• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.4
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• pp.173-178
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• 2007

As development of industry is accelerated, most electricity load system requires power supply that could be high precision and effective control. Among supply and control unit of suitable power supply in these load characteristic, inverter systems of constant current regulate is used widely control of lighting & beaconing of aerodromes and electric heating system. Therefore, in this paper proposed a inverter systems of constant current regulate that using improved measurement and switching techniques. Proposed measure techniques that used moving average method of instantaneous r.m.s. for measuring current sensing improved response and precision. Also, in this paper proposed improved high effectiveness switching techniques that get high efficiency of inverter by the double-carrier modulation. Results of an experiment proved effect of proposed system.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.79-82
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• 2009

This work presents a novel lighting technology based on a YAG:$Ce^{3+}$ phosphor converter with micro line lenticular structure, to accompany an array of bare LED chips on a board. This technology is especially effective in TFT-LCD backlight applications as it offers the advantages of high light radiation efficiency, low color deviation, uniform luminance distribution and compact backlight thickness. Additionally, the proposed configuration is low-cost, can be manufactured quickly, and can be mass-produced economically.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1297-1299
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• 2009

A series of $Eu^{2+}/Mn^{2+}$ co-activated $Ba_{1.98-x}Sr_xZnS_3$ red emission phosphors was synthesized using the polymerizable complex method. The excitation spectra of the materials contain two wide bands centered at 345nm and 445nm, implicating their possible use for white LED lighting applications. In addition, substitution of Sr for Ba by 20% (x=0.4) improved drastically the emission intensity as well as the internal quantum efficiency compared to those for Sr-free $Ba_2ZnS_3:Eu^{2+}/Mn^{2+}$ phosphor.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.7
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• pp.370-376
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• 2004

The metal halide lamps are now widely used in the application and commercial lighting due to their attracting properties such as good color rendering and high efficiency. But, they have the serious problem of acoustic resonance for high frequency operation and they need the high voltage to ignite. So, they have not been applied to indoors. Over the past few years, a considerable number of studies have been conducted on the electronic ballast together with hot restarting and resonance phenomenon. But, Very few attempts have been made with the adaptive ignition method according to the lamp state. In this paper, electronic ballast is proposed for metal halide lamps with an igniter for adaptive ignition. The proposed electronic ballast can generate different ignition voltages according to the arc tube state.

• Journal of Industrial Technology
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• v.30 no.A
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• pp.83-88
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• 2010

Recently, the LED lighting is widely used to illumination purpose due to its high luminous efficiency and the long life time. However, the light power and lifetime is reduced by junction temperature increment of LED. So it is important to measure the junction temperature accurately. In this paper, we proposed a new design and implementation method of high power LED junction temperature measurement circuit. The proposed circuit has two current sources which are a driving current source and a measurement is verified by experiment, and the result shows that the proposed circuit is appropriate to practical use.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.205-209
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• 2004

The metal halide lamps are now widely used in the application and commercial lighting due to their attracting properties such as good color rendering and high efficiency. But they have the serious problem of acoustic resonance for high frequency operation and they need the high voltage to ignite. So, they have not been applied to indoors. Over the past few years, a considerable number of studies have been conducted on the electronic ballast together with hot restarting and resonance phenomenon. But very few attempts have been made with the adaptive ignition method according to the lamp state. In this paper, electronic ballast is proposed for metal halide lamps with an igniter for adaptive ignition. The proposed electronic ballast can generate different ignition voltages according to the arc tube state.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.589-592
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• 2001

In this paper, Electronic ballast for multiple fluorescent lamps based on the use of ferrite beads are presented. The use of this system in place of the conventional electromagnetic ballast results in lower power consumption and reduced maintenance cost, because the electronic system has higher efficiency and longer lamp lifetime than the electromagnetic ballast. In comparison with the conventional electronic ballast. The proposed system presents a significant reduction of cost. This reduction becomes were meaningful with the growing of the lamp number. The description of the lighting system, We show that the proposed model can be applied to multiple lamps electronic ballast by simulation processes.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.67-68
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• 2007

The introduction of high brightness LEDs with white light and monochromatic colors have led to a movement towards specialty and general illumination applications. Because drive circuit of illumination LED has an effect on efficiency and life, research about the drive circuit following LED characteristic is needed. This paper proposed a implementation of the stand-alone LED lighting system using battery from photovoltaic power generation.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.86-88
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• 2004

정공주입 버퍼층(PTFE)두께에 변화에 따른 유기발광소자 전압-전류-휘도 효율을 측정한 결과 ITO/PTFE/Al 구조에서 두께가 증가하면 전류 밀도 및 전압이 증가하며, 두께가 0.7 (nm)일 때 부성 저항 영역이 나타났었고, ITO/PTFE/NPB/$Alq_3$/Al 구조에서 두께가 1.0 [nm]에서는 가장 좋은 휘도와 효율을 나타났었다. 두께가 증가하면 이것은 PTFE 내의 정공의 이동을 어렵게 하기 때문에 효율이 감소하는 것으로 판단된다. 그래서 적당한 PTFE 두께만이 가장 좋은 휘도와 효율을 얻을 수가 있다.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.4
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• pp.297-302
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• 2014

In this paper, a LED driver compatible with TRIAC-dimmer applying active bleeder is proposed. If TRIAC-dimmer is connected with LED driver, flicker phenomenon occurs by TRIAC malfunction. In order to prevent this problem, a current over holding current must flow into TRIAC. Therefore, additional circuit compatible with TRIAC-dimmer is required to provide enough current. Passive bleeder has power loss in whole operation period. The proposed circuit apply a valley-fill circuit for power-factor-correction and a novel active bleeder detecting malfunction point of TRIAC. Therefore, it prevent malfunction of TRIAC-dimmer and have advantage of higher efficiency than passive bleeder. To verify the validity of proposed circuit, 13W-lighting LED driver prototype has been proposed.