• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.6
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• pp.504-513
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• 2009

This paper proposes the new type LED driver modularization for illumination LED driver. The proposed LED driver circuit insulates a hot GND of AC input power and a cold GND of LED driver part by using a fly-back converter. In order to control easily the current of the LED, the fly-back converter is operated in the discontinuous mode with excellent dynamic characteristics, and the characteristics of the LED are verified after the closed loop control is performed using a KIA2431. The LED driver module allows the wide AC power input ranges and realizes the burst dimming function which directly regulates a PWM control IC. This paper describes the operation principle of the LED driver module and it is proved the usefulness through the real model with experimentation. Besides, this paper proposes the multi-channel LED driver which the miniaturized and modularized LED driver module are connected by parallel, and verified its propriety by experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.329-332
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• 2012

LEDs are using widely in a field of illumination, LCD LED backlight, mobile signals because they have several merits, such as low power consumption, long lifetime, high brightness, fast response, environment friendly. To achieve high performance LEDs, one needs to enhance output power, reduce operation voltage, and improve device reliability. In this paper, we have proposed that the optimum design and specialized process could improve the performance of LED chip. It was showed an output power of 7cd and input supplied voltage of 3.2V by the insertion technique of current blocking layer. In this paper, GaN-based LED chip which is built on the sapphire epi-wafer by selective MOCVD were designed and developed. After that, their performances were measured. It showed the output power of 7cd more than conventional GaN-based chip. It will be used the lighting source of a medical equipment and LCD LED TV with GaN-based LED chip.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.382-383
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• 2011

본 논문에서는 출력 LED 전류의 120Hz 저주파 리플 저감을 위한 새로운 방식의 역률개선 LED 구동 회로를 제안한다. 제안된 회로는 역률개선용 플라이백 컨버터의 출력이 LED 구동을 위한 부스트 컨버터의 입력이 되는 구조로 높은 역률 보상과 출력 LED 전류의 120Hz 리플 저감이 가능하고, 기존에 비해 저 내압 및 저 용량의 부피가 작은 링크 캐패시터를 사용 할 수 있는 장점이 있다. 또한 제안 회로는 전력평형 만족을 위해 하나의 PWM IC 만으로 플라이백 컨버터와 부스트 컨버터를 각각 DCM 및 BCM모드로 제어하여 스위치 및 다이오드의 전류 스트레스 저감이 가능한 장점이 있다. 최종적으로 시작품을 제작하여 고찰된 실험결과를 제시하여, 제안 회로의 우수성과 이론적 분석의 타당성을 검증한다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2295-2296
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• 2008

본 논문에서는 에너지 절감을 위하여 POWER LED 구동회로를 PIR(Pyroelectric Infrared Ray) 센서를 이용하여 ON/OFF 제어를 하였다. POWER LED의 전류 특성을 설명하였으며 설명된 전류 특성을 개선하고자 정전류 유지 회로를 구성하였다. 그리고 인체 감지 센서에서 발생되는 ON/OFF 신호를 증폭시키는 구동 회로를 설계하여 정전류 유지 회로에 직접 결합하는 방식을 제안하였다. 실험한 결과는 POWER LED의 ON 상태시 4Watt, OFF 상태시 0.5Watt를 소비하였으며, 정전류 유지 회로에 의해 POWER LED 구동 전류의 리플이 줄어들어 안정적인 동작을 하는 것으로 나타났다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.2
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• pp.75-78
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• 2016

This research was designed 700 level power MOSFET for smart LED driver ICs package. And we analyzed electrical characteristics of the power MOSFET as like breakdown voltage, on-resistance and threshold voltage. Because this research is important optimal design for smart LED ICs package, we designed power MOSFET with design and process parameter. As a result of this research, we obtained $60{\mu}m$ N-drift layer depth, 791.29 V breakdown voltage, $0.248{\Omega}{\cdot}cm^2$ on resistance and 3.495 V threshold voltage. We will use effectively this device for smart LED driver ICs package.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.682-686
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• 2005

Recently the study is being addressed on the energy economy as greatly as possible. The researches on light source that have higher efficiency than the exiting are performing. The high-power LED is the representative one among those. There are two fields in the research on the high-power LED, the ordinary illuminating apparatus and the night illuminating apparatus using wind and solar energy. In this paper, we validated the probability of using high-power LED as illuminating apparatus and proposed the novel LED power equipment that has more stability and better efficiency than the exiting method. By using the propose method the -R-E-A-C-T is reduced and the efficiency improved.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.75-77
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• 2008

Flexible electronics devices such as plastic display, thin film battery, membrane switch, organic memory for smart card applications will be presented. The performance and power consumption of various display technologies will be compared for OTP requirement in smart cards. Wireless power transmission by RF coupling through an antenna provides a potential power solution to smart cards. Finally, the general trend of smart card future developments will be discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.8
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• pp.629-634
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• 2013

The rectified voltage supplied to LED lamp is used in load and then the surplus voltage can be produced in LED lighting. In this case, LED lighting is proposed that can recyclable the excess voltage to supply power to the controller.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.2
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• pp.24-31
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• 2011

The purpose of this study is to find an efficient way using dimmable LED lamps to describe specific target illuminance and color temperature. This study used 14 dimmable LED lamps as same or different color temperature. The method of study is to measure of electric power consumption using different color temperature of dimmable LED lamps that were combination of two or three dimmable LED lamps by simultaneously dimming. Through this method, the electric power consumption was compared with all combinations of the illuminance and color temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.702-708
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• 2020

Recently, as LED display systems have become larger, research on effective power control methods for the systems has been in progress. This paper proposes a power control method to minimize power loss due to the difference in LED characteristics for each channel of a backlight unit (BLU) system. The proposed LED driver IC has a power optimization function and detects the minimum headroom voltage for constant current operation of all channels and linearly controls the DC-DC converter output. Thus, it minimizes power consumption due to unnecessary additional voltage. In addition, it does not require a voltage sensing comparator or a voltage generation circuit for each channel. This has a great advantage in reducing the chip size and for stabilization when implementing an integrated circuit. In order to verify the proposed function, an IC was designed using Cadence and Synopsys' design tools, and it was fabricated with a Magnachip 0.35um 5V/40V CMOS process. The experiments confirmed that the proposed power control method controls the minimum required voltage of the BLU system.