• 제목/요약/키워드: LED driving

검색결과 256건 처리시간 0.028초

높은 역률을 가지는 단순 구조 LED 구동 전력컨버터 (Simple Structure LED-Driving Power Converter with High Power Factor)

  • 정강률
    • 전기전자학회논문지
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    • 제22권3호
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    • pp.767-773
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    • 2018
  • 본 논문에서는 높은 역률을 가지는 단순 구조 LED 구동 직류 전력컨버터를 제안한다. 제안한 전력컨버터는 PFC 부스트 컨버터와 전통적인 플라이백 컨버터를 오직 하나의 전력변환 회로로 병합함으로써 LED 구동 전력컨버터의 구조를 단순화한다. 그리하여 제안한 컨버터는 오직 하나의 PWM 제어기 IC를 이용하여 제어되고 높은 역률과 정출력 전압/전류 및 제작비용의 효율성을 달성한다. 따라서 제안한 컨버터는 LED 조명시스템의 산업 생산과 이용에 적합하다. 본 논문에서는 제안한 컨버터의 동작분석과 설계예시를 간단하게 설명한다. 또한 설계된 회로파라미터들에 근거하여 제작된 프로토타입의 실험결과를 통하여 제안한 컨버터의 동작특성을 입증한다.

Tunnel lane-positioning system for autonomous driving cars using LED chromaticity and fuzzy logic system

  • Jeong, Jae-Hoon;Byun, Gi-Sig;Park, Kiwon
    • ETRI Journal
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    • 제41권4호
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    • pp.506-514
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    • 2019
  • Currently, studies on autonomous driving are being actively conducted. Vehicle positioning techniques are very important in the autonomous driving area. Currently, the global positioning system (GPS) is the most widely used technology for vehicle positioning. Although technologies such as the inertial navigation system and vision are used in combination with GPS to enhance precision, there is a limitation in measuring the lane and position in shaded areas of GPS, like tunnels. To solve such problems, this paper presents the use of LED lighting for position estimation in GPS shadow areas. This paper presents simulations in the environment of three-lane tunnels with LEDs of different color temperatures, and the results show that position estimation is possible by the analyzing chromaticity of LED lights. To improve the precision of positioning, a fuzzy logic system is added to the location function in the literature [1]. The experimental results showed that the average error was 0.0619 cm, and verify that the performance of developed position estimation system is viable compared with previous works.

Y형 밸런싱 트랜스포머를 적용한 AC초퍼 LED 구동 시스템 (The AC Chopper LED Driving System Using The Y Type Balancing Transformer)

  • 김진구;유진완;김용하;박종연
    • 조명전기설비학회논문지
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    • 제29권3호
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    • pp.22-29
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    • 2015
  • The AC-LED driving system which is connected directly to alternative current source is suitable for commercialization because of it's simple structure and low cost. However, it requires additional circuits compensating for current differences between the parallel connected LED strings. In this paper, we proposed the circuit compensating for current error of the three LED strings using the Y type balancing transformer. The proposed Half-bridge AC Chopper LED driving system used the ferrite material's balancing transformer. at the same time, it is able to dimming control. The proposed system is applied to 80W AC-LED module consist of three parallel strings. Experiment results present that Power factor and THD measured with power analyzer are 0.958 and 26.473% respectively satisfied with IEC61000-3-2 harmonics standard.

New X-Y Channel Driving Method for LED Backlight System in LCD TVs

  • Cho, Dae-Youn;Oh, Won-Sik;Cho, Kyu-Min;Moon, Gun-Woo;Yang, Byung-Choon;Jang, Tae-Seok
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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    • pp.1001-1004
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    • 2007
  • This paper proposes a novel RGB-LED (light emitting diode) backlight system, for 32" LCD TVs, accompanied by a new X-Y Channel driving method in which its row and column switches control the individual division screen. This proposed driving method is able to produce division driving effects such as image improvement and reduced power consumption. Not only that, the number of driver needed in this method, that is 3 power supplies with 3*(m+n) switches, is much fewer than that of cluster driving method, that is 3*(m*n) driver.

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색 영역의 확장을 위한 LED 구동회로에 대한 연구 (Study of a LED Driver for Extension of Color Gamut)

  • 신동석;박찬수
    • 방송공학회논문지
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    • 제21권5호
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    • pp.760-769
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    • 2016
  • 본 논문에서는 LED의 색 영역을 확장하기 위해서 Hybrid LED 구동회로와 제어 기법을 제안하였다. 제안된 Hybrid LED 구동회로는 고 전류에서는 스위칭 레귤레이션 동작을 하고 저 전류에서는 리니어 레귤레이션 동작을 함으로써 LED에 일정한 정 전류를 공급하였다. 또한 고 전류와 저 전류의 크기를 각각 CC 제어기법과 PWM 제어기법으로 제어하였다. 제안된 구동회로와 제어 기법으로 RGB LED 각각의 전류를 가변하였고, 전류가 최대 전류대비 2%까지 선형적으로 제어됨 실험을 통해 확인하였다. 게다가 출력된 광색을 CIE1931 색도좌표로 측정하였다. 그 결과 기존의 표현할 수 없었던 색이 균일하게 출력됨을 확인하였으며, 제안된 구동회로와 제어 기법이 저 전류제어가 가능함으로 색 영역 확장이 가능함을 증명하였다.

전압제어 링 발진기를 이용한 LED구동회로 및 조명제어기설계 (Design of LED Driving Circuit using Voltage Controlled Ring Oscillator and Lighting Controller)

  • 권기수;서영석
    • 조명전기설비학회논문지
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    • 제24권4호
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    • pp.1-9
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    • 2010
  • LED구동회로및 제어회로를 개발하였다. 개발된 LED구동회로는 새로운 PWM회로를 가지고 있으며 LED열의 디밍, 전류 및 온도제어 및 통신 기능을 할 수 있다. 개발된 PWM회로는 기본적인 디지털 논리소자를 사용하여 만들어 질 수 있는 두 개의 링 발진기와 한 개의 카운터로 구성되어 있다. 부가적으로 이 회로는 온-오프 제어 모드, 비상모드, 전력절감모드를 가지고 있으며 직열통신을 이용해서 제어된다. 설계 된 PWM 발생기와 제어회로는 마그나칩/하이닉스의 디지털 공정을 이용하여 제작되었다. 제작된 칩은 LED구동장치와 제어기 보드에 장착되어 테스트 되었으며 성공적으로 동작하였다.

Current Controlled X-Y Channel Driving White LED Backlight System for 46" LCD TV

  • Cho, Dae-Youn;Oh, Won-Sik;Cho, Kyu-Min;Moon, Gun-Woo;Yang, Byung-Choon;Jang, Tae-Seok
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.1503-1506
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    • 2008
  • A novel white-LED (light emitting diode) backlight system for 46"LCD TVs which involves the current controlled X-Y channel driving method is proposed in this paper. There are two problems related to the LED current in the conventional X-Y channel driving driven by a constant voltage source. To solve these problems, a real time current sensing system is applied to the conventional one and the time-division current sensing method is employed.

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LED 가로등 구동용 하이브리드 태양광 전원장치 개발 (Development of Solar Power System of Driving a Hybrid LED Streetlight)

  • 박대수;오성철
    • 한국산학기술학회논문지
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    • 제13권12호
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    • pp.6006-6012
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    • 2012
  • 태양광 가로등 시스템에 사용되는 전원 장치는 배터리 충전을 위한 충전기와 LED Lamp를 구동하기 위한 LED 드라이버로 구성되어 있는데 일반적인 시스템에서는 별도의 전원장치로 구성되어 있다. 본 연구에서는 충전기와 LED 드라이버를 한 개의 전원장치로 구성하였다. 특히 장치의 효율을 높이기 위하여 계통 연계형 태양광 발전시스템에 적용하는 최대전력추적(Maximum Power Point Tracking: MPPT) 방식을 충전기에 적용하였다. LED 드라이버에 필수적인 정전류 방식은 충전기의 전류제어 루틴을 사용하여 구현하였다.

LED Backlight Driving Circuits and Dimming Method

  • Kwon, Oh-Kyong;Jung, Young-Ho;Lee, Yong-Hak;Cho, Hyun-Suk;Nam, Ki-Soo;In, Hai-Jung
    • Journal of Information Display
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    • 제11권4호
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    • pp.173-181
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    • 2010
  • In this paper, light-emitting-diode (LED) backlight driving circuits and dimming method for medium-sized and large liquid crystal displays (LCDs) are proposed. The double loop control method, the intelligent-phase-shifted PWM dimming method, the fast-switching current regulator, and the current matching techniques are proposed to improve not only the current regulation characteristics and the power efficiency but also the current matching characteristics and the transient response of the LED current. The brightness of the backlight using the proposed local dimming method was determined from the histogram of the local block to reduce the power consumption of the backlight without image distortion. The measured maximum power efficiency of the LED backlight driving circuit for medium-sized LCDs was 90%, and the simulation results showed an 88% maximum power efficiency of the LED backlight driving circuit for large LCDs. The maximum backlight power-saving ratio of the proposed dimming method was 41.7% in the simulation with a high-contrast image. The experiment and simulation results showed that the performance of LEDs as LCD backlight units (BLUs) improved with the proposed circuits and method.

다분할 디밍구조를 갖는 LED BLU 구동회로에 관한 연구 (Study on the LED BLU Driving Circuit with a Local-dimming Structure)

  • 박유철;김희준;채균;백주원
    • 전기학회논문지
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    • 제58권2호
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    • pp.292-300
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    • 2009
  • This paper presents an LED BLU driving circuit with a local-dimming structure. The efficiency of the proposed LED driver has been improved by parallel driving 8 serial-connected LED arrays. It employed the soft-switching boost converter topology to reduce the switching power loss of the hard switching boost converter. Soft- and hard-switching converters have the same structure except that the free-wheeling diode in the hard-switching converter is replaced with the n-channel MOSFET in the soft-switching one. The proposed boost converter was compared with the hard switching converter. The soft-switching converter reveals superior ripple and efficiency. A smaller inductance can be used for the soft-switching converter contrasting to the hard-switching one. We also studied on an over-voltage protection circuit of the output of the driver at the no load condition. The protection circuit was applied to the proposed driver, and its operation was confirmed by experiment. Using a local-dimming technique, power consumption of LCD BLUs can be reduced as low as possible according to the brightness of its image.