• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.405-407
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• 2005

As the screen size of LCD increases, EEFL(External Electrode Fluorescent Lamp) has been suggested to be applicable as backlight source for LCD . Since the electrodes of EEFL are outside of the tube, EEFL enhances the lifetime compared with CCFL(Cold Cathode Fluorescent Lamp), and a single inverter can drive multiple EEFL tubes of which luminance is uniform Therefore, a compact design can be realized and the cost of EEFL application would be much lower than that of CCFL. Moreover, EEFL inverter has higher efficiency per unit power than CCFL inverter. In this paper, a complementary full-bridge PWM(Pulse Width Modulation) inverter was designed for 32-inch LCD TV backlight which has 20 EEFL tubes and adapted two different driving methods to the EEFL inverter. The validity of this study is confirmed from the experimental results.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.2 s.31
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• pp.37-41
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• 2004

Parallel combination of cold chathode fluorescent lamps (CCFL) are widely used as the light sources of LCD TV backlight. Brightness uniformity is safisfied by using one transformer per one CCFL. Instead of using one transformer per oneCCFL, one transformer is used to drive 8 CCFLs by using differential driving method. A differential driving inverter with two transformers is developed to drive 16 CCFLs of 26' backlight for LCD TV. The brightness uniformity of $88\%$ was obtained by driving 26' backlight with the developed differential driving inverter successfully.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.465-469
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• 2004

액정 디스플레이의 백라이트 광원으로 냉음극 방전램프(CCFL: Cold Cathode Fluorescent Lamp)가 일반적으로 사용된다 최근 LCD 모니터의 두께는 갈수록 얇아지며, 화면은 넓어지고 있는 대형화 추세이다. 기존의 권선형 변압기를 이용 인버터를 구성하여 멀티램프를 구동하고 있지만 이는 코어나 권선 손실에 의한 효율 저하와 부피나 중량의 증가, 그리고 과열에 의한 화재의 위험성을 가지고 있다. 이러한 문제들을 해결하기 위해 본 논문에서는 압전 변압기를 이용한 멀티램프 구동용 인버터를 설계 지침에 따라 구성하였다. 인버터 하나로 압전변압기를 병렬로 연결하는 방식을 이용하였고, 또한 전류 부담이 적은 외관 전극 형광 램프(EEFL: External Electrode Fluorescent Lamp)를 이용한 멀티램프 구동 방법을 압전 인버터에 적용 가능한지 고찰하였다. 적용한 방식으로는 풀-브리지 (Full-Bridge)회로를 응용하였다.

• 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.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.5
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• pp.416-423
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• 2007

To drive the CCFL In LCD backlight inverter, a new transformer structure with small volume is proposed which have a boosting voltage and a lamp current balancing functions. The proposed transformer structure has been verified through experimental test with 40inch LCD backlight inverter.

• Proceedings of the KIEE Conference
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• summer
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• pp.1208-1210
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• 2004

The Cold-Cathode Fluorescent Lamps (CCFL) are widely used to illuminate the liquid crystal displays(LCD) used in many battery powered instrument. This paper presents analysis of fly-back converter for universal-line applications($90\sim265Vac$) and half-bridge type resonant inverter for CCFL drive for stable characteristic and life improvement of fluorescent lamp operation frequency is higher than resonant frequency for safe operation. The validity of this study was confirmed from the simulation and experiential result.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.5
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• pp.454-462
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• 2006

To enhance the competitive edge of the material cost, various techniques lowering the material cost of inverter to drive Cold Cathode Fluorescent Lamp (CCFL) have been developed. In this paper, the theoretical analysis has been done for the existing techniques such as Jin Balance and O2Micro technique. Especially, How to design the value of magnetizing inductance to meet the specification of the lamp current tolerance between lamps has been disclosed. Based on this result, two kinds of hybrid type balancing techniques have been proposed and analyzed mathematically, Also, the accuracy of the proposed techniques has been verified through Pspice simulation.

• Transactions on Electrical and Electronic Materials
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• v.8 no.4
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• pp.166-169
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• 2007

In applying LCD to TV application, one of the most significant factors to be improved is image sticking on the moving picture. LCD is different from CRT in the sense that it's continuous passive device, which holds images in entire frame period, while impulse type device generate image in very short time. To reduce image sticking problem related to hold type display mode, we made an experiment to drive TN-LCD like CRT. We made articulate images by turn on-off backlight, and we realized the ratio of Back Light on-off time by counting between on time and off time for video signal input during 1 frame (16.7 ms). Conventional CCFL (cold cathode fluorescent lamp) cannot follow fast on-off speed, so we evaluated new fluorescent substances of light source to improve residual light characteristic of CCFL. We realized articulate image generation similar to CRT by CCFL blinking drive and TN-LCD overdriving. As a result, reduced image sticking phenomenon was validated by naked eye and response time measurement.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.9
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• pp.8-17
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• 2012

This paper proposes high performance control of light emitting diode(LED) drive system for liquid crystal display(LCD) backlight. The CCFL(cold cathode fluorescent lamp)was used to a conventional LCD backlight. Due to improvement on luminous efficiency, long life and wide color gamut, LED has gradually substituted for CCFL as backlight. The backlight using LED is necessary to use many LED. For that reason, the LED backlight is using a lot of LED driving circuits. The many LED driving circuit is generated a current deviation between LED. Eventually, it is caused brightness deviation between LED. Therefore, this paper improves the current deviation using transformer and balancing capacitor to solve this problem. Also, for accurate and uniform brightness control, this paper is applied the artificial intelligent control to a dimming control. This paper is compared with conventional system, and validity of this paper proves through that result.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.190-192
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• 2007

LCD TV의 대형화에 따라 하나의 백라이트용 냉음극 방전램프(Cold Cathode Fluorescent Lamp ; CCFL)를 이용한 백라이트는 휘도의 한계가 있어 대형 디스플레이에서는 여러 개의 램프를 사용하여 필요한 휘도를 만들고 있다. 본 논문에서는 냉음극 방전램프 16개를 사용하는 42인치 LCD TV용 대형 백라이트 구동을 위한 인버터의 트랜스포머를 각기 다른 램프의 특성에 대해 동일한 관 전류 출력을 갖도록 설계하였다.