• 한국의류학회지
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• 제35권3호
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• pp.292-303
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• 2011

This research suggested a draft proposal for a smart jacket design, which has applied wearable technologies to provide convenience in daily life. The smart jacket combined with a vest was the casual item for autumn and winter. The heating device was composed of the heating element, battery, controller, electric wire, connector, switch, and charger. A stable electronic conductor fiber of good heating effect with a flexible zigzag form has been selected for the heating element. The lighting device has been made in a way that attaches the LED and its power controller in the same mechanical device. As the result of the wearing test, the heating effect turned out to be effective in the order of: back, both the back and abdomen and only the abdomen. When wearing a smart jacket, the back and abdomen have been selected as favorable body parts for heating. Pockets and hems are selected as the adequate place to attach the LED lighting, and the brightness of LED lighting has turned out to be suitable and useful. Based on the test results, the first draft proposal has attached the heating element only in the back and its controller located in the inside pocket of the vest. In addition, the LED has been attached to the front pocket of the jacket. As to the second draft proposal, heating elements have been placed in the back and the abdomen. Each controller for the heating elements has been placed in the front and inside pocket of vest, and the LED lighting has been attached to the hem of the jacket. The smart jacket combined with a wearable device was assessed by functioning categories. The user showed a high satisfaction in the heating and illuminating function of a smart jacket.

• 한국항행학회논문지
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• 제21권3호
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• pp.220-229
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• 2017

본 연구는 다양한 DC 전원을 활용할 수 있는 승압형 DC-DC 컨버터로 설계사양을 통한 인덕터 L과 커패시터 C의 값을 산출하여 PSPICE를 통한 최적의 값을 추정하였다. 승압형 DC-DC 컨버터는 스위치 소자로 IRF840을 사용하였으며 역회복 시간(reverse recovery time)이 뛰어난 쇼트키 다이오드(schottky rectifiers)인 D10SC6M을 사용하여 정전류 제어 (constant current controller)가 가능하도록 구성하였으며 열저항을 고려한 파워 LED 모듈 (power LED module)을 제작하여 구동하였다. 컨버터의 스위칭 주파수는 50 kHz로 최초 듀티비는 10 %에서 출력전압의 검출 값에 따라 점차적으로 증가시키도록 하였다. 그 결과로 승압형 파워 LED 구동기를 시뮬레이션 한 특성은 설계사양과 비교하여 5 %이하의 오차로 근사적으로 나타났고, 입력전압 15 V를 인가하여 안정된 24 V의 안정된 출력전압을 얻었으며 디밍제어 (dimming control)를 통한 밝기 조절 및 소비전류의 조정이 가능하였다.

• Journal of Power Electronics
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• 제11권3호
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• pp.271-278
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• 2011

This paper presents a LLC resonant controller IC for secondary side control without external active devices to achieve low profile and low cost LED back light units. A gate driving transformer is adopted to isolate the primary side and the secondary side instead of an opto-coupler. A new integrated dimming circuitry is proposed to improve the dynamic current control characteristic and the current density of a LED for the brightness modulation of a large screen LCD. A dual-slope clock generator is proposed to overcome the frequency error due to the under shoot in conventional approaches. This chip is fabricated using 0.35 ${\mu}m$ BCD technology and the die size is $2{\times}2\;mm^2$. The frequency range of the clock generator is from 50 kHz to 500 kHz and the range of the dead time is from 50 ns to 2.2 ${\mu}s$. The efficiency of the LED driving circuit is 97 % and the current consumption is 40 mA for a 100 kHz operation frequency from a 15 V supply voltage.

• 한국전기전자재료학회논문지
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• 제26권8호
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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 Power Electronics
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• 제15권4호
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• pp.861-875
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• 2015

This paper presents a wide frequency range LLC resonant controller IC for LED backlight units. In this paper a new phase-domain resonance deviation prevention circuit (RDPC), which covers a wide frequency and input voltage range, is proposed. In addition, a wide range gate clock generator and an automatic dead time generator are proposed. The chip is fabricated using 0.35 μm BCD technology. The die size is 2 x 2 mm2. The frequency of the clock generator ranges from 38 kHz to 400 kHz, and the dead time ranges from 300 ns to 2 μs. The current consumption of the LLC resonant controller IC is 4 mA for a 100 kHz operation frequency using a supply voltage of 15 V.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.980-981
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• 2015

A quasi-resonant flyback converter using a simple 8-bit microcontroller for a LED lighting is proposed in this paper. The proposed converter is easily and precisely controlled by the simple controller using a low-cost 8-bit microcontroller. Also, in order to operate the 8-bit microcontroller, the proposed converter system does not require any additional power supply for the controller. A prototype power supply is developed to supply a 270[W] LED lighting with the wide input voltage ranges ($175[V_{ac}]-265[V_{ac}]$). Experimental results will be show the practicality and validity of the proposed circuit.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.206-209
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• 2003

This paper deals with stand-alone PV power generation system with charge and discharge controller for the LED road sign. Main power source of PV system are generally solar cell and battery. Therefore PV system can be classified into variable types in accordance with connection type between battery and solar sell. Mainly used on of them is direct connection type which has advantage such as simple structure and simple controller. To verify the proposed PV generation system for the LED road sign, the detail simulation and experiment results indicate that operating characteristics are verified by experiment with a laboratory prototype in this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.261-263
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• 2004

This paper studies the lighting pattern control of a high-brightness LED warning light. The driving circuit for the warning light is composed of a full-wave rectified circuit and of a control circuit using a micro-controller (AT89c2051). The micro-controller is programmed in a suitable manner to accomodate a number of variable lighting patterns and to adjust the blinking speed. To reduce the total number of LEDs installed a special consideration is made to the bundled pattern in a lamp module which is lit simultaneously. The resultant LED warning light has merits not only over the conventional incandescent warning light on the energy saving aspect but also over some other LED-type ones in the market.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.104-110
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• 2011

High-brightness LED control is required for stable operation, thus the driver and control system must be designed to deliver a constant current to optimize reliability and ensure consistent luminous flux. In this paper, the sliding mode current controller is designed to adjust the illumination density of power LEDs. The controller design model of power LEDs, including its driving circuit, is proposed to realize the dimming control of power LEDs. A buck converter is introduced to drive the power LEDs and reduce the input voltage to a lower level. The sliding mode software controller is implemented to adjust the dimming of power LEDs. The proposed strategy for driving power LEDs is investigated and comparatively studied by experiments.

• 조명전기설비학회논문지
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• 제27권4호
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• pp.48-53
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• 2013

In general, the LLC resonant topology consists of three stages as; square wave generator, resonant network, and rectifier network. LLC resonant converter has the time slowly varying parameters. However, the power LEDs as the load of LLC converter can be regarded as fast time varying parameters. In this paper, the mathematical model of half-bridge resonant converter including with the power LEDs is introduced for the current controller design model. Using this controller design model, the parameter adaptive output feedback controller will be designed to control the power LEDs current. In order to show the validities of the proposed model, the parameter adaptive output feedback controller, the experimental investigation will be presented.