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Driver of high brightness white LED
Tomášek, Petr ; Kubíček, Michal (referee) ; Frýza, Tomáš (advisor)
This document is analysing LED driving with switch power supply from classic electric network 230V/50Hz. First chapter analysis LED diodes function and its fundamental parameters . In the second chapter, there is essential information about electric power supply. Third chapter is analysing switch power supply, including simple techniques, which are not used nowadays. In the fourth chapter, there is analysis of LED driver and circuit design. Fifth chapter is analysing construction of driver and its safety. There i salso information about measuring of parameters of constructed driver.
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Switching LED drivers
Doležal, Miroslav ; Pavlík, Michal (referee) ; Šteffan, Pavel (advisor)
In this bachelor’s these are three basic typologies of drivers (step down, step up, step up and down output voltage) described. Five specific integrated circuits fulfilling the requirement for supplying LED diodes are selected. The output of this thesis is the design and construction of LED driver for supplying high brightness LEDs with 900 mA constant current.
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Switching driver for high power LEDs with higher efficiency
Doležal, Miroslav ; Háze, Jiří (referee) ; Šteffan, Pavel (advisor)
Problems in swithing converter and power losses in this circuit describe these master’s theses. Power losses have the primar influence on the total effectivity circuit. The first chapter deal swith principle of basic parts switching converter (buck, boost, buck-boost). The power losses on main elements used in switching circuit (diode, transistor) are explained in the next part this thesis. Theory of synchronous rectifiction for reduction of losses. A choice of two integrated circuit useful for future design of LED driver working in buck-boost mode is on the end of the theoretical part. The practical part is fosud on the design of circuits (with integrated circuits chose in the theoretical part) including schematic diagram, calculation of parts and PCB layout. The build samples are evaluated by set of measurements in the field of effeciency, temperatures of components, stability output LED current, EMC and soon. Finally the particular parameters of both tested circuits are compared
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Analysis of switched-mode LED drivers
Stehlík, Ota ; Vyskočil, Pavel (referee) ; Kubíček, Michal (advisor)
The aim of this thesis is to design, produce and verify the operation of two different LED drivers for automotive industry, which controls the ultra-bright white LEDs. At the beginning of a brief introduction explaining the principle of operation of LEDs. Furthermore theory describes the functions of all three basic drivers involved as buck, boost and buck-boost. Based on the requirements are selected ICs suitable for this implementation, theoretically described their block diagrams including the individual diagrams and eventually these samples are made, revived and measured their parameters.
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Switched power supply
Krist, Jakub ; Kosina, Petr (referee) ; Pavlík, Michal (advisor)
The thesis is focused on design the switching power supply according to Push-pull topology rules. The work describes basic theoretic principles of Push-pull topology with design of circuit and circuit elements.
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Driver of high brightness white LED
Tomášek, Petr ; Kubíček, Michal (referee) ; Frýza, Tomáš (advisor)
This document is analysing LED driving with switch power supply from electric distribution network 230V/50Hz. In the first chapter you can find short thesis about electric power supplies. Second chapter contains info about power supplies and their safety and EMC requirements. In the third chapter is analysis of LED. Chapter IV. is dedicated to LED power supply circuit desing and the last chapter is about construction and measuring of parametres of designed power supply.
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Methods for Analysis of Switched Circuits
Kovář, Jan ; Ondráček, Oldřich (referee) ; Kalous, Jaroslav (referee) ; Kolka, Zdeněk (advisor)
The dissertation deals with simulations of the DC-DC converters in their basic configurations (Buck, Boost, Buck-boost, Cuk, SEPIC). In the first part of the thesis derivation of transfer functions Line-to-Output (LTO) and Control-To-Output (CTO) can be found. These symbolic responses are derived for three types of basic converters (Buck, Boost, Buck-boost) using well-known average model [1]. Derived expressions are very complicated. For reduction of these expressions symbolic approximation method was used, however the generality is lost. The average model was used to for decreasing the computational effort of analysis of DC-DC converters in the time domain. For these simulations VHDL-AMS language was used. The main topic of the thesis is harmonic balance method, which was adapted to DC-DC converters. Because conditions and assumptions for LTO and CTO functions are very different, harmonic balance method was derived into two variants. For obtaining of LTO response, duty cycle of switching signal can be considered as constant in time. Spectrum of this signal is simple as follows from well-known sinc function. For obtaining of CTO response PWM modulation must be used. Compared to sinc function spectrum of PWM modulation is richer (contains more combination frequencies). Many types of PWM modulation is described in [31]. For simulation PWM modulation with uniform sampling in two variants (single and double edge) was used. Non-ideal switching of PWM switch was modeled by PWM pulse with defined slew rate. Last section deals with comparison of all derived functions (LTO, CTO, modulation type, defined slew rate) with well-known averaged model.
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Driver for LED automotive lights
Christen, Jiří ; Vochyán, Josef (referee) ; Dřínovský, Jiří (advisor)
This master's thesis deals with a design and realization of a LED driver that is based on integrated circuits NCV78703 and NCV78723 from ON Semiconductor. The aim of the project is to create a demonstration application with these integrated circuits for the use of company. The circuits can be especially used for driving LED automotive lights. The driver is controlled with a microcontroller also providing a communication with a software running on a PC via USB interface. This software enables to simply modify parameters of the driver in order to adjust an intensity of LEDs.
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Design of synchronous switched-mode power supply for automotive
Sedlák, Jakub ; Šebesta, Jiří (referee) ; Kubíček, Michal (advisor)
This bachelor´s thesis deals with the DC/DC convertors and their application in automotive lighting. In first part of thesis, there are mentioned DC/DC convertors, their basic topologies and synchronous rectification. In next part of thesis, there are compared selected integrated circuits, which are suitable for this application. For one of these circuits is created a design. For this design was created a simulation to find out, that design is working. This design was realized and was tested according to automotive standards. In the end, there is a working DC/DC convertor, which meets requirements and basic limits from automotive standarts.
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Design of synchronous switched-mode power supply for automotive
Sedlák, Jakub ; Šebesta, Jiří (referee) ; Kubíček, Michal (advisor)
This bachelor´s thesis deals with the DC/DC convertors and their application in automotive lighting. In first part of thesis, there are mentioned DC/DC convertors, their basic topologies and synchronous rectification. In next part of thesis, there are compared selected integrated circuits, which are suitable for this application. For one of these circuits is created a design. For this design was created a simulation to find out, that design is working. This design was realized and was tested according to automotive standards. In the end, there is a working DC/DC convertor, which meets requirements and basic limits from automotive standarts.
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