navigation algorithms and lead to testable predictions to inform future neuroscience experiments.

A fault diagnosis method based on low signal to noise ratio vibration measurement for use in casing cutters

In this paper, a method for fault diagnosis in casing cutters is proposed. A vibration signal acquisition circuit for use in a high-temperature environment was designed, and a casing cutter measurement model was established, including a model of the casing cutter in a trouble-free state and two other common fault states. The vibration characteristics of the model were analyzed. A fault feature enhancement model based on enhancement of the signal to noise ratio and sparse representation, which effectively solves the fault diagnosis problem caused by the limited installation location and the limited performance of the vibration measurement at high temperature, was also designed. The MobileNet-V3-Small convolutional neural network (CNN) model was improved by reducing the basic blocks of the continuous homogeneous structure in the original model, and the Squeeze and Excitation structure expanded to the global level to obtain a lightweight CNN fault recognition model. The effectiveness and efficiency of the proposed method were validated by various experiments.

Synthesizing Electrically Equivalent Circuits for Use in Electrochemical Impedance Spectroscopy through Grammatical Evolution

Electrochemical impedance spectroscopy (EIS) is an important electrochemical technique that is used to detect changes and ongoing processes in a given material. The main challenge of EIS is interpreting the collected measurements, which can be performed in several ways. This article focuses on the electrical equivalent circuit (EEC) approach and uses grammatical evolution to automatically construct an EEC that produces an AC response that corresponds to one obtained by the measured electrochemical process(es). For fitting purposes, synthetic measurements and data from measurements in a realistic environment were used. In order to be able to faithfully fit realistic data from measurements, a new circuit element (ZARC) had to be implemented and integrated into the SPICE simulator, which was used for evaluating EECs. Not only is the presented approach able to automatically (i.e., with almost no user input) produce a more than satisfactory EEC for each of the datasets, but it also can also generate completely new EEC configurations. These new configurations may help researchers to find some new, previously overlooked ongoing electrochemical processes.

Dipolar polarization as an energy source of tribo-electric power generator

Dipolar polarization in solids is proposed as an energy source of a tribo-electric power generator. This power generator does not require periodic displacement of electrodes to induce electrical current, but transient current due to dipolar depolarization conveys polarization energy to external load R. Based on the dielectric physics approach, a rigorous mathematical solution of the transient current is obtained. The transient current is described using two time-constants, α−1 and β−1, which are functions of dielectric relaxation time τ, R, static capacitance of film Cs, and capacitance of film at optical frequency C∞, and it gives one current peak at time tmax=lnβαα−β. The theoretical maximum power of this generator is half of the dipolar energy stored in films P024CsA (P0: dipolar polarization, A: working area of capacitor), and it is achieved under matching condition CsR=τ (τ: dielectric relaxation time of solids). The equivalent electrical circuit of the power source is illustrated by using current source Is=P0τA and shunt conductance Gi=εsτAL (L: thickness of film). This power generator is available in electrical circuits for use by supplying dipolar polarization P0 in a cyclic manner with mechanical force, such as rubbing.

An area efficient memory-less ROM design architecture for direct digital frequency synthesizer

This paper introduces a new technique of designing a read-only memory (ROM) circuit, namely; memory-less ROM as a novel approach to designing the ROM lookup table (LUT) circuit for use in a direct digital frequency synthesizer (DDFS). The proposed DDFS design uses the pipelined phase accumulator (PA) based on the kogge-stone (KS) adder. Verilog HDL programming is encoded on the architecture circuit of pipelined PA and contrasted with other PA based on various adders. The obtained results define the KS adder as having good capabilities for improving the throughput. In addition to the quarter symmetry technique, the built memory-less ROM to obtain the quarter sine amplitude waveform is proposed and implemented in the DDFS system. The implementation of the proposed technique replaces the necessary ROM registers (384 D flip-flops) and multiplexers with simple logic gate circuits instead of traditional ROMs. This technique would reduce the area size and cell count by 56% and 32.6% respectively.

Charging device for wearable electromagnetic energy-harvesting textiles

The study aims to develop charging devices for wearable electromagnetic energy harvesting textiles (WEHT). Electromagnetic energy through human movement can be easily and naturally generated and is not significantly affected by environmental factors, however, the electric current generated by the electromagnetic method of human movement is difficult to efficiently charge. Three charging circuits for use with wearable electromagnetic energy-harvesting textiles were developed. The three types of charging circuits developed are rectifier, voltage doubler, and voltage quadrupler circuits. The performances of the developed circuits were evaluated in comparison with a normal storage circuit, in which the generated energy is stored immediately. The results show that storage energy was generated from the WEHT in all the developed circuits, and the charging efficiency improved as the simulated walking frequency increased. Energy generated from wearable electromagnetic energy harvesting textiles has the highest storage efficiency when charged with a rectifier circuit. The rectifying circuit method showed a charging rate twice that of a normal storage circuit. The charging speed of the rectifier circuit was faster to reach 3.7 V, the nominal maximum barrier voltage of the single-cell lithium-ion batteries used in portable devices, than the normal charging circuit. In the voltage multiplier circuit, the voltage drop generated in the circuit was large, so the charging efficiency was not superior to the normal circuit or rectifier circuit. In conclusion, it is most effective to use a rectifier circuit for charging portable electronic devices using the energy harvested by wearable electromagnetic energy harvesting textiles.

A Two-Electrode, Double-Pulsed Sensor Readout Circuit for Cardiac Troponin I Measurement

This paper presents a pulse-stimulus sensor readout circuit for use in cardiovascular disease examinations. The sensor is based on a gold nanoparticle plate with an antibody post-modification. The proposed system utilizes gated pulses to detect the biomarker Cardiac Troponin I in an ionic solution. The characteristic of the electrostatic double-layer capacitor generated by the analyte is related to the concentration of Cardiac Troponin I in the solvent. After sensing by the transistor, a current-to-frequency converter (I-to-F) and delay-line-based time-to-digital converter (TDC) convert the information into a series of digital codes for further analysis. The design is fabricated in a 0.18-μm standard CMOS process. The chip occupies an area of 0.92 mm2 and consumes 125 μW. In the measurements, the proposed circuit achieved a 1.77 Hz/pg-mL sensitivity and 72.43 dB dynamic range.

Readout integrated circuit with multi-mode background suppression for long wavelength infrared focal plane arrays

Due to the large background current and the large dark current of non-uniformity, the readout integrated circuit (ROIC) will have the small dynamic range and the large spatial noise. For currently-used background and dark current suppression (BDS) techniques, reduction of spatial noise and provision of fast frame rates by a single circuit is impractical. In this paper, we propose a novel BDS circuit for use in different situations. With this circuit, three readout modes can be selected based on the magnitudes of the dark current and the background current, dynamic range, heterogeneity, and frame rate, while a double-threshold comparator is used to ensure the accuracy of BDS. To design the BDS module, we measured the dark current of a collection of long wavelength infrared mercury cadmium telluride photovoltaic detectors, to ensure that suppression could be provided for a statistically significant proportion of devices. Noise in the BDS module was analyzed based on BDS accuracy. Finally, the outputs obtained in the three readout modes were compared in simulation, to verify the operation of the BDS module. The BDS circuit can be used as reference for the large scale of an infrared focal plane array.

Engineering immune responses

Synthetic Biology Cytokines mediate various immune responses and have potential as drugs to treat cancer and other diseases. However, cytokines have diverse and competing roles; although some cytokine therapies are approved, they come with side effects and their efficacy can be limited. In a Perspective, Li and Lim discuss the synthetic biology approaches to engineering better cytokine-based drugs. They discuss improving on naturally occurring cytokines, engineering cytokine-signaling circuits for use with engineered cell therapies, and the possibility of designing cytokines that do not exist naturally. If efficacious, such approaches could improve the potency of cytokines as drugs and add to our understanding of cytokine-based communication. Science , this issue p. [1034][1] [1]: /lookup/doi/10.1126/science.abb5607