A High Temperature 4H-SiC Voltage Reference for Depletion Mode GaN-Based Circuits

2017 ◽  
Vol 2017 (HiTEN) ◽  
pp. 000118-000121
Author(s):  
ZiHao Zhang ◽  
Jebreel M. Salem ◽  
Dong Sam Ha

Abstract High temperature electronics are highly demanded for many applications such as automotive, space, and oil and gas exploration. Electronic circuits for those applications are required to operate reliably without using bulky cooling systems. Circuits based on silicon (Si) suffer from high leakage currents at high temperatures. Silicon Carbide (SiC) circuits, on the other hand, are suitable for high temperature applications due to the wide bandgap and offer high breakdown voltage and low leakage current. This paper presents a negative voltage reference for high temperature applications using commercial-off-the-shelf (COTS) 4H-SiC transistors. The proposed voltage reference adopts Widlar bandgap reference topology, and it aims to provide a negative reference voltage for Gallium Nitride (GaN) circuits operating at high temperatures. Measurement results indicate that the proposed circuit provides a negative reference voltage with a low temperature coefficient of 42 ppm/°C for temperatures ranging from 25 °C to 250 °C. The proposed circuit also operates reliably for a wide supply voltage range of −7.5 V to −15 V for the temperature range.

2019 ◽  
Vol 2019 (HiTen) ◽  
pp. 000099-000106
Author(s):  
Tom Morris

Abstract The use and growth of high temperature electronics in a variety of applications (such as oil and gas exploration and production, automotive under the hood, aerospace and satellite/space to name a few), has necessitated a closer look at the technology used in passive components (such as resistors). A variety of resistor technologies may be suitable for high temperature applications. In the paper information, on thin film technologies (both nichrome and tantalum nitride thin film information is presented), thick film, and wire-wound construction is presented, with discussions regarding their respective characteristics that make them more or less suitable for high temperature and other excessive environments. This paper presents information on resistor construction details, material information and manufacturing processing, along with test data and performance summaries under short and long term high temperature conditions. Additionally, other pertinent test data through typical environmental tests is presented Although resistors and other passive components are often taken for granted, high temperature applications can tax the performance of many resistor types. The proper selection of resistive components will insure that the stability, temperature coefficient (and temperature coefficient tracking for resistor networks), and reliability is maintained to insure reliable circuit performance.


2020 ◽  
Vol 15 (3) ◽  
pp. 1-12
Author(s):  
Ana Isabela Araújo Cunha ◽  
Antonio José Sobrinho De Sousa ◽  
Edson Pinto Santana ◽  
Robson Nunes De Lima ◽  
Fabian Souza De Andrade ◽  
...  

This work presents a CMOS four quadrant analog multiplier architecture for application as the synapse element in analog cellular neural networks. For this reason, the circuit has voltage-mode inputs and a current-mode output and the chief design targets are compactness and low energy consumption. A signal application method is proposed that avoids voltage reference generators, which contributes to reduce sensitivity to supply voltage variation. Performance analysis through simulation has been accomplished for a design in CMOS 130 nm technology with 163 µm2 total active area. The circuit features ±50 mV input voltage range, 86 µW static power and ‑28.4 dB maximum total harmonic distortion. A simple technique for manual calibration is also presented.


RSC Advances ◽  
2019 ◽  
Vol 9 (58) ◽  
pp. 33733-33746
Author(s):  
Zhifeng Luo ◽  
Nanlin Zhang ◽  
Liqiang Zhao ◽  
Lin Wu ◽  
Pingli Liu ◽  
...  

Oil and gas exploration and development extends from medium-low temperatures to high and ultra-high temperatures with the development of the oil and gas industry.


Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1271
Author(s):  
Brito ◽  
Colombo ◽  
Moreno ◽  
El-Sankary

This work presents an investigation of the temperature behavior of self-cascode composite transistors (SCCTs). Results supported by silicon measurements show that SCCTs can be used to generate a proportional to absolute temperature voltage or even a temperature-compensated voltage. Based on the achieved results, a new circuit topology of a resistorless voltage reference circuit using a Schottky diode is also presented. The circuit was fabricated in a 130 nm BiCMOS process and occupied a silicon area of 67.98 µm × 161.7 µm. The averaged value of the output voltage is 720.4 mV, and its averaged line regulation performance is 2.3 mV/V, calculated through 26 characterized chip samples. The averaged temperature coefficient (TC) obtained through five chip samples is 56 ppm/°C in a temperature range from −40 to 85°C. A trimming circuit is also included in the circuit topology to mitigate the impact of the fabrication process effects on its TC. The circuit operates with a supply voltage range from 1.1 to 2.5 V.


2016 ◽  
Vol 49 (4) ◽  
pp. 1253-1265 ◽  
Author(s):  
Ralph Gilles ◽  
Debashis Mukherji ◽  
Lukas Karge ◽  
Pavel Strunz ◽  
Premysl Beran ◽  
...  

Co–Re alloys are being developed for ultra-high-temperature applications to supplement Ni-based superalloys in future gas turbines. The main goal of the alloy development is to increase the maximum service temperature of the alloy beyond 1473 K,i.e.at least 100 K more than the present single-crystal Ni-based superalloy turbine blades. Co–Re alloys are strengthened by carbide phases, particularly the monocarbide of Ta. The binary TaC phase is stable at very high temperatures, much greater than the melting temperature of superalloys and Co–Re alloys. However, its stability within the Co–Re–Cr system has never been studied systematically. In this study an alloy with the composition Co–17Re–23Cr–1.2Ta–2.6C was investigated using complementary methods of small-angle neutron scattering (SANS), scanning electron microscopy, X-ray diffraction and neutron diffraction. Samples heat treated externally and samples heatedin situduring diffraction experiments exhibited stable TaC precipitates at temperatures up to 1573 K. The size and volume fraction of fine TaC precipitates (up to 100 nm) were characterized at high temperatures within situSANS measurements. Moreover, SANS was used to monitor precipitate formation during cooling from high temperatures. When the alloy is heated the matrix undergoes an allotropic phase transformation from the ∊ phase (hexagonal close-packed) to the γ phase (face-centred cubic), and the influence on the strengthening TaC precipitates was also studied within situSANS. The results show that the TaC phase is stable and at these high temperatures the precipitates coarsen but still remain. This makes the TaC precipitates attractive and the Co–Re alloys a promising candidate for high-temperature application.


Author(s):  
Iurii Bogomol ◽  
Petro Loboda

The processing techniques, microstructures, and mechanical properties of directionally solidified eutectic ceramics are reviewed. It is considered the main methods for preparing of eutectic ceramics and the relationships between thermal gradient, growth rate, and microstructure parameters. Some principles of coupled eutectic growth, main types of eutectic microstructure and the relationship between the eutectic microstructure and the mechanical properties of directionally solidified eutectics at ambient and high temperatures are briefly described. The mechanical behavior and main toughening mechanisms of these materials in a wide temperature range are discussed. It is shown that the strength at high temperatures mainly depends on the plasticity of the phase components. By analyzing the dislocation structure, the occurrence of strain hardening in single crystalline phases during high-temperature deformation is revealed. The creep resistance of eutectic composites is superior to that of the sintered samples due to the absence of glassy phases at the interfaces, and the strain has to be accommodated by plastic deformation within the domains rather than by interfacial sliding. The microstructural and chemical stability of the directionally solidified eutectic ceramics at high temperatures are discussed. The aligned eutectic microstructures show limited phase coarsening up to the eutectic point and excellent chemical resistance. Directionally solidified eutectics, especially oxides, revealed an excellent oxidation resistance at elevated temperatures. It is shown sufficient potential of these materials for high-temperature applications.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wenxi Zhu ◽  
Xiuhua Zheng

Abstract Colloidal gas aphrons (CGA) are finding increasing application in depleted oil and gas reservoirs because of their distinctive characteristics. To overcome the limitations of its application in high-temperature drilling, a modified starch foams stabilizer WST with a temperature resistance of 160 °C was synthesized via radical polymerization. The chemical structure of WST was characterized by Fourier infrared spectroscopy and results showed that all three monomers acrylamide, 2-acrylamido-2-methyl-1-propane sulfonic acid, and N-vinylpyrrolidone have been grafted onto starch efficiently. Based on the microscopic observations, highly stable aphrons have been successfully generated in the WST-based CGA drilling fluids within 160 °C, and most aphrons lie in the range of 10–150 μm. WST can provide higher viscosity at high temperatures compared to xanthan gum, which helps to extend foam life and stability by enhancing the film strength and slowing down the gravity drainage. Results show that WST-CGA aged at elevated temperatures (120–160 °C) is a high-performance drilling fluid with excellent shear-thinning behavior, cutting carrying capacity, and filtration control ability. The significant improvement of filtration control and well-building capability at high temperatures is an important advantage of WST-CGA, which can be attributed to the enhancement of mud cake quality by WST.


2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Michael McKee ◽  
Faramarz Gordaninejad

This study reviews the work performed in the field of reciprocating shaft seals from the advent of the scientific topic in the 1940s. Concepts of leakage, film layers, friction, wear, and other concerns with shaft seals are discussed. The importance of shaft seals as it pertains to liquid springs is brought to light along with issues requiring a need for these seals to withstand high temperatures and high pressures. Issues resulting from a seal exposure to high temperatures, such as thermosetting and embrittlement, are discussed in conjunction with materials and properties that allow seals to operate in high-temperature environments. High-pressure sealing challenges are identified along with the techniques currently employed to overcome these issues, such as fiber reinforcement and backup rings. Sealing solutions have been implemented independently for both high-pressure and high-temperature applications; however, the combination of high pressures coupled with high temperatures is still a challenge today.


2011 ◽  
Vol 679-680 ◽  
pp. 754-757 ◽  
Author(s):  
Viorel Banu ◽  
Phillippe Godignon ◽  
Xavier Jordá ◽  
Mihaela Alexandru ◽  
José Millan

This work demonstrates that a stable voltage reference with temperature, in the 25°C-300°C range is possible using SiC bipolar diodes. In a previous work, we have been demonstrated both theoretical and experimentally, the feasibility of SiC bandgap voltage reference using SiC Schottky diodes [1]. The present work completes the investigation on SiC bandgap reference by the using of SiC bipolar diodes. Simulated and experimental results for two different SiC devices: Schottky and bipolar diodes showed that the principles that govern the bandgap voltage references for Si are also valid for the SiC. A comparison between the output voltage levels of the two types of bandgap reference is also presented.


Author(s):  
Michele Scervini

Recent progresses on the new Nickel based thermocouples for high temperature applications developed at the Department of Materials Science and Metallurgy of the University of Cambridge are described in this paper. Isothermal drift at temperatures above 1000°C as a function of the thermocouple diameter has been studied for both conventional Nickel based thermocouples and the new Nickel based thermocouple. The new Nickel based thermocouple experiences a much reduced drift compared to conventional sensors. Tests in thermal cyclic conditions have been undertaken on conventional and new Nickel based thermocouples, showing a clear improvement for the new sensors at temperatures both higher and lower than 1000°C. The improvements achievable with the new Nickel based thermocouple in both isothermal and thermal cycling conditions suggest that the new sensor can be used at high temperatures, where current conventional sensors are not reliable, as well as at temperatures lower than 1000°C with improved performance compared to conventional sensors.


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