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Powell, Matthew Reid 1980. "Integrated feedback circuit for organic LED display driver." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17967.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.<br>Includes bibliographical references (leaf 65).<br>Organic LEDs (OLEDs) offer the potential of ultra low power, portable display technology. The chief barrier to their usage lies in producing OLEDs that will emit light at predictable and consistent amplitudes. We propose the use of optical feedback to generate the desired luminosity pixel by pixel. We implement this technique in an integrated silicon chip. The simulation and verification of fabricated integrated circuits with deposited OLEDs validates the utility of the technique.<br>by Matthew Reid Powell.<br>M.Eng.
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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.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.<br>Includes bibliographical references (leaves 44-45).<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>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.<br>by Eko T. Lisuwandi.<br>M.Eng.
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Stevens, Eric G. "A low-noise CCD electrometer using buried-channel LDD NMOSFETs /." Online version of thesis, 1987. http://hdl.handle.net/1850/9018.
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Hodáňová, Adéla. "LED driver se synchronním usměrněním." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400539.
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The main goal of this diploma thesis is to compare two circuits designed for LED powering with output current of units of Amperes. Both circuits are based on step-down converter topology, one with technology of synchronous rectifying and the other one without it. Calculations and selection of used components with real prototypes were made for both selected circuits. All selected components meet automotive qualification requirements for discrete products. Produced prototypes were compared in terms of functionality, efficiency, EMC and thermal radiation.
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Lamba, Kartik S. "An integrated circuit for feedback control & compensation of an organic LED display." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36801.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.<br>Includes bibliographical references (p. 55-56).<br>Organic LEDs (OLEDs) have the potential to be used to build large-format, thin, flexible displays. Currently, the primary drawback to their usage lies in the difficulty of producing OLEDs which emit light at a constant and predictable brightness over their lifetime. A solution has been proposed which uses organic photo-detectors and optical feedback to control the desired luminosity on a per-pixel basis. This thesis demonstrates the design and fabrication of an integrated silicon control chip and an organic pixel/imaging array, which together form a stable, usable display. The simulation, verification, and testing of this OLED display demonstrates the utility of our solution. In particular, this thesis focuses on the Loop Compensator silicon design and feedback aspects of this circuit. The results demonstrate that the Loop Compensator has the desired DC and frequency characteristics with a measured gain of 100.2 and a variable dominant pole located at digitally-selectable frequencies (using a programmable capacitor array) of 10.8 Hz, 13.5 Hz, 22.8 Hz, and 64.8 Hz, given a clock frequency of 20 kHz.<br>by Kartik S. Lamba.<br>M.Eng.
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Круглій, Назар Тарасович, та Nazar Kruhlii. "Розробка електронного драйвера для LED світильника". Bachelor's thesis, Тернопільський національний технічний університет ім. І. Пулюя, Факультет прикладних інформаційних технологій та електроінженерії, Кафедра автоматизації технологічних процесів і виробництв, 2021. http://elartu.tntu.edu.ua/handle/lib/35359.
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Робота виконана на кафедрі автоматизації технологічних процесів і виробництв факультету прикладних інформаційних технологій та електроінженерії Тернопільського національного технічного університету імені Івана Пулюя Міністерства освіти і науки України. Захист відбудеться «17» червня 2021 р. о 9.00 год. на засіданні екзаменаційної комісії №21 у Тернопільському національному технічному університеті імені Івана Пулюя<br>В даній кваліфікаційній роботі розроблено однокаскадне джерело живлення для вуличних світлодіодних світильників загального призначення. Створений пристрій забезпечує стабільний вихідний струм величиною 350 мА. Блок живлення спроектований на основі мікросхеми UCC28810 компанії Texas Instruments і забезпечує максимальну вихідну потужність 80 Вт та живиться від мережі змінного струму з номінальною напругою 220 В.
Наявність в даній мікросхемі вбудованої функції корекції коефіцієнта потужності дозволило реалізувати перетворювач з коефіцієнтом потужності (КП) – 0,9 без використання додаткового коректора.
Імпульсний перетворювач напруги побудований по технології SEPIC і, відповідно, немає гальванічної ізоляції між входом і виходом. Проте, це допустимо для вуличних світильників. В імпульсному блоці живлення передбачений захист від перенапруг та обриву навантаження.<br>In this qualification work a single-stage power supply for general purpose LED street lamps has been developed. The created device provides a stable output current of 350 mA. The power supply is designed based on the UCC28810 chip from Texas Instruments and provides a maximum output power of 80 watts and is powered by AC mains with a nominal voltage of 220 V.
The presence of a built-in power factor correction function in this chip allowed to implement a converter with a power factor (KP) of 0.9 without the use of an additional corrector.
The pulse voltage converter is built on SEPIC technology and, accordingly, there is no galvanic isolation between input and output. However, this is acceptable for street lamps. The switching power supply provides protection against overvoltages and load breakage.<br>Вступ 4
1 Аналітична частина 7
1.1 Призначення та основні параметри електронного драйвера LED світильника 7
1.2 Структурні схеми джерел вторинного електроживлення 8
1.3 Схемотехніка і принципи роботи перетворювачів DC/DC 12
2 Проєктна частина 21
2.1 Опис структурної схеми електронного драйвера LED світильника 21
2.1 Вибір вихідних параметрів електронного драйвера LED світильника 23
2.2 Корекція коефіцієнта потужності 25
2.3 Засоби і системи захисту джерел живлення 27
2.4 Опис блок-схеми контролера UCC28810 32
2.5 Опис принципової схеми електронного драйвера LED світильника 33
2.6 Розрахунок надійності 38
3 Спеціальна частина 43
4 Безпека життєдіяльності, основи охорони праці 54
Висновок 63
Література 64
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Lim, Seungbum. "A Merged two-stage power conversion architecture with switched capacitor circuit for an LED driver module." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/75662.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 71).<br>In a power converter specified to convert from wide-range and high-level DC voltage or AC line voltage to low-level DC voltage, satisfying high efficiency, high power density, and high power factor is challenging because of the higher device stress and difficulty of maintaining ZVS/ZCS conditions. Our purpose of the proposed two-stage power conversion architecture is to manage this high peak voltage stress and widely-varying operating conditions and to reduce dissipation by placing a switched capacitor pre-regulator stage in front of a very high frequency DC-DC converter stage. Our proposed two-stage architecture has been designed, built, and tested.<br>by Seungbum Lim.<br>S.M.
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Seauve, Yoann. "Exploration, conception et mise en œuvre de circuit de pilotage pour micro-écrans à LED GaN." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALT069.
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Les avancées récentes dans le domaine de la fabrication de LEDs Inorganiques permettent la production de LEDs GaN à l’échelle micrométrique. Ces composant optiques, jusqu’ici produits uniquement dans des dimensions importantes, peuvent être associés à un circuit de pilotage CMOS afin de produire des micro-écrans. Les micro-LEDs produites en GaN offrent une luminance maximum et une vitesse de commutation bien supérieures aux autres technologies LEDs généralement utilisées à l’échelle micrométrique. Cependant, elles présentent aussi des caractéristiques électriques spécifiques, telles qu’une efficacité réduite et une dispersion de fonctionnement accrue pour une utilisation sous un faible courant. Ainsi, les méthodes de pilotage couramment utilisées avec d’autres technologies LED s’avèrent peu adaptées.Cette thèse a pour objectif le développement de circuits de pilotage pixel adaptés aux micro-LEDs GaN, autant par le type de pilotage mis en place que par un encombrement compatible avec la surface des LEDs employées. Une première partie des travaux porte sur les applications d’affichage, avec une matrice de pixels compacte exploitant la forte luminance des LEDs, tout en présentant une grande résolution. L’utilisation d’un pilotage de type PWM, avec un fonctionnement intermittent des LEDs sous un fort courant, est retenu en raison des spécificités électriques de ces dernières. Afin de maintenir des dimensions réduites pour ce circuit pixel malgré la relative complexité du pilotage mis en place, une construction en 3D du circuit est présentée. Un dérivé de la technologie 3D CoolCube développée au CEA Leti est envisagé afin de construire un micro-écran sur trois niveaux superposés. Le circuit de pilotage est réparti entre les deux premiers niveaux, constitués de circuits CMOS implémentés avec des transistors de natures différentes. Tandis que les LEDs GaN constituent le troisième niveau de l’assemblage.La seconde partie des travaux est orientée vers l’exploitation du temps de commutation réduit des LEDs GaN. Cette capacité à générer un signal optique de fréquence élevée s’avère particulièrement intéressante pour la réalisation de systèmes de communication optique. Plusieurs émetteurs de communication optique en champ libre, utilisant une LED GaN pour réaliser des transferts de données avec un débit de plusieurs Gb/s, sont présentés dans la littérature. Ces systèmes mono-LED, bien que rapides, s’avèrent complexes à mettre en œuvre et particulièrement encombrants. Des émetteurs utilisant une multitude de LEDs, émettant chacune une fraction du signal optique utilisé pour la transmission, constituent une implémentation alternative. Bien que les transmissions réalisées avec ce type d’équipement restent pour l’instant plus lentes, les émetteurs matricés s’avèrent beaucoup plus compacts. Le développement d’un circuit pixel binaire, permettant la commutation d’une LED entre les deux seuls états, allumé et éteint, est présenté. Grace à un mécanisme de compensation de la capacité parasite induite par la LED, ce circuit atteint une fréquence de commutation de 333 MHz. Enfin, une réflexion quant à l’organisation d’un ensemble de ces pixels au sein d’un émetteur matricé, amène à un contrôle thermométrique des différents pixels. La répartition des LEDs à allumer en fonction du code d’entrée qui en découle permet en effet d’assurer la monotonicité de la conversion réalisée, et offre une linéarité accrue par rapport à d’autres modes de décodages plus simples d’implémentation<br>Recent advances in the field on inorganic LEDs, allow for manufacturing of GaN LEDs at micrometer scale. These optical devices, which were initially only manufactured with large dimensions, can be associated to a CMOS driving circuit to form micro-displays. GaN based micro-LEDs offer a maximum brightness and a commutation speed, well above other LEDs technologies used at micrometer scale. However, they also have specific electrical characteristics, such as reduced efficiency and large dispersion of behavior, when used with a reduced current. Consequently, driving methods commonly used with other types of LEDs are not appropriate for the control of such devices.This thesis focusses on the design of pixel driving circuits suitable for micro GaN LEDs, both in terms of implemented driving method and footprint compliance with the size of used LEDs. The first part of this work focusses on display applications, with a compact pixel matrix exploiting LEDs high brightness, while offering a large resolution. A PWM driving scheme, which implies sporadic operation of the LEDs under high current, is chosen to deal with LEDs specificities. In order to insure low silicon footprint despite the relatively high complexity of PWM driving, a 3D manufacturing of the circuit is introduced. A derivative of the CoolCube 3D technology that is developed by CEA Leti, is considered to manufacture a micro-display on three superposed levels. The driving circuit is split between the two first levels, made a CMOS circuit with different types of transistors. An array of GaN LEDs form the third level for the display.The second part of this thesis focusses on exploiting the reduced commutation time of the GaN LEDs. The ability to generate a high frequency optical signal is appropriate for building visible light communication emitters. Several free space optical communication emitters reported in the literature use a single GaN LED to transmit data at several Gb/s. Although, these single LED emitters are very fast, they are cumbersome and complex to build. Other emitters, based on a group of LEDs each emitting a part of the optical signal, forms an alternative solution. Even though data transmission is currently slower using these emitters, matrix based emitters are much more compact. This work introduce the design of a binary pixel, which make the LED switch between its two possible states, ON and OFF. Thanks to a LED introduced parasitic capacitance compensation method, this circuit reaches a 333 MHz operation frequency. Finally, a study of the best pixels organization inside the array led to a thermometer type of pixel control. The resulting association between each input code and the activated pixels insures the conversion monotonicity. It also shows a better linearity than other matrix control schemes with simpler implementations
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Shiau, Yu-Da, and 蕭鈺達. "Design of Full-Color LED Driver Control Circuit by Low Dropout (LDO) Liner Regulator and Temperature Modulator." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/vcb2a9.
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碩士<br>國立中山大學<br>電機工程學系研究所<br>103<br>Nowadays, people raise the conscious of environmental protection in recent years. As a third of the total electricity consumption of all kinds of lighting, it’s a bigger problem that we needs to save energy. In recent years, the use of light-emitting diode (Light Emitting Diode- LED) have replaced the incandescent lamps and halogen lamps because the traditional incandescent bulb has short life of its usage and low luminous efficiency which do not meet the needs of energy saving policy. LED is environmental friendly without mercury materials and luminous efficiency. But the brightness of LED depends on the forward current, thus, the supplication of constant current becomes the most important topic of LED driving circuit. Normally the household light of dimming mainly use the bulbs and it only need to match the dimmer. However, it is not the fluorescent lamp. The dimmable LED can also adjust color via RGB lighting. Furthermore, LED extensively use in household lighting and medical usage. In the research, the power supply Vdd is 3.3V, the change of output current lower 3% when the temperature is -25 ℃ to 100 ℃. In the dimming control; the auto control can deliver the current via temperature sensor so as to control the output current which make people feel comfortable. Manual control can adjust the light by the users via low dropout liner regulator to meet the customers’ needs. It is fabricated with CIC provided by TSMC 0.35μm 2P4M 3.3V/5V CMOS process in an active area of 1.1 × 1.1 mm 2 . The total power dissipation is 0.48W.
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Shao, Kuei-Yu, and 邵桂裕. "Multi-Channel LED Driver Circuit." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/4mxxhr.
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碩士<br>崑山科技大學<br>電子工程研究所<br>96<br>Displayer has become the inportant part of Electronical prudoct, and it also requires light source by Back light module. High brightness White Emitting Diode(LED) has become the important back light source. The profites of White light Led are cheep price、long life、and low power etc. The White light led is going to replace the traditional Sunlight bulb in the future. Therefore,driver IC will reveal its is important.
In this paper, three LED drivers with uniform current adjustment mechanism were designed by the H-Spice tool. The first chip uses a high-gain OPA, an NMOS transistor and a resistor to implement a current source that can be controlled by an external voltage. It would drive sixteen high-brightness white-light LEDs through sixteen current mirrors. The second chip is trying to add a bandgap reference voltage circuit and to use a cascode mirror circuit construction. Because the chip will produce heat by itself, in order to promote the precision and yield of the whole circuit, we need a steady reference voltage. which will not change a lot when the input voltage and temperature change. The cascode mirror circuit construction is designed to reduce the effects of drain-source voltage drop on the mirrored current because the turn-on voltage of LED is process-dependent. The third chip is designed to improve the bandgap reference construction of the second chip in order to make LED driving current adjustable.
These LED drivers use the full-custom-design methodology of the 0.35μm 2P4M CMOS technology provided by Taiwan Semiconductor Manufacturing Company (TSMC) as the design and simulation platform in this paper.
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Huang, Liang-Chieh, and 黃亮傑. "Flyback LED Driver Circuit Design." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/h334j5.
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碩士<br>國立虎尾科技大學<br>光電與材料科技研究所在職專班<br>101<br>The purpose of this thesis is focus on designing a driver and controller for LED Circuit.
The main components are a flyback converter, PWM controller, and fine tuning regulator to drive the LED light. The key points are to drive the LED circuit by using the flyback converter, and to adjust the brightness of the LED light by changing the forward current of PWM controller output. Moreover, the method to design a driver to run LED circuit is the operational principle, analysis, and structure of design. Finally, in this thesis includes the collected data from the measurement of waveform to prove the feasibility and performance of the forward LED circuit.
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Liu, Kuan-Chun, and 劉冠均. "Designing the LED Lighting Driver Circuit." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/tyvy75.
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Qiu, Chui-Yuan, and 邱垂淵. "LED drive circuit for TRIAC dimmer." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/05144021523737222065.
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碩士<br>明新科技大學<br>電子工程研究所<br>102<br>This paper proposes a solution to the TRIAC dimmer at low brightness, resulting in LED flashing improvement. After changing the input power TRIAC dimmers so also with changes in the conduction period, and then change the brightness light-emitting diodes emitting light strings. When the conduction angle is very small, could make light-emitting diodes string lights flashing, then turn off the light-emitting diodes string lights, making light-emitting diodes string lights are not flashing. By experiments show that this solution can be used both to change the TRIAC dimmer brightness light-emitting diodes, but also allows light emitting diodes string lights will not flash in low light emission quantity and improve the AC drive light emitting diodes the lighting output stability of the light source.
In this circuit, the whole is not only small, and easy to manufacture, low cost and the possibility of the product as large, and the function matches the user needs. Based on the above advantages of this circuit is to reach the industry's needs, and is also very practical.
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Kong, Chih-Hsiang, and 龔志祥. "High efficiency AC LED circuit study." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/51278249124163728968.
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碩士<br>淡江大學<br>電機工程學系碩士在職專班<br>103<br>The High efficiency AC LED circuit study (LED; Light Emitting Diode) lighting components in common at the moment, compared to traditional incandescent bulbs with high luminous efficiency, low power consumption and low pollution characteristics, so that all kinds of LED AC light emitting circuits also began to appear on the market, however, because the light emitting diode itself can only be a single Wizard works, makes it difficult to use in an AC environment.
The papers Research Department an high efficient AC LED circuit has a rectifier glow unit and the a passive load steady stream component; the rectifier glow unit has four group rectifier glow Department, the Group rectifier glow Department contains has plural series received of LED component, and connection for a full bridge circuit; which the passive load steady stream component Department series received Yu the rectifier glow unit of output end to stable guide pass loop current and not over the LED component by rated of safe rating, Ensure the rectifiers have the desired luminous efficiency light emitting unit and to prevent excessive current burning of the LED components
This research LED AC light circuit only requires the rectification made light unit can achieve effectiveness and increase the power factor of rectification and luminescent, able to reduce the use of components in order to reduce the circuit size.
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Chiou, Hsin-Fu, and 邱信福. "Design of an LED Driver Circuit." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/53113388239425610058.
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碩士<br>崑山科技大學<br>機械工程研究所<br>105<br>Recently, light-emitting diodes(LEDs) have become more and more attractive and have great opportunity to replace traditional lighting sources such as incandescent, fluorescent and HID because of the advantages such as high luminous efficacy, long lifetime, quick on/off time, wide color gamut, eco-friendly etc.
In automobile industry, LED lighting is used very frequently due to reliable and efficient nature. This paper focuses on design of a driver for LED with nonlinear I-V characteristic curve. The driver design is improved for increasing the LED life while driven by constant current.
This paper includes the mathematical calculations for the design according to automotive industry standards. Furthermore, circuit design was simulated and fine-tuned using MultiSIM. As this driver is designed for automobile use, EMI effects are considered during design process. Furthermore, the circuit was then analyzed against ISO7637 electromagnetic compatibility standards. The simulation data confirms that proposed design is ready for automotive applications. A prototype was also created as a proof of concept to confirm the simulation data.
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Kaiwei, Chang, and 張凱瑋. "PWM based LED linear dimming circuit." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/38810433529719651332.
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碩士<br>亞洲大學<br>光電與通訊學系碩士班<br>100<br>This paper presents an optimal design of dimmable light-emitting diode (LED) driver with adaptive feedback control in terms of lighting efficiency.
A simple and low cost pulse width modulation dimming technique is studied for regulating the LED current and brightness. Under universal input voltage operation, high efficiency still can be achieved with a simple commercial transition-mode PFC controller.
The operation principles and design considerations of the studied LED driver are analyzed and discussed. based on simulation results.
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LAI, CHIEN-HUNG, and 賴建宏. "Wide input range LED driver circuit." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7y8n3z.
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碩士<br>明志科技大學<br>電子工程系碩士班<br>106<br>Energy efficiency is the common demand of all electronic products.In order to improve the conversion efficiency of the linear architecture,usually we hope to achieve this by increasing the number of load switching segments.However,the traditional segmented linear architecture,load configuration is anLED with a grounded power switch; Multi-segment switching will result inhighnumbers of power switches and logicalcontrol circuits.Moreover, the chipareaisoversizedand the costis too highas well.The main purpose of this paper is to implement the circuit implementation of "Wide input range LED driver circuit".When AC input is set up in,the circuit can be turned on and off by a high voltage-power switching transistor.Different numbers of LEDs are turned on at different times to increase the efficiency of the LEDs.This paperdevelops an intelligent UHV LED driver IC. The developed LED driver IC integrates a constant current circuit,Highside and low side gate driver circuit, bias circuit, voltage detection circuit and intelligent control circuit in its design. Thus, the developed LED driver IC does not need to use AC-DC conversion circuit in this designanymore, and it becomeshighlyefficient. The Ultra-High-Voltage（UHV）LED driver circuit is able tocover the current range from 50mA to 200mA, and the input voltage is between 0 and 160V. It is designedinand proved througha Taiwan Semiconductor Manufacturing Company 0.5-um Ultra-High-Voltage（UHV）CMOS process technology.
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Wu, Zong-hua, and 吳宗樺. "An RGB-LED Back-Light Driving Circuit." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/4829ez.
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碩士<br>國立中山大學<br>電機工程學系研究所<br>95<br>This thesis proposes a novel driving circuit of the RGB light emitting diodes (LEDs) for the back-light source of the liquid crystal display. In stead of employing three dc-to-dc converters, a fly-back converter with three secondary windings is used to drive RGB-LED light bars. By adjusting the duty-ratio, the fly-back converter provides compromised voltages to RGB-LEDs in accordance with the operating modes of dimming control, so as to retain current magnitudes within the acceptable values. LEDs of three colors are dimmed by regulating the duty-ratios of three active power switches individually. By changing the ratio of the average currents of the three primary color LEDs, the color temperature range of driving can reach the requests of dimming control. As compared with a consumer product using the conventional driving circuit, the proposed circuit is obviously much simpler with less components and a higher efficiency.
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KANG, SHU-HSUAN, and 康書軒. "Design and Implementation of LED Driver Circuit." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/99426984333728077690.
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碩士<br>東南科技大學<br>電機工程研究所<br>97<br>Abstract
In this thesis, a LED driving circuit with current balance strategy is proposed. A multiple series and parallel LED circuits on a panel is built for performance evaluation. A positive voltage reference is referred to collocate with voltage follower to drive the multiple series and parallel LED circuits. Balance currents for each series LEDs are given even the referred positive voltage is varied in a wide range. In addition, the LEDs current can also be controlled to dim in the range of 0~100%, during which the spectrum image will not be changed and the situation of color shifting will not be appeared. The experimental results demonstrate the feasibility of the proposed circuits and are so close to the predictions.
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Lai, Shih-Tao, and 賴世道. "Implementation of RGB Mixed LED Backlight Circuit." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/61022110861728633701.
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碩士<br>中原大學<br>電機工程研究所<br>95<br>Abstract
Conventionally, multiple cold cathode fluorescent lamps (CCFLs) are required to provide sufficient backlighting for a large-scale of LCD panels. Growing concerns about environmental issues will exhibit the use of CCFLs that contain poisonous mercury. Owing to improvement in long operative life, wider operation temperature range, and the simplicity of driver circuit: work with low and safe voltages, LED has gradually substituted for CCFL as backlight. In this thesis, a LED backlight circuit for a large-scale LCD panel is studied. The design considerations for RGB LED backlighting circuit are discussed in detail. Burst-mode dimming control is designed to achieve the brightness regulation of the backlighting LEDs. A laboratory prototype for the studied RGB LED backlight circuit is implemented and tested. The experimental results of the prototype circuit are shown and discussed to verify the proposed scheme.
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Chen, Po-Tsun, and 陳柏村. "LED Driver Circuit For Plant Growth Control." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/95967896409372056111.
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碩士<br>中原大學<br>電子工程研究所<br>100<br>Intensity and time of light exposure are some of the key factors that affect the growth rate of vegetables. With enough light intensity and extending the time of light exposure can effectively reduce the growth period.[1] It was realized through experiment that light emitting diode (LED) compensation system has a significant effect with the plant growth rate, though it is not comparable to the light intensity produce by sunlight. This study presents the use of light emitting diodes for light compensation technique in extending the plant exposure to light with enough radiation intensity. The system composed of light emitting diode, driver circuit and light intensity sensing circuit. When the sunlight intensity is below 2000 LUX through the light intensity circuit, light emitting diode lamps will switch on. Two sets of lighting were used; 5000 LUX white light emitting diode and combination of red-blue light emitting diode with light intensity of 2500 LUX. In the experiment, lettuce plant was used, from seedling to crop harvest, under the sunlight exposure, it takes 60 to 90 days but with the proposed lighting compensation system it only takes 30 to 45 days, in which the growth rate is doubled and the growth period is reduced to 50%.
The design process used for this study is MXIC 0.5um CMOS DPDM BCD 5V/65V HV Process. The LED boost converter circuit has a slope compensation mechanism therefore when the input source voltage or the load voltage changes, it will automatically adjust the output voltage to reach the steady state. The design is based from the boost converter circuit; it uses pulse width modulation and peak current mode to control the output.
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Yang, Chang-Yi, and 楊昌易. "Bridgeless boost rectifier based LED driver circuit." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/11432943607735777999.
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碩士<br>國立高雄海洋科技大學<br>微電子工程研究所<br>101<br>This paper discusses the development of bridgeless boost circuit rectifier based LED driver with the bridgeless boost rectifier is composed of two power electronic switches with common ground.
The power electronic switches are controlled by pulse width modulation (PWM). Accordingly, the input current of bridgeless rectifier is sinusoidal and in phase with input voltage, and it performs the unity power factor. For verifying the driver circuit, the prototype is developed.
The experimental results show. that the proposed bridgeless boost rectifier has the expected performance.
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Tsai, Chun-Yi, and 蔡駿毅. "LED Driving Circuit with Adjustable Output Currents." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/73e8dq.
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碩士<br>國立臺灣科技大學<br>電機工程系<br>105<br>Nowadays, technological innovations in the high-brightness LED (Light-Emitting Diode) would lead a revolution in the field of lighting, which used about one-quarter of the electricity for home application. Comparing with compact fluorescent lamp (CFL), the advantages of LED lamps include energy saving, no toxic substances and high reliability and high lifetime. However, the specification of LED lamps varies according to consumer’s requirement, which means that each LED lamp requires specially designed power supplies at an additional cost. To deal with this problem, LED drivers with adjustable output voltage / current is needed.
In this thesis, a LED driving circuit which can drive three different kinds of LED lamps is proposed. To validate the correctness of the presented system, an 14 W prototyping circuit is first built and experiments are carried out using this platform. According to the experimental results, the constructed system can successfully drive three different kinds of LED lamps, and the conversion efficiencies are all higher than 85.0 %.
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Cheng, Shih-I., and 鄭士毅. "Dimming Interface Circuit Design for LED Light." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/y9vff7.
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碩士<br>國立交通大學<br>電機學院電機與控制學程<br>105<br>In addition to the Triac dimming interface, linear dimming and PWM dimming is most used in the dimming market, in this paper, we will design a dimming control interface for two dimming methods(linear dimming and PWM dimming). LED lighting for the Earth's environmental protection is helpful, so in the circuit design for LED lighting, you must be consided the shutdown can not consume power; in standby state, if having other circuits should maintain power less than 0.5 watts; input power factor (PF) must be designed higher than 0.7, so select an appropriate PFC (Power Factor Correction) architecture is necessary. Light and small size is the trend of design circuit for LED lighting, so active PFC architecture is the first choice for LED lighting. Due to cost considerations and safety requirements, when we select the type of power supply, Flyback converter is our first choice, because it have advantages of isolation and the fewer components. In the selection of the control loop circuit, the numbers of components that Primary Side Regulation (PSR) is less than Secondary Side Regulation (SSR). It mean if we choose PSR, we can save some components including optical coupler, error amplifier, reference voltage. That can help saving the using PCB area and reduce the components. According to the above three conditions, we choice the power control chip CPU6563C of Champion microelectronic Corp. to design circuit of power control and add our design of the dimming interface circuit to dimmer, to explore the dimming design will encounter problems and solutions.
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Huang, Chih-tsan, and 黃志讚. "Study of High Power Factor LED Lighting Circuit." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/38228788230228721370.
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碩士<br>雲林科技大學<br>電機工程系碩士班<br>96<br>The power converter with APFC (Active Power Factor Correction), can reduce power loss and current harmonic. So far, power factor correctors are popular in many applications. Such as power transmission, manufacture power supply, and many kind of information technology equipment. Base on environment protecting and power saving, LED (light emitting diode) lightings are obvious developing focus. Combining APFC and LED lighting will be much more benefit in environment protecting and power saving.
This thesis will discuss about Single Stage Single Switch Flyback AC/DC Converter which have APFC and output voltage/output current feedback to drive LED Lighting. It has advantages of power factor correction and simple circuit. Beside that, it is design for LED lighting which has constant voltage and constant current. The adapted circuit has simple circuit, cheaper price and easy to meet IEC (International Electro technical Commission) standard.
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Lee, Chia-Hsi, and 李嘉璽. "A Linear LED Dimming Circuit With Temperature Compensation." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/2f62hw.
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碩士<br>國立雲林科技大學<br>電子工程系<br>102<br>In this thesis, a linear Light-Emitting Diode (LED) dimming circuit with temperature compensation is analyzed and designed to improve the error occurs when LED dimming circuit is affected by temperature. The proposed method is to make an analog dimming signal convert to a multilevel digital signal through Time-Division-Adder (TDA) to control the temperature compensated current regulation circuit, then quantizing the digital signal to the current and doing dimming process. TDA is used for analog-to-digital conversion by the average amount of delay. The temperature compensated current regulation circuit with thermal characteristic for transistor is used to control its threshold voltage (Vth) and carrier mobility (μ), arising positive and negative temperature coefficient of linear current sources which could be complemented each other to form an unaffected by temperature current source. This experiment is verified that the error can be substantially reduced when Light-Emitting Diode (LED) dimming circuit with temperature compensation is operated at -20℃~100℃.
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Liao, Hsuan, and 廖軒. "LED Driving Circuit with Stand-Alone Photovoltaic Power." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/aspx69.
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碩士<br>國立中山大學<br>電機工程學系研究所<br>103<br>The research proposes an LED driving circuit with stand-alone photovoltaic (PV) Power. A bi-directional converter is incorporated to adequately distribute powers among the solar-cell panel, the battery and the LED lamp according to the sunshine intensity, the battery state-of-charge as well as the load requirement. The proposed LED driving circuit is applied to two exemplar applications of the traffic light and the garden light. By matching the voltage-current (V-I) characteristic curves, the capacities of the solar-cell panel and the battery are specified to mostly operate the solar-cell panel around the maximum power point.
The traffic light needs to work 24 hours a day. During the daytime with strong sunshine, the solar-cell panel is operated near the maximum power point, providing the LED power and delivering the excess energy to the battery. If the battery might not have enough power to supply what LEDs need at night, then the load shedding and battery can have more power. However, the solar-cell panel doesn''t have enough power to the load, the battery set would supply what the load required. The garden lights work at night. All the power from solar-cell panel needs to store in the battery with the bi-directional converter, providing LED power from battery. User also can decide whether turn the garden lights off or dimming.
To verify the theoretical analyses of the LED driving circuit, a laboratory system is set up for experimental tests. The tested results demonstrate that the system can perform the designated functions in accordance with different states. The measured efficiencies are always over 88%. The maximum efficiency is 97% when the solar-cell panel provides power to the LED strings.
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Lin, Ding-Jun, and 林鼎鈞. "A Novel Dimming Control Circuit for LED Lamps." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/bh5p8v.
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Huang, Chun-Piao, and 黃俊標. "A Study for Improved LED Fault Tolerance Circuit." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/5dv936.
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Song, Yuan-Siang, and 宋源翔. "High efficiency synchronous rectifier converter LED driver circuit." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/39109232972702359429.
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碩士<br>國立勤益科技大學<br>電子工程系<br>102<br>This thesis is improved LED driver circuitry. Currently, the global mains
voltage range is AC90 ~ 265V which cannot directly for LED use. So we need LED driver circuitry to control LED. Since varies current values can be transformed by LED driver circuitry, investigations and researches are compared to achieve a high power, high current accuracy, high power factor and low-cost LED driver circuitry architecture.
Power converter with flyback converter as the main framework for flyback converter architecture is preferred below 100W converter. Its’ cheap, simple
structure does not need secondary side of the output inductor. For cost and size consideration, these advantages are superior relatively.
In this paper, the use of synchronous rectification flyback converter architecture improves efficiency and reduces unnecessary power consumption.
Use synchronous rectification technology to replace traditional of diode rectifier mode, and take rate field effect transistor low on-resistance characteristics to replace two-pole pressure drop along the body can improve the secondary side
rectification losses. When the output current is inadequate or too low, the use of inductive compensation is proposed to provide a stable LED current to avoid flicker.
Another standby mode is when the load reaches, close the secondary side synchronous rectifier circuit. It can reduce standby consumption.
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Cheng, Chih-cheng, and 鄭至呈. "LED-Driving Circuit Design with Constant Illumination Control." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/31527447942663063755.
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碩士<br>國立臺南大學<br>電機工程學系碩士班<br>100<br>With aids of the resonant circuit, a method to improve the LED lighting performance is proposed in this thesis. As compared with the traditional method, the proposed circuit generates a high-frequency ripple-coupled dc voltage so as to increase the LED current when the driving voltage oscillates near its peak and to cool down the circuit temperature when the voltage is down to its valley value. In addition, a microprocessor-aided illuminant control circuit is developed in this thesis, By uses of such a control circuit, the proposed LED lighting output can be fine tuned to match the user-defined level. This proposed system has been analyzed through a laboratory prototype. From the test results, it shows that the LED lighting driven by the proposed method really have the lower the operational temperature and the higher the average lumen per watt, thus helping to improve the lighting performance. Test results gained from this experiment are anticipated to be useful reference for lighting system performance improvement.
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Wang, Wei-lun, and 王偉倫. "Improve Buck and Buck-Boost circuit LED driver." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/36723731737946120972.
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碩士<br>國立中央大學<br>電機工程研究所碩士在職專班<br>100<br>Light-emitting diode (LED) always are applied in indicator lighting before.
As the technique of the LED is mature, the luminous efficiency of the LED is upgraded.Therefore,the LED are applied in lighting area now. Moreover,the
cost keep going down,the power-saving LED are attractive us .
There are many species of LED applied in lighting area,In this thesis a cup light selected as the LED lighting source.The cup light is applied as a shop lighting.It is always used project onto commodity in cupboard.It is can highlight commodity quality and different.Prior to this is used lighting source of Halogen.However,its problems are high power consumption and short life.
The application specification of the cup light LED is input voltage AC/DC
12 Volts and loading current is 350mA.The tradition control modes of the LED application are Buck and Buck-Boost modes.The Buck control mode has higher energy efficiency.But when the input voltage is under the specification,the LED current will not setting into the specification range.The Buck-Boost can stable LED current for setting range when input voltage is under.But it is lower efficiency.
This thesis improves the circuit architecture of the LED control mode.It is integrate with Buck and Buck-Boost circuit.By input voltage via resistor divide and reference voltage compare,it is can control operating mode with Buck and Buck-Boost by input voltage.It is can stable LED current.
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Tsai, Ying-Xu, and 蔡瀛緒. "A Study On Continuous-Time LED Dimming Circuit." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/96534509897378162563.
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碩士<br>國立雲林科技大學<br>電子與光電工程研究所碩士班<br>100<br>In this paper, we present an innovative continuous-time light-emitting diodes (LED) dimming circuit , that is used to enhance performance and service life of the light-emitting diodes, and improve the resolution of the LED current . The method proposed in this paper the analog signal to digital signal by the Time-Division-Adder (TDA), and through the digital filter unfold of the number of bits. Finally, the weighted current quantitative digital signal is a current output. TDA is built on the pulse width modulation signal, through the delay of the average amount of finishing to get the digital signal output with a linear change. In order to improve the TDA output amount of data, add the digital filter with interpolation. After increasing the amount of data each time interval, the weighted current quantitative digital signal is a current output at last. To available LED current modulation results.
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Hsu, Ching-Yuan, and 許清淵. "The Study of Smart LED Dimming Control Circuit." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/55385940785117407567.
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碩士<br>逢甲大學<br>資電碩士在職專班<br>101<br>The purpose of this thesis is to construct the intelligent LED digital dimmer system.The thesis a purpose in the construction of intelligent LED digital dimmer system. This intelligent LED digital dimmer systems can be applied to all kinds of lighting levels. such as office lighting can change with ambient light adjusted brightness, not only saves energy but also consistents with the physiological response. So far the system has completed of every 25% dimmer range 0%~100%, between the forward current 0~160mA. The thesis has advanced for further study in illumination change vision optometrists and light detection. It has been proved that room were lit as experimental (540 Lux) eyesight optometry value does better than a darkroom (15 Lux). Either in the bright room (540 Lux) or dark (15 Lux), binocular vision is better than monocular.
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CHEN, PIN-HAN, and 陳品翰. "A Study for Improved LED Current-Balancing Circuit." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/kzsf65.
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Wang, Min chi, and 王敏芝. "Thermal Effect of LED on Flexible Circuit Board Structure." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/93279803419874231467.
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碩士<br>國立高雄應用科技大學<br>電機工程系博碩士班<br>96<br>Following the improvement in luminous of light emitting diodes’(LEDs) luminous, Light Emitting Diodes (LEDs) have application to general and back lighting applications. However, as the evolution of ICs, the evolution of LED also encounters the serious heat dissipation problems. A good thermal pass way can help an LED chip to good its junction temperature low to maintain the reliability of LED.
A finite volume method package (Flotherm) is used to analyze the temperature field and Taguchi methods to do analyze thermal features of LED module. This research is to use three kinds of different parameters and two kinds of parameter levels, discuss effect the FPC structure and LED thermal. The three parameters are thickness of copper’s adhesive, thickness of coverlay’s polyimide film and thickness of coverlay’s adhesive, and two levels are include adhesive copper or not. For LED thermal, the influence of two layer and three layer is the unapparent; the influence of insulation material is the great, the insulation material uses thermal adhesive can be to reduced by about 30 degrees Centigrade. Various modes were simulated for the system, and the simulation results showed that the system should be coincident. The FPC structure studies for LED thermal design rule.
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LU, HUNG-LAN, and 盧宏嵐. "A Novel Constant Current Driving Circuit for LED Lighting." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/946vmx.
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碩士<br>國立高雄應用科技大學<br>電機工程系博碩士班<br>104<br>This study proposed a light-emitting diode (LED) constant current driving circuit that can serve as a two-terminal constant current source or a constant current sink. This LED constant current driving circuit can receive current directly from a rectified commercial alternating current power supply; no inductor or capacitor is needed in the circuit configuration. When this constant current-driving circuit operates with a constant current, the minimal voltage is lower than 6 V. To this constant current-driving circuit with a 20-mA operating constant current, the dynamic output resistance of the circuit can exceed 1 MΩ.In the actual test, within a terminal voltage input range of 5.34–118 V, this circuit served as a 20 mA ± 0.147% constant current source; in addition, within a terminal voltage input range of 5.82–118 V, this circuit served as a 20 mA ± 0.005 % constant current source. Furthermore, a temperature-compensating feature can be designed for this circuit. Within a temperature range of 25°C–80°C, the temperature coefficient was -143 ppm/°C at a terminal voltage of 6 V in a constant current.
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Zhuang, Jia-Zhang, and 莊佳璋. "Scanning LED Backlight Driving Circuit with Digital Dimming Control." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/91713871374266810469.
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碩士<br>國立成功大學<br>電機工程學系碩博士班<br>96<br>The purpose of this thesis is to develop a scanning light emitting diode (LED) backlight driving circuit which can improve the blur phenomenon of dynamic image for liquid crystal display (LCD) and reduce the power consumption of backlight. In order to let scan lines of LCD panel and backlight achieved synchronous control, must discuss the video signal source of LCD. At first the video signals of D-SUB interface for computer graphic card are studied, and then decided the timing of scanning backlight. The backlight plate was divided into six regions and 8 LEDs are arranged in series in each region. The video signals of D-SUB interface for computer graphic card will input to the single chip control circuit to achieve scanning backlight control. The brightness and color temperature of backlight can be adjusted freely. The stable current control circuit can avoid the drift of domain wave and chromaticity for LED. Experimental results show that the scanning backlight can reduce power consumption.
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Huang, Te-Wei, and 黃特瑋. "Study on LED Backlight Driving Circuit with Dynamic Scanning." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/68987016639592810807.
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碩士<br>國立成功大學<br>電機工程學系碩博士班<br>96<br>The purpose of thesis is to design a dynamic scanning LED backlight driving circuit to achieve the reduction of power consumption. An LCD panel was divided into six regions and each region had eight RGB LEDs as the backlight was used as an object for the experiments.
Regarding the power supply, a flyback converter, which can provide a constant output voltage by using the fixed frequency current mode pulse width modulation (PWM), is used to achieve the purpose of circuit stability and power saving.The controlling part, which is the brain of lighting the regional LED in turn, is basically a counter circuit that consists of digital logic circuit, mono-stable circuit and the synchronous horizontal and vertical signal of D-sub.
The experimental results show that power consumption could be reduced drastically from 100% of the full lighting to 16.52% of the regional lighting.
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Hsu, Tai-Yuan, and 許泰源. "Research and Development for White LED Drive Integrated Circuit." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/23396335868594670250.
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碩士<br>輔仁大學<br>電子工程學系<br>92<br>The fast growing market on color screens or panels makes the large demanding on backlights for cellular phones, PDA or pocket PCs. Among the backlight sources such as CCFLs, Els and white LED, white LED is the best solution due to the low DC driving voltage, low cost, long lifetime, less pollution problem and easy for mass production. Therefore, the research and development on a small size, high efficiency and low cost white LED driver IC will be a good lift on this highly competitive business.
The solutions to drive white LEDs are discussed and how they relate to the main power supply requirements. Another hardware design and implementation are presented in this paper using current-limited, Pulse Frequency Modulation control architecture, which is capable to drive 6 white LEDs for 20mA including over-voltage protection and soft-start functions. It achieves 90% of efficiency in 1400μm by 960μm of die size.
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Liao, Te-Chih, and 廖得志. "New LCD-TV LED Backlight Driver Circuit Module Design." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/12403200046454449179.
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碩士<br>元智大學<br>電機工程學系<br>99<br>ABSTRACT
In the carbon reduction of environmental consensus, unlike the traditional backlighting elements (such as CCFL), the lower power consumption of the LED has become a new generation of LCD TV backlight trend. Compared to the application of monitor, TV as a larger size, they need more strings of the LED backlight modules to achieve the required brightness of the LED control and on it’s multi-serial LED strings. The first problem is the current imbalances will be encountered among LED strings. The imbalance will cause the serial current uneven brightness, and thus the image quality. How to reach a balance under the given cost and getting the current balance among the LED strings, will be a challenge to for LED driver designers.
Conventional AC load multiple drivers [ such as CCFL, EEFL ( External Electrode Fluorescent Lamp ), etc. ] often connected passive components in each group sharing the loads among AC power input, so one can achieve multiple AC load flow with current balance.
This thesis proposes a lower power loss and cheaper method LED driver module for a typical 60” LED TV. For balancing the multiple LED strings, the LCD-TV LED driver circuit prototype design with passive components used in the DC load current connection. In addition, the circuit outputs data and waveforms were also measured. The AC power connecting with a rectifier can provide the DC power for the DC loads. By the connection of passive components, it will get the current balance among the DC loads.
This thesis uses a LLC resonant converter design integrated with "A power supply with a H- balance LED driver for the multiple DC loads." The main purpose of the new power module for LED driver is to provide a cheaper and also efficient power supply circuit for current balance. Different from the traditional with linear structure, the new design can have current balance in each group of DC loads and the same brightness, the lower power consumption and high efficiency. The new design has relatively few components and low complexity, and substantial cost savings. With the actual measurements, we will measure and evaluate the performance of the new LED driver design with current balance circuits.
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Wu, Chih-hung, and 吳志宏. "DESIGN OF LED BACKLIGHT CIRCUIT MODULE FOR LCD-MONITOR." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/85132301767942524568.
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碩士<br>大同大學<br>電機工程學系(所)<br>98<br>A LED arrays driver circuit of module is proposed, and is used in the backlight of LCD-monitor and illumination system. As constant-power dissipation curve, calculate the optimal voltage and current and determine the appropriate LED arrays. With Fly-back converter to be a AC to DC power supply and get the fixed voltage (12V) by pulse width modulation (PWM) of current feedback mode, then adopt the Boost converter to arise the voltage. Depend on feedback of LED arrays and generate the driver voltage. In order to reduce the luminance difference between each LED, this makes stable current of LED arrays by current mirror. And using the dynamic select function let LED arrays light at the same. The feature of this circuit is module design that applies various LED backlight models and generates the applicable voltage and stable current then achieve the common-design purpose.
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Zhou, Min-Feng, and 周名峰. "Adjustable circuit of constant current for LED driver module." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/33949132432992942033.
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碩士<br>國立清華大學<br>產業研發碩士積體電路設計專班<br>95<br>Abstract
Recently, many electronic product designers have a hallenge on the requirement of the market.There are a lot of roblems including low cost of electronic products, shortening products design cycle, and higher performance, generality and high reliability. The technical staff was asked to use
more effective method for solving these problems. According to electronic technology, most designers use distributed components and the parameter type of power supply to design products. They also need complicated parameter to compute and long working period time to research and develop the electronic products. In addition, the competitive market and new technology have brought the hope for the wide electronic technical people; a lot of company has already to build the reliable integrated circuit of power electronic module. It is convenient that utilizing dc/dc converter for obtaining smaller size, connect easily and
reliable function. System designers choose proper dc/dc power module to obtain simple circuits and debug correctly. Therefore, it can reduce design cycle of products, increase the product reliability and enhance total design level. Because micro electronic circuits’ technique develops very quickly,there are a lot of VLSI circuits expanding so fast. The power supply is becoming more and more important in the electronic system. To make it smaller and lighter is the trend of the design direction.
In today's market, engineers must take a design from engineering through manufacturing with shorter design cycles and faster time to market. To be successful, you need a set of powerful,intuitive, and integrated tools are the main stream for development modern electronic product.
OrCAD 10.5 personal productivity tools have a long history of addressing these demands-and more. Designed to boost productivity for smaller design teams and individual printed circuit board (PCB) designers, OrCAD PCB design suites grow with your needs and technology challenges. The
powerful, tightly integrated PCB design suites include design capture, librarian tools, a PCB editor, an auto/interactive router, and optional analog and mixed-signal simulator. The affordable cheaper, high-performance OrCAD product line is easily scalable with the full complement of Cadence® Allegro® PCB solutions. The OrCAD product line is owned by Cadence Design Systems, Inc. and
supported by a worldwide network of Cadence Channel Partners. Based on above description, we also test and verify the simulation results and measurement results. It can reduce a lot of time to check the function work in simulation tool before in PCB work was done. In fact, we can use PSpice to simulate different parameters with the LED driver module,and understand how to design the correct results, such as constant current and output voltage. In this thesis, we believe LED will be substituted for other light sources in backlight, and will be applied in
more optical products with dc/dc converter.
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Chiang, Ta-Hsiang, and 江大祥. "High Power Ultraviolet LED Driver Circuit Design and Implementation." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/66801458763961298325.
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Wu, Jun-wei, and 吳俊緯. "Design and Analysis of Constant Power LED-Driven Circuit." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/67036336406007728874.
Full textAbstract:
碩士<br>國立臺南大學<br>通訊工程研究所碩士班<br>98<br>Recently, LEDs are expected to replace conventional incandescent, halogen and fluorescent lamps in the near future. However, innovative driver circuits optimized with respect to functionality, efficiency, cost, size and reliability are an enabler for the successful introduction of new LED based lighting products. Therefore, in this thesis, the circuit design of resonant inverter for LED-driven circuit is studied. Based on the half-bridge inverter structure, the proposed circuit has included the soft-switching techniques so that the investment on heat dissipation can be greatly saved. Moreover, the paper has investigated the LED power control under different conditions. Via the developed control circuit to formulate the relationships between the output power and voltage as a quadratic function, the output power of system can be then controlled and becomes insensitive to LED voltage variations. In order to solidify the practicality of this circuit design, mathematical analyses and experimental validations have been thoroughly performed. Test results help confirm the effectiveness of the method, demonstrating its feasibility and practicality for high-frequency drive industry applications.
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Cheng, Shih-Jen, and 鄭世仁. "Design and Implementation of DSP-Based LED backlight Circuit." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/12831719293977376866.
Full textAbstract:
碩士<br>中原大學<br>電機工程研究所<br>95<br>Abstract
This thesis presents a LED backlight driving system for
large-scale of LCD panels. High efficiency, high power factor, circuit
simplicity, and low cost can be achieved by using a single-stage
charge-pump asymmetrical-half-bridge converter. To regulate the
LED current and brightness for the LED backlight system, some
current sharing methods are presented and compared. The
requirements for the current sharing and luminance balance among
paralleled LED arrays can be satisfied while current ripple is
eliminated significantly. Because of the addition of bypass diodes, an
alternative current path can be offered when a single LED fails. The
LED array will not distinguish. Reliability of the LED backlight
system can thus be improved effectively. A laboratory prototype has
been built and tested. The simulation and experimental results are
shown to verify the feasibility of the proposed method.
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Hung, Chien-Chung, and 洪健忠. "High Power RGB-LED Model and its Circuit Applications." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/12189294601121264832.
Full textAbstract:
碩士<br>和春技術學院<br>電機工程研究所<br>96<br>The purpose of this thesis is to investigate the optical and electrical characteristics of high power LEDs under different current and ambient temperature. At the same time, Is Spice software is used to build its model and modulize it. In this thesis, integrating sphere system is used to measure the variation of characteristics of 1W RGB-LED, such as luminous flux, dominant wavelength and equivalent resistance, etc., at the driving current from 100mA to 350mA and ambient temperature controlled at 10oC to 70oC. Based on experimental data, a model is built for further verification by practical circuit application after the establishment of such module. The performance of this modulized model is found more accurate through comparison between simulation result and experimental data using a lighting circuit design composed of 5 pieces of 1 W-LED. This finding could provide a reference for future design aiming at high power LED driving circuit to reduce development and design cost.
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Liang, Hua-Peng, and 梁化鵬. "Design and Implementation of High Luminance LED Lighting Circuit." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/68245829907386885455.
Full textAbstract:
碩士<br>國立雲林科技大學<br>電機工程系碩士班<br>100<br>LED possesses the characteristics of energy saving and high efficiency. In the near future when energy shortage will come as no surprise, LED lighting will become the mainstream product in the lighting market. This paper presents low-cost and easy-to-maintain flyback converter as the LED driver. The author adopts constant-current and constant- voltage combo IC controller as the feedback control circuit, which feedbacks output to PWM IC to control switch and which is able to maintain a stable DC output voltage even under the condition of a wide range of AC input. The function of constant current provides overload protection to avoid the LED getting burned. In the safety design, the author uses transformer and opto isolator to meet the requirement of electrical isolation. On the basis of the operation principles of flyback converter, this thesis proposes a LED driver circuit, whose AC voltage input works in the range of 85V to 265V and whose DC output power supply is 24V/0.4A. In the final phase, this circuit is assembled into household LED lamps to verify the design theory and its practicality.
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Chang, Wen-Hsuan, and 張文瑄. "Power Conversion Circuit for Stand-Alone Photovoltaic LED Lighting." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/42727111030318570710.
Full textAbstract:
碩士<br>國立中山大學<br>電機工程學系研究所<br>101<br>A stand-alone photovoltaic power conversion circuit is proposed for driving the white Light-Emitting Diode (LED) lamps in series, which is powered by a solar-cell panel with a subsidiary battery set. In the case that the generated power from the solar-cell panel is insufficient for the load, the battery set has to be discharged to complement the required load power. When adequate power is obtained from the solar-cell panel, the excess energy can be stored in the battery set, to make full use of the generated solar power.
The power conversion circuit consists of a boost conversion and a bidirectional conversion circuit. According to the load requirements under different sunlight intensities and battery status, the operation of the power conversion circuit is analyzed by five operation states to derive the design equations. The power coordination among the solar-cell panel, the battery set and the LED lamp is made by adjusting the duty-ratios of the corresponding active power switches. A laboratory circuit designed for a 15-W lamp with 13 LEDs connected in series is built and tested to verify the theoretical analyses and circuit functions. Experimental results have shown that the power conversion circuit can be effectively operated in each state under different conditions. The measured power conversion efficiency is always higher than 88 %.
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Chou, Sheng-Chien, and 周勝千. "Applying a Novel Current Balancing Circuit to LED Lighting." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/56f64d.
Full textAbstract:
碩士<br>國立臺北科技大學<br>電機工程系所<br>97<br>In this paper, a current balancing cicuit is presented and applied to driving paralleled light-emitting diode (LED) strings. As generally acknowledged, LEDs are getting more and more popular instead of incandescent lamps, halogen light bulbs and street lights. Therefore, a single LED string does not provide enough illumination, and hence paralleled LED strings are indispensable. There are some features of the LED given as follows: (i) LED illumination is proportional to the driving current; and (ii) slight variations in voltage on the LED cause significant variations in current in the LED. Based on the mention above, the constant current control has been widely used to drive the LED up to now. Concerning the high efficiency and small volume of the LED product, it is indispensable for using the power electronics circuit to tackle energy conversion. However, up to the present the paralleled LED strings are driven based on the fact that each LED string is independently controlled, thereby causing the corresponding circuit to be complicated and the resulting cost to be high. Consequently, the proposed LED driving circuit is presented herein and has the following features: (i) it is simple in structure; (ii) it is suitable for different types of converters, such as buck converter, forward converter, resonant converter, etc.; (iii) there are two stages in such a LED driving circuit, one is a front-ended buck converter to provide a constant current for LED strings, and the other is a current balancing circuit to balance current among LED strings; and (iv) it has easy expansion by modifying the current balancing circuit. In this paper, mathematical derivation and software simulation are used to verify the feasibility of the proposed topology whereas some experimental results are provided to further demonstrate its effectiveness.