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1
Malmqvist, Robert. "Tuneable recursive active monolithic microwave integrated circuit filters /". Linköping : Univ, 2001. http://www.bibl.liu.se/liupubl/disp/disp2001/tek698s.pdf.
Testo completo
2
Morrow, I. L. "Investigation of radiation from active integrated circuit antennas". Thesis, Cranfield University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320638.
Testo completo
3
Lisuwandi, Eko T. 1977. "Feedback circuit for organic LED active-matrix display drivers". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/16849.
Testo completoAbstract (sommario):
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (leaves 44-45).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
A feedback circuit for an Organic Light Emitting Diode (OLED) based display is proposed and demonstrated. An OLED-based flat panel display is brighter, much lower power, has no viewing angle limitation and potentially cheaper compared to available Liquid Crystal (LC) based displays. Despite these advantages, an OLED-based display is not widely commercialized mainly due to its short practical lifetime. The I-V characteristics of the individual OLED pixels vary over time, temperature and processing-dependent parameters. Moreover, the variation is not uniform across an array of OLED pixels, causing OLED based displays to lose brightness accuracy after a few thousand hours of operation. The proposed feedback circuit is used to compensate for the non-uniformities in the individual OLED characteristics. The resulting display leverages the beneficial aspects of OLED display technology, while maintaining pixel uniformity and grayscale reproducibility. A demonstration system is built proving the feasibility of a flat panel display using direct optical feedback. The feedback loop monitors the output light level using a sensor and adjusts the current fed to the pixels to set the output light power to a digitally set reference level. The system shares a single feedback loop among a number of pixels, saving power and real estate. The demonstration system consists of a 5x5 array of LEDs, a CMOS camera, analog pixel circuitry, driver and feedback loop, as well as a digital controller. The demonstration system also shows the feasibility of time-sharing a feedback loop among a number of output devices.
by Eko T. Lisuwandi.
M.Eng.
4
SCHOENEMAN, DONALD WARREN. "COMPUTER-AIDED DESIGN OF THERMIONIC INTEGRATED CIRCUIT ACTIVE DEVICES". Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188077.
Testo completoAbstract (sommario):
Two computer-aided design methods are described in this dissertation for the design of Thermionic Integrated Circuits (TIC). Such circuits combine vacuum tube techniques with modern integrated circuit techniques to produce microminiature vacuum tube circuits, with possibly hundreds of vacuum triodes on a single substrate. The first method described in the line charge approximation technique in which the TIC devices are modelled as collections of line charges. A TIC is produced by evaporating metal electrodes on one or two sapphire substrates. The entire structure is heated to about 850°C so that electrons are emitted from the cathode electrodes to travel to the plate electrodes as in a conventional vacuum triode. The line charge approximation method is easy to implement and provides a simple means of satisfying the sapphire dielectric boundary conditions of the TIC basic problems, which are electrostatics problems since space charge effects are neglected. The method requires only a single matrix inversion and is a finite element Green's function approach. The method uses no iteration as in previous TIC analysis methods. Later as the development of TIC devices proceeded further it was found that conducting shields had to be placed over the unused sapphire surface so that the basic problem became a metal box problem. For this case a second method was developed called the step and ramp function method in which each electrode is modelled by a step function, which is the electric field solution for a potential step on a zero potential boundary. A superposition of these step functions models the TIC electrodes. The method provides direct calculation of the electric fields from equations and requires no iteration or matrix inversion. The potential variation between electrodes is modelled by linear potential functions called ramps. A superposition of steps and ramps completely specifies a TIC structure. The method does not solve for the case of electrodes which are elevated above substrates. For this case a modified line charge method was developed but not implemented.
5
Girlevicius, Lukas. "Active magnetic bearing driver circuit design featuring current measurement integration". Thesis, Uppsala universitet, Elektricitetslära, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-269215.
Testo completoAbstract (sommario):
Researchers at Uppsala University are developing a flywheel energy storage device intended to be used in electrical vehicles. Kinetic energy storage technology has potential to make purely electric powertrain both more effective and efficient. While deployment of the third prototype is approaching there has been a request for a more precise and noise-immune circuitry to power active magnetic bearings that hold and stabilise the rotor. A similar circuit designed for powering electromagnets was recently developed at the Uppsala University’s Electricity department and is used as a template in development of the new active magnetic bearing driver circuit. Current measurement integration technique is tested and implemented as a way to increase circuit’s control feedback loop performance. To further boost precision and noise-immunity 0-20 mA current loop signals are adapted as the standard for output signals. Results of this project include a thorough analysis of the electromagnet driver circuit development, implementation of a new current sensing technique including an experimental self-inductance measurement, printed circuit board layout design and a full list of components necessary to power and control two sets of active magnetic bearings consisting of 8 individual electromagnets.
6
Zhou, Chen. "Design and analysis of an active power factor correction circuit". Thesis, Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/53729.
Testo completoAbstract (sommario):
The design of an active-unity power factor correction circuit with variable-hysteresis
control for off-line dc-to-dc switching power supplies is described. Design
equations relating the boost inductor current ripple to the circuit components selection
and circuit performance arc discussed. A computer-aided design program (CADO) is
developed to give the optimal circuit components selection. A 500 watt, 300 volt experimental
circuit is built to verify the simulation and analysis results.
The control-to-output response of the power factor circuit is verified with the experimental
results. Design guidelines for the low-frequency feedback network are presented.
Small-signal closed-loop responses are measured with an experimental power
factor circuit.Master of Science
7
Williams, David. "Active power decoupling for a boost power factor correction circuit". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/59145.
Testo completoAbstract (sommario):
During AC-DC conversion, the ripple power at the input of the converter must be filtered from the output. This filtering can be easily done by placing a capacitor on the DC bus. For systems with power output of hundreds of Watts or more, this capacitor must be quite high to effectively perform the filtering, and in order to be cost effective, an aluminum electrolytic capacitor (Al e-caps) needs to be used. The lifespan of Al e-caps is notoriously short, so for long lifespan systems, their use is not advisable. Film capacitors have longer lifespans than Al e-caps but are more expensive on a cost per Farad basis. Methods have been proposed to reduce the required capacitance so that film capacitors can be cost effectively used. One of these methods is to use a separate decoupling port in the circuit that can filter the ripple power without the limitation of being connected directly to the DC bus. The first contribution is a method of using an active power decoupling (APD) port with a buck-based circuit that does not require direct measurement of the AC input signal for controlling the ripple power to the port. This APD port requires only two extra switches and some simple signal processing circuitry to generate a reference signal and control the voltage to the APD port capacitor. The second contribution is a design guide for a sliding mode control (SMC) system for the APD port. SMC shows promise as a control system for power electronics circuits and has never been demonstrated on an APD port before. The proposed circuit and control system is used in a 700 Watt AC-DC converter with power factor correction and is compared in simulation to a benchmark converter using a passive capacitor on the DC bus. The capacitance is reduced from 300μF to a 35μF and a 75μF capacitor without any effect on performance as indicated by measures of the voltage ripple, power factor and total harmonic distortion. The capacitance reduction results in a cost savings of $175 on capacitors when using prices that were current at time of publication.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
8
Petrili, Daniele. "Active filter circuit and control methods to reduce energy storage". Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187679.
Testo completoAbstract (sommario):
The high market demand for power electronics converters nowadays requires converters with high power quality, great reliability and low cost. However, there are several challenges related to these systems, one relevant example is the energy ripple in the DC bus for single phase converters which causes problems such as overheating and reduction of the capacitor lifetime. To limit this energy ripple, which consists of the second order harmonic in the DC bus, a bulky DC link capacitor is usually required. Although, it results in low power density and large converter volume. Some of these capacitors can also present some problems such as shorter life-time and reliability. This thesis addresses this problem by adding active filter storage elements to the DC bus to absorb the pulsating power at twice the frequency on the bus line. In this way, there is no need to increase in the capacitor size to reduce the ripple. On the contrary, this method allows to replace the DC capacitor used for the conventional method by two smaller capacitors. The size of the DC bus capacitor is reduced, as is the energy ripple, and thereby the power density is increased. Besides, with the significant improvement of power semiconductor devices nowadays, the storage element method can be applied with acceptable cost and high reliability. In this thesis, component design and ripple analysis are explained in detail. The effectiveness of the power storage method is confirmed by simulations.Dagens höga efterfrågan på kraftelektronikbaserade omvandlare kräver hög kvalitet, hög tillförlitlighet och låg kostnad. Det finns dock flera utmaningar för dessa system. Ett relevant exempel är energivariationer i DC-bussen hos enfas-omvandlare. Variationerna kan orsaka problem som överhettning och minskning av kondensatorernas livslängd.Variationerna, som är en andra ordningens överton av den fundamentala frekvensen, begränsas vanligen med en skrymmande kondensator kopplad till DC-bussen. Det resulterar i låg effekttäthet och stor omvandlarvolym. Några av dessa kondensatorer kan också medföra problem med kortare livslängd och lägre tillförlitlighet.I denna rapport behandlas detta problem genom att lägga till ett aktivt filter med effektlager vid DC-bussen för att absorbera den andra övertonen. Därmed behövs ingen ökning av kondensatorns storlek för att absorbera den andra övertonen. Den konventionella DC-busskondensatorn kan istället ersättas med två mindre kondensatorer.När både kondensatorns storlek och övertonen minskas fås högre effekttäthet som konsekvens. Med den senaste tidens utveckling inom halvledarkomponenter kan metoden dessutom implementeras med hög tillförlitlighet till en rimlig kostnad.Komponenternas utformning och analysen av variationerna i DC-bussen förklaras i detalj i denna avhandling. Funktionen hos metoden bekräftas av simuleringar.
9
Neal, Edward Alexander. "An active-template mechanistic approach to homo- and hetero-circuit [3]rotaxanes". Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/15016.
Testo completoAbstract (sommario):
Although known to chemists for nearly a century, interlocked structures have only been synthetically accessible since the 1980s when 'passive template' methods allowed the pre-complexation of components to increase yields. 'Active template' methods, initially developed by the Leigh group in 2006, have resulted in even higher yields of rotaxanes - "interlocked structures formed of at least one macrocycle penetrated by at least one impassably-stoppered axle" - and a phenomenal surge in interest in their properties as a result of this increased availability. This first method adapted highly efficient 'click' methodology to give the Active Template Copper-Mediated Alkyne-Azide Cycloaddition reaction (AT-CuAAC) and is still the most used rotaxane-forming method today. In this work, I provide the reader with an overview of these mechanically-interlocked architectures from synthesis to application. Later work by the Goldup group showed that a smaller macrocycle could make [2]rotaxanes (one macrocycle, one axle) with complete efficiency compared to their larger forebears, while intermediate sizes gave incomplete conversion, with unused macrocycle unrecovered. In this investigation, I then identify a series of novel doubly-interlocked [3]rotaxane products from this reaction that explain the absence of unused macrocycle. I then explore the variation of conditions and show how these novel products are favoured by high temperatures and high catalyst loading in a non-coordinating solvent, whereas their yields are suppressed in low temperatures and catalyst loading in a co-ordinating solvent with base, giving up to quantitative [2]rotaxane formation. To provide a mechanistic rationale for the formation of these products I then assess the effects of stopper length, macrocycle structure and lithiation experiments on the ratio of the [2]- to [3]rotaxane. The results of the above allow me to derive a new mechanistic hypothesis when I then test in a series of experiments to form [3]rotaxanes with two rings differing in either structure, size or both. Finally, the design, synthesis and testing of a stopper developed and used by myself for the AT-CuAAC reaction is described such that where two macrocycles differ in size, the larger can only be held in a novel heterocircuit [3]rotaxane, produced in synthetically useful yields.
10
Goldman, Matthew 1965. "A low sensitivity dual feedback active RC bandpass filter". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277139.
Testo completoAbstract (sommario):
This thesis presents the analysis and characterization of a low sensitivity dual feedback active RC bandpass filter. Chapter 2 details the analysis of the network and a method of simplifying the resultant transfer function by a single pole/zero cancellation. Chapter 3 characterizes the simplified transfer function through an analysis of the quality factor and of the center frequency gain as functions of the individual variables of the circuit. It also details sensitivity analyses of these characteristic quantities and a stability analysis. Lastly, chapter 3 presents graphical representations of the equations developed so that they can be used as design tools. It then goes through the details of applying these graphs to an example network. Chapter 4 explains the differences between experimental data and predicted data by discussing some of the nonlinearities neglected in the original analysis. Finally chapter 5 restates the design technique in light of the predominant nonlinearities.
11
Oliver, John Marcus. "3D Micromachined Passive Components and Active Circuit Integration for Millimeter-wave Radar Applications". Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/77049.
Testo completoAbstract (sommario):
The development of millimeter-wave (30-300 GHz) sensors and communications systems has a long history of interest, spanning back almost six decades. In particular, mm-wave radars have applications as automotive radars, in remote atmospheric sensing applications, as landing radars for air and spacecraft, and for high precision imaging applications. Mm-wave radar systems have high angular accuracy and range resolution, and, while susceptible to atmospheric attenuation, are less susceptible to optically opaque conditions, such as smoke or dust. This dissertation document will present the initial steps towards a new approach to the creation of a mm-wave radar system at 94 GHz.
Specifically, this dissertation presents the design, fabrication and testing of various components of a highly integrated mm-wave a 94 Ghz monopulse radar transmitter/receiver. Several architectural approaches are considered, including passive and active implementations of RF monopulse comparator networks. These architectures are enabled by a high-performance three-dimensional rectangular coaxial microwave transmission line technology known as PolyStrataTM as well as silicon-based IC technologies. A number of specific components are examined in detail, including: a 2x2 PolyStrata antenna array, a passive monopulse comparator network, a 94 GHz SiGe two-port active comparator MMIC, a 24 GHz RF-CMOS 4-port active monopulse comparator IC, and a series of V- and W-band corporate combining structures for use in transmitter power combining applications.
The 94 GHz cavity-backed antennas based on a rectangular coaxial feeding network have been designed, fabricated, and tested. 13 dB gain for a 2 x 2 array, as well as antenna patterns are reported. In an effort to facilitate high-accuracy measurement of the antenna array, an E-probe transition to waveguide and PolyStrata diode detectors were also designed and fabricated. AW-band rectangular coaxial passive monopulse comparator with integrated antenna array and diode detectors have also been presented. Measured monopulse nulls of 31.4 dB in the ΔAZ plane have been demonstrated.
94-GHz SiGe active monopulse comparator IC and 24 GHz RF-CMOS active monopulse comparator RFIC designs are presented, including detailed simulations of monopulse nulls and performance over frequency. Simulations of the W-band SiGe active monopulse comparator IC indicate potential for wideband operation, with 30 dB monopulse nulls from 75-105 GHz. For the 24-GHz active monopulse comparator IC, simulated monopulse nulls of 71 dB and 68 dB were reported for the azimuthal and elevational sweeps. Measurements of these ICs were unsuccessful due to layout errors and incomplete accounting for parasitics.
Simulated results from a series of rectangular coaxial power corporate power combining structures have been presented, and their relative merits discussed. These designs include 2-1 and 4-1 reactive, Wilkinson, and Gysel combiners at V- and W-band. Measured back-to-back results from Gysel combiners at 60 GHz included insertion loss of 0.13 dB per division for a 2-1 combination, and an insertion loss of 0.3 dB and 0.14 dB for "planar" and "direct" 4-1 combinations, respectively. At 94 GHz, a measured insertion loss of 0.1 dB per division has been presented for a 2-1 Gysel combination, using a back-to-back structure. Preliminary designs for a solid-state power amplifier (SSPA) structure have also been presented. Finally, two conceptual monopulse transceivers will be presented, as a vehicle for integrating the various components demonstrated in this dissertation.Ph. D.
12
Pizniur, Oleksandr. "Active adaptive auxiliary circuit for stabilizing dc distribution systems with constant power loads". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52817.
Testo completoAbstract (sommario):
The portion of high-bandwidth power converters in modern DC distribution systems has been increasing and is projected to dominate over time. These devices having fast response act as constant power loads (CPLs) and possess the so-called negative incremental input impedance characteristics at the input terminals, which may ultimately cause dynamic interactions and instability at certain interfaces in the system. Most existing approaches that address this problem use passive or active damping to reshape the source/load impedances so that stability may be achieved. The drawbacks of most existing methods include energy losses in passive components and/or requirement of changing the internal controls in existing loads.
This thesis presents a new active damping methodology using an auxiliary converter circuit to stabilize DC distribution systems with CPLs. A simplified single frequency criterion is proposed for identifying the damping parameters. The proposed auxiliary converter circuit exchanges the energy between very strong power bus and a potentially unstable bus with CPLs, which requires very small injected damping current and achieves lossless damping (conserves the energy during transients). The methodology may operate by emulating fixed or operating-point-depended virtual RC values of the equivalent damping, with the latter having potential advantages of achieving faster damping.
To verify and demonstrate the proposed concept, the auxiliary converter circuit has been designed and built with innovative compensated average current control mode. The experimental studies have been carried out on a reduced scale subsystem of a DC microgrid installed by Alpha Technologies Ltd., in Kaiser building at UBC. It is envisioned that the proposed active damping methodology using low-power auxiliary converter circuit may be very cost-effective and practical solution for the future DC systems with modular design and multiple sources/loads being constructed by different vendors with limited knowledge of their parameters and access to their internal controls.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
13
Josse, Stève. "Transportabilité de fonctions analogiques en technologies CMOS submicroniques : application : contrôle du retard des fronts d'horloges d'un imageur CCD". Toulouse, INPT, 2003. http://www.theses.fr/2003INPT029H.
Testo completoAbstract (sommario):
Dans le cadre de la transportabilité de circuits, nous étudions le transfert de circuits analogiques CMOS par une approche semi-analytique. Appliquée aux fonctions amplifications élémentaires, elle consiste à représenter graphiquement les caractéristiques de circuits normalisés afin d'en déduire un premier dimensionnement suivant les performances souhaitées. Cette approche est validée par l'étude de 2 amplificateurs opérationnels. L'écart relatif du produit gain bande passante obtenu avec celui de la simulation n'excède pas ± 20 %. Un circuit mixte pour des applications spatiales générant des retards programmables de l'ordre de la nanoseconde a été transporté dans 2 technologies. La validation expérimentale de ces 2 circuits intégrés montre les contributions importantes de la dispersion des éléments passifs et de leurs capacités parasites distribuées. Ces phénomènes sont minimisés en introduisant des commutateurs analogiques et en optimisant le dimensionnement des composants passifs.
14
Walpole, Mark Edward. "Intrinsically Safe (IS) Active Power Supplies". Queensland University of Technology, 2003. http://eprints.qut.edu.au/15896/.
Testo completoAbstract (sommario):
Intrinsically safe (IS) active power supplies subjected to certain transient load conditions can deliver power to a circuit at significantly higher levels than indicated on their nameplate ratings. During a transient load such as an intermittent short-circuit, energy is transferred from the power supply to the short-circuit and an electrical arc may form when the short-circuit is applied or removed. This poses a spark ignition risk as energy is transferred from the arc to the surrounding atmosphere. Currently various International and Australian Standards define the performance requirements for IS electrical apparatus. A duly accredited laboratory is required to establish the intrinsic safety compliance of an apparatus with the Standards. It involves an assessment of the apparatus and may include testing. The assessment of the apparatus determines adequate segregation, separation, construction, and selection of components. The tests performed on the apparatus include a temperature rise test and in some cases, the sparking potential of the circuit is tested using the spark test apparatus (STA). Testing the sparking potential of active power supplies to establish compliance adds significantly to the time and costs involved in establishing compliance. A new alternative assessment method is proposed in this report to augment or replace the testing phase of the compliance certification process for active power supplies. The proposed alternative assessment method (PAAM) is derived from a determination of the steady-state and transient output characteristics of the active power supply under consideration. Parameters such as peak output current, time constant of peak current decay, and the output voltages at these times are measured from the circuit's output characteristics. These measurements can subsequently be used to derive the topology and component values of an equivalent circuit. The resulting equivalent circuit is then considered like a linear power supply and the sparking potential can be determined using existing assessment methods. This thesis investigates in detail the equivalent circuit of a number of direct current (DC) active power supplies whose transient output characteristics exhibit predominantly capacitive behaviour. The results of the PAAM using the equivalent circuit are then compared with results achieved using the current testing procedure with a STA. A small sample of active power supplies is used to generate data from which a relationship between the current testing procedure and the PAAM can be established. The PAAM developed in this research project can be used as a pre-compliance check by designers, manufacturers, or IS testing stations. A failure of this test would indicate that the active power supply's sparking energy is not low enough to be regarded as intrinsically safe. The PAAM requires fewer resources to establish a result than the STA. The benefits of a simplified spark ignition test would flow on from designers and manufacturers to end users.
15
陳卓雄。 e Chuk-hung Chan. "Design and evaluation of active power factor correction circuit operation in discontinuous inductor current mode". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31220344.
Testo completo
16
Chan, Chuk-hung. "Design and evaluation of active power factor correction circuit operation in discontinuous inductor current mode /". Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2062315X.
Testo completo
17
Edqvist, Erik. "Applications of active materials". Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-108696.
Testo completoAbstract (sommario):
Energy efficiency is a vital key component when designing and miniaturizing self sustained microsystems. The smaller the system, the smaller is the possibility to store enough stored energy for a long and continuous operational time. To move such a system in an energy efficient way, a piezoelectrical locomotion module consisting of four resonating cantilevers has been designed, manufactured and evaluated in this work. The combination of a suitable substrate, a multilayered piezoelectric material to reduce the voltage, and a resonating drive mechanism resulted in a low power demand. A manufacturing process for multilayer cantilever actuators made of P(VDF-TrFE) with aluminum electrodes on a substrate of flexible printed circuit board (FPC), has been developed. An important step in this process was the development of an etch recipe for dry etching the multilayer actuators in an inductive plasma equipment. Formulas for the quasi static tip deflection and resonance frequency of a multilayered cantilever, have been derived. Through theses, it was found that the multilayered structures should be deposited on the polymer side of the FPC in order to maximize the tip deflection. Both a large and a miniaturized locomotion module were manufactured and connected by wires to verify that the three legged motion principal worked to move the structures forward and backward, and turn it right and left. By touching and adding load, to a fourth miniaturized cantilever, its ability to act as a contact sensor and carry object was verified. The presented locomotion module is part of a multifunctional microsystem, intended to be energy efficient and powered by a solar panel with a total volume of less than 25 mm3 and weight 65 mg. The whole system, consisting of a solar cell, an infra red communication module, an integrated circuit for control, three capacitors for power regulating, the locomotion module and an FPC connecting the different modules, was surface mounted using a state of the art industrial facility. Two fully assembled systems could be programmed both through a test connector and through optical sensors in the multifunctional solar cell. One of these was folded together to the final configuration of a robot. However, the entire system could not be tested under full autonomous operating conditions. On the other hand, using wires, the locomotion module could be operated and used to move the entire system from a peak-to-peak voltage of 3.0 V.
18
El-Habrouk, Mohamed. "A new configuration for shunt active power filters". Thesis, Brunel University, 1998. http://bura.brunel.ac.uk/handle/2438/5241.
Testo completoAbstract (sommario):
This thesis presents a new power circuit configuration to be used in shunt active power filters. A new control algorithm based on the linear voltage control suitable for the proposed circuit is introduced. The system is analysed both in time and frequency domains. The practical implementation of the system proves its suitability for the proposed task. The switching frequency of the proposed circuit is much lower than that in other active filters. The switching losses are then considerably reduced, in addition to the fact that the switching devices can withstand larger values of currents being switched on and off at lower frequencies which is an advantage to this circuit. The component sizes (capacitors and inductors) in the proposed circuit are also much smaller than those in other filter configurations. In addition, the thesis presents a new method for categorising the active filter systems proposed in the surveyed literature. The survey includes a comparison of these techniques showing their respective merits and drawbacks. The thesis also includes an implementation of a reference current generator that is suitable for single-phase applications without the need for excessive computations. The technique involves a modified Fourier analysis, which is suitable for active filtering applications.
19
Tang, Qi, e Qi Tang. "Active Metamaterial: Gain and Stability, and Microfluidic Chip for THz Cell Spectroscopy". Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/623025.
Testo completoAbstract (sommario):
Metamaterials are artificially designed composite materials which can exhibit unique and unusual properties such as the negative refractive index, negative phase velocity, etc. The concept of metamaterials becomes prevalent in the electromagnetic society since the first experimental implementation in the early 2000s. Many fascinated potential applications, e.g. super lens, invisibility cloaking, and novel antennas that are electrically small, have been proposed based on metamaterials. However, most of the applications still remain in theory and are not suitable for practical applications mainly due to the intrinsic loss and narrow bandwidth (large dispersion) determined by the fundamental physics of metamaterials .In this dissertation, we incorporate active gain devices into conventional passive metamaterials to overcome loss and even provide gain. Two types of active gain negative refractive index metamaterials are proposed, designed and experimentally demonstrated, including an active composite left-/right-handed transmission line and an active volumetric metamaterial. In addition, we investigate the non-Foster circuits for broadband matching of electrically small antennas. A rigorous way of analyzing the stability of non-Foster circuits by normalized determinant function is proposed. We study the practical factors that may affect the stability of non-Foster circuits, including the device parasitics, DC biasing, layouts and load impedance. A stable floating negative capacitor is designed, fabricated and tested. Moreover, it is important to resolve the sign of refractive index for active gain media which can be quite challenging. We investigate the analytical solution of a gain slab system, and apply the Nyquist criterion to analyze the stability of a causal gain medium. We then emphasize that the result of frequency domain simulation has to be treated with care. Lastly, this dissertation discusses another interesting topic about THz spectroscopy of live cells. THz spectroscopy becomes an emerging technique for studying the dynamics and interactions of cells and biomolecules, but many practical challenges still remain in experimental studies. We present a prototype of simple and inexpensive cell-trapping microfluidic chip for THz spectroscopic study of live cells. Cells are transported, trapped and concentrated into the THz exposure region by applying an AC bias signal while the chip maintains a steady temperature at 37°C by resistive heating. We conduct some preliminary experiments on E. coli and T cell solution and compare the transmission spectra of empty channels, channels filled with aqueous media only, and channels filled with aqueous medium with un-concentrated and concentrated cells.
20
Sarmiento, Leon Mayra Susana. "Testing platform implementation and system integration for an active/passive imager system including readout circuit design". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 5.32 Mb., 170 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3220740.
Testo completo
21
Eleyele, Abidemi Oluremilekun. "Isolated Single-Stage Interleave Resonant PFC Rectifier with Active and Novel Passive Output Ripple Cancellation Circuit". Thesis, Uppsala universitet, Institutionen för elektroteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-423117.
Testo completoAbstract (sommario):
With the increasing demand for fast, cheaper, and efficient power converters come the need for a single-stage power factor correction (PFC) converter. Various single-stage PFC converter proposed in the literature has the drawback of high DC bus voltage at the input side and together with the shift to wide bandgap switches like GaN drives the converter cost higher. However, an interleaved topology with high-frequency isolation was proposed in this research work due to the drastic reduction in the DC bus voltage and extremely low input current ripple thereby making the need for an EMI filter circuit optional. Meanwhile, this research work focuses on adapting the proposed topology for a high voltage low current application (EV charger - 400V, 7KW) and low voltage high current application (telecom power supply - 58V, 58A) owing to cost benefits. However, all single-stage PFC are faced with the drawback of second-order (100Hz) output harmonic ripple. Therefore, the design and simulation presented a huge peak to peak ripple of about 50V/3A and 26V/26A for the EV charger and telecom power supply case, respectively. This created the need for the design of a ripple cancellation circuit as the research required a peak to peak ripple of 8V and 200mV for the EV - charger and telecom power supply, respectively. A novel output passive ripple cancellation technique was developed for the EV charger case due to the ease it offers in terms of control, circuit complexity and extremely low THDi when compared with the active cancellation approach. The ripple circuit reduced the 50V ripple to 431mV with the use of a total of 2.2mF capacitance at the output stage. Despite designing the passive technique, an active ripple cancellation circuit was designed using a buck converter circuit for the telecom power supply. The active approach was chosen because the passive has a slow response and incurs more loss at a high current level. Adding the active ripple cancellation circuit led to a quasi-single stage LLC PFC converter topology. A novel duty-ratio feedforward control was added to synchronize the PFC control of the input side with the buck topology ripple cancellation circuit. The addition of the ripple circuit with the feedforward control offered a peak to peak ripple of 6.7mV and a reduced resonant inductor current by half. After analysis, an extremely low THDi of 0.47%, PF of 99.99% and a peak efficiency of 97.1% was obtained for the EV charger case. The telecom power supply offered a THDi of 2.3%, PF of 99.96% with a peak efficiency of 95%.
22
Lyson, Kyle Joshua. "On-chip automatic tuning of CMOS active inductors for use in radio frequency integrated circuit (RFIC) applications". Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/lyson/LysonK1206.pdf.
Testo completo
23
Zakka, el Nashef Georges. "Développement de modèles et d'outils de cosimulation EM/Circuit pour application aux antennes agiles actives". Limoges, 2010. https://aurore.unilim.fr/theses/nxfile/default/f2b7d885-5f00-4474-ba83-2d4731bfc8fa/blobholder:0/2010LIMO4044.pdf.
Testo completoAbstract (sommario):
Les antennes actives ont pour particularité d'associer à l'émission d'amplificateurs de puissance à proximité d'éléments rayonnants. Leur mise en réseau offre beaucoup d'avantages pour la chaîne d'émission, comme la formation de faisceau, la création de zéros de rayonnement, de faisceaux dépointés avec augmentation de directivité, mais le couplage entre antennes entraîne leur désadaptation et la dégradation du rayonnement du réseau. Ce manuscrit présente un ensemble de démarches adaptées afin de quantifier cet inconvénient majeur. La première partie est consacrée à la problématique du couplage au sein des réseaux d'antennes. Ce couplage induit des variations de charge qui modifient le comportement des amplificateurs et impactent les performances globales de l'antenne. Afin de prendre en compte cet effet, un outil de simulation pour antennes passives a été développé. Cette partie est illustrée avec la conception, la réalisation et la mesure de différents prototypes. La deuxième partie concerne la modélisation bilatérale comportementale d'amplificateurs de puissance pour répondre à la problématique de désadaptation de charge. Un modèle a donc été développé pour prendre en compte des fortes désadaptations de charges (TOS 4), puis validé avec des résultats de mesures. Finalement, un démonstrateur actif comprenant à la fois amplificateurs et réseau d'antennes a été réalisé dans le but de valider ces deux formalismes, et permet de présenter une première approche de cosimulation d'antennes actives tenant compte de tous les effets décritsActive antennas have the distinctive feature of having, for transmission mode, high power amplifiers located at the vicinity of the radiating elements. An active array of antennas offers lots of advantages to TX systems, such as beamforming, nulling patterns, beam steering and directivity enhancement, but coupling between antennas leads to output impedance mismatching and degradation of the radiation pattern. This manuscript develops a set of methods to address this major drawback. The first part is devoted to the mutual coupling problem in antenna arrays. This mutual coupling can lead to load variations at the amplifiers output, which might affect their transfer characteristics and modify the overall performance of the array. In order to overcome this coupling effect, a simulation tool for passive antennas has been developed. This part is illustrated with the design, implementation and measurement of different prototypes. A second part concerns the behavioural modelling (X- parameters) of power amplifiers, in order to solve the mismatching problem for the power amplifiers. A bilateral behavioural model of power amplifiers has thus been developed and it will eventually be able to take into account strong load mismatch (VSWR = 4). The comparison between the power amplifier model and the measurements show an excellent agreement. Finally, an active antenna prototype including power amplifiers and antennas array has been built in order to validate both theoretical concepts, and shows a first approach of active antennas cosimulation, taking into account all the mentioned effects
24
Miko, Radoslav. "Třífázový síťový napaječ s aktivním usměrňovačem". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-242035.
Testo completoAbstract (sommario):
Diploma thesis deals with problems of power factor correction and total harmonic distortion of line current in three phase industrial power supplies. It focuses mainly on using of single phase active PFC topologies based on the principle of step up converter, which are applicable to three phase systems. Verification of operation and comparison of parameters of several circuits was done by simulation in program Matlab Simulink. Then for selected circuit of active PFC was done complete design. The result is a prototype of single phase active PFC circuit with an output power 2 kW for input voltage range from 180 to 528 V (47 – 63 Hz) and a prototype of three phase active PFC circuit with an output power 6 kW for input voltage range from 3 x 180 to 3 x 528 V (47 – 63 Hz).
25
Zhu, Ning. "Electrically Small, Near-Field Resonant Parasitic (NFRP) Antennas Augmented with Passive and Active Circuit Elements to Enhance their Functionality". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/297013.
Testo completoAbstract (sommario):
Metamaterials have drawn considerable attention because they can exhibit epsilon-negative (ENG) and/or mu-negative (MNG) properties, which in turn can lead to exotic physical effects that can enable interesting, practical applications. For instance, ENG and MNG properties can be engineered to yield double negative (DNG) properties, such as a negative index of refraction, which leads to flat lenses. Similarly, their extreme versions enable cloaking effects. Inspired by such metamaterial properties, a promising methodology has been developed to design electrically small antennas (ESAs). These ESAs use unit cells of metamaterials as their near-field resonant parasitic (NFRP) elements. This new metamaterial-inspired antenna miniaturization method is extended in this dissertation by augmenting the antenna designs with circuits. A rectifying circuit augmentation is used to achieve electrically small, high efficiency rectenna systems. Rectennas are the enabling components of power harvesting and wireless power transmission systems. Electrically small, integrated rectennas have become popular and in demand for several wireless applications including sensor networks and bio-implanted devices. Four global positioning system (GPS) L1 frequency (1.5754 GHz) rectenna systems were designed, fabricated and measured: three resistor-loaded and one supercapacitor-loaded. The simulated and measured results will be described; good agreement between them was obtained. The NFRP ESAs are also augmented with active, non-Foster elements in order to overcome the physical limits of the impedance bandwidth of passive ESA systems. Unlike conventional active external matching network approaches, the non-Foster components are incorporated directly into the NFRP element of the ESA. Three 300 MHz non-Foster circuit-augmented broadband, ESA systems were demonstrated: an Egyptian axe monopole (EAM) antenna, an Egyptian axe dipole (EAD) antenna, and a protractor antenna. The simulated and measured results will be described; reasonable agreement between them was obtained. Moreover, a deeper practical engineering understanding of how lumped components with tighter tolerances, more accurate transistor models, and integrated circuit-based implementations will lead to more satisfactory performance characteristics of the non-Foster circuit-augmented ESAs was accomplished and is also reported.
26
Normand, Guy. "Les circuits translineaires : contribution a leur etude et a leur mise en oeuvre dans les domaines analogique et logique". Nantes, 1987. http://www.theses.fr/1987NANT2056.
Testo completoAbstract (sommario):
Les circuits translineaires sont des circuits constitues d'un certain nombre de jonctions bipolaires, organisees en mailles translineaires. Le processus translineaires conduit a la realisation de nombreuses fonctions electroniques lineaires ou non lineaires, analogiques ou logiques. Les structures translineaires sont destinees a commander electroniquement le facteur transfert des reseaux lineaires
27
Maupas, Eric. "Etude dans la spasticité de la modulation de l'excitabilité du circuit prémotoneuronal lombaire active par les afférences musculaires du groupe II". Dijon, 2003. http://www.theses.fr/2003DIJOMU20.
Testo completoAbstract (sommario):
Il existe chez l'homme, après hémiplégie d'origine vasculaire, une hyperexcitabilité du circuit prémotoneuronal lombaire activé par les afférences musculaires du groupe I et du groupe II. Compte tenu de l'importance des projections des afférences du groupe II sur les groupes d'interneurones lombaires chez l'animal, cela permet de supposer l'importance des afférences du groupe II dans la physiopathologie de la spasticité. Dans ce travail, nous avons pu confirmer l'existence de l'hyperexcitabilité de ce circuit prémotoneuronal lombaire chez des patients spastiques, que ce soit pour des lésions acquises à l'âge adulte après accident vasculaire cérébral, ou dans le cadre de lésions périnatales de l'infirmité motrice cérébrale. Par ailleurs, la tizanidine, médicament antispastique noradrénergique, provoque chez le sujet sain une diminution sélective de la facilitation tardive du réflexe H du quadriceps attribuée aux afférences musculaires du groupe II. Chez les sujets hémiplégiques vasculaires, la tizanidine induit une diminution préférentielle de la facilitation tardive du groupe II et une diminution moindre de la facilitation précoce du groupe I. Ces arguments pourraient apporter un élément supplémentaire en faveur de l'existence chez l'homme d'un contrôle monoaminergique descendant inhibiteur s'exercant préférentiellement sur les afférences du groupe II.
28
Claveau, Régis. "Contribution à l'étude des amplificateurs distribuéset des circuits de polarisation active. Applicationsaux circuits de commande de modulateurs électro-optiques". Phd thesis, INSA de Rennes, 2005. http://tel.archives-ouvertes.fr/tel-00143887.
Testo completoAbstract (sommario):
L'augmentation des débits à 10Gbps et 40Gbps dans les télécommunicationsoptiques couplée à des besoins de portées supérieures à 150 km privilégie l'emploi de la
modulation externe, et en particulier, des modulateurs électro-optiques. Les circuits de
commande des modulateurs optiques apparaissent alors comme un élément clé de ces
systèmes de transmission.
Les premiers chapitres permettent, suite à une présentation des systèmes et architectures les
plus couramment utilisés, de définir les spécifications en performances requises pour les
circuits de commande de modulateurs externes et en particulier des modulateurs électrooptiques.
Une étude complète des amplificateurs distribués, et de leurs différentes
configurations, est menée. Ces amplificateurs, par leur produit gain-bande passante élevé,
répondent en effet au mieux aux exigences définies. Les amplificateurs conçus ont été réalisés
à partir de transistors PHEMT sur arséniure de gallium, de 0.15 μm de longueur de grille.
Afin de simplifier la mise en boîtier et de résoudre les désagréments de la polarisation
classique des amplificateurs distribués, deux nouveaux circuits de polarisation intégrés ont été
développés. Tout d'abord une nouvelle charge active, tenant lieu de terminaison de la ligne de
sortie de l'amplificateur distribué, permet de polariser et de conserver l'adaptation en sortie de
l'amplificateur distribué lors d'une variation du courant de polarisation, pour d'un contrôle de
gain par exemple. Egalement un dispositif intégré de sources de courant connectés à la ligne
de sortie de l'amplificateur distribué, appelé té de polarisation actif, a été étudié. La
réalisation d'un circuit de commande, par le report et la mise en boîtier d'un amplificateur
distribué utilisant le té de polarisation actif, a été validée par des mesures de paramètres [S] et
des diagrammes de l'oeil électriques et optiques.
29
Fischer, Craig J. "Design of an Active Harmonic Rejection N-Path Filter for Highly Tunable RF Channel Selection". DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1930.
Testo completoAbstract (sommario):
As the number of wireless devices in the world increases, so does the demand for flexible radio receiver architectures capable of operating over a wide range of frequencies and communication protocols. The resonance-based channel-select filters used in traditional radio architectures have a fixed frequency response, making them poorly suited for such a receiver. The N-path filter is based on 1960s technology that has received renewed interest in recent years for its application as a linear high Q filter at radio frequencies. N-path filters use passive mixers to apply a frequency transformation to a baseband low-pass filter in order to achieve a high-Q band-pass response at high frequencies. The clock frequency determines the center frequency of the band-pass filter, which makes the filter highly tunable over a broad frequency range. Issues with harmonic transfer and poor attenuation limit the feasibility of using N-path filters in practice. The goal of this thesis is to design an integrated active N-path filter that improves upon the passive N-path filter’s poor harmonic rejection and limited outof- band attenuation. The integrated circuit (IC) is implemented using the CMRF8SF 130nm CMOS process. The design uses a multi-phase clock generation circuit to implement a harmonic rejection mixer in order to suppress the 3rd and 5th harmonic. The completed active N-path filter has a tuning range of 200MHz to 1GHz and the out-ofband attenuation exceeds 60dB throughout this range. The frequency response exhibits a 14.7dB gain at the center frequency and a -3dB bandwidth of 6.8MHz.
30
DING, MENGMENG. "REGRESSION BASED ANALOG PERFORMANCE MACROMODELING: TECHNIQUES AND APPLICATIONS". University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1146145102.
Testo completo
31
Chen, Ming-Chieh, e 陳銘傑. "The Study of Active Inductor Integrated Circuit". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/43974798791116632043.
Testo completoAbstract (sommario):
碩士國立高雄應用科技大學
電機工程系碩士班
92
The purpose of this thesis is to implement active inductor integrated circuits with a very high quality value and a tunable inductance. The active inductor can be extensively used in the application basic modules of front-end transceiver in wireless communication system, such as LNA (Low Noise Amplifier), VCO (Voltage Controlled Oscillator) … etc. Because of the smaller area, the higher quality factor and the tunable inductance, active inductor exhibits charming characteristics that spiral inductor can’t exceed. The simulation results in the thesis show that a simple cascode active inductor can work at 5.7 GHz with 9.45 mW power consumption. It can deliver a maximum equivalent inductance of 24 nH with a maximum quality-factor of 40. Besides, the effective inductance and quality-factor can be tuned by controlling the bias current. Using the above active inductor, a common-source low noise amplifier with an active inductor load is developed. The amplifier operates at 5.7 GHz with 11.1dB power gain, -15 dBm , and 4.1dB noise figure in simulation.
32
Chen, Cheng-Chieh, e 陳政杰. "Active Quenching Circuit Design for Avalanche Photodiode Arrays". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/93431086325455151362.
Testo completoAbstract (sommario):
碩士國立中正大學
電機工程所
95
The photodiode operating at a reverse biased voltage can yield electrons and holes when the light is incident upon it. Additionally, while the reverse biased voltage exceeds the breakdown voltage, the numbers of the electrons and holes increase rapidly through ionizing. The operation of the photodiode biased by a voltage higher than the breakdown voltage is called the Geiger mode. Such operation mode can produce a large electric current. The experimental results show that the photodiode continuously operating at a high reverse biased voltage tends to breakdown easily. In order to avoid damage of the semiconductor components and instability of the circuit operation, two kinds of protection mechanisms are proposed: one is the forward biased mechanism and the other is the shorting mechanism. The experimental results demonstrate that these two protection mechanisms can slow down the breakdown tendency. In the image detection system, the real-time image capture is realized by means of the Time-of-Flight (TOF) way. The 850nm laser light source is employed to conduct the experiments on the CMOS photodiodes with various structures The TSMC 0.35um CMOS technology is used to implement the pixel array, including 32x32 photodiodes, row/column decoders, shift register, controller, multiplexor, and Correlated-Double-Sampling (CDS) circuit. In a 3D image detection system, the real-time image capture is usually realized by means of the Time-of-Flight (TOF) manner. This 32x32 CMOS sensor array was fabricated and will be tested to verify our 3-D image detection system.
33
Jiang, Chin-Jung, e 江致榮. "Study on P3HT FET and active matrix circuit". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/49830524507630797119.
Testo completoAbstract (sommario):
碩士國立清華大學
電子工程研究所
94
Integrating polymer light-emitting diodes (LED) and polymer field-effect transistors (FET) on one substrate to fabricate 2T1C active-matrix array circuit by solution process can reduce the cost substantially. The polymer devices can be fabricated on various substrates, such as flexible substrate. Additionally, organic LEDs are regarded as the potential technology in display with advantages of high brightness, high contrast, and low operating voltage. We use P3HT as semiconductor, use SiO2 as insulator, and successfully fabricate FET with mobility of 10-2 (cm2/V-s) and on/off ratio of 104 on glass substrate. To increase reliability of P3HT FET, we use chromium as gate material. To lower leakage current, we design new mask. We also use different coating methods and O2 plasma treatment to enhance mobility. Eventually, we applied P3HT FETs to 1T1C active-matrix circuit and obtained successful operation of charging and discharge in this 1T1C circuit at 10Hz, 100Hz, 500Hz, and 1KHz. The fastest rise time is 0.3 (ms).
34
Chang, Shih-ju, e 張世儒. "Implementation of Active Filter Circuit with Boost Converter". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/ep33uq.
Testo completoAbstract (sommario):
碩士崑山科技大學
電機工程研究所
97
A fixed frequency, fixed duty cycle boost converter with discontinuous input inductor current for active power factor correction(PFC) operation is studied in this thesis. Because of the traditional passive power factor correction is easy to create the product large scale, also passive power factor correction is not good. This thesis is to implement the active power factor correction circuit, which compared with the passive power factor correction, to improve the shortcoming of the passive power factor correction. A load is designed in 120W, output 400V to the circuit proposed in this thesis, which the power factor up to above 0.95, the efficiency up to above 95%. Finally, through simulation results and experimental responses, the circuit proposed is never to need the complicated inner-loop controller, the multiplier and the current sensor neither. It can not only save the cost of element, but also achieve high power factor.
35
Zhu, Hung-Zhung, e 朱宏章. "CMOS-based Microwave Active and Passive Circuit Design". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/14272941113231232284.
Testo completoAbstract (sommario):
碩士國立清華大學
電子工程研究所
93
ABSTRACT To enhance the circuit and system performance, the major effort has been focused on improving the device speed through scaling of device dimensions. The decrease in minimum feature size of devices has led to a property decrease in interconnect cross-sectional area and pitch. The parasitic resistance, capacitance, and inductance associated with interconnects are beginning to influence the circuit performance and the evolution of deep sub-micron ULSI technology. Therefore, in chapter 2, variable structures of Si-based IC interconnects are discussed, and a deeper understanding of the loss and delay characteristics is obtained. The trade-offs of different designs are also addressed. As operation frequency keep increasing, microwave IC structures have suffered from a lack of high Q miniature passive elements, which have applications such as high-performance filters and low-phase noise oscillators. Furthermore, that millimeter microwave integrated-circuit combine with CMOS technology to decrease cost is the current trend for MMIC design. In chapter 3, a high Q, multiple-ring resonant filter is designed in a standard 0.18 µm CMOS process. The measurement results show a loaded and unloaded Q of 38 and 83, respectively. In chapter 4, a high-performance Ka-band balanced amplifier is designed in a standard 0.18 µm. A 3-dB Lange coupler is designed using the multiple-interconnect process of CMOS. A bandwidth of 7.5 GHz and a maximan gain of 21 dB are obtained.
36
LEE, Yi-Te, e 李奕德. "Active/Passive Vibration Suppression With Piezoelectric Shunt Circuit". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/08853568756748762535.
Testo completo
37
Hsu, Hung-Jen, e 許宏任. "Single-Photon Avalanche Diode Controlled by Active Quenching Circuit". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/03584007415633380886.
Testo completoAbstract (sommario):
碩士國立交通大學
電子研究所
100
In this work, we study single-photon-avalanche-diodes (SPADs) with an active quenching circuit (AQC) by using the standard 0.18 µm CMOS technology. Because the dead time of SPAD with passive quenching circuit is too long, the main target of the AQC design is to shorten it. On the other hand, the large chip area of AQC will reduce the spatial resolution of the fabricated SPAD array so to minimize the AQC is also important. Our SPADs with well-designed AQC show the fastest dead time of 4 ns, and use the smallest chip area of 15.7×15.2 〖µm〗^2, comparing with others using 0.18 µm CMOS technology. In addition, we demonstrate the function of tunable hold-off time which can be adjusted, according to the characteristics of SPAD, to reduce afterpulsing effect and to lower dark counts. The measured dead time can be extended to more than 280 ns, and the reduced equivalent dark counts are also obtained. Finally, we observe that dark counts and photon detection efficiency (PDE) both increase with increasing excess bias voltages. The highest PDE of 7.5% is achieved. The noise equivalent power (NEP) is about 10-14 WHz-1/2.
38
Chen, Yi-Ming, e 鄭一民. "Designing Active Inductors by Multi-Stage RF CMOS Circuit". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/81622651082317110419.
Testo completoAbstract (sommario):
碩士逢甲大學
電子工程所
92
Abstract Passive spiral inductor are widely used in the design of RFIC(Radio Frequency Integrated Circuits). However, the area they occupied is quite large, which increases the costs and the unavoidable parasitic effects. The Q-value of the spiral inductor is typically lower than 7 and being too small for the design of high frequency circuits The purpose of this project is to implement an active inductor, which has high Q-value. Their size is quite small and independent of the inductance value. This active inductor will be used in the circuits of wireless communication system such as LNA、Mixer、BPF… etc. We expect that the performances of RF circuits can be improved due to these advantages of active inductor. Keyword: Spiral-Inductor, Active-Inductor, Quality Factor,Inductance Value
39
Chang, Sheng-Yu, e 昌聖喻. "Common Noise Reduction Filter For Active Noise Cancellation Circuit". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/42421308968305601577.
Testo completoAbstract (sommario):
碩士華梵大學
機電工程研究所
92
In this thesis, a common noise reduction filter topology is used in the feedback control technique to design an active noise cancellation (ANC) circuit for headphone. This new topology has the advantage of reducing the manufacturing cost and improving the air pressure imbalance problem of ANC headphone. Two types of common noise reduction filters, there are 4-amplifiers and 2-amplifiers circuits respectively, are designed in this thesis. From circuit simulation, it found that the center frequency and bandwidth of the 4-amplifiers filter can be tuned easily. However, the 2-amplifier filter has the low cost advantage. Finally, the noise cancellation performance of the proposed ANC headphone is measured with an experimental setup. Comparison between the performance has been made with other commercially available ANC headphones.
40
Huang, Jhao-Cyuan, e 黃昭銓. "Soft switching Flyback Converter with an Active-Clamp Circuit". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/93831458333763774295.
Testo completoAbstract (sommario):
碩士南台科技大學
電機工程系
98
The traditional pulse-width-modulated flyback converter power switch has serious electromagnetic interference (EMI) and lower conversion efficiencies problems due to the hard-switching operations. This paper produces a soft switching flyback converter with an active-clamp circuit, the traditional pulse-width-modulated flyback converter with a active clamp circuit to achieve zero-voltage-switching (ZVS) at both main and auxiliary switches, the active-clamp circuit can reduce most of switching loss and voltage spikes across the switches and improve the overall efficiency of the converter. The theoretical analysis of soft switching flyback converter with an active-clamp circuit is verified exactly by a prototype of 120W with 100V input voltage, 24V output voltage and 50kHz operated frequency. During full load condition experimental results showed an 82.3% efficiency.
41
Lee, Han-Hsiang, e 李漢祥. "Development of PV Inverters with Active Power Dcoupling Circuit". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/03376325469286274260.
Testo completoAbstract (sommario):
碩士國立清華大學
通訊工程研究所
94
In a photovoltaic system, an inverter is an essential interface to convert the direct power produced by solar cell into alternating power. However, the inherent instantaneous second harmonic power phenomenon of a PV system affects the Maximum Power Point Tracking (MPPT) and output current quality of the system. One most common solution is by connecting a large electrolytic capacitor to the DC link of PV inverters to reduce the effect of the instantaneous second harmonic power component. Yet, comparing with AC capacitors, the lifetime of an electrolytic capacitor is much shorter, and its reliability becomes much lower. Therefore, the major purpose of this thesis is to develop a PV inverter which contains an active power decoupling circuit to eliminate the instantaneous second harmonic power of the PV system effectively and to enable the use of an AC capacitor with lower capacitance value to substitute for the large DC link capacitor. The contributions of this thesis may be summarized as follows. First, the distribution of the instantaneous second harmonic power of each element in the PV inverter adopted was analyzed and its influence on MPPT and output current quality of the PV module was also discussed. Second, based on the understanding of the first point which we have studied in depth, two simple power decoupling circuits were proposed to eliminate the second harmonic voltage ripple so that we can use an AC capacitor to replace traditional large electrolytic capacitor to enhance the reliability of the entire PV system. Third, a prototype is also constructed by using a TMS320F2812 DSP (developed by Texas Instrument Company) to verify the validity of the power decoupling circuit.
42
Wang, Xuan-Han, e 王炫涵. "Improving active harmonic mode-locked laser by PLL circuit". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/23692993120694375819.
Testo completo
43
Chang, Chao-Kuei, e 張昭貴. "The Design of Analog Circuit Using Current-Mode Active Components". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/64985760795378868193.
Testo completoAbstract (sommario):
碩士中原大學
電子工程研究所
90
In recent years, the current-mode active components is popular in scholastic discussion and commercially used. Current-mode active components have the advantages of wider bandwidths, larger dynamic range, lower power-consumption, smaller area and easier to design. The object of this study is the design analog filter circuit using current-feedback amplifier. This thesis divided into two topics. First, several current-feedback amplifiers to carry out the three-inputs and single-output, second-order universal filter and the single-input and multi-outputs second-order universal filter published in the recent years. I study them in order to find out the skills of designing analog circuits. Second, a voltage-mode four-inputs and single-output second-order universa filter is proposed. The proposed circuit employs only one current-feedback amplifier, two capacitors and three resistors. The use of only one active components simples configuration. PSpice simulation and experimental results of the proposed circuit consist with the theoretical results.
44
Lin, Chang Ching, e 林長青. "Multi-function Active Antenna system-Logic and Switch Circuit Design". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/69711598425308197065.
Testo completoAbstract (sommario):
碩士元智大學
通訊工程學系
98
This thesis covers the development of a multi-function active antenna system which uses logic and switch control circuitry. One of the applications for this system is to be used in Wireless Local Network Area (WLAN) access point (AP) which will assist in improving communication quality and distance. The main research is on the logic and switch circuitry. It uses the 89S52, the micro-controller, for processing the data. The system also comprises of an array antenna, and RF detection circuit. This thesis will also cover the designing of analog to digital converter (ADC) circuit, the antenna control switch circuit and how the whole system is controlled using C-language making it able to detect the user location. This multi function active antenna system will combine the peripheral circuit elements. These elements include array antenna, signal strength analysis circuit, display circuit, power circuits for all components which include DVB-T. This project uses parts and components which are easily and commonly available, hence making it a low cost in design. This design also makes it very easy to integrate 2.4GHz WLAN applications.
45
Chen, Tiao-cong, e 陳調聰. "A Novel Active Matrix Pixel Driving Circuit Design of OLED". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/49594285575748882366.
Testo completoAbstract (sommario):
碩士國立中山大學
電機工程學系研究所
93
New generation of Flat Panel Displays, Organic Light Emitting Diode (OLED) with fast response, high brightness, high contrast plays an important role gradually in the further market of flat penal display (FPD). The characteristics of OLED like as bright light、thin、short、small subverts the concept of LCD displays. But the life time of organic materials become the obstruction on the further development of OLED-FPD. In addition, the non-uniformity of OLED Panel could cause the quality of frames worse. Hence, for solve the problem, A more powerful Pixel driving circuit will be designed for achieving the high performance of OLED based FPD. Recently, many researches were related to the compensating pixel driving circuits have reported. The catalogs of pixel driving circuits were divided into two types as voltage-driving circuit and current-driving circuit, which were used to solve the problems like the variation of the threshold voltage, the electronic mobility and the long time with storing capacitors charge and discharge. In this study, a novel pixel driving circuit with new discharged paths was design in order to solve the long time of charge and discharge. Theoretical and circuit simulation show this design can enhance the frame rates effectively. At the same time, it also achieves better performance such as higher resolution and quality of frame rate for the large size OLED panels.
46
Lin, Chuan-Che, e 林傳哲. "A Novel High Gain Boost Converter with Active Snubber Circuit". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3y8n6j.
Testo completoAbstract (sommario):
碩士輔仁大學
電機工程學系碩士在職專班
106
The thesis presents a method to achieve a high voltage gain by voltage stacking technology and increasing the number of secondary winding of the coupled inductor. Then, the active snubber circuit is added to absorb the spike energy of the transformer leakage inductance for reducing the surge in the source system. Experiments and simulation results are used to verify the performance of the proposed converter operated in continuous conduction mode (CCM), discontinuous conduction mode (DCM) and boundary condition mode (BCM).
47
Huang, Wei-Syun, e 黃煒勛. "Silicon Photomultiplier Based on Short Deadtime Active Reset Quenching Circuit". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/g5d37r.
Testo completoAbstract (sommario):
碩士國立交通大學
電子研究所
106
In this work, we realize a photodetector whose deadtime is controllable from 2 ns~30 ns with an external passive quenching and active reset circuit by using single photon avalanche diodes (SPADs) applying TSMC 0.18 m HV standard CMOS technology. In addition to single pixel, we also complete a 6x4 pixel array made of SPADs tape-out to increase light absorption area. This system composed of the chip, laser and optical path design demonstrates a range-finding function. In addition, we finish the results and analysis them further, then compare the range detection of the single device with the 6x4 pixel array. Because of the shortening of deadtime, we can estimate that afterpulsing probability(app) which is highly correlated to deadtime will increase. Then we do the experiment about app to analysis. In this LIDAR system, we use pulse laser whose reputation rate is 1 MHz and its wavelength is 780 nm. We complete the detection of 100 meter in the short integration time, and the maximum deviation value is less than 0.2%. These results demonstrate that SPAD has great potential for combining it with Autonomous Emergency Braking system which can be applied to autonomous cars.
48
Kuo, Li-Fang, e 郭立芳. "Design of an Active Balance Circuit for Lithium Battery Pack". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/4dzmy9.
Testo completoAbstract (sommario):
碩士國立虎尾科技大學
電機工程研究所
101
This paper proposed a driving circuit for Lithium battery pack with balancing feature. The driving circuit consists of Class-D series resonant converter with multiple series transformers, on which primary windings are connected in series, while secondary sides are loaded by Lithium battery pack.The primary winding and secondary winding are used for the isolation and energy conversion. The load equivalent circuit is based on fundamental analysis to derive design equations and processes. Zero-voltage switching(ZVS) is operated on the active power switches. The unbalanced cell can be balanced individually. The prototype circuit is designed for series-connected LiFePO4 battery pack 24V(8S1P), and which has been built and tested to verify the analytical predictions.
49
Lin, ChangChing, e 林長青. "Multi-function Active Antenna system- Logic and Switch Circuit Design". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/45949664878408723075.
Testo completoAbstract (sommario):
碩士元智大學
通訊工程學系
98
This thesis covers the development of a multi-function active antenna system which uses logic and switch control circuitry. One of the applications for this system is to be used in Wireless Local Network Area (WLAN) access point (AP) which will assist in improving communication quality and distance. The main research is on the logic and switch circuitry. It uses the 89S52, the micro-controller, for processing the data. The system also comprises of an array antenna, and RF detection circuit. This thesis will also cover the designing of analog to digital converter (ADC) circuit, the antenna control switch circuit and how the whole system is controlled using C-language making it able to detect the user location. This multi function active antenna system will combine the peripheral circuit elements. These elements include array antenna, signal strength analysis circuit, display circuit, power circuits for all components which include DVB-T. This project uses parts and components which are easily and commonly available, hence making it a low cost in design. This design also makes it very easy to integrate 2.4GHz WLAN applications.
50
王建龍. "An Active Guarding Circuit for Giga-Hertz Substrate Noise Suppression". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/58562775503814689364.
Testo completo