• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.79-80
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• 2016

A discrete time domain analysis for the duty-cycle-controlled buck LED driver is performed in this paper. Based on the analysis, the design guidelines are derived. Experimental results are presented to confirm the design.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.321-322
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• 2017

A discrete time domain analysis for the slope-compensated buck LED driver is performed in this paper. Based on the analysis, the design guidelines are derived. Experimental results are presented to confirm the design.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.218-220
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• 2008

This paper describes buck converter's MOSFET driver for high-brightness LED strings. The power driving high-side MOSFET is supplied from the power source of control circuit part. The practical considerations and future work are also described.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4177-4185
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• 2012

LEDs are becoming the most suitable candidate replacing traditional fluorescent lamps because of its eco-friendly characteristics. LEDs are also actively used to design green building system and to make outdoor billboard as a back-light system due to its high energy efficiency. In this paper, we have developed AC direct driver for $12{\times}12$ FLB(flexible LED board) and LED flat light without SMPS. It has LID-PC-R101B driver IC that can support the high power factor and be composed of LED switching circuit in group. Also, an elaborate system designs can guarantee a high luminous efficiency, a high reliability and a low power consumption. The proposed FLB has the ultra slim shape of $450{\times}450$ mm, width of 4 mm and weight of 280 g. In the end, we have developed a prototype of FLB for billboard and flat light for room lighting with AC direct driver iposrder to verify the performance of the proposed system.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.522-523
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• 2008

This paper presents an LED lighting which can control its color temperature. It consists of a power factor correction (PFC) circuit, an LED driver, and an LED color control circuit. The proposed system can adjusts the light intensity to obtain a desired color with independently changeable illuminance. The power factor of the PFC circuit is 98%. The LED driver has 90% efficiency at 300mA output current. The output power of the experimented LED lighting is 150 W. The achieved color temperature range was from 3000K to 7500K, and the illumination one was from 500 lux to 1500 lux.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.161-161
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• 2010

In order to achieve low power consumption and the uniform power spectrum of LED BLU (Back Light Unit) system, new circuits with a 2 stage L-C (Inductor-Capacitor) coupler have been proposed. From the simulation results based on our proposed model, the ripple power of the L-C regulation-embedded BLU circuit shows a dramatic reduction by more than 89.3% as compared to the normal BLU (without L-C circuits). This indicates that the proposed circuit is very promising for the realization of high-efficiency BLU circuits.

• Journal of Industrial Technology
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• v.32 no.A
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• pp.109-114
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• 2012

In this paper, We studied LED(Light Emitted Diode) sensor lights system using PIR(Pyroelectric Infrared Ray) sensor, CdS and MCU(Micro Controller Unit). And applied the valley fill circuit to improve the power factor. We designed the amplifier for each sensor and the LED driver for constant current which is the buck converter. Also, we proposed the algorithm of LED control by each sensors using MCU. Experimental results showed that power factor is 92% with valley fill circuit.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.347-348
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• 2014

본 논문에서는 3D TV를 위한 다채널 전류평형 단일스위치 LED 구동회로를 제안한다. 제안된 구동회로는 각각의 LED 채널의 정전류 제어를 위해 별도의 전력단을 사용하는 대신에 2차 측에 단 1개의 switch를 추가하여 하나의 채널 전류를 정전류 제어하고 나머지 다른 채널의 전류를 캐패시터의 성질을 이용한 회로를 사용함으로써 모든 채널 전류의 정전류 제어 및 전류평형이 가능한 회로이다. 추가된 switch는 ZCS(Zero Current Switching) 동작하므로 스위칭 손실을 최소화하여 고효율화 시킬 수 있다. 또한, 여러 LED 채널의 정전류 제어를 별도의 LED Driver단을 사용하지 않고 캐패시터의 성질을 이용하여 구현하기 때문에 소형화 및 저가격화가 가능하다. 최종적으로 제안된 회로의 우수성과 이론적 분석의 타당성 검증을 위해 46" LED 3D-TV 구동회로를 위한 시작품을 제작하여 고찰된 실험 결과를 제시한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.4
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• pp.249-255
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• 2021

A novel current balancing technique for multichannel light-emitting diode (LED) that uses a series resonance and coupled inductor is proposed in this paper. The proposed LED driver balances output currents through frequency control and enables zero-voltage switching. The proposed converter utilizes the charge balance condition of the resonant capacitor and the current sharing function of the coupled inductor to achieve whole LED current balancing without an additional controller. The proposed coupled inductor can integrate the current balancing function and the resonant inductor, so the power density can be increased by reducing the number of magnetic devices. A 40 W prototype is built to verify the validity of this LED driver, and the experimental results are successfully obtained.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.99-106
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• 2016

Wearable display market is a consistently growing field to handle a smart device with ease. Wearable display is an efficient device that can show the information to the user. In this paper, propose the scheme of a wearable display using LED and implement it including controlling remotely with BLE. Traditional outdoor LED display requires the dedicated controller and its software. Therefore, to control those LED display, it should implement a driver and its own way of communication. The proposed method is to ensure the independence and extensibility by separating driver module and communication module for controlling LED display. In addition, by adopting a short-range communication with Bluetooth 4.0 and a LED driver with low-power technology, it can be showed to control system configuration and display with a smart device.