• Title/Summary/Keyword: LED Driver

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Visible Light Communication LED driver For research to improve power (가시통신용 LED 드라이버 전력 효율 성능 향상을 위한 연구)

  • Kwon, Jae-hyun;Park, Keon-jun;Kim, Hyo-jun;Choi, Gil-Sang;Kim, Young-kab
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.10a
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    • pp.15-16
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    • 2012
  • General lighting will be replaced into LED due to the high efficiency, low power consumption, long life than conventional light, moreover, since it is a basically semiconductor device that can convert the electric energy to visible light at a very high speed, using these characteristics can be performed communication modulation via the high-speed ON-OFF switching. Recently, visible light communication (VLC: Visible Light Communication) technology is received attention and there have been many researches. This paper is implemented media signal transmission by combining LED with VLC, a transmitter used the LED light-emitting device and receiver used an infrared sensor. In order to increase the efficiency of the communication system to improve the existing LED visible light communication driver of power conversion efficiency and thermal issues that is applied to the visible light communication in order to improve the speed of transmission media to research a new way of LED driver.

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A Study of Designing of Energy Efficient LED Driver Apparatus (고효율 가변 전력 LED조명기기 Driver 개발)

  • Yoo, Soo-Yeub;Um, Kee-Hong;Kim, Harry
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2009.05a
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    • pp.28-31
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    • 2009
  • This paper is a report of designing for high efficient LED lights driver. The main purpose of driver designing is meet the requirement the high efficient energy regulation for light of Korea. To meet the regulation the high efficient the circuit adapted wide range resonant power supply and current regulate circuit to adjust LED current. This product archived excellent performance as well as reliable operation.

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High Step-Down Multiple-Output LED Driver with the Current Auto-Balance Characteristic

  • Luo, Quanming;Zhu, Binxin;Lu, Weiguo;Zhou, Luowei
    • Journal of Power Electronics
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    • v.12 no.4
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    • pp.519-527
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    • 2012
  • A high step-down multiple-output LED driver is proposed in this paper. Firstly, the derivation of the driver with dual-output is presented and its operation principle and steady state performance are analyzed in detail. Secondly, a high step-down N-channel LED driver is proposed and its current auto-balance characteristic and step-down ratio are analyzed. Finally, an experimental prototype is built and the experimental results are given. The theoretical analysis and experimental results show that the proposed driver has the following virtues: First, if load balancing is achieved, the voltage gain is 1/N that of a Buck driver, where N is the number of channels. Second, each output automatically has an equal output current, without requiring more current close-loop control circuits than a Buck driver. Last, the voltage stresses of the switches and diodes are lower than those of a Buck driver, meaning that lower voltage switches and diodes can be used, and a higher efficiency can be expected.

Design and Implementation of Transformerless 40W LED Light Driver Circuit for Ships (선박용 변압기 없는 40W LED 조명 구동회로의 설계 및 구현)

  • Song, Jong-Kwan;Park, Jang-Sik;Yoon, Byung-Woo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.7 no.3
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    • pp.485-490
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    • 2012
  • In this paper, driver circuit of LED lights for ships is designed and implemented to replace conventional lights with filament which have short life time due to vibration of ships. The driver of LED module is switching circuit without transformer to reduce volume and cost. As switch circuit controls input 220 VAC with PWM, LED module is reliably driven. Power factor is improved by using valley-fill PFC compensation circuit which is handled to pulse current of switching circuit. Serial-parallel LED circuit is applied to reduce change period of lights of long-term navigation ships. Array of serial-parallel can operate even if some of LEDs is damaged. It is suitable for ships that power consumption and power factor of lights including developed drive circuit have 39Watt and 0.925 respectively.

Design and Fabrication of a Seven Segment Decoder/Driver with PMOS Technology (PMOS 집적회로 제작기법을 사용한 Seven Segment Decoder/Driver의 설계와 제작)

  • 김충기;박형규
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.15 no.3
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    • pp.11-17
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    • 1978
  • A medium scale integrated circuit, BCD to seven segment decoder/driver is designed and fabricated by employing P-channel metal-oxide-semiconductor technology. The device configuration is specifically designed for a common cathode seven segment LED display unit. The decoder logic is composed of two serially connected read-only-memory matrices and the LED drivers are implemented with wide channel FET's. The fabricated integrated circuit performed successfully with a supply voltage between -7 Volt and -26 Volt and the non-uniformity of the LED segment current is about 10%.

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Direct AC LED Driver for Wide Power Range and Precise Constant Current Regulation

  • Hwang, Minha;Eum, Hyunchul;Yang, Seunguk;Park, Gyumin;Park, Inki
    • Proceedings of the KIPE Conference
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    • 2018.07a
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    • pp.522-524
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    • 2018
  • A New Direct AC LED Driver has been proposed for wide output power range and precise constant current regulation using an advanced auto commutation topology. The conventional shunt regulation method provides a stepped input current shape by fixed regulation references in the linear regulator of the each channel, which results in poor current regulation and high THD. The conventional method needs to assign a linear regulator in each LED channel so that the number of linear regulator increases when extending the number of channels especially at high power application. The proposed regulation method can drive multiple switches to regulate each LED channel current by a single amplifier with sinusoidal reference so that large number of LED channel can be simply extended with less BOM cost and low THD is obtained with the accurate current regulation thanks to the sinusoidal input current control in the closed loop control. To confirm the validity of the proposed circuit, theoretical analysis and experimental results from a 20-W LED driver prototype are presented.

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Power Factor Correction LED Driver with Small 120Hz Current Ripple (낮은 120Hz 출력 전류 리플을 갖는 역률개선 LED 구동 회로)

  • Sakong, Suk-Chin;Park, Hyun-Seo;Kang, Jeong-Il;Han, Sang-Kyoo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.1
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    • pp.91-97
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    • 2014
  • Recently, the LED(Light Emitting Diode) is expected to replace conventional lamps including incandescent, halogen and fluorescent lamps for some general illumination application, due to some obvious features such as high luminous efficiency, safety, long life, environment-friendly characteristics and so on. To drive the LED, a single stage PFC(Power Factor Correction) flyback converter has been adopted to satisfy the isolation, PFC and low cost. The conventional flyback LED driver has the serious disadvantage of high 120Hz output current ripple caused by the PFC operation. To overcome this drawback, a new PFC flyback with low 120Hz output current ripple is proposed in this paper. It is composed of 2 power stages, the DCM(Discontinuous Conduction Mode) flyback converter for PFC and BCM(Boundary Conduction Mode) boost converter for tightly regulated LED current. Since the link capacitor is located in the secondary side, its voltage stress is small. Moreover, since the driver is composed of 2 power stages, small output filter and link capacitor can be used. Especially, since the flyback is operated at DCM, the PFC can be automatically obtained and thus, an additional PFC IC is not necessary. Therefore, only one control IC for BCM boost converter is required. To confirm the validity of the proposed converter, theoretical analysis and experimental results from a prototype of 24W LED driver are presented.

Robust Active LED Driver with High Power Factor and Low Total Harmonic Distortion Compatible with a Rapid-Start Ballast

  • Park, Chang-Byung;Choi, Bo-Hwan;Cheon, Jun-Pil;Rim, Chun-Taek
    • Journal of Power Electronics
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    • v.14 no.2
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    • pp.226-236
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    • 2014
  • A new active LED driver with high power factor (PF) and low total harmonic distortion (THD) compatible with a rapid-start ballast is proposed. An LC input filter is attached to the ballast to increase PF and reduce THD. A boost converter is then installed to regulate the LED current, where an unstable operating region has been newly identified. The unstable region is successfully stabilized by feedback control with two zeroes. The extremely high overall system of the 10th order is completely analyzed by the newly introduced phasor transformed circuits in static and dynamic analyses. Although a small DC capacitor is utilized, the flicker percentage of the LED is drastically mitigated to 1% by the fast controller. The proposed LED driver that employs a simple controller with a start-up circuit is verified by extensive experiments whose results are in good agreement with the design.

Design and Implementation of a Wearable LED Display Device

  • Shin, Seung-Hyeok
    • Journal of the Korea Society of Computer and Information
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    • v.20 no.10
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    • pp.7-13
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    • 2015
  • Wearable device, next generation smart device, is consistently growing. The flexible display will be a kind of display in the wearable device. The flexible display technology is now evolving with end-user requirement such as portability and easy installation. Previous wearable display products still have some difficulties in manufacturing and in flexibility whole device. But it can be a flexible display with LED device and utilized in commercial area. In this paper, we propose a driver to control the LED display and implement a flexible LED display system.

A Study on Flicker Free LED Driver for Dimming MR16 Electronic Transformer (조광기용 MR16 안정기 호환 Flicker Free LED 구동회로 연구)

  • Kim, Taek-Woo;Hong, Sung-Soo;Yeom, Bong-Ho
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.4
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    • pp.327-331
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    • 2014
  • LED(Light Emitting Diode) is a semiconductor device utilizing electroluminescent effect is a phenomenon in which a type of P-N junction diode, the light of short wavelength which a voltage is applied in the forward direction is released. LED is advantageous in reducing the energy as environmentally materials that can greatly reduce the carbon emissions, recent it has attracted attention IT(Information Technology) and GT(Green Technology) industry. In addition, there are advantages long life, high efficiency, and excellent response speed, LED have come into the spotlight as the illumination means to replace the existing fluorescent light and incandescent light bulb. When connecting to MR16 electronic transformer for existing LED driver circuit, due to malfunction of the dimmer and the electronic transformer, flicker occurs and linear dimming is not possible. Therefore, in this paper, we suggest an LED drive circuit there is no flicker with the corresponding dimming MR16 electronic transformer. Further, we explain the principles of the LED current control technique and the principle of the drive circuit of the LED, in order to validate the proposed circuit through prototyping and simulation.