• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2847-2850
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• 2003

A input voltage conversion dimming control formula and a PMW dimming control formula which have been used for dimming control of CCFL driving inverter in TFT-LCD backlight, are the existing facilities so far, however, in this thesis the circuit is designed by applying The rover inverter that are able to measure output brightness according to changing of duty ratio at PWM and voltage. consequently, it's able to be confirmed that we can have dimming control more detailed than before.

• 조명전기설비학회논문지
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• 제27권9호
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• pp.15-22
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• 2013

A new LED lamp driving technology with a charge pump instead of a conventional DC-DC converter is proposed. The proposed driving technology is used to control the LED lamp with digital dimming. The power loss in the zener diodes is reduced because the charging process of the capacitors is selectively controlled according to the digital control signal. From the experimental results, when dimming four LED lamps simultaneously, the average driving circuit efficiency of 89% is obtained, regardless of the dimming level. White light with color temperature over a range of 2800~7200K was produced by dimming control of red, green, blue and amber LED lamps with the proposed driving circuit. The characteristics of the driving circuits can be changed depending on the characteristics of the R, G, B, and A LED lamps. The efficiency of the driving circuits up to a maximum 89% can also be obtained depending on the combination of LED lamps. The driving technology with digital dimming control for LED lamps proposed in this paper would be effective for obtaining high efficiency in LED driving circuits and remote control of LED lamps using digital communications.

• 전기학회논문지
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• 제58권10호
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• pp.1947-1953
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• 2009

Metal halide (MH) lamps have been largely used due to high luminous efficiency, good color rendering, and long life. Since the metal halide lamps have problems of high ignition voltage and acoustic resonance. Thus, the design of ballast is very difficult for engineers. This paper proposes prototype of electric ballast in order to solve above two problems. The proposed electric ballast is consisted of EMI filter, full wave rectifier circuit, active PFC, DBI(Dual Buck Inverter), dimming circuit and ignitor circuit. The DBI supplies both rectangular voltage and current to the lamp. As the result of the experiment, the acoustic resonance was eliminated and the ignitor circuit was designed to generate high ignition voltage than 5kV. It makes the dimming circuit possible to control the lamp power in range between 230W and 350W.

• 조명전기설비학회논문지
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• 제29권2호
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• pp.8-18
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• 2015

This paper proposes a dimming method and a hybrid LED driving circuit suitable for the ultra high definition (UHD) broadcasting. There are major two problems during the dimming control for traditional LED broadcast lightings; one is a flicker that occurred when camera filming to these lightings, and the other is that linear control is impossible for LED luminous intensity under 10% due to LED electrical characteristics. The proposed dimming method and the driving circuit are designed to solve two problems simultaneously. For high level dimming control region from 10 to 100%, the analog control method was applied to the switching regulator constructed by MOSFET operated in the saturation region. For low level dimming control region under 10%, the fast PWM control method with the linear regulator constructed by MOSFET in the ohmic region was used. We verified experimentally that the dimming method is able to control the luminous intensity linearly from 1 to 100% and the flicker disappears on images taken by the charge coupled device (CCD) and the complementary metal oxide semiconductor (CMOS) cameras. Therefore, the proposed method is suitable for the UHD broadcasting.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제4B권4호
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• pp.201-205
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• 2004

The CCFL dimming control methods are generally used lamp current regulation or average current adjustment method feeding the CCFL inverter. Inverter operation frequency is higher than resonant frequency for safe operation. In this study, we design the half-bridge type series and parallel resonant converter circuit that switches at variable frequency modulation methods to control the output power. This method has advantages such as low EMI and reduced harmonics, and it is convenient for dimming control using a microprocessor. The validity of this study is confirmed from the simulation and experimental results.

• 한국정보통신학회논문지
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• 제18권9호
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• pp.2280-2288
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• 2014

기존의 고출력 LED의 디밍(Dimming) 제어 방법에는 펄스폭변조, 주파수변조, 아날로그 제어 방법이 있으며, 아날로그 디밍은 순방향 고출력 LED 전류를 조정하는 방법으로 0%~100%의 전 범위에서 선형 밝기 조절이 가능하나 순방향 전류를 변화시킴으로써 파장의 변화가 존재하고, 펄스폭변조 디밍 제어는 고출력 LED에 흐르는 정격 전류의 듀티를 가변하여 조도를 제어하는 방식으로 저 레벨(0%~10%)에서 선형 밝기 조정이 어렵다. 그리고 주파수변조 디밍 또한 저 레벨의 디밍에서 빛이 깜박거리는 문제를 내포하고 있다. 본 논문은 이러한 디밍 방식의 단점을 보완하고자 저 레벨 디밍 제어 시 아날로그 방식을 적용하고, 10%~100%의 디밍 제어 시에 펄스폭변조 방식을 적용하는 효율적인 디밍 제어 회로의 설계 및 구현을 제안한다. 전 범위에 걸쳐 선형 밝기 조절이 가능하고, 다양한 디밍 레벨에서 일정한 파장의 출력이 가능한 디밍 제어 회로를 구현하였으며, 실험 결과는 제안한 방법의 우수성을 보여주고 있다.

• 조명전기설비학회논문지
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• 제26권8호
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• pp.1-7
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• 2012

In this paper, a new LED driving circuit which is able to control dimming of LED is proposed using charge pump. The proposed LED driving circuit steps down the input voltage to operate LED without DC-DC converter. The operation of this driving circuit is verified by P-Spice simulation, and the characteristics of the driving circuit is measured and evaluated in the experiments. As a result, the driving circuit efficiency of 88.5[%] is obtained when all LEDs are turned on by digital control method at the highest dimming level(255/255).

• 한국조명전기설비학회지:조명전기설비
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• 제13권2호
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• pp.149-149
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• 1999

This paper is to present a selected method of circuit parameters in the inverter part of the electronic dimming ballast for fluorescent lamps, that is adequate to use with the prevailing dimming controller IC. Through the experiment result using the prototype of the electronic dimming ballast produced by this method, its validity is verified from the electrical and light output characteristics on fluorescent lamps. Also, it is feasible to remote automatic and passive control fur dimming electronic ballast as using a microprocessor, and we easily recognize the lamp condition owing to make a program indicate abnormal behavior for fluorescent lamp at PC screen.

• 조명전기설비학회논문지
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• 제13권2호
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• pp.17-23
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• 1999

이 논문에서는 현재 사용되고 있는 Dimming 형 IC의 특성에 최적인 전자식 안정기의 인버터내 회로상수를 결정하여 Dimming 형 전자식 안정기를 제작하였고, 제작된 안정기를 이용하여 형광램프의 전기적 특성과 광출력 특성을 비교하여 회로상수 선정법의 타당성을 증명하였다. 또한 제작된 Dimming 형 전자식 안정기를 마이크로프로세서를 이용하여 수동조작 뿐만 아니라 PC를 통한 원격자동제어가 가능하도록 하였고, 램프의 동작 상태, 주위 온도, 전자식 안정기의 이상유무를 PC의 화면상에 표시되도록 프로그램하여 원격제어시스템을 구축하였다.

• 산업기술연구
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• 제29권B호
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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.