Browse Topic: Transistors

Items (397)
United States microchip fab plants can cram billions of data-processing transistors onto a tiny silicon chip, but the “clock,” which times the transistors’ operations, must be made separately, which creates a flaw in chip security as well as the supply line. However, a new approach uses commercial chip fab materials and techniques to fabricate specialized transistors to serve as the building block of the timing device
ABSTRACT The need for improved electrical power conversion systems and components is being driven by requirements for higher efficiency, performance, and improved survivability and lethality capabilities on current and future Army platform power system. The U.S. Army Research Laboratory (ARL) has demonstrated a 1200 V, 400 A silicon carbide (SiC) power module based on a standard commercial design. This module uses large area SiC MOS-FETs and diodes and has been evaluated under varying temperatures, loads, and switching frequencies. Throughout the operating range, the module has demonstrated improved efficiency and thermal performance, and higher frequency operation, when compared with similarly rated silicon insulated gate bipolar transistor (IGBT) modules
Geil, Bruce R.Tipton, Charles W.Urciuoli, Damian P.
ABSTRACT BAE Systems has developed a system level approach for identifying the issues associated with collocating Blue Force Communications with other on-board emitters. Specific scenarios include broadband interference caused by Electronic Warfare (EW) and radio congestion. Our approach is divided into three (3) functional areas to resolve this complex situation: (1) the proper selection and placement of Advanced Antenna Structures. (2) Receiver front end overloading protection through the use of a Wide Band Frequency Domain Cancellation Analog/Digital RF cancellation process. (3) The further refinement of the signal through the use of Digital Signal Processing for interference estimation, tracking, and cancellation based on efficient adaptive algorithms
Beltz, RandolphHombs, BandonMouyos, William
After announcing a ferroelectric semiconductor at the nanoscale thinness required for modern computing components, a University of Michigan team has demonstrated a reconfigurable transistor using that material. The study is featured in Applied Physics Letters
In the coming years, moving towards a hundred percent electric vehicles will be one of the key areas in the automotive industry. The main advantages of using e-mobility are operational flexibility, lower carbon emission and regenerative energy. Thermal management in an e-vehicle plays a vital role for the reliability of the system and any thermal failure can cost a significant amount of money to a company per vehicle. Inverter assembly is widely used to convert Direct Current (DC) to Alternating Current (AC) in the e-mobility platform to operate the motor for vehicle propulsion. It consists of various electronic transmitters, controllers, capacitors, and semi-conductors which will emit an enormous amount of heat during their operation. Since inverters are highly temperature sensitive in nature, it is necessary to improve the temperature distribution in the device. For this reason, adequate cooling system and ventilation is inevitable to keep the components operational. In this study
Govindarasu, AnbarasuT, SukumarSathyamoorthy, GugainamasivayamSubramanian, Vivek
A Northwestern University research team has developed a revolutionary transistor that is expected be ideal for lightweight, flexible, high-performance bioelectronics. The electrochemical transistor is compatible with blood and water and can amplify important signals
NASA’s Watts on the Moon Challenge is seeking solutions to transfer at least 1.065 kW power from a 120 V dc source to a 24-32 V dc load over a 3-km distance under the same environmental conditions as the Lunar surface (i.e., 77 K temperature and 1 mTorr pressure). The selected solution from the author’s team proposed utilizing two modular multilevel Gallium Nitride (GaN) based isolated dc-dc converters to connect the 120 V dc source with the 24-32 V dc load bank via 1.5 kV rated dc transmission lines. The modular multilevel converters feature frequency multiplication, high step-down voltage ratio and low device voltage stress. In the converters, GaN gate injection transistor (GaN GIT) and GaN High-Electron-Mobility Transistor (GaN HEMT) devices are chosen as switching devices, due to the merits of lower power loss, radiation hardness and ability to work under cryogenic and vacuum conditions. In addition, LiFePO4 battery based energy storage with a power condition system is added in
Yao, YuzhouZhang, ZhiningFan, JunchongAdina, NihanthBharmal, NaeemShah, SiddhantZhang, JesseShi, YifanHu, PhD, BoxueFu, PhD., PengyuWang, PhD., Jin
Ultrafine particles, in particular solid sub-100 nm particles pose high risks to human health due to their high lung deposition efficiency, translocation to all organs including the brain and their harmful chemical composition; due to dense traffic, the population in urban environments is exposed to high concentrations of those toxic air contaminants, despite these facts, they are still widely neglected. Therefore, the EU-Commission set up a program for clean and competitive solutions for different problem areas which are regarded to be hotspots of such particles. HORIZON AeroSolfd is an EU project, co-funded by Switzerland that will deliver affordable, adaptable, and sustainable retrofit solutions to reduce exhaust tailpipe emissions from petrol engines, brake emissions and pollution in semi-closed environments. VERT, a Swiss based international industry organization, has a long research history in the field of nanoparticle filtration and it is in charge of reducing tailpipe emissions
Rubino, LaurettaMayer, AndreasCzerwinski, JanLutz, ThomasLarsen, LarsEngelmann, DaniloLehmann, Martin
In modern electronics, a lot of heat is produced as waste during usage — hence why in-use devices become excessively hot and require cooling solutions. Over the last decade, the concept of managing such heat via electricity has been tested, leading to the development of electrochemical thermal transistors
The molecules in our bodies are in constant communication. Some of these molecules provide a biochemical fingerprint that could indicate how a wound is healing, whether or not a cancer treatment is working, or whether a virus has invaded the body. If we could sense these signals in real time with high sensitivity, then we might be able to recognize health problems faster and even monitor disease as it progresses
Two-dimensional materials, which consist of just a single layer of atoms, can be packed together more densely than conventional materials, so they could be used to make transistors, solar cells, LEDs, and other devices that run faster and perform better. One issue holding back these next-generation electronics is the heat they generate when in use. Conventional electronics typically reach about 80 °C, but the materials in 2D devices are packed so densely in such a small area that the devices can become twice as hot. This temperature increase can damage the device
Developers of aerospace and defense systems need RF power amplifiers (PAs) to perform much better across both existing and emerging applications such as military 5G and satellite communication. Systems need to meet higher gain targets but not if it comes with any increases in cost and complexity, or size and weight. As systems move to higher-order modulation schemes, they also must deliver adequate linearity and efficiency in an environment that is even more susceptible to distortion than was the case with earlier schemes. Reducing board space is another critical issue that has required challenging peak-to-average power ratio (PAPR) tradeoffs
The Grainger College of Engineering at the University of Illinois at Urbana–Champaign was established in 1868. The department has historically spearheaded worldwide innovation in technology with inventions such as the transistor, the integrated circuit, the LED, the first web browsers (Mosaic and Netscape), and (JavaScript) — all produced by students, faculty, or alumni of the college
This AIR provides guidance to the EMI test facility on how to check performance of the following types of EMI test equipment: Current probe Line Impedance Stabilization Network (LISN) Directional coupler Attenuator Cable loss Low noise preamplifier Rod antenna base Passive antennas All performance checks can be performed without software. A computer may be required to generate an electronic or hard copy of data. This is not to say that custom software might not be helpful; just that the procedures documented herein specifically eschew the necessity of automated operation
AE-4 Electromagnetic Compatibility (EMC) Committee
Pulse shaping, as it is done today, is an effort to fix fidelity issues caused by the transmitting amplifier and is accomplished by a combination of imperfect methods, most external to the amplifier. This article will explain a new approach that matches input pulse signal shape, minimizing droop, overshoot, ringing, and rise and fall times
A new composition of germanosili-cate glass created by adding zinc oxide has properties good for lens applications. The new family of zinc germanosilicate glass has a high refractive index comparable to that of pure germania glass. Samples showed high transparency, good ultraviolet-shielding properties, and good glass forming ability, making them suitable for lens applications. Germanosilicate glass is essential in the manufacture of optical amplifiers, waveguides, and solid-state lasers
The insulated-gate bipolar transistor (IGBT) is the most important part of a power converter. The heat generated during operation will cause the junction temperature of the IGBT to rise above ambient temperature. The junction temperature must stay within its predefined limit to ensure reliable operation. A properly designed cooling system is crucial for the overall operation, and an accurate prediction of power loss is critical in the design of a good thermal system. In this paper, a pulse-width modulation (PWM) full-bridge converter is designed for free-piston engine generators (FPEGs), and a low-cost forced-air cooling system is used for heat dissipation. For the converter to choose the IGBT module or discrete IGBT as the switching device, loss and thermal analyses are carried out. The loss analysis model of the converter is established, which considers the influence of the IGBT parasitic capacitance and gate driver voltage on the switching losses. The accuracy of the loss analysis
Wu, FanXu, ZhaopingLiu, Liang
Researchers devised and tested a highly sensitive method of detecting and counting defects in transistors — a matter of urgent concern to the semiconductor industry as it develops new materials for next-generation devices. These defects limit transistor and circuit performance and can affect product reliability
Although wireless charging pads already exist for smartphones, they only work if the phone is sitting still. For cars, that would be just as inconvenient as the current practice of plugging them in for an hour or two at charging stations
Electrically conducting polymers have made possible the development of flexible and lightweight electronic components such as organic biosensors, solar cells, light-emitting diodes, transistors, and batteries. The electrical properties of the conducting polymers can be tuned using a method known as “doping.” In this method, various dopant molecules are added to the polymer to change its properties. Depending on the dopant, the doped polymer can conduct electricity by the motion of either negatively charged electrons (an n-type conductor) or positively charged holes (a p-type conductor
Researchers at Chalmers University of Technology have developed an optical amplifier that they expect will revolutionize both space and fiber communication. The new amplifier offers high performance, is compact enough to integrate into a chip just millimeters in size, and crucially, does not generate excess noise
Ultrathin, flexible computer circuits have been an engineering goal for years but technical hurdles have prevented the degree of miniaturization necessary to achieve high performance. Now, researchers have invented a manufacturing technique that yields flexible, atomically thin transistors less than 100 nanometers in length — several times smaller than previously possible
To design better power converters with enhancement-mode Gallium Nitride high-electron-mobility transistor (eGaN HEMT) for emerging applications such as Electric Vehicles (EV), it is essential to model their switching transients and loss accurately. Analytical modeling has proved to be an effective approach to study the transistor’s dynamic behaviors and analyze the switching energy loss during the turn-on and turn-off transients. Furthermore, it helps to understand the essential factors that influence the switching transients and loss calculation. The accuracy of the analytical model mainly depends on the equivalent circuits and the parasitic parameters inside the transistor packaging and external circuits under different switching stages. It is always challenging to extract the parasitic parameters accurately due to its natural character of nonlinearity and complex correlation during the switching transients. In this article, a comprehensive analytical model is proposed considering
Tian, JamesLai, ChunyanLuo, YangTurco, StevenGangavarapu, SivanagarajuKorta, PhilipIyer, Lakshmi VarahaKar, NarayanVakacharla, VenkataRatnam
Like commercial communications, radar and electronic warfare (EW) systems must now function successfully in an increasingly crowded and, therefore, unpredictable electromagnetic spectrum operations environment (EMSO). In fact, the radio frequency (RF) spectrum grows only more congested as these intentional aerospace defense systems intersect with everything else that might interfere, such as terrestrial broadcast signals, different generations of cellular communications, and satellite communications. Modern threats and countermeasures flood the modern EM spectral environment with thousands of emitters, including radios, wireless devices, and radar transmissions. This, in conjunction with advanced digital signal processing (DSP), creates a dramatically complex electromagnetic spectrum
NASA Glenn has developed a method to correct for variations in transistor threshold voltage due to die location on the wafer for silicon carbide (SiC) op amps, enabling improved electrical circuits for sensor signal conditioning in harsh environments. Important system-level benefits are enabled by improved performance data from sensor circuitry mounted within very hot gas turbine flows or the primary coolant loop of a nuclear reactor, for example
Performance of solar cells and other electronic devices, such as transistors, can be improved greatly if carrier mobility is increased. Si and Ge have Type-II bandgap alignment in cubically strained and relaxed layers. Quantum well and superlattice with Si, Ge, and SiGe have been good noble structures to build high electron mobility layer and high hole mobility layers
Acoustical studies of atmospheric events like convective storms, tornadoes, shear-induced turbulence, micro-bursts, acoustic gravity waves, and hurricanes over the past 50 years have established that these events are strong emitters of infrasound. Current methods to forecast near-term weather phenomenon is electromagnetic (EM)-based radar and data from radiosondes
All of our most-used electronic devices rely on increasingly smaller microchips. One of the biggest hurdles to putting more circuits and power onto a smaller chip is managing the heat. As chips become smaller, heat increases exponentially. Not only are there more transistors in a given area — which generates more heat in a small space — but they also are closer together, making it harder for heat to dissipate
Superconductors — materials that conduct electricity without resistance — provide a macroscopic glimpse into quantum phenomena, which are usually observable only at the atomic level. Superconductors are found in medical imaging, quantum computers, and cameras used with telescopes. But often, they are expensive to manufacture and prone to error from environmental noise
A hacker can reproduce a circuit on a chip by discovering what key transistors are doing in a circuit — but not if the transistor type is undetectable. Engineers have demonstrated a way to disguise which transistor is which by building them out of a sheet-like material called black phosphorus. This built-in security measure would prevent hackers from getting enough information about the circuit to reverse-engineer it
Communications in space demand the most sensitive receivers possible for maximum reach, while also requiring high-bit-rate operations. A concept for laser beam-based communications using an almost noiseless optical preamplifier in the receiver has been developed. The free-space optical transmission system relies on an optical amplifier that, in principle, does not add any excess noise, in contrast to all other pre-existing optical amplifiers referred to as phase-sensitive amplifiers (PSAs
The main objective of the RadCNT program was the characterization of fundamental mechanisms and charge transport phenomena governing the interactions between ionizing and non-ionizing radiation with carbon-based (nanotube and graphene) field-effect transistors (FETs) devices and integrated circuits (ICs). This effort was supported through the fabrication of aligned single-walled carbon nanotubes (SWCNT) FETs at the University of Southern California’s (USC) Nanotechnology Research Laboratory and through a collaboration with the Naval Research Laboratories (NRL) for radiation testing and expertise in radiation effects characterization
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