• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.393-395
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• 2006

This Paper represents a dimming control characteristics of an external electrode fluorescent lamp (EEFL) inverter, which is replacing a cold cathode (luorescent lamp (CCFL) in the area of the large-sized LCD backlight. The analog and burst dimming control methods for the EEFL are compared and the control characteristics are anlayzed through the experiments.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1055-1056
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• 2006

This paper presents a remote dimming control method for the electrodeless lamps using 2.4 GHz RF communication. Since the proposed dimming method are implemented with a simplest open loop control using ISM band HF modem and low cost MCUs, and the remote controller has just several functions such as On/Off and duty ratio increasing/decreasing. It can be made with low cost. In this paper, the detailed digital logics of the proposed remote dimming control are described and the experimental results are presented.

• Journal of information and communication convergence engineering
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• v.19 no.4
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• pp.269-275
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• 2021

Light-emitting diodes (LEDs) are modulated using a square wave pulse sequence for flicker prevention and dimming control in visible light communication (VLC). In a VLC transmitter, the high and low bits of the non-return-to-zero (NRZ) data are converted to two square waves of different frequencies, which continue for a finite time defined by the fill ratio in an NRZ bit time. As the average optical power was kept constant and independent of data transmission, the LED was flicker-free. Dimming control is carried out by changing the fill ratio of the square wave in the NRZ bit time. In the experiments, the illumination of the LED light was controlled in the range of approximately 19.2% to 96.2% of the continuous square wave modulated LED light. In the VLC receiver, a high-pass filter combined with a latch circuit was used to recover the transmitted signal while preventing noise interference from adjacent lighting lamps.

• Journal of Industrial Technology
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• v.29 no.B
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• pp.193-198
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• 2009

In this paper, we developed remote dimming control system of electronic ballast for 400W metal halide lamp. This ballast could limit ignition current and soft start-up technique by the inverter with LCsCp resonance tank. The dimming circuit can dim from 400W to 200W by varying of the inverter switching frequency. The PLM consists of coupling circuit, BPF(Band-Pass Filter), FSK(Frequency Shift Keying) Modem and ${\mu}$-controller(Micro Controller). By coupling electronic ballast with PLM, the system that able to dimming the lamp through PLM is demonstrated by experimental results.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.8
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• pp.553-561
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• 2010

This study examines the influence of light variation on visual responses in a small office space where a daylight dimming control system is applied. Field measurements and survey were performed in a full-scale mocked-up small office space under clear sky day conditions. Maximum fluctuation range for desktop was 133.5 lx and it just happened once for entire monitoring period. For the majority of time, the fluctuation range did not exceed 50 lx, which did not cause visual discomfort to subjects. The daylight dimming control system successfully kept required illuminance levels for an office environment when desktop illuminance by daylight ranged up to 300 lx. The most serious contributor to the sensation of glare was direct daylight through window. The dimming of electric light was not a significant contributor to visual discomfort for the subjects under clear sky day conditions. Visual comfort was significantly influenced by the sensation of glare, feeling for visual stimulation and distraction, and required illuminance level.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.24-33
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• 2005

This paper presents dimming control system for automotive 35[W] metal halide discharge(MHD) lamp electronic ballast using digital control method. HID system has been becoming increasingly popular due to its superior performance(high luminous efficacy, good color rendering and long life etc.)over the conventional halogen system. However, this lamp demands a highly efficient ballast and very complex control circuitry that can control complex transient state in applying to automotive. Therefore, in this paper, digital control method for the HID lamp ballast is presented for optimal control that can adapt complex transient state, steady state and various environments. In developed dimming system, the system is designed to control the lamp output voltage step by step using microcontroller according to cds sensor. Therefore the designed dimming control system give good driving condition to diver and realize the power control effectively. The results of the proposed system is verified through various simulation results and the experiment results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.123-128
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• 2005

This study purposes to increase the energy-saving effects by reducing excessive intensity of radiation of artificial lighting through analyzing daylight incident A photosensor sends amounts of detected luminous flux to digital control unit(DCU) as a signal and then, it can decide dimming ratios, received a proper dimming signal from DCU. Generally it Is effective to control artificial lighting with the different control ratio of each row by setting a photosensor as same numbers and rows as artificial lighting. However, it is ineffective to do in initial costs of systems aspect in offices. As a result of grasping the distribution of daylight previously, we can dim different dimming ratios to each row of artificial lighting by a single photosensor.

• Journal of Industrial Technology
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• v.31 no.B
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• pp.67-73
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• 2011

Ceramic metal halide lamps have been widely used due to long lifetime, high luminous efficiency and good colour rendering. In this paper, we developed dimming control system of electronic ballast for 70W ceramic metal halide lamp by using 1-10V interface. The proposed electronic ballast is consists of EMI filter, Full-wave rectifier, Active PFC, DBI(Dual Buck Inverter), Igniter and control circuit.It enables to supply both low-frequency rectangular wave voltage and current to the lamp by using DBI(Dual Bcuk Inverter) structure. By using 1-10V interface, the system that able to dimming the lamp is demonstrated by P-spice simulation and experimental results.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.747-750
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• 1999

A 30Watt inverter with 300: 1 dimming capability for high luminance, one cell, surface discharge plasma light source for LCD backlight was designed and tested. It was possible to achieve 300:1 dimming control by using the push-pull type inverter with burst-mode dimming control. The surface discharge plasma light cell with luminance of more than 5, 260 cd/$m^2$ was successfully operated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8B
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• pp.1204-1210
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• 2010

In this paper, in order to reduce the power consumption of LCD TV, we present a two-dimensional dimming algorithm for LED BLU(Backlight Unit) using light spread function and a pragmatic implementation method. In conventional two dimensional dimming algorithms, LED BLU is divided into MxN blocks and proper backlight luminance for each block is computed according to input image and used for dimming control. But, LED light of each block is diffused and affects the neighboring blocks so that luminance of each block becomes larger than that of intent. In the proposed algorithm, dimming control values are reduced by the amount of quantity affected by the neighboring blocks using light spread function, resulting in additional reduction of power consumption.