Circuit Design Principles Research Articles

Study on All-Solid High Repetition-Rate Pulse Generator Based on DSRD

The pulse generator based on drift step recovery diode (DSRD) has broad development prospects in the research of high pulse repetition frequency (PRF), high power pulse generators. In this letter, a pulse generator based on DSRD is successfully developed. The design of circuit topology and design principles are presented. The pulse generator can work stably outputting almost 30kV peak voltage at 100 kHz PRF or 140kV at 25kHz with a 50kΩ load. What's more, the influences of power supply voltage and load resistance are studied experimentally.

Retrodirective Antenna for Inter-Satellite Data Transmission

A new X-band retrodirective antenna based on superheterodyne mixer and phase conjugating technology is proposed for inter-satellite data transmission in this paper. The novel phase conjugating circuit, utilizing the reciprocity of the passive mixers, achieves high RF-IF and LO-IF isolations, high communication link gain, and a very compact low profile layout with all antenna elements and circuit components arranged at one common layer of a double-sided printed circuit board (PCB). Its mathematical principles of circuit design are derived, and the effect of up and down conversion loss deviation of mixers on the amplitude and phase error of the circuit, thus on the beam pointing error and the side-lobe of the antenna is discussed. A prototype of circularly polarized one dimension retrodirective antenna is fabricated, and its bistatic RCS measurement in an anechoic chamber is implemented to verify the effectiveness of the proposed antenna array. The results show that, within the scanning range from -30° to +30°, the array has good retrodirective performance. The proposed antenna would be a good choice for the inter-satellite data transmission inside a distributed satellite cluster.

Simulation and Optimal Design of Magnetic Coupler and its Shielding for EV Wireless Charger

This paper is focus on the coupler design of wireless power transfer (WPT) system for Electric Vehicle(EV). The author describes the coupler circuit model, design principles and steps, calibration methods and magnetic shielding methods for the coupler. Four shielding methods are simulated and compared in this paper. Through simulation, the author believes that aluminium plate shielding is the best for magnetic shielding, but it will cause more losses. Therefore, we need to do a more optimal design in the next study.

Temporal Pattern Recognition through Analog Molecular Computation.

Living cells communicate information about physiological conditions by producing signaling molecules in a specific timed manner. Different conditions can result in the same total amount of a signaling molecule, differing only in the pattern of the molecular concentration over time. Such temporally coded information can be completely invisible to even state-of-the-art molecular sensors with high chemical specificity that respond only to the total amount of the signaling molecule. Here, we demonstrate design principles for circuits with temporal specificity, that is, molecular circuits that respond to specific temporal patterns in a molecular concentration. We consider pulsatile patterns in a molecular concentration characterized by three fundamental temporal features: time period, duty fraction, and number of pulses. We develop circuits that respond to each one of these features while being insensitive to the others. We demonstrate our design principles using general chemical reaction networks and with explicit simulations of DNA strand displacement reactions. In this way, our work develops building blocks for temporal pattern recognition through molecular computation.

Principles of synthetic biology: a MOOC for an emerging field.

Synthetic biology requires students and scientists to draw upon knowledge and expertise from many disciplines. While this diversity is one of the field’s primary strengths, it also makes it challenging for newcomers to acquire the background knowledge necessary to thrive. To address this gap, we developed a course that provides a structured approach to learning the biological principles and theoretical underpinnings of synthetic biology. Our course, Principles of Synthetic Biology (PoSB), was released on the massively open online course platform edX in 2016. PoSB seeks to teach synthetic biology through five key fundamentals: (i) parts and layers of abstraction, (ii) biomolecular modeling, (iii) digital logic abstraction, (iv) circuit design principles and (v) extended circuit modalities. In this article, we describe the five fundamentals, our formulation of the course, and impact and metrics data from two runs of the course through the edX platform.

Functional Diversity in the Retina Improves the Population Code.

Within a given brain region, individual neurons exhibit a wide variety of different feature selectivities. Here, we investigated the impact of this extensive functional diversity on the population neural code. Our approach was to build optimal decoders to discriminate among stimuli using the spiking output of a real, measured neural population and compare its performance against a matched, homogeneous neural population with the same number of cells and spikes. Analyzing large populations of retinal ganglion cells, we found that the real, heterogeneous population can yield a discrimination error lower than the homogeneous population by several orders of magnitude and consequently can encode much more visual information. This effect increases with population size and with graded degrees of heterogeneity. We complemented these results with an analysis of coding based on the Chernoff distance, as well as derivations of inequalities on coding in certain limits, from which we can conclude that the beneficial effect of heterogeneity occurs over a broad set of conditions. Together, our results indicate that the presence of functional diversity in neural populations can enhance their coding fidelity appreciably. A noteworthy outcome of our study is that this effect can be extremely strong and should be taken into account when investigating design principles for neural circuits.

Deep(er) Learning.

Animals successfully thrive in noisy environments with finite resources. The necessity to function with resource constraints has led evolution to design animal brains (and bodies) to be optimal in their use of computational power while being adaptable to their environmental niche. A key process undergirding this ability to adapt is the process of learning. Although a complete characterization of the neural basis of learning remains ongoing, scientists for nearly a century have used the brain as inspiration to design artificial neural networks capable of learning, a case in point being deep learning. In this viewpoint, we advocate that deep learning can be further enhanced by incorporating and tightly integrating five fundamental principles of neural circuit design and function: optimizing the system to environmental need and making it robust to environmental noise, customizing learning to context, modularizing the system, learning without supervision, and learning using reinforcement strategies. We illustrate how animals integrate these learning principles using the fruit fly olfactory learning circuit, one of nature's best-characterized and highly optimized schemes for learning. Incorporating these principles may not just improve deep learning but also expose common computational constraints. With judicious use, deep learning can become yet another effective tool to understand how and why brains are designed the way they are.

أسس تصميم الدوائر المرنة کأحد التقنيات المستخدمة في إنتاج الملابس الذکية.

ملخص البحث إرتبط مفهوم الموضة سابقا بالشکل الجمالي، ولکن حاليا دخلت عليها مستجدات متنوعة بفضل التقدم العلمي والتکنولوجيا، مما أدى إلى ظهور الذکية .فلم تعد وظيفة الملابس والمنسوجات تنحصر في الوظائف الجسدية فقط مثل الحماية ولکنها إمتدت لتشمل الجانب التکنولوجي أيضا عن طريق دمج التکنولوجيا في المنسوجات من أجل الحصول علي وظائف جديدة. فلقد أدي التقدم الهائل في تکنولوجيا المنسوجات والملابس الذکية ومجال الإلکترونيات إلي نشأة جيل جديد من الملابس الوظيفية الذکية، وبناءا عليه يهدف البحث إلي التعرف علي تکنولوجيا الدوائر الإلکترونية المرنة المستخدمة في تصميم الملابس الذکية وکذلک عرض للخامات والأدوات المستخدمة في تنفيذها علي الملابس. ويتناول البحث أسس ومباديء تصميم الدوائر المرنة علي الأقمشة من خلال التطبيق العملي لعدد ست عينات منفذة بإستخدام کل من الليدات - البطاريات – الخيوط الموصلة – الحساس الضوئي - مفاتيح للتحکم بفتح وغلق الدائرة الإلکترونية، مع تطبيق طرق التوصيل المختلفة للليدات مع البطارية کالتوصيل علي التوالي والتوصيل علي التوازي، وتوظيف بعض إکسسوارات الملابس کمفتاح لفتح وغلق الدائرة الإلکترونية. Summery The concept of fashion was previously associated with aesthetics, but now it has undergone various innovations through scientific progress and technology, leading to the emergence of smart clothing. Garments and textiles are no longer limited to physical functions such as protection and coverage, but they also extend to integrating technology into textiles for new function. The advancement of textile technology, smart clothing and electronics has led to a new generation of smart functional clothing. The research aims to identify the flexible circuit technology used in smart clothing design. Display of materials and electronic tools used in implementation samples. The research produce principles of soft circuit design on fabrics through the practical application of six samples were applied using: LEDs, batteries, conductive threads, light sensor and switches to control the opening and closing of the electronic circuit. Apply different ways of connecting LEDs with battery, such as parallel and Series circuit, and use some of clothing accessories as a switch to open and close the electronic circuit.

Endocytosis as a stabilizing mechanism for tissue homeostasis

Cells in tissues communicate by secreted growth factors (GF) and other signals. An important function of cell circuits is tissue homeostasis: maintaining proper balance between the amounts of different cell types. Homeostasis requires negative feedback on the GFs, to avoid a runaway situation in which cells stimulate each other and grow without control. Feedback can be obtained in at least two ways: endocytosis in which a cell removes its cognate GF by internalization and cross-inhibition in which a GF down-regulates the production of another GF. Here we ask whether there are design principles for cell circuits to achieve tissue homeostasis. We develop an analytically solvable framework for circuits with multiple cell types and find that feedback by endocytosis is far more robust to parameter variation and has faster responses than cross-inhibition. Endocytosis, which is found ubiquitously across tissues, can even provide homeostasis to three and four communicating cell types. These design principles form a conceptual basis for how tissues maintain a healthy balance of cell types and how balance may be disrupted in diseases such as degeneration and fibrosis.

Circuit Design Features of a Stable Two-Cell System

Cell communication within tissues is mediated by multiple paracrine signals including growth factors, which control cell survival and proliferation. Cells and the growth factors they produce and receive constitute a circuit with specific properties that ensure homeostasis. Here, we used computational and experimental approaches to characterize the features of cell circuits based on growth factor exchange between macrophages and fibroblasts, two cell types found in most mammalian tissues. We found that themacrophage-fibroblast cell circuit isstable and robust to perturbations. Analytical screening of all possible two-cell circuit topologies revealed the circuit features sufficient for stability, including environmental constraint and negative-feedback regulation. Moreover, we found that cell-cell contact is essential for the stability of the macrophage-fibroblast circuit. These findings illustrate principles of cell circuit design and provide a quantitative perspective on cell interactions.

Improvement of magnetic induction-wire sawing process using a magnetic system

ABSTRACTMagnetic induction-free abrasive wire sawing is a hybrid process that applies a homogeneous magnetic field to transport more abrasives into the sawing channel. This causes the performance of wire sawing significantly improved. Magnetic field strength is a key factor in determining the magnetic force acting on the magnetic abrasives, then affecting the quantity of abrasives adsorbed on the saw wire surface. However, the background magnetic induction strength produced by two permanent magnets is limited in this process. To further investigate the influence of magnetic field strength on the wire sawing performance, a magnetic system, which is based on the magnetic circuit design principle and the structure of single-wire sawing machine, is designed and fabricated. The magnetic field characteristics of the designed magnetic system are investigated both by numerical simulations and experiments. An experimental setup that installs the fabricated magnetic system on the single-wire sawing machine is built to conduct the magnetic induction-wire sawing experiments. The results show that the optimal magnetic induction strength is about B0 = 135 mT. In this case, the kerf loss is decreased by 10% compared to the free abrasive wire sawing technology without a magnetic field.

Study and design on chemical oxygen demand measurement based on ultraviolet absorption

Chemical Oxygen Demand (COD) is an important parameter for the detection of organic pollutants in water. UV absorption detection method of COD is a simple physical method that can detect water samples online without secondary contamination from chemical reagent. In this paper, the detection of COD based on UV absorption method was studied. The UV absorption method was used to detect COD in water samples, and the COD online detection device was designed. Optical path and circuit design principle of the device were introduced to overcome the difficulties including weak signal and the output signal instability, and the size of the system was effectively reduced. Contrast experiments showed that the system performance and measurement results are reliable and can be used for accurate COD detection within its range (up to 1000mg/L).

Interrogating the topological robustness of gene regulatory circuits by randomization.

One of the most important roles of cells is performing their cellular tasks properly for survival. Cells usually achieve robust functionality, for example, cell-fate decision-making and signal transduction, through multiple layers of regulation involving many genes. Despite the combinatorial complexity of gene regulation, its quantitative behavior has been typically studied on the basis of experimentally verified core gene regulatory circuitry, composed of a small set of important elements. It is still unclear how such a core circuit operates in the presence of many other regulatory molecules and in a crowded and noisy cellular environment. Here we report a new computational method, named random circuit perturbation (RACIPE), for interrogating the robust dynamical behavior of a gene regulatory circuit even without accurate measurements of circuit kinetic parameters. RACIPE generates an ensemble of random kinetic models corresponding to a fixed circuit topology, and utilizes statistical tools to identify generic properties of the circuit. By applying RACIPE to simple toggle-switch-like motifs, we observed that the stable states of all models converge to experimentally observed gene state clusters even when the parameters are strongly perturbed. RACIPE was further applied to a proposed 22-gene network of the Epithelial-to-Mesenchymal Transition (EMT), from which we identified four experimentally observed gene states, including the states that are associated with two different types of hybrid Epithelial/Mesenchymal phenotypes. Our results suggest that dynamics of a gene circuit is mainly determined by its topology, not by detailed circuit parameters. Our work provides a theoretical foundation for circuit-based systems biology modeling. We anticipate RACIPE to be a powerful tool to predict and decode circuit design principles in an unbiased manner, and to quantitatively evaluate the robustness and heterogeneity of gene expression.

Augmented Buck Converter Design using Resonant Circuits for Fast Transient Recovery

High-performance buck converters are often required in modern power electronic applications. An augmented buck converter (a main buck converter with augmentation circuits) can achieve fast transient recovery and small output voltage deviation. Compared with other augmentation circuits, a resonant augmentation circuit offers potential electromagnetic interference reduction due to the relatively low $di/dt$ value and compacts the circuit through a reduced inductance for resonance. In this paper, the performance analysis of an augmented buck converter constructed with the resonant circuit are described in detail in terms of voltage-deviation band and power loss. A circuit design and control principle is also proposed for achieving the required voltage deviation for a given transient-detection delay. A 12-to-5-V converter prototype is built to verify the analysis and effectiveness of the proposed methodology. It is demonstrated that the voltage deviation is reduced from 360 to 200 mV using the proposed resonant augmentation circuits and control scheme. The efficiency study shows that the power loss varies from 0.02 to 0.72 W, when the repetition frequency of 5-to-10-A transients changes from 100 to 5 kHz.

The Bandgap Reference [A Circuit for All Seasons

Since its inception in the late 1960s, the bandgap circuit has served as an essential component in most integrated circuits. This simple, robust idea provides a temperature-independent (TI) voltage and a proportional-toabsolute-temperature (PTAT) current. In this article, we study the principles of bandgap circuit design.

Research on the Full Electronic Light Detector of the Coach

In order to solve the light failure problems that cannot be found in the process of coach running in time, a new type of full electronic automotive light detector is designed in this research. The detector, as one of fixed electrical parts, is installed on the coach central control box in the process of automobile manufacture. It, as a sensitive element, controls circuits to work through divider resistance in tandem with car lamps. This article introduces working principles of the detector and circuit design and its performance. The detector is subjected to the test by being installed on the coach. The result shows that it has excellent performance and the test has also set a trouble-free record of 500,000 km.

Research Trends in Formal Verification Process for Analog and Mixed Signal Design

Formal verification is one of the crucial stages of design phase that ensure the preciseness of the circuit design and its corresponding behavior with respect to specific system design. From last decade, there has been an abundant formal verification techniques introduced by the research community for analog and mixed signal circuits that used as an interface between analog and digital components. Owing to the maximized sophistication, and shrinking sizes of chip, analog, and mixed signal verification is encountering challenges in increasing verification requirement that calls for analyzing the prior techniques. The prime purpose of this paper is to discuss the most standard models, and techniques introduced till date and to excavate the various facts about their effectiveness in the area circuit design principles. The paper also discusses some of the critical research gaps explored from the study.

Employing threshold‐based behavior and network dynamics for the creation of memristive logic circuits and architectures

AbstractThis work focuses on the creation of logic circuits by employing the collective dynamics of assembles of reciprocal memristors. A novel circuit design methodology is described where the computing systems comprise passive memristors interfaced with active CMOS circuitry, working under already known circuit design principles from the CMOS technology. The accuracy and completeness of this straightforward methodology is demonstrated through SPICE simulations which are based on a threshold‐type device model for memristors. Overall, this work contributes to the creation of proper methodologies which will enable the development of efficient design flows for circuits and architectures comprising memristors. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The natural history of sound localization in mammals--a story of neuronal inhibition.

Our concepts of sound localization in the vertebrate brain are widely based on the general assumption that both the ability to detect air-borne sounds and the neuronal processing are homologous in archosaurs (present day crocodiles and birds) and mammals. Yet studies repeatedly report conflicting results on the neuronal circuits and mechanisms, in particular the role of inhibition, as well as the coding strategies between avian and mammalian model systems. Here we argue that mammalian and avian phylogeny of spatial hearing is characterized by a convergent evolution of hearing air-borne sounds rather than by homology. In particular, the different evolutionary origins of tympanic ears and the different availability of binaural cues in early mammals and archosaurs imposed distinct constraints on the respective binaural processing mechanisms. The role of synaptic inhibition in generating binaural spatial sensitivity in mammals is highlighted, as it reveals a unifying principle of mammalian circuit design for encoding sound position. Together, we combine evolutionary, anatomical and physiological arguments for making a clear distinction between mammalian processing mechanisms and coding strategies and those of archosaurs. We emphasize that a consideration of the convergent nature of neuronal mechanisms will significantly increase the explanatory power of studies of spatial processing in both mammals and birds.

Multicriteria global optimization for biocircuit design.

BackgroundOne of the challenges in Synthetic Biology is to design circuits with increasing levels of complexity. While circuits in Biology are complex and subject to natural tradeoffs, most synthetic circuits are simple in terms of the number of regulatory regions, and have been designed to meet a single design criterion.ResultsIn this contribution we introduce a multiobjective formulation for the design of biocircuits. We set up the basis for an advanced optimization tool for the modular and systematic design of biocircuits capable of handling high levels of complexity and multiple design criteria. Our methodology combines the efficiency of global Mixed Integer Nonlinear Programming solvers with multiobjective optimization techniques. Through a number of examples we show the capability of the method to generate non intuitive designs with a desired functionality setting up a priori the desired level of complexity.ConclusionsThe methodology presented here can be used for biocircuit design and also to explore and identify different design principles for synthetic gene circuits. The presence of more than one competing objective provides a realistic design setting where every solution represents an optimal trade-off between different criteria.Electronic supplementary materialThe online version of this article (doi:10.1186/s12918-014-0113-3) contains supplementary material, which is available to authorized users.