• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.10
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• pp.9-15
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• 2014

Standby power, so called an electric vampire, is a power which is consumed by appliances and office equipments connected to power sources while the devices are not performing. Sensor luminaires consist of PIR(Pyroelectric Infrared Ray) sensor, illuminance sensor(CdS), and light source. The sensor luminaires are one of the devices that consume a huge amount of standby power; it stands by for an average sum of 23 hours a day and performs only when moving subjects are detected under it, which barely takes up an hour per day. The purpose of this study is to provide basic materials to the selection of standby power items and to enable to explore a way to decrease the standby power by measuring and analyzing the power consumption of sensor luminaires. According to the results, the average standby power of LED sensor luminaires is 1.1W which is significantly higher than other products, and decrease in the standby power consumption of SMPS is important through the measurement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.11
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• pp.938-941
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• 2012

LED is divided to multichannel in order not to exceed a certain voltage in aspects of electric standard. However, it's not possible to know in accordance with what channel SMPS controls the constant voltage and current. In order to solve this problem, it needs to detect the maximum LED String voltage which is applied to LED control circuit, and it is possible to minimize the voltage drop when a difference of LED string voltage occurs by each channel if LED is controlled by the maximum LED string voltage detected. In addition, it is also possible to maximize the efficiency of LED if change LED voltage by detecting the maximum voltage. Feasibility of this claim was verified through implementation of the circuit.

• 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.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.737-743
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• 2014

This paper dealt with a retrofit high power LED searchlight to replace conventional 1kW halogen searchlights. The design specification meets KDS 6230-1046-1 and KS V 8469. An optical lens with the beam angle of $6^{\circ}$ was used to meet the luminous intensity of 800,000cd at $0^{\circ}$ in horizontal line. Heat dissipation of the LED searchlight adopted a free air cooling type which does not use a fan or a heat-pipe. From the test results, power consumption of the prototype LED searchlight was 148W which was saved by 85% comparing a halogen searchlight of 1kW. Luminous intensity was 945,000cd at $0^{\circ}$ in horizontal line, satisfying KS V 8469. Luminous efficacy was improved by 4.7 times higher than that of the halogen searchlights. Beam angle, color temperature, and color rendering index(CRI) was $5.4^{\circ}$, 5,500K, and 70, respectively. Surface temperature of the LED searchlight was below $60^{\circ}C$ and surrounding temperature of the SMPS installed inside was below $50^{\circ}C$ which were satisfied with the IEC 60092-306.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.107-112
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• 2008

Solar Cell을 이용한 15W 휴대용 조명 시스템을 개발하기 위하여, 휴대용에 적합한 solar cell을 선정하고, Solar Cell을 충전하기 위한 태양광 궤적 변화에 대한 Simulation을 행하였으며, 1W 백색 LED 6EA를 사용하여 휴대용 LED Lighting System을 개발하였다. LED Lighting System은 solar cell 충방전 회로 및 LED SMPS 구동회로 설계, 글레어차단을 위한 리플렉터 설계, 방열 설계 및 기구 구조 설계를 통하여 개발되었으며, 직접 시제품을 제작하고 그 성능을 측정하였다.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.105-109
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• 2020

This study was conducted to the improvement of solar light-based artificial light supply system and effect of lettuce cultivation. The artificial light supply system was consisted of units such as light source, power, system measurement and controller. The light source supply was composed of a solar transmitter and an LED lamp. The power supply consisted of an leakage breaker, SMPS, LED controller and relay. The solar transmitter was made of a quartz optical fiber with optimal light transmission. Artificial light used white lamp among LEDs. System measurement and control consisted of touch screen, Zigbee communication module and light quantity sensor. The results of test confirmed that the LED light is automatically activated when the intensity measured by the light intensity sensor is 200 μmolm^-2s^-1 or less. Moreover, the leaf length, root length, chlorophyll content and root fresh weight of optical fiber treatment was hight than LED lamp treatment. Therefore, it can be inferred that the energy-saving solar light collector device can be effective in the indoor lettuce production. However, the use of LED lamp is also recommended to assure the availability of sufficient sunlight in cloudy and rainy days.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.3
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• pp.230-236
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• 2016

This research attempted simplifications to the LED street light for price competitiveness. The street light was simplified by replacing the SMPS with an IC driver on the PCB using an AC-type LED. The optical element that shape of a line-shaped lens covered LED crowded. Thus, this study aims to improve LED efficiency by using the minimum optical system. In order to satisfy the M3 regulation of street lighting at grade, the lens was divided into two parts depending on the forward direction of the light. Further, the changes in the number of LEDs located on part 1 and part 2 of the lens were analyzed. Through simulation, we determined the proper light distribution that meets M3 regulation of street lighting.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.197-200
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• 2009

주광의 색온도와 일치하는 실내 전반 조명용 60W급 LED 조명제품 개발하기 위하여 실내 주광에 적합한 LED를 선정하고, 색온도, 광색제어를 위한 구동회로 및 제어회로를 설계 제작 하였다. 그리고 1W급 Cool White, Warm White Package LED 총 168 EA를 적용하여 주광의 색온도와 일치하는 실내전반 조명용 LED 조명 System 을 개발하였다. 주광의 색온도와 일치하는 실내 전반용 LED 조명제품은 60W급 LED SMPS 구동회로 및 광색/색온도 제어회로 설계, 면발광을 위한 방열 설계 및 기구 구조 설계를 통하여 개발되었으며, 직접 시제품을 제작하고 그 성능을 측정하였다. 그 결과 회로 효율은 85% 이상, 색온도는 $3,000{\sim}7,000K$에서 실시간으로 제어 가능 하고, 원하는 색온도을 구현 할 수 있도록 하였으며, 발산각 또한 최대 광도의 1/2 기준으로 $100^{\circ}$ 이상을 만족시켰다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.191-198
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• 2015

The purpose of this study is to develope a current variation control system appropriate to the various LED(Light Emitting Diode) lamps using current control system equipped with microcontroller based voltage regulator of power driving circuit. For this, we will suggest a stable control system of current variation to enable a stable power-supply and current-control, consisting of circuit to minimize the affects on the LED forward voltage using variable resistance and compensating resistance. The method of constant current circuit and energy savings using microcontroller based voltage regulator suggested in this study can be applied to various a big capacity LED lamp to minimize the unnecessay heat generation and to control resistace delicately. Ultimately, we expect the results of this study will upgrade the reliability of LED lamp by supplying the current stably.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.151-155
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• 2016

In this paper, we present the LED dimming control system by using ADPCM (Adaptive Differential Pulse Code Modulation). This ADPCM apparatus accurately controls the LED current with high resolution reducing the RFI (radio frequency interference) due to the spreading out of the harmonics of current of pulses. Additionally, this makes it easier to increase the accuracy of control operation. This study introduces to make a digitally controlled circuit for controlling LED with high-energy efficient by adopting pulse current to LED. The LED current drive system we designed are two systems, the digitally-controlled unit and analog switching mode power supply unit, can be developed separately. The simulation shows the sigma delta modulation of digital to analog converter's output when the input level is 0.7. From this simulation, the output is approached to accurately 0.15% to target value with 510 pulses.