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Liu, Hai Rui, e Jun Sheng Yu. "Characterization of Metal-Semiconductor Schottky Diodes and Application on THz Detection". Advanced Materials Research 683 (aprile 2013): 729–32. http://dx.doi.org/10.4028/www.scientific.net/amr.683.729.
Testo completoAbstract (sommario):
This paper presents a kind of air-bridged GaAs Schottky diodes which offer ultra low parasitic capacitance and series resistance in millimeter and THz wavelength. The Schottky barrier diodes have several advantages when used as millimeter wave and terahertz video, or power detectors. These include their fast time response, room temperature operation, simple structure and low cost. This paper describes the characterization of the metal-semiconductor Schottky diodes including principle, diode structure, non-linear voltage-current characteristic and signal-rectifying performance. For application, a quasi-optical THz detector was made by using the proposed Schottky diodes. It utilized a hyper hemispherical silicon lens to coupleand THz radiation to the diodes by integrating on a broadband planar bow-tie antenna. The measurement results of the Schottky diode based detector show a good room temperature performance.
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Levacq, David, Vincent Dessard e Denis Flandre. "Low Leakage SOI CMOS Static Memory Cell With Ultra-Low Power Diode". IEEE Journal of Solid-State Circuits 42, n. 3 (marzo 2007): 689–702. http://dx.doi.org/10.1109/jssc.2006.891494.
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Schwarz, Mike, Alexander Kloes e Denis Flandre. "Temperature-dependent performance of Schottky-Barrier FET ultra-low-power diode". Solid-State Electronics 184 (ottobre 2021): 108124. http://dx.doi.org/10.1016/j.sse.2021.108124.
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Lin, Ling, Zhong Tang, Nianxiong Tan e Xiaohui Xiao. "Power Management in Low-Power MCUs for Energy IoT Applications". Journal of Sensors 2020 (14 dicembre 2020): 1–12. http://dx.doi.org/10.1155/2020/8819236.
Testo completoAbstract (sommario):
In this paper, we identify and address the problems of designing effective power management schemes in low-power MCU design. Firstly, this paper proposes an application-based multipower domain architecture along with a variety of working modes to effectively realize the hierarchical control of power consumption. Furthermore, devices in energy IoT (eIoT) do not always work under the main power supply. When the main power supply is unavailable, the standby power supply (usually the battery) needs to maintain the operation and save the data. In order to ensure the complete isolation between these two power sources, it is always necessary to insert a diode in both select-conduction paths, respectively. In this paper, we built a stable and smooth power switching circuit into the chip, which can effectively avoid the diode voltage loss and reduce the BoM cost. In addition, in the sleep mode, considering the relaxed output voltage range and a limited driving capability requirement, an ultra-low-power standby power circuit is proposed, which can autonomously replace the internal LDO when in sleep, further reducing the sleep power consumption under the main power supply. Fabricated in a standard 0.11 μm CMOS process, our comparative analysis demonstrates substantial reduction in power consumption from 1 μA to 0.1 μA.
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Azevedo, Eduardo, Andressa Silva, Raquel Martins, Monica L. Andersen, Sergio Tufik e Gilberto M. Manzano. "Activation of C-fiber nociceptors by low-power diode laser". Arquivos de Neuro-Psiquiatria 74, n. 3 (marzo 2016): 223–27. http://dx.doi.org/10.1590/0004-282x20160018.
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ABSTRACT Objective The evaluation of selective activation of C-fibers to record evoked potentials using the association of low-power diode laser (810 nm), tiny-area stimulation and skin-blackening. Method Laser-evoked potentials (LEPs) were obtained from 20 healthy young subjects. An aluminum plate with one thin hole was attached to the laser probe to provide tiny-area stimulation of the hand dorsum and the stimulated area was covered with black ink. Results The mean intensity used for eliciting the ultra-late laser-evoked potential (ULEP) was 70 ± 32 mW. All subjects showed a clear biphasic potential that comprised a negative peak (806 ± 61 ms) and a positive deflection (1033 ± 60 ms), corresponding to the ULEP related to C-fiber activation. Conclusion C-fiber-evoked responses can be obtained using a very low-power diode laser when stimulation is applied to tiny areas of darkened skin. This strategy offers a non-invasive and easy methodology that minimizes damage to the tissue.
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Fernandes, Ricardo Dias, João Nuno Matos e Nuno Borges Carvalho. "Low‐power ultra‐wide band pulse generator based on a PIN diode". IET Microwaves, Antennas & Propagation 9, n. 11 (agosto 2015): 1230–32. http://dx.doi.org/10.1049/iet-map.2014.0491.
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Khindria, Ishita, Kashika Hingorani e Vandana Niranjan. "Low Power ALU using Wave Shaping Diode Adiabatic Logic". Indian Journal of VLSI Design 2, n. 2 (30 settembre 2022): 1–4. http://dx.doi.org/10.54105/ijvlsid.d1209.091422.
Testo completoAbstract (sommario):
The evolution of portable electronic devices and their widespread application has led to an increased focus on power dissipation as one of the critical parameters. An increase in functionality requirement and design complexity on a single chip has resulted in increased power dissipation. High power dissipation has motivated study and innovation on low power circuit design techniques. Adiabatic logic has been studied as one of the design techniques to reduce power dissipation by reusing the power that was getting dissipated in conventional designs. This paper presents the application of Wave Shaping Diode Adiabatic Logic (WSDAL) to implement an ALU and analyse the improvement in power dissipation as compared to the conventional CMOS design. The WSDAL design uses a slow and time-fluctuating 2-phase sinusoidal Power Clock (PC), which supplies power as well as a clock to the designs. WSDAL uses an Ultra-Low Power Diode (ULPD) structure that operates as a wave shaping device and reduces glitches at the output. The design has been implemented in OrCAD Capture and simulated using Pspice in TSMC 180nm technology. The simulations were performed at 200MHz PC frequency and power dissipation was studied over a range of voltages from 1.4V to 2.2V. The simulations show that WSDAL ALU dissipates less power than the CMOS design. This study indicates that WSDAL-based designs have the potential to be deployed for power dissipation reduction in portable devices.
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Chang, Yi Tsun, Yu Da Shiau, Po Chun Wu, Ren Hao Xue e Po Yu Cheng. "LDO of High Power Supply Rejection with Two-Stage Error Amplifiers and Buffer Compensation". Advanced Materials Research 989-994 (luglio 2014): 3236–39. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.3236.
Testo completoAbstract (sommario):
This study develops a low dropout regulator linear regulator, characterized by a high power supply rejection ratio using ultra-low output resistance buffer and two-stage error amplifiers. The high power supply rejection is based on a closed-loop LDO regulator. The ultra-low output resistance buffer achieves ultra-low output impedance with dual shunt feedback loops, subsequently improving load and line regulations, as well as the transient response for low voltage applications. The proposed LDO regulator linear regulator functions under an input voltage of 1.8~3V, and the output voltage can be maintained at around 1.27V. Moreover, its output voltage is independent of input voltage. The proposed regulator is applicable to light-emitting diode driver integrated circuits. The layout chip area of the LDO linear regulator is 21.5μm × 42.6μm.
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Matys, Maciej, Kazuki Kitagawa, Tetsuo Narita, Tsutomu Uesugi, Jun Suda e Tetsu Kachi. "Mg-implanted vertical GaN junction barrier Schottky rectifiers with low on resistance, low turn-on voltage, and nearly ideal nondestructive breakdown voltage". Applied Physics Letters 121, n. 20 (14 novembre 2022): 203507. http://dx.doi.org/10.1063/5.0106321.
Testo completoAbstract (sommario):
Vertical GaN junction barrier Schottky (JBS) diodes with superior electrical characteristics and nondestructive breakdown were realized using selective-area p-type doping via Mg ion implantation and subsequent ultra-high-pressure annealing. Mg-ion implantation was performed into a 10 μm thick Si-doped GaN drift layer grown on a free-standing n-type GaN substrate. We fabricated the JBS diodes with different n-type GaN channel widths Ln = 1 and 1.5 μm. The JBS diodes, depending on Ln, exhibited on-resistance ( RON) between 0.57 and 0.67 mΩ cm2, which is a record low value for vertical GaN Schottky barrier diodes (SBDs) and high breakdown (BV) between 660 and 675 V (84.4% of the ideal parallel plane BV). The obtained low RON of JBS diodes can be well explained in terms of the RON model, which includes n-type GaN channel resistance, spreading current effect, and substrate resistance. The reverse leakage current in JBS diodes was relatively low 103–104 times lower than in GaN SBDs. In addition, the JBS diode with lower Ln exhibited the leakage current significantly smaller (up to reverse bias 300 V) than in the JBS diode with large Ln, which was explained in terms of the reduced electric field near the Schottky interface. Furthermore, the JBS diodes showed a very high current density of 5.5 kA/cm2, a low turn-on voltage of 0.74 V, and no destruction against the rapid increase in the reverse current approximately by two orders of magnitude. This work demonstrated that GaN JBS diodes can be strong candidates for low loss power switching applications.
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Wang, Yunzhen, Shengxi Diao, Fujiang Lin e Haiquan Yuan. "An Ultra-Low Power Subthreshold CMOS RSSI for Wake-Up Receiver". Journal of Circuits, Systems and Computers 25, n. 08 (17 maggio 2016): 1650090. http://dx.doi.org/10.1142/s0218126616500900.
Testo completoAbstract (sommario):
This paper reports an ultra-low power received signal strength indicator (RSSI) for low frequency (LF) wake-up receiver. Topology theory analysis and subthreshold operation are performed to lower power consumption. Each gain stage of the subthreshold limiting amplifier (LA) employs cascade diode-connected loads to obtain high output impedance while maintaining low power. An offset cancelation circuit with different tail currents, which also operates in the subthreshold region, is employed to reduce the DC offset voltage. Unbalanced source-coupled pairs of subthreshold devices adopted in the full-wave rectification are optimized. A 45[Formula: see text]dB input dynamic range and [Formula: see text][Formula: see text]dB indicating error are achieved at 125[Formula: see text]KHz frequency. The prototype occupies an active area of 0.39[Formula: see text][Formula: see text][Formula: see text]0.28[Formula: see text]mm using CSMC 0.153-[Formula: see text]m complementary metal-oxide-semiconductor (CMOS) technology. With a 1.8[Formula: see text]V supply voltage, the overall current consumption is only 6[Formula: see text][Formula: see text]A.
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Li, R. N., S. T. Jia, D. Bloch e M. Ducloy. "Frequency-stabilization of a diode laser with ultra-low power through linear selective reflection". Optics Communications 146, n. 1-6 (gennaio 1998): 186–88. http://dx.doi.org/10.1016/s0030-4018(97)00478-1.
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Matsumoto, Kaori, Hiroki Asano, Yuichiro Nakazawa, Nobutaka Kuroki, Masahiro Numa, Osamu Maida, Daisuke Kanemoto e Tetsuya Hirose. "An 11.8 nA ultra-low power active diode using a hysteresis common gate comparator for low-power energy harvesting systems". IEICE Electronics Express 17, n. 11 (10 giugno 2020): 20200103. http://dx.doi.org/10.1587/elex.17.20200103.
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Wagih, Mahmoud, Alex S. Weddell e Steve Beeby. "Powering E-Textiles Using a Single Thread Radio Frequency Energy Harvesting Rectenna". Proceedings 68, n. 1 (25 gennaio 2021): 16. http://dx.doi.org/10.3390/proceedings2021068016.
Testo completoAbstract (sommario):
Radio frequency energy harvesting (RFEH) and wireless power transfer (WPT) are increasingly seen as a method of enabling sustainable computing, as opposed to mechanical or solar EH WPT does not require special materials or resonators and can be implemented using low-cost conductors and standard semiconductor devices. This work revisits the simplest antenna design, the wire monopole to demonstrate the lowest-footprint, lowest-cost rectifying antenna (rectenna) based on a single Schottky diode. The antenna is fabricated using a single Litz-wire silk-coated thread, embroidered into a standard textile substrate. The rectifier is fabricated on a compact low-cost flexible printed circuit board (PCB) using ultra-thin polyimide copper laminates to accommodate low-footprint surface mount components. The antenna maintains its bandwidth across the 868/915 MHz license-free band on- and off-body with only −4.7 dB degradation in total efficiency in human proximity. The rectenna achieves up to 55% RF to DC efficiency with 1.8 V DC output, at 1 mW of RF power, demonstrating its suitability as a power-supply unit for ultra-low power e-textile nodes.
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Garcia-Garcia, Joan J. "Considerations for the Design and Implementation of Ambient RF Signal Rectifiers in the 2.45 GHz WiFi Band". Applied Sciences 12, n. 15 (5 agosto 2022): 7884. http://dx.doi.org/10.3390/app12157884.
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Ambient RF energy harvesting (RF-EH) is a particular case of wireless power transfer (WPT), which is characterized by ultra-low power operation. This work points out theoretical and practical aspects that should be considered in the design of RF rectifiers for ambient RF energy harvesting systems. The most common RF rectifier circuits are compared and discussed using simulations and experimental data. The efficiency is analyzed in terms of the input power and load resistance. It is demonstrated that the most efficient RF rectifier in ultra-low power conditions is the simple diode capacitor structure. As an illustrative example, an RF rectifier has been fabricated by designing an impedance-matching network to operate into the WIFI band. The fabricated prototype shows a measured 12% efficiency working at 2.47 GHz with around −30 dBm ambient input power, which is higher than the reported efficiencies in the literature. The fabricated energy harvesting system delivers power between 25.6 nW and 129.6 nW to a resistive 10 kΩ load. The obtained results are applicable to ambient RF up to 6 GHz.
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Goto, Taiga, Takuma Shirai, Akira Tokuchi, Takashi Naito, Kenji Fukuda e Noriyuki Iwamuro. "Experimental Demonstration on Ultra High Voltage and High Speed 4H-SiC DSRD with Smaller Numbers of Die Stacks for Pulse Power". Materials Science Forum 924 (giugno 2018): 858–61. http://dx.doi.org/10.4028/www.scientific.net/msf.924.858.
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This paper presents the experimental results of static and dynamic characteristics of the newly developed 14 kV 4H-SiC high-speed drift step recovery diode (DSRD) for pulse power applications for the first time. The feature of the diode structure is to be designed based upon the p+/p-/n+ structure and is to make an additional extremely low doping and thin n-drift layer between the p-drift layer and n+ substrate. This device successfully exhibits higher breakdown voltage of 14kV and high-speed voltage pulse in a range of a few nanoseconds, simultaneously.
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Liu, Yuewei, Ruixia Yang, Yongwei Wang, Zhiguo Zhang e Xiaochuan Deng. "Theoretical and Experimental Study of 13.4 kV/55 A SiC PiN Diodes with an Improved Trade-Off between Blocking Voltage and Differential On-Resistance". Materials 12, n. 24 (12 dicembre 2019): 4186. http://dx.doi.org/10.3390/ma12244186.
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In this paper, a 13.4 kV/55 A 4H-silicon carbide (SiC) PiN diode with a better trade-off between blocking voltage, differential on-resistance, and technological process complexity has been successfully developed. A multiple zone gradient modulation field limiting ring (MGM-FLR) for extremely high-power handling applications was applied and investigated. The reverse blocking voltage of 13.4 kV, close to 95% of the theoretical value of parallel plane breakdown voltage, was obtained at a leakage current of 10 μA for a 100 μm thick, lightly doped, 5 × 1014 cm−3 n-type SiC epitaxial layer. Meanwhile, a fairly low differential on-resistance of 2.5 mΩ·cm2 at 55 A forward current (4.1 mΩ·cm2 at a current density of 100 A/cm2) was calculated for the fabricated SiC PiN with 0.1 cm2 active area. The highest Baliga’s figure-of-merit (BFOM) of 72 GW/cm2 was obtained for the fabricated SiC PiN diode. Additionally, the dependence of the breakdown voltage on transition region width, number of rings in each zone, as well as the junction-to-ring spacing of SiC PiN diodes is also discussed. Our findings indicate that this proposed device structure is one potential candidate for an ultra-high voltage power system, and it represents an option to maximize power density and reduce system complexity.
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Aziz, Jamal, Honggyun Kim e Deok-Kee Kim. "(Digital Presentation) Power Efficient Transistors with Low Subthreshold Swing Using Abrupt Switching Devices". ECS Meeting Abstracts MA2022-02, n. 35 (9 ottobre 2022): 1283. http://dx.doi.org/10.1149/ma2022-02351283mtgabs.
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With the rapid development of transparent integrated circuits, transistors with extremely low subthreshold swing (SS) is becoming a necessary requirement. Here, we fabricated three transparent device structures that show abrupt electrical switching and make their series connection to the source terminal of the conventional field effect transistors (FET) to lower the SS value. Firstly, we demonstrate an environment friendly, disposable, and transparent conductive bridge random access memory (CBRAM) device composed of a cellulose nanocrystals active layer. Our CBRAM consists of a silver (Ag) electrochemically active top electrode and a cellulose nanocrystals-based switching layer on the FTO coated glass substrate. Devices with CBRAM can enable FET with an ultra-steep slope that is SS < 0.24 mV/dec and has a significantly high on/off ratio (~105) by switching the Ag metallic filament between on and off. Niobium oxide (NbO2) based threshold switching devices and zinc oxide (ZnO) based flexible Schottky diodes that show electrical breakdown were also stacked with FET, which gave SS values < 0.74 mV/dec and < 5.20 mV/dec, respectively. Comparatively, a nano-watt transistor called filament transistor (FET + CBRAM stack) can significantly improve the SS slope value with the lowest leakage current (~nA) and a record low turn on-voltage (~0.2 V) with a set power of only ~197 nW compared to the other series stack, which thereby attracts the attention of low power operations. Keywords: filament transistor, threshold switching, Schottky diode, subthreshold swing, on/off ratio Figure 1
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De Souza, Michelly, Bertrand Rue, Denis Flandre e Marcelo A. Pavanello. "Performance of Ultra-Low-Power SOI CMOS Diodes Operating at Low Temperatures". ECS Transactions 35, n. 5 (16 dicembre 2019): 325–30. http://dx.doi.org/10.1149/1.3570813.
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Sanadhya, Minakshi, e Devendra Kumar Sharma. "Low power architecture of logic gates using adiabatic techniques". Indonesian Journal of Electrical Engineering and Computer Science 25, n. 2 (1 febbraio 2022): 805. http://dx.doi.org/10.11591/ijeecs.v25.i2.pp805-813.
Testo completoAbstract (sommario):
The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
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Algamluoli, Ammar Falah, e Xiaohua Wu. "A New Single-Cell Hybrid Inductor-Capacitor DC-DC Converter for Ultra-High Voltage Gain in Renewable Energy Applications". Electronics 12, n. 14 (17 luglio 2023): 3101. http://dx.doi.org/10.3390/electronics12143101.
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In this paper, a new single-cell hybrid switched inductor DC-DC converter is proposed to demonstrate the verification of ultra-high voltage gain in renewable energy applications (REA). The modification involves adding a single cell of an inductor with a diode and double capacitor to increase voltage transfer gain. Additionally, this modification helps prevent the input current from becoming zero, pulsating at very low duty cycles. The single cell of the hybrid inductor is interleaved with the main switch to reduce current stress when the capacitor of the single-cell inductor charge becomes zero. Moreover, the addition of a modified hybrid switch inductor with a capacitor, operating in dual boosting mode with a single switch, allows the converter to achieve ultra-high voltage gain. The proposed converter offers several advantages, including ultra-high voltage gain, high efficiency, low voltage stress on power MOSFETs, diodes, inductors, and capacitors, as well as low switching and conduction losses. Furthermore, the proposed converter utilizes transformerless and non-coupled inductors. Mathematical equations have been derived for the discontinuous conduction mode (DCM) and continuous conduction mode (CCM) and implemented using Matlab Simulink software to validate the results. In addition, a dual PI controller is designed for the proposed converter to verify the fixed output voltage. Experimental results have also been obtained for a 200 W prototype, with the input voltage varying between 20 V and 40 V, and an output voltage of 200 V at an efficiency of 96.5%.
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Moghaddam, Majid, Mohammad Hossein Moaiyeri, Mohammad Eshghi e Ali Jalali. "A Low-Power Multiplier Using an Efficient Single-Supply Voltage Level Converter". Journal of Circuits, Systems and Computers 24, n. 08 (12 agosto 2015): 1550124. http://dx.doi.org/10.1142/s0218126615501248.
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This paper presents a new high-performance and low-power single-supply voltage level converter (SSLC) and a new carry save array multiplier based on clustered-voltage scaling (CVS) technique for ultra-low-power applications. The multiplier operates with low and high supply voltage (V DDL , V DDH ) and at its end stage, the proposed low-power SSLC is utilized to prevent static power dissipation at the next stage working with V DDH and to enhance the output driving capability. In the proposed SSLC, dynamically-controlled source-body voltage, reduced drain induced barrier lowering (DIBL) effect and diode-connected transistor with body-biasing have been utilized properly in order to reduce the power consumption significantly without considerable speed degradation. The results of the simulations conducted using Cadence with standard 90-nm CMOS technology demonstrate the superiority of the proposed multiplier utilizing the proposed LC in terms of static and total power consumptions as well as power-delay product (PDP) as compared to the multipliers utilizing the previous level converters (LCs) and the single supply multiplier. It is worth mentioning that the static power, total power and PDP of the proposed low-power multiplier are on average 75%, 73% and 16%, respectively lower than the single-supply multiplier.
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Cho, Kunhee. "An Ultra-Low Quiescent Current Under-Voltage Lockout Circuit for a High-Voltage Gate Driver IC". Electronics 9, n. 10 (20 ottobre 2020): 1729. http://dx.doi.org/10.3390/electronics9101729.
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An ultra-low quiescent current under-voltage lockout (UVLO) circuit for a high-voltage gate driver integrated circuit (HVIC) is described for application in portable devices. The UVLO circuit consumes the static current in the high-side circuitry and the resistive divider used to detect the supply-voltage was the major consumer of power in the circuit. Hence, a supply-voltage sensor based on a diode-connected metal–oxide–semiconductor field-effect transistor (MOSFET) with a voltage limiter design is proposed to ensure low power consumption. Unlike the conventional UVLO design, where a resistive divider is used, the proposed structure dissipates the negligible current at a low supply-voltage and significantly reduces the static current at the nominal and high supply-voltage. The high-side quiescent current using the proposed design and the conventional designs at various supply-voltage levels are analyzed. In the proposed structure, the size of the voltage sensor is considerably smaller when compared with those in conventional designs.
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Arahira, S., N. Mineo, K. Tachibana e Y. Ogawa. "40 GHz hybrid modelocked laser diode module operated at ultra-low RF power with impedance-matching circuit". Electronics Letters 39, n. 3 (2003): 287. http://dx.doi.org/10.1049/el:20030215.
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Man, Jia-Xiu, Jun-Tao Hu, Deng-Ke Wang, Shou-Jie He e Zheng-Hong Lu. "Ytterbium oxide electron injection interface in organic light-emitting diode". Applied Physics Letters 120, n. 12 (21 marzo 2022): 121101. http://dx.doi.org/10.1063/5.0084140.
Testo completoAbstract (sommario):
The ytterbium oxide (Yb3+) is found to have an extremely low work function of 2.42 eV, which is even lower than that of its metallic form Yb0 (2.64 eV). The stability of oxides makes Yb3+ an ideal electron injection material for both top-emitting and bottom-emitting organic light-emitting diodes (TOLED and BOLED). The device test data indeed show that at 1000 nit luminance, the TOLED has a 94 cd/A current efficiency and 70 lm/W power efficiency, and BOLED has a 76 cd/A and 60 lm/W efficiency, respectively. X-ray and ultraviolet photoemission spectroscopical studies indicate that the Fermi level of the metal oxide is pinned to the lowest unoccupied molecular orbital of the electron transport layer, leading to the formation of a cathode interface with an ultra-low electron injection barrier.
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Centurelli, Francesco, Riccardo Della Sala, Pietro Monsurrò, Giuseppe Scotti e Alessandro Trifiletti. "A Tree-Based Architecture for High-Performance Ultra-Low-Voltage Amplifiers". Journal of Low Power Electronics and Applications 12, n. 1 (17 febbraio 2022): 12. http://dx.doi.org/10.3390/jlpea12010012.
Testo completoAbstract (sommario):
In this paper, we introduce a novel tree-based architecture which allows the implementation of Ultra-Low-Voltage (ULV) amplifiers. The architecture exploits a body-driven input stage to guarantee a rail-to-rail input common mode range and body-diode loading to avoid Miller compensation, thanks to the absence of high-impedance internal nodes. The tree-based structure improves the CMRR of the proposed amplifier with respect to the conventional OTA architectures and allows achievement of a reasonable CMRR even at supply voltages as low as 0.3 V and without tail current generators which cannot be used in ULV circuits. The bias currents and the static output voltages of all the stages implementing the architecture are accurately set through the gate terminals of biasing transistors in order to guarantee good robustness against PVT variations. The proposed architecture and the implementing stages are investigated from an analytical point of view and design equations for the main performance metrics are presented to provide insight into circuit behavior. A 0.3 V supply voltage, subthreshold, ultra-low-power (ULP) OTA, based on the proposed tree-based architecture, was designed in a commercial 130 nm CMOS process. Simulation results show a dc gain higher than 52 dB with a gain-bandwidth product of about 35 kHz and reasonable values of CMRR and PSRR, even at such low supply voltages and considering mismatches. The power consumption is as low as 21.89 nW and state-of-the-art small-signal and large-signal FoMs are achieved. Extensive parametric and Monte Carlo simulations show the robustness of the proposed circuit to PVT variations and mismatch. These results confirm that the proposed OTA is a good candidate to implement ULV, ULP, high performance analog building blocks for directly harvested IoT nodes.
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Zhang, Xiao Feng, Fo Chang Xie, Guo Wei Yang e Wei Zhang. "The Transceiver Circuit Design of Digital Ultrasonic System". Advanced Materials Research 834-836 (ottobre 2013): 968–73. http://dx.doi.org/10.4028/www.scientific.net/amr.834-836.968.
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This paper introduces the design process of the digital ultrasonic transmission circuit: echo receiving circuit and the echo signal regulate circuit. Among them, outside 500 V DC - DC module for high voltage power input, use non-tuned type circuit design ultrasonic transmission circuit ; Select high voltage fast recovery diode FR107 design echo receiving limiter circuit; Using ultra-high speed, low noise, low distortion of the integrated operational amplifier MAX4104ESA design preamplifier circuits and the band-pass filter circuits; Using linear decibels, low noise, wide bandwidth, high gain accuracy amplifier AD603 design echo amplifying circuit. The experimental results indicate that the basic realization of the ultrasonic transceiver circuit and echo signal conditioning functions.
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Li, Ning, Kevin Han, William Spratt, Stephen Bedell, John Ott, Marinus Hopstaken, Frank Libsch, Qinglong Li e Devendra Sadana. "Ultra-low-power sub-photon-voltage high-efficiency light-emitting diodes". Nature Photonics 13, n. 9 (17 giugno 2019): 588–92. http://dx.doi.org/10.1038/s41566-019-0463-x.
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Sarker, Mahidur R., Azah Mohamed e Ramizi Mohamed. "Modelling and Simulation an AC-DC Rectifier Circuit Based on Piezoelectric Vibration Sensor for Energy Harvesting System". Applied Mechanics and Materials 785 (agosto 2015): 131–35. http://dx.doi.org/10.4028/www.scientific.net/amm.785.131.
Testo completoAbstract (sommario):
This paper presents the modeling of a full-wave rectifier circuit based on piezoelectric vibration transducer for energy-harvester system. Piezoelectric vibration crystals are a viable means of harvesting energy for low-power embedded systems e.g. wireless sensor network. Distinct power handling circuits are assessed with the presence of piezoelectric vibration based energy harvesting transducer. Inside the interface circuit, the voltage should be started up when the AC input voltage is very low to supply a regulated DC voltage up to 2V. An active technique is chosen to design an ultra-low power circuit from a piezoelectric vibration transducer. MOSFET bride ac–dc rectifier, energy storage device e.g. capacitor and boost converter with regulator are the common components of the energy harvesting circuits. An integrated promoter ac-dc rectifier circuit and boost converter that accept a maximum input voltage of 0.3V and provide a regulated output voltage of 2V serve as the supply. The MOSFET and thyristor are considered to develop the proposed circuit replacing conventional ac-dc rectifier due to low input voltage at which diode does not work.
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Tekin, Serdar B., Saeed Almalki, Andrea Vezzoli, Liam O’Brien, Steve Hall, Paul R. Chalker e Ivona Z. Mitrovic. "(Digital Presentation) Optimization of MIM Rectifiers for Terahertz Rectennas". ECS Meeting Abstracts MA2022-01, n. 19 (7 luglio 2022): 1076. http://dx.doi.org/10.1149/ma2022-01191076mtgabs.
Testo completoAbstract (sommario):
There is a significant demand for harvesting renewable infrared (IR) energy from unused heat sources. The rectifying antenna (rectenna) device has the ability to capture alternating current (AC) IR radiation and rectify it into usable direct current (DC) electricity. Metal-Insulator-Metal (MIM) diodes have shown to be the most prominent contenders for rectenna applications. This is due to their ultra-fast current transport mechanism in the femtosecond range by means of quantum mechanical tunnelling. Optical rectification at 28.3 THz has recently been demonstrated by rectenna devices based on MInM diodes using Au/Al2O3/Ti [1] and Ti/TiO2/ZnO/Al [2] configurations. Although the results are promising, the overall conversion efficiency is quite low, 2.05 × 10-14 [1], mainly due to the poor rectification properties of the diodes. Other recent research [3-5] has focused on the combination of stoichiometric and non-stoichiometric oxides with the aim of engineering the barrier heights to achieve low dynamic resistance (R0 ), high responsivity (β0 ) and asymmetry (η0 ) at zero-bias where the results are very promising for self-biased rectennas. The most recent experimental breakthrough was achieved by Ni/NiO/AlOx/CrAu bowtie rectennas that feature a device area of 0.035 µm2, low R0 of 13 kΩ and high β0 of 0.5 A/W. The results show that 5.1% coupling efficiency and 1.7 × 10−8% power conversion efficiency can be achieved with correct optimization of oxide stack. Furthermore, the most recent theoretical study [6] shows that the β0 of the MI2M diodes can be further improved to ~ 5 A/W by keeping the impedance match between the diode and the antenna at around 100 Ω. The proposed Ti/1 nm TiO2/1 nm Nb2O5/Ti rectenna design can achieve diode cut-off frequency (fc ) of 17 THz and resistance × capacitance (RC) time constant of 9 fs assuming the diode area of 0.01 µm2. Liverpool group has demonstrated recently [7,8] the effect of resonant tunnelling in non-cascaded (Al/Ta2O5/Nb2O5/Al2O3/Al) and cascaded (Al/Nb2O5/Al2O3/Ta2O5/Al) triple insulator diode structures with an oxide thickness ratio of 1:3:1 (in nm) deposited by atomic layer deposition (ALD). The diodes exhibit superior β = 5 A/W at 0.2 V and η = 12 at 0.1 V, with a drawback of high R0 due to high barrier heights between the metal/oxide layers. In this paper, we further optimize the MInM diode configurations so that the metal/oxide barrier is significantly lowered to ~ 0.1 eV. This is achieved by using the combinations of rectenna contender oxides such as Al2O3, NiO and ZnO that have high electron affinity and low dynamic permittivity [9]. Ultra-thin (≤ 5 nm) insulating layers were fabricated using radio frequency (RF) magnetron sputtering and ALD. Metal electrodes were deposited by thermal evaporation and RF sputtering using shadow mask, photolithography and nanolithography processes. The device areas range from 100 µm × 100 µm, 1 µm × 1 µm and 100 nm × 100 nm depending on the patterning process to observe the effect of device scaling on the conduction mechanisms and direct current (DC) rectification properties. The deposited oxide layers were measured by variable angle spectroscopic ellipsometry (VASE) to ascertain their thickness, uniformity and optical constants. DC current voltage measurements were performed on fabricated diodes to evaluate key rectification parameters such as R0 , β0 , η and non-linearity (fNL ) around zero-bias. Complementary theoretical calculations were performed to substantiate the experimental results and allow comparison of different MInM diode configurations such as NiO/Al2O3, ZnO/Al2O3, NiO/ZnO and NiO/ZnO/Al2O3. This work shows that the coupling efficiency at IR cut-off frequencies can be improved by optimizing the barriers in MInM rectifiers. References. [1] Jayaswal et al.,Materials Today Energy, 7, 1-9 (2018); [2] Elsharabasy et al., IEEE J. Photovoltaics, 9, 1232, (2019); [3] Matsuura et al., Sci. Rep. 9, 1-7 (2019); [4] Weerakkody et al., ACS Appl. Nano Mater. 4, 2470–2475 (2021); [5] Belkadi et al., Nat. Commun., 12, 1–6 (2021); [6] Elsharabasy et al., Results Mater. 11, 100204 (2021); [7] Mitrovic et al., ECS Trans. 72, 287 (2016); [8] Tekin et al., Solid State Electron. 185, 108096 (2021); [9] Mitrovic et al., Materials, 14, 5218 (2021).
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Li, Xiaokang, Wenxing Liu, Kai Chen, Chunyu Yu, Xiaoyang Xia, Guojun Liu e Liang Zhou. "Very bright and efficient ITO-free narrow-spectrum micro-cavity top-emitting organic light-emitting diodes with low operation voltage". Journal of Materials Chemistry C 10, n. 8 (2022): 3241–47. http://dx.doi.org/10.1039/d1tc05697b.
Testo completo
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Abdelnour, Abanob, Antonio Lazaro, Ramón Villarino, Darine Kaddour, Smail Tedjini e David Girbau. "Passive Harmonic RFID System for Buried Assets Localization". Sensors 18, n. 11 (26 ottobre 2018): 3635. http://dx.doi.org/10.3390/s18113635.
Testo completoAbstract (sommario):
A passive harmonic tag for buried assets localization is presented for utility localization. The tag design is based on a dual-polarized patch antenna at Ultra High Frequency (UHF) band. One of its feeders is connected to a frequency doubler based on a Schottky diode that generates the second harmonic, which is transmitted using a linear-polarized patch tuned at this frequency. The power received at the other feeder of the dual-polarized antenna is harvested by an RF to DC converter based on a five-stage voltage multiplier whose energy is used to bias a low-power quartz oscillator that modulates the output of the doubler. The different parts of the system are presented, and the theoretical read range is estimated as a function of the soil composition and the water content. A low-cost reader based on a software defined radio is also presented. Finally, experiments with a prototype of the tag are performed for different soil conditions.
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Lima, Elessandro Váguino de, Cristina Pacheco-Soares e Newton Soares da Silva. "Photobiomodulation assay of muscle cells C2C12 after irradiation with LED device". Research, Society and Development 11, n. 6 (2 maggio 2022): e41511628884. http://dx.doi.org/10.33448/rsd-v11i6.28884.
Testo completoAbstract (sommario):
Introduction: One of the ways that have been observed to reduce musculoskeletal fatigue is the use of protocols for the application of light sources (photobiomodulation) such as low-intensity laser and LED (Light Emitting Diode). Work involving photobiomodulation has shown promising results in strength performance or reduction of muscle fatigue. At the cellular level, photobiomodulation can modulate fibroblasts proliferation, the fixation and synthesis of collagen and procollagen, promote angiogenesis and improving energy metabolism in mitochondria. Compared with laser devices, LED has several advantages, such as being smaller, lighter, lower cost, and easier for operation. Objective: The present work objective is to verify if irradiation with LED device (650 nm and 860 nm) in muscle cells C2C12 modify the viability, morphology and cytoskeleton components. Methodology: C2C12 cells line (ATCC CRL - 1772) were cultured in 25 cm2 bottles at 37ºC under 5% CO2 in DMEM. The cells were irradiated with the light-emitting diodes (LED) device, Sportllux Ultra that consists of 84 LEDs, each individual LED has 8 mW of power, emitting in 660±20 nm (42 LEDs) and 850±20 nm (42 LEDs), and covering an area (A) of 120 cm2. The power density of delivered light was 5,6 mW/cm2, and the exposure time was 10 minutes, totalizing the fluence of 3,4 J/cm2. Viability assay was performed where the cells were incubated with 100 µL of Crystal Violet (CV) solution and mitochondrial activity assay was evaluated by the colorimetric MTT assay. Nucleus (DAPI) and Cytoskeleton (Rhodamine Phalloidin) fluorescence assay was performed to study the cytoskeleton based on the change in the actin filaments. Results: Our results demonstrate that the synergism of LED irradiation (660nm and 850nm) induced the proliferation of C2C12 cells. The light-emitting diode (LED) device, Sportllux Ultra has a significant effect on C2C12 cell culture. Mitochondrial activity and cell viability showed a significative increase in their activities after irradiation. The microscopy fluorescence observations showed an alignment of cytoskeletal components of C2C12 cells after irradiation. Conclusion: The application of irradiation with the Sportlux Ultra LED device stimulated an increase of energy by mitochondrial activity assay, number of cells by cell viability assay and alignment of cytoskeleton components by fluorescence assay in C2C12 line cells. Our results suggest that organizated cytoskeletal actin filaments normally contribute to cell survival and that induced major cell changes in the cytoskeleton that result in cell shape change. These results suggest that the Sport Lux Ultra LED device can help in the repair of tissue injuries and to collaborate to increase of performance in athletes in a faster way.
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Sundaresan, Siddarth G., Charles Sturdevant, H. Issa, Madhuri Marripelly, Eric Lieser e R. Singh. "Hybrid Si-IGBT/SiC Rectifier Co-Packs and SiC JBS Rectifiers Offering Superior Surge Current Capability and Reduced Power Losses". Materials Science Forum 717-720 (maggio 2012): 945–48. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.945.
Testo completoAbstract (sommario):
Novel device design and process innovations made at GeneSiC on SiC JBS rectifiers result in a significant increase in surge current capability with a 33% decrease in power dissipation at 10x rated current. On the 1200 V-class rectifiers, a clear signature of avalanche-limited breakdown with ultra-low leakage currents is observed at temperatures as high as 240 °C. Almost temperature independent Schottky barrier heights of 1.2 eV and ideality factors 2K2 (for 4H-SiC) is directly extracted from the forward I-V characteristics. When compared with an off-the-shelf all-Si IGBT power co-pack, GeneSiC’s GA100XCP12-227 co-pack offers 88% and 47% reduction at 125 °C in the IGBT and free-wheeling diode switching energy losses, respectively. This results in an overall switching loss reduction of about 28% as compared to its silicon counterpart.
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Aftab, Sikandar, Muhammad Waqas Iqbal, Amir Muhammad Afzal, M. Farooq Khan, Ghulam Hussain, Hafiza Sumaira Waheed e Muhammad Arshad Kamran. "Formation of an MoTe2 based Schottky junction employing ultra-low and high resistive metal contacts". RSC Advances 9, n. 18 (2019): 10017–23. http://dx.doi.org/10.1039/c8ra09656b.
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Malajner, Marko, Danijel Šipoš e Dušan Gleich. "Design of a Low-Cost Ultra-Wide-Band Radar Platform". Sensors 20, n. 10 (18 maggio 2020): 2867. http://dx.doi.org/10.3390/s20102867.
Testo completoAbstract (sommario):
This paper proposes an improved design of a pulse-based radar. An improved design of a pulse generator is presented using step recovery diodes and a signal mixer for the received signal. Two-step recovery diodes produce pulses of 120 ps in duration. A pulse generator is improved by removing the negative power supply, resulting in a reduced number of electronic pulses. A sampling mixer at the receiver’s site receives the generated signal and stretches it from picoseconds into microseconds. The improved pulse generator is also used in the sampling mixer as a strobe pulse generator, which makes the sampling mixer much simpler. The stretched signal is then sampled by a low sample rate using an analog to digital converter. The proposed radar design achieves up to 8 GHz bandwidth and an equivalent receiving sample rate of about 100 GSa/s. The radar is controlled using a software-defined radio called Red Pitaya, which is also used for data acquisition. The proposed radar design uses widely available commercial components, which makes radar design widely available with low cost implementation.
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Srinivasulu, Avireni, e Madugula Rajesh. "ULPD and CPTL Pull-Up Stages for Differential Cascode Voltage Switch Logic". Journal of Engineering 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/595296.
Testo completoAbstract (sommario):
Two new structures for Differential Cascode Voltage Switch Logic (DCVSL) pull-up stage are proposed. In conventional DCVSL structure, low-to-high propagation delay is larger than high-to-low propagation delay this could be brought down by using DCVSL-R. Promoting resistors in DCVSL-R structure increase the parasitic effects and unavoidable delay and it also occupies more area on the chip (Turker et al., 2011). In order to minimize these problems, a new Ultra-Low-Power Diode (ULPD) structures in place of resistors have been suggested. This provides the minimum parasitic effects and reduces area on the chip. Second proposed circuit uses Complementary Pass Transistor Logic (CPTL) structure, which provides complementary outputs. This contributes an alternate circuit for conventional DCVSL structure. The performances of the proposed circuits are examined using Cadence and the model parameters of a 180 nm CMOS process. The simulation results of these two circuits are compared and presented. These circuits are found to be suitable for VLSI implementation.
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Hashimoto, Takuma, Hikaru Nekozuka, Yoshitaka Toeda, Masayuki Otani, Yasuhiko Fukuoka e Toru Tanzawa. "A −31.7 dBm Sensitivity 0.011 mm2 CMOS On-Chip Rectifier for Microwave Wireless Power Transfer". Electronics 12, n. 6 (15 marzo 2023): 1400. http://dx.doi.org/10.3390/electronics12061400.
Testo completoAbstract (sommario):
This paper pursued both the lower operating power limit and small area of on-chip rectifiers for microwave wireless power transfer (MWPT). RF–DC charge pump rectifiers can operate in the fast switching limit at a high frequency of 920 MHz even with a small stage capacitor Cin of 100 fF, which contributes to an area reduction in the on-chip rectifiers. Circuit design starts with Cin determined as small as possible, followed by the determination of switching transistors and the number of stages. Even at an extremely low input power of 1 μW, wiring resistance in RF inputs is critical. Routing of the RF inputs is designed in line with stage capacitors. Bonding pad structure also affects the lower input power limit. Ground-shielded pad design can reduce the lower limit. Various types of RF–DC charge pump rectifiers are fabricated in 65 nm CMOS. An ultra-low-power diode RF–DC charge pump rectifier with 32 stages had a lower input power limit of −31.7 dBm at an output voltage of 1.0 V. Its small silicon area of 0.011 mm2 allows RF–DC rectifiers to be integrated in sensor ICs. More advanced technology providing MIM capacitors with higher capacitance density and placing switching MOSFETs under the MIM capacitors will further reduce the area of RF–DC charge pump rectifiers, allowing them to be integrated in sensor ICs.
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Shahroury, Fadi R., Hani H. Ahmad e Ibrahim Abuishmais. "Design Aspects of a Single-Output Multi-String WLED Driver Using 40 nm CMOS Technology". Journal of Low Power Electronics and Applications 12, n. 1 (18 gennaio 2022): 5. http://dx.doi.org/10.3390/jlpea12010005.
Testo completoAbstract (sommario):
This work presents various essential features and design aspects of a single-inductor, common-output, and multi-string White Light Emitting Diode (WLED) driver for low-power portable devices. High efficiency is one of the main features of such a device. Here, the efficiency improvement is achieved by selecting the proper arrangement of WLEDs and a proper sensing-circuit technique to determine the minimum, real-time, needed output voltage. This minimum voltage necessary to activate all WLEDs depends on the number of strings and the forward voltage drops among the WLEDs. Advanced CMOS technology is advantageous in mixed-signal environments such as WLED drivers. However, this process suffers from low on-resistance, which degrades the accuracy of the current sinks. To accommodate the above features and mitigate the low node process issue, a boost-converter that is single output with a load of a three-string arrangement, with 6 WLEDs each, is presented. The designed driver has an input voltage range of 3.2–4.2V. The proposed solution is realized with ultra-low power consumption circuits and verified using ADS tools utilizing 40 nm 1P9M TSMC CMOS technology. An inter-string current accuracy of 0.2% and peak efficiency of 91% are achieved with an output voltage up to 25 V. The integrated WLED driver circuitry enables a high switching frequency of 1MHz and reduces the passive elements’ size in the power stage.
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Ueda, Ken-Ichi. "Present status and prospect of KrF laser physics and technology–large volume excitation and UV optics". Laser and Particle Beams 7, n. 3 (agosto 1989): 375–82. http://dx.doi.org/10.1017/s0263034600007333.
Testo completoAbstract (sommario):
The physics and technology for e-beam generation, large volume excitation and the ultra-violet optics for high power KrF lasers is presented. The potential, due to the charge deposition, induces a return current in the plasma which balances the e-beam current. The local equilibrium mechanism stabilizes the large volume excitation using intense electron beams. The spatial and temporal characteristics of large aperture diodes are analyzed. Substantial progress in ultra violet optics in Japan has been achieved. The damage threshold of HR dielectric coating increases up to 11 J/cm2 by using low absorption materials.
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El Boutahiri, Abdelali, Mounir Ouremchi, Ahmed Rahali, Mustapha El Alaoui, Fouad Farah, Karim El khadiri, Ahmed Tahiri e Hassan Qjidaa. "Design of new power generating circuit for passive UHF RFID tag". International Journal of Power Electronics and Drive Systems (IJPEDS) 10, n. 3 (1 settembre 2019): 1389. http://dx.doi.org/10.11591/ijpeds.v10.i3.pp1389-1397.
Testo completoAbstract (sommario):
In this paper, we propose a new power generating circuit for passive ultra high frequency (UHF) RFID tag. The proposed power generating circuit consists of a RF limiter, a high power efficiency and high sensitivity full wave radio frequency (RF) wave rectifier and a low-power regulator with NMOS diodes work like a DC-limiter. The design method proposed in this study use one low drop out (LDO) regulator to provide tow output stable supply voltages vdd1 of value 1V for the digital section supply, and vdd2 of value 0.5V for the analog front-end section power supply. The proposed power generating circuit is optimized in terms of power consumption of RFID tag system to have a high operating range under conditions of 50 Ohm antenna, -24 dBm input RF power, 900MHz and 1 M DC, with low power dissipation and 29.15% large power conversion efficiency. The power generating circuit was designed, simulated and layouted in Cadence using TSMC 180 nm technology. The final design occupies approximately 0.25mm<sup>2</sup>.
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Kong, Moufu, Zewei Hu, Ronghe Yan, Bo Yi, Bingke Zhang e Hongqiang Yang. "A novel SiC high-k superjunction power MOSFET integrated Schottky barrier diode with improved forward and reverse performance". Journal of Semiconductors 44, n. 5 (1 maggio 2023): 052801. http://dx.doi.org/10.1088/1674-4926/44/5/052801.
Testo completoAbstract (sommario):
Abstract A new SiC superjunction power MOSFET device using high-k insulator and p-type pillar with an integrated Schottky barrier diode (Hk-SJ-SBD MOSFET) is proposed, and has been compared with the SiC high-k MOSFET (Hk MOSFET), SiC superjuction MOSFET (SJ MOSFET) and the conventional SiC MOSFET in this article. In the proposed SiC Hk-SJ-SBD MOSFET, under the combined action of the p-type region and the Hk dielectric layer in the drift region, the concentration of the N-drift region and the current spreading layer can be increased to achieve an ultra-low specific on-resistance (R on,sp). The integrated Schottky barrier diode (SBD) also greatly improves the reverse recovery performance of the device. TCAD simulation results indicate that the R on,sp of the proposed SiC Hk-SJ-SBD MOSFET is 0.67 mΩ·cm2 with a 2240 V breakdown voltage (BV), which is more than 72.4%, 23%, 5.6% lower than that of the conventional SiC MOSFET, Hk SiC MOSFET and SJ SiC MOSFET with the 1950, 2220, and 2220 V BV, respectively. The reverse recovery time and reverse recovery charge of the proposed MOSFET is 16 ns and18 nC, which are greatly reduced by more than 74% and 94% in comparison with those of all the conventional SiC MOSFET, Hk SiC MOSFET and SJ SiC MOSFET, due to the integrated SBD in the proposed MOSFET. And the trade-off relationship between the R on,sp and the BV is also significantly improved compared with that of the conventional MOSFET, Hk MOSFET and SJ MOSFET as well as the MOSFETs in other previous literature, respectively. In addition, compared with conventional SJ SiC MOSFET, the proposed SiC MOSFET has better immunity to charge imbalance, which may bring great application prospects.
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Milinčić, Danijel D., Nemanja S. Stanisavljević, Aleksandar Ž. Kostić, Uroš M. Gašić, Slađana P. Stanojević, Živoslav Lj Tešić e Mirjana B. Pešić. "Bioaccessibility of Phenolic Compounds and Antioxidant Properties of Goat-Milk Powder Fortified with Grape-Pomace-Seed Extract after In Vitro Gastrointestinal Digestion". Antioxidants 11, n. 11 (31 ottobre 2022): 2164. http://dx.doi.org/10.3390/antiox11112164.
Testo completoAbstract (sommario):
This study deals with the evaluation of the bioaccessibility and antioxidant properties of phenolic compounds from heat-treated skim goat-milk powder fortified with grape-pomace-seed extract, after in vitro gastrointestinal digestion. Ultra-high performance liquid chromatography coupled to diode array detection and mass spectrometry (UHPLC-DAD MS/MS) analysis confirmed the abundant presence of phenolic acids and flavan-3-ols in the grape-pomace-seed extract (SE) and heat-treated skim goat-milk/seed-extract powder (TME). After in vitro digestion of TME powder and recovery of total quantified phenolics, flavan-3-ols and phenolic acids were 18.11%, 24.54%, and 1.17%, respectively. Low recovery of grape-pomace-seed phenolics indicated strong milk protein–phenolic interactions. Electrophoretic analysis of a soluble fraction of digested heat-treated skim goat milk (TM) and TME samples showed the absence of bands originating from milk proteins, indicating their hydrolysis during in vitro gastrointestinal digestion. The digested TME sample had better antioxidant properties in comparison to the digested TM sample (except for the ferrous ion-chelating capacity, FCC), due to the presence of bioaccessible phenolics. Taking into account the contribution of the digestive cocktail, digested TME sample had lower values of total phenolic content (TPC), in vitro phosphomolybdenum reducing capacity (TAC) and ferric reducing power (FRP), compared to the undigested TME sample. These results could be attributed to low recovery of phenolic compounds. TME powder could be a good carrier of phenolics to the colon; thus, TME powder could be a promising ingredient in the formulation of functional food.
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Böttcher, Lars, S. Karaszkiewicz, D. Manessis, Eckart Hoene e A. Ostmann. "Next Generation High Power Electronic Modules Based on Embedded Power Semiconductors". Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2014, DPC (1 gennaio 2014): 000694–719. http://dx.doi.org/10.4071/2014dpc-tp12.
Testo completoAbstract (sommario):
The spectrum of conventional power electronics packaging reaches from SMD packages for power chips to large power modules. In most of these packages the power semiconductors are connected by bond wires, resulting in large resistances and parasitic inductances. Power chip packages have to carry semiconductors with increasing current densities. Conventional wire bonds are limiting their performance. Today's power modules are based on DCB (Direct Copper bonded) ceramic substrates. IGBT switches are mounted onto the ceramic and their top side contacts are connected by thick Al wires. This allows one wiring layer only and makes an integration of driver chips very difficult. Additionally bond wires result in a high stray inductance which limits the switching frequency. Especially for the use of ultra-fast switching semiconductors, like SiC and GaN, it is very difficult to realize low inductive packages. The embedding of chips offers a solution for many of the problems in power chip packages and power modules. While chip embedding was an academic exercise a decade ago, it is now an industrial solution. A huge advantage of packaging using PCB technology is the cost-effective processing on large panel. Furthermore embedded packages and modules allow either double-side cooling or 3D assembly of components like capacitors, gate drivers or controllers. The advanced results of research projects will be discussed in the paper. An ultra-low inductance power module with SiC switches at 20 A / 600 V has been realized and characterized. The DC link inductance of the module was 0,8 nH only. These results sparked a huge interest in currently starting follow up projects creating package for fast switches. In a further project power modules for automotive power inverters for motor control are under development. As a project demonstrator, a 10 kW module with IGBTs and diodes at 400 V / 500 A, was manufactured. This demonstrator is based on high power PCB technology and was fully characterized; the results will be presented in detail. Recently started research projects will face the challenges of MW solar inverters at 1000 A and 1000 V, using SiC semiconductors as switches. First concepts will be presented as an outlook.
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Palazzi, Valentina, Luca Roselli, Manos M. Tentzeris, Paolo Mezzanotte e Federico Alimenti. "Energy-Efficient Harmonic Transponder Based on On-Off Keying Modulation for Both Identification and Sensing". Sensors 22, n. 2 (14 gennaio 2022): 620. http://dx.doi.org/10.3390/s22020620.
Testo completoAbstract (sommario):
This paper presents a novel passive Schottky-diode frequency doubler equipped with an on-off keying (OOK) modulation port to be used in harmonic transponders for both identification and sensing applications. The amplitude modulation of the second-harmonic output signal is achieved by driving a low-frequency MOSFET, which modifies the dc impedance termination of the doubler. Since the modulation signal is applied to the gate port of the transistor, no static current is drained. A proof-of-concept prototype was manufactured and tested, operating at 1.04 GHz. An on/off ratio of 23 dB was observed in the conversion loss of the doubler for an available input power of −10 dBm. The modulation port of the circuit was excited with a square wave (fm up to 15 MHz), and the measured sidebands in the spectrum featured a good agreement with the theory. Then, the doubler was connected to a harmonic antenna system and tested in a wireless experiment for fm up to 1 MHz, showing an excellent performance. Finally, an experiment was conducted where the output signal of the doubler was modulated by a reed switch used to measure the rotational speed of an electrical motor. This work opens the door to a new class of frequency doublers, suitable for ultra low-power harmonic transponders for identification and sensing applications.
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Li, Lingfeng, Hao Gu, Yanzhen Lv, Yunjing Zhang, Xingli He e Peng Li. "Ultra-Fast Polarity Switching, Non-Radioactive Drift Tube for the Miniaturization of Drift-Time Ion Mobility Spectrometer". Sensors 22, n. 13 (27 giugno 2022): 4866. http://dx.doi.org/10.3390/s22134866.
Testo completoAbstract (sommario):
Drift-time ion mobility spectrometer (DT-IMS) is a promising technology for gas detection and analysis in the form of miniaturized instrument. Analytes may exist in the form of positively or negatively charged ions according to their chemical composition and ionization condition, and therefore require both polarity of electric field for the detection. In this work the polarity switching of a drift-time ion mobility spectrometer based on a direct current (DC) corona discharge ionization source was investigated, with novel solutions for both the control of ion shutter and the stabilization of aperture grid. The drift field is established by employing a switchable high voltage power supply and a serial of voltage regulator diode, with optocouplers to drive the ion shutter when the polarity is switched. The potential of aperture grid is stabilized during the polarity switching by the use of four diodes to avoid unnecessary charging cycle of the aperture grid capacitor. Based on the proposed techniques, the developed DT-IMS with 50 mm drift path is able to switch its polarity in 10 ms and acquire mobility spectrum after 10 ms of stabilization. Coupled with a thermal desorption sampler, limit of detection (LoD) of 0.1 ng was achieved for ketamine and TNT. Extra benefits include single calibration substance for both polarities and largely simplified pneumatic design, together with the reduction of second drift tube and its accessories. This work paved the way towards further miniaturization of DT-IMS without compromise of performance.
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Faizan, Muhammad, Xiaolei Wang e Muhammad Zain Yousaf. "Design and Comparative Analysis of an Ultra-Highly Efficient, Compact Half-Bridge LLC Resonant GaN Converter for Low-Power Applications". Electronics 12, n. 13 (28 giugno 2023): 2850. http://dx.doi.org/10.3390/electronics12132850.
Testo completoAbstract (sommario):
For low-power applications, this paper presents the development and design of a compact and ultra-highly efficient half-bridge LLC resonant converter. By using Galium Nitride (GaN) devices and high-efficient magnetics, the efficiency and power density of resonant converters can be improved. Compared to Silicon MOSFETs, GaN high-electron-mobility transistors (GaN HEMT) have a lower output capacitance and gate charge, resulting in lower driving loss and shorter dead times. Consequently, the proposed LLC converter based on GaN devices has excellent performance characteristics such as ultra-high efficiency, low switching losses, compact size, high voltage endurance, high operating temperature and high operating frequency. Furthermore, the proposed resonant converter features soft switching properties that ensure that the switches and diodes on the primary side are always switched at zero voltage and current. By doing so, LLC resonant converter switching losses are significantly reduced by up to 3.1%, and an overall efficiency of 98.5% is achieved. The LLC resonant converter design with GaN HEMT has great advantages over Si MOSFET solution regarding efficiency, overall losses, switching loose and power factor correction. A 240 W, 240 V to 60 V half-bridge GaN HEMT LLC resonant converter is simulated with a switching frequency of 75 KHz, along with the comparative analysis of the Si metal oxide semiconductor field effect transistor (MOSFET) solution. Moreover, the design and analysis of highly efficient magnetics with a power factor of 0.99 at full load is presented. A 240-Watt single stage LED driver with power factor correction is also designed to verify and compare the performance of proposed LLC resonant converter.
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Uoosefian, Hamidreza, Keivan Navi, Reza Faghih Mirzaee e Mahdi Hosseinzadeh. "High-Performance CML approximate full adders for image processing application of laplace transform". Circuit World 46, n. 4 (6 aprile 2020): 285–99. http://dx.doi.org/10.1108/cw-12-2018-0106.
Testo completoAbstract (sommario):
Purpose The high demand for fast, energy-efficient, compact computational blocks in digital electronics has led the researchers to use approximate computing in applications where inaccuracy of outputs is tolerable. The purpose of this paper is to present two ultra-high-speed current-mode approximate full adders (FA) by using carbon nanotube field-effect transistors. Design/methodology/approach Instead of using threshold detectors, which are common elements in current-mode logic, diodes are used to stabilize voltage. Zener diodes and ultra-low-power diodes are used within the first and second proposed designs, respectively. This innovation eliminates threshold detectors from critical path and makes it shorter. Then, the new adders are employed in the image processing application of Laplace filter, which detects edges in an image. Findings Simulation results demonstrate very high-speed operation for the first and second proposed designs, which are, respectively, 44.7 per cent and 21.6 per cent faster than the next high-speed adder cell. In addition, they make a reasonable compromise between power-delay product (PDP) and other important evaluating factors in the context of approximate computing. They have very few transistors and very low total error distance. In addition, they do not propagate error to higher bit positions by generating output carry correctly. According to the investigations, up to four inexact FA can be used in the Laplace filter computations without a significant image quality loss. The employment of the first and second proposed designs results in 42.4 per cent and 32.2 per cent PDP reduction compared to when no approximate FA are used in an 8-bit ripple adder. Originality/value Two new current-mode inexact FA are presented. They use diodes as voltage regulators to design current-mode approximate full-adders with very short critical path for the first time.
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Remigy, Alice, Salima Kasri, Thibault Darny, Hiba Kabbara, Ludovic William, Gérard Bauville, Kristaq Gazeli et al. "Cross-comparison of diagnostic and 0D modeling of a micro-hollow cathode discharge in the stationary regime in an Ar/N2 gas mixture". Journal of Physics D: Applied Physics 55, n. 10 (6 dicembre 2021): 105202. http://dx.doi.org/10.1088/1361-6463/ac3c74.
Testo completoAbstract (sommario):
Abstract A micro-hollow cathode discharge (MHCD) operated in Ar/N2 gas mixture, working in the normal regime, was studied both experimentally and with a 0D (volume-averaged) model in this work. This source provides high electron densities (up to 1015 cm−3) at low injected power (1 W). To understand the mechanisms leading to the production of N atoms, the densities of electrons, N atoms and argon metastable atoms (Ar*) were monitored over a wide range of experimental conditions. Electrons, N atoms and Ar* densities were probed by means of optical emission spectroscopy, vacuum ultra violet Fourier transform spectroscopy and tunable diode laser absorption spectroscopy, respectively. Measurements showed that using a smaller hole diameter enables to work with less injected power, while increasing the power density inside the hole and, subsequently, increasing the densities of excited species. Varying the percentage of N2 in the gas mixture highlighted that, up to 80%, the density of N atoms increases although the dissociation rate drops. Looking at the processes involved in the production of N atoms with the help of the 0D model, we found that at very low N2 fraction, N atoms are mostly produced through dissociative electron-ion recombination. However, adding more N2 decreases drastically the electron density. The density of N atoms does not drop thanks to the contribution of Ar* atoms, which are the main species dissociating N2 between 5% and 55% of N2 in the gas mixture. A reasonable agreement is found between the experiments and the model results. This study shows that, with this MHCD, it is possible to significantly modify the production of N atoms when modifying the physical parameters, making it particularly relevant for applications requiring a N atoms source, such as nitride deposition.
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Jin, Renfeng, Subrata Halder, Walter R. Curtice, James C. M. Hwang e Choi L. Law. "Sub-Nanosecond Greater-Than-10-V Compact Tunable Pulse Generator for Low-Duty-Cycle High-Peak-Power Ultra-Wideband Applications". Active and Passive Electronic Components 2011 (2011): 1–8. http://dx.doi.org/10.1155/2011/871474.
Testo completoAbstract (sommario):
An ultra-wideband pulse generator was designed and fabricated in GaAs HBT IC technology. The generator includes delay and differential circuits to convert a TTL input into a Gaussian pulse signal as well as a Class-C amplifier to boost the pulse amplitude while compressing the pulse width. By adjusting the collector bias of the Class-C amplifier, the pulse amplitude can be varied linearly between 3.5 V and 11.5 V while maintaining the pulse width at 0.3 ± 0.1 nanosecond. Alternatively, by adjusting the base bias of the Class-C amplifier, the pulse width can be varied linearly between 0.25 ns and 0.65 ns while maintaining the pulse amplitude at 10 ± 1 V. Finally, the amplified Gaussian signal can be shaped into a monocycle signal by anL-Cderivative circuit. The present pulse generator compares favorably with pulse generators fabricated in CMOS ICs, step-recovery diodes, or other discrete devices.
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Hao, Lili, Rui Chang, Xiaokai Hou, Jun He e Junmin Wang. "Narrow-Linewidth 852-nm DBR-LD with Self-Injection Lock Based on High-Finesse Optical Cavity Filtering". Photonics 10, n. 8 (16 agosto 2023): 936. http://dx.doi.org/10.3390/photonics10080936.
Testo completoAbstract (sommario):
Narrow-linewidth lasers have a high spectral purity, long coherent length, and low phase noise, so they have important applications in atomic clocks, precision measurement, and quantum computing. We inject a transmitted laser from a narrow-linewidth (∼15 kHz) flat-concave Fabry–Perot (F-P) cavity made from ultra-low expansion (ULE) optical glass into an 852 nm distributed Bragg reflector-type laser diode (DBR-LD), of which the comprehensive linewidth is 1.67 MHz for the free running case. With an increase in the self-injection power, the laser linewidth gradually narrows, and the injection locking current range gradually increases. The narrowest linewidth measured by the delayed frequency-shifted self-heterodyne (DFSSH) method is about 365 Hz, which is about 1/4500 of the linewidth for the free running case. Moreover, to characterize the laser phase noise, we use a detuned F-P cavity to measure the conversion signal from the laser phase noise to the intensity noise for both the free running case and the self-injection lock case. The laser phase noise for the self-injection lock case is significantly suppressed in the analysis frequency range of 0.1–10 MHz compared to the free running case. In particular, the phase noise is suppressed by more than 30 dB at an analysis frequency of 100 kHz.