As an ultra-wide bandgap semiconductor, <inline-formula> <tex-math notation="LaTeX">\beta </tex-math></inline-formula>-Ga 2 O 3 has attracted great attention for high-power, high-voltage, and ...optoelectronic applications. However, until now, high-frequency performance of gallium oxide devices has been limited to relatively low current gain cutoff frequencies below 5 GHz. Here, we show that highly localized delta-doping designs can enable high-sheet-charge density to enable devices with short gate lengths that allow high-frequency operation. Field-effect transistors with a gate length of 120 nm on such delta-doped <inline-formula> <tex-math notation="LaTeX">\beta </tex-math></inline-formula>-Ga 2 O 3 are reported here with extrinsic unity current gain frequency of 27 GHz. The device has a peak drain current of 260 mA/mm, transconductance (gm) of 44 mS/mm, and three-terminal off-state breakdown voltage of 150 V. These results demonstrate that the potential of <inline-formula> <tex-math notation="LaTeX">\beta </tex-math></inline-formula>-Ga 2 O 3 for future RF and millimeter-wave device applications.
This article proposes a health indicator estimation method based on the digital-twin concept aiming for condition monitoring of power electronic converters. The method is noninvasive, without ...additional hardware circuits, and calibration requirements. An application for a buck dc-dc converter is demonstrated with theoretical analyses, practical considerations, and experimental verifications. The digital replica of an experimental prototype is established, which includes the power stage, sampling circuit, and close-loop controller. Particle swarm optimization algorithm is applied to estimate the unknown circuit parameters of interest based on the incoming data from both the digital twin and the physical prototype. Cluster-data of the estimated health indicators under different testing conditions of the buck converter is analyzed and used for observing the degradation trends of key components, such as capacitor and MOSFET. The outcomes of this article serve as a key step for achieving noninvasive, cost-effective, and robust condition monitoring for power electronic converters.
The stochastic switching mechanism and intrinsic variability of resistive random access memory (RRAM) present severe challenges for memory applications, which, however, may be utilized to implement ...the physical unclonable function (PUF) for hardware security. A PUF based on RRAM resistance variability is proposed in this letter. Unlike PUFs based on manufacturing variation, this proposal exploits an intrinsic variability in physical mechanisms with reconfigurability. Key characteristics of the PUF design are assessed by simulation using measured RRAM properties and device model. Truly random variation of RRAM resistance is critical for PUF uniqueness (or unclonability). The reliability (or robustness) of the proposed PUF is affected by temperature and voltage dependence of RRAM resistance as well as retention characteristics. Large separation between inter-chip and intra-chip Hamming distance as the measure of uniqueness and reliability confirms the feasibility of the PUF proposal.
This article mainly concerns the performance improvement of active flux (AF)-based sensorless control for permanent magnet synchronous machines (PMSMs) in the low-speed range. An adaptive position ...observer based on the AF model is adopted to provide rotor position estimate. A convenient implementation of phase voltage measurement circuit mainly consists of a divider and a low-pass filter (LPF) is designed. Then, the AF-based observer uses the measured phase voltages directly instead of command voltages. Meanwhile, the phase shift and amplitude attenuation due to the hardware LPF are compensated. Moreover, a robust online resistance and inductance identification strategy is integrated to the position observer. The high-frequency sinusoidal voltages are imposed on the <inline-formula><tex-math notation="LaTeX">\alpha \beta</tex-math></inline-formula>-axis to identify the <inline-formula><tex-math notation="LaTeX">d</tex-math></inline-formula>- and <inline-formula><tex-math notation="LaTeX">q</tex-math></inline-formula>-axis inductances, and the dc voltage injected on the <inline-formula><tex-math notation="LaTeX">\alpha</tex-math></inline-formula>-axis is used to identify the resistance. The experimental results carried out on a 150-W PMSM drive demonstrate the effectiveness of the proposed sensorless control strategy. With the use of phase voltage measurements, the low-speed operating range can be extended and speed reversal can also be implemented. And the online multiple parameter identification can improve the accuracy of the estimated position.
This paper reviews the latest development and emerging technologies on the application of process tomography to multiphase flow measurement in industrial and biomedical fields. In the industrial ...applications, electrical resistance tomography and electrical capacitance tomography are popularly applied in multiphase flow measurement dependent on the electrical properties of the objects. In particular, applications to circulating fluidized bed, trickle-bed reactor and temperature measurement are discussed. In the biomedical applications, in most cases, measurement is conducted in a static condition. Two latest applications in flowing condition are reviewed, which are thrombus detection in blood flow and cell sensing with a microfluidic device. Finally, the challenges to process tomography for multiphase flow measurement on industrial and biomedical applications are addressed.
The traditional testing methods for freezing point measurement cannot accurately and quickly determine the freezing points of soils with a low water content and/or oil. Therefore, a new measurement ...method, which is more precise and has less error or deviation, was developed to determine the freezing point of soil and was verified by a series of laboratory tests. Additionally, the effects of oil content, water content, soil type, and dry density on freezing point were investigated. The results show that the water/oil mixing sequence remarkably affects the freezing point of sandy organic silt and lean clay; however, it does not affect the freezing point of poorly graded sand with silty clay. At water contents of <15%, the water content affects the freezing point more than the oil content does. At a water content of 5%, the freezing point decreases with increasing oil content. The effect of oil content on freezing point gradually decreases with increasing water content. At the same water and oil contents, the freezing point decreases with decreasing grain size. Moreover, the dry density has little effect on freezing point. The experimental results reveal the factors affecting the freezing point and their influencing mechanism, and provide important thermal parameters for thermal calculation for cold regions engineering.
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•A new testing method was developed to determine the freezing point of oil-contaminated soils.•The water/oil mixing sequence remarkably affects the freezing points of the three soils.•The water content affects the freezing point more than the oil content does.•Freezing point decreases with decreasing grain size.
RRAM crossbar consisting of memristor devices can naturally carry out the matrix-vector multiplication; it thereby has gained a great momentum as a highly energy-efficient accelerator for ...neuromorphic computing. The resistance variations and stuck-at faults in the memristor devices, however, dramatically degrade not only the chip yield, but also the classification accuracy of the neural-networks running on the RRAM crossbar. Existing hardware-based solutions cause enormous overhead and power consumption, while software-based solutions are less efficient in tolerating stuck-at faults and large variations. In this paper, we propose an accelerator-friendly neural-network training method, by leveraging the inherent self-healing capability of the neural-network, to prevent the large-weight synapses from being mapped to the abnormal memristors based on the fault/variation distribution in the RRAM crossbar. Experimental results show the proposed method can pull the classification accuracy (10%-45% loss in previous works) up close to ideal level with ≤ 1% loss.
Online junction temperature <inline-formula><tex-math notation="LaTeX">({{T_j}})</tex-math></inline-formula> measurement enables robust power converter operations by providing overtemperature ...protection and condition monitoring of the power devices. For SiC MOSFETs, the real-time <inline-formula><tex-math notation="LaTeX">{T_j}</tex-math></inline-formula> information is especially critical as limited field data are available regarding the reliability. In this article, utilizing the turn -on delay time as temperature sensitive electrical parameter, an online <inline-formula><tex-math notation="LaTeX">{T_j}</tex-math></inline-formula> measurement is realized through an intelligent gate drive. Specifically, the turn -on delay time is translated into the pulsewidth of a digital signal through the conditioning/logic circuits. During <inline-formula><tex-math notation="LaTeX">{T_j}</tex-math></inline-formula> measurements, the adjustable gate resistance circuit is activated to improve the measurement sensitivity beyond 600 ps/°C. Using the high-resolution capture module (300-ps resolution) in the system microcontroller, this pulsewidth is measured and then converted to junction temperature with a resolution of <0.5 °C. A prototype is built to validate the online <inline-formula><tex-math notation="LaTeX">{T_j}</tex-math></inline-formula> measurement method. The switching test results show that the circuit is able to precisely measure <inline-formula><tex-math notation="LaTeX">{T_{d,{\rm{on}}}</tex-math></inline-formula> and offers a good linearity/sensitivity for <inline-formula><tex-math notation="LaTeX">{T_j}</tex-math></inline-formula> estimation. In the continuous operation, the junction temperature of a decapsulated device using an infrared camera and <inline-formula><tex-math notation="LaTeX">{T_j}</tex-math></inline-formula> obtained from the circuit match well with <1 °C difference under various operating conditions. In addition, the gate-oxide degradation's impact on <inline-formula><tex-math notation="LaTeX">{T_{d,{\rm{on}}}</tex-math></inline-formula> is considered for SiC MOSFETs, and an aging compensation scheme is discussed to maintain the measurement accuracy throughout the device's lifetime. It is shown that the proposed circuit provides an accurate real-time <inline-formula><tex-math notation="LaTeX">{T_j}</tex-math></inline-formula> measurement for SiC MOSFETs, which can be deployed to improve the power converters' reliability.
A novel CMOS-compatible bond structure using Cu-to-Cu bonding with Ti passivation is demonstrated at low temperature and investigated. With the Ti protection of inner Cu, Cu bonding temperature can ...be reduced to 180 °C. In addition, excellent electrical stability against humidity and temperature cycling is achieved. Diffusion behavior and mechanism of Cu and Ti are also discussed. With excellent bond results and reliability, this bonded scheme has the potential to be applied in 3-D integration.
Constructing APN Functions Through Isotopic Shifts Budaghyan, Lilya; Calderini, Marco; Carlet, Claude ...
IEEE transactions on information theory,
2020-Aug., 2020-8-00, 2020-08, Letnik:
66, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Almost perfect nonlinear (APN) functions over fields of characteristic 2 play an important role in cryptography, coding theory and, more generally, mathematics and information theory. In this paper ...we deduce a new method for constructing APN functions by studying the isotopic equivalence, concept defined for quadratic planar functions in fields of odd characteristic. In particular, we construct a family of quadratic APN functions which provides a new example of an APN mapping over <inline-formula> <tex-math notation="LaTeX">{\mathbb F}_{2^{9}} </tex-math></inline-formula> and includes an example of another APN function <inline-formula> <tex-math notation="LaTeX">x^{9}+ \mathop {\mathrm {Tr}}\nolimits (x^{3}) </tex-math></inline-formula> over <inline-formula> <tex-math notation="LaTeX">{\mathbb F}_{2^{8}} </tex-math></inline-formula>, known since 2006 and not classified up to now. We conjecture that the conditions for this family are satisfied by infinitely many APN functions.
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