• 전력전자학회논문지
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• 제19권4호
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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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
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• pp.280-282
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• 2009

본 논문은 AC LED에 적합한 Digital Dimmer에 관한 연구이다. PWM 방식을 이용하여 조광 범위를 0~100% 되게 하였을 뿐만 아니라 AC LED를 상용 전원에 연결하여 사용 시 발생하는 플리커 문제를 플리커 개선 알고리즘을 추가하여 해결하였다.

• 조명전기설비학회논문지
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• 제26권6호
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• pp.73-80
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• 2012

Generally, the phase control dimmer has been widely used due to simple interface and easy handling. However, the electrical characteristics are not good for the method in which the phase control dimmer cuts the input voltage. This paper has researched about DALI(Digital Addressable Lighting Interface) controller, that is the digital lighting control method, and implemented DALI protocol satisfied with the IEC-62386 standard. In addition, the existing phase control dimmer was used as the controller of DALI and not only individual control but also group control was possible. And the performance was proved to be good by applying our theory to 30[W] LED lighting control system.

• 조명전기설비학회논문지
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• 제25권4호
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• pp.16-23
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• 2011

Since the first lighting light source was invented, lighting has turned into superior-quality lighting considering the amenity of occupants, and the characteristics of a light source has developed rapidly. So this research confirmed the lighting performance of a dimmer control system and an ON-OFF control system via the existing light source, and analyzed the basic lighting environment of Permanent Supplementary Artificial Lighting of Interiors(PSALI) through the physical comparison and evaluation of a LED lamp substituted for a fluorescent lamp used in a dimmer control system, showing that the lighting physical quantity characteristics of an ON-OFF control system and a dimmer control system are similar to each other and that they are effective in terms of energy saving. Besides, it was shown that introducing a LED light source to a dimmer control system improves lighting environments and largely reduces energy consumption.

• 한국정보전자통신기술학회논문지
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• 제11권5호
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• pp.586-592
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• 2018

본 논문은 140W 급 저면적 LED 전원 제어 회로 설계를 위해 다양한 기능이 집적된 HIC를 제안한다. 제안된 HIC는 정전압/정전류 구동회로, 단락 보호회로, 내부 정전압회로, dimmer 회로를 하나로 집적해, 제작 시 기존 시스템 대비 PCB 가로 길이를 16% 절감하는 효과를 보였다. 다양한 실험을 통해 HIC 내부에 설계된 각 블록의 성능을 검증했고, (정전압 구동회로 변동률 2.9%, dimmer 회로 오차 5%이내, 720 mA에서 안정적인 short protection) 제안된 HIC를 적용해 시스템에서 필요로 하는 전력 대비 PCB 면적을 상당히 줄일 수 있기 때문에, 제작 시간의 대부분을 차지하는 PCB 제조시간을 단출할 수 있는 효과와 전원 제어 회로에서 발생하는 불량에 대해 기존과 같이 PCB 전체를 교체하지 않고 HIC만 교체할 수 있도록 하여 유지/보수를 쉽게 할 수 있는 효과를 기대한다.

• 조명전기설비학회논문지
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• 제27권2호
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• pp.84-94
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• 2013

In case when the existing TRIAC phase controlled dimmer is drove for the LED lighting equipments, there are many problems such as the LED flicker in low phase-angles, the acoustic noise and elements damage by increase of the peak voltage in the input filter capacitor, mulfunction by insufficiency of the TRIAC holding current, and the abnormal oscillation by LC resonant. In this paper, we proposes the single-stage quasi-resonant PSR(Primary Side Regulation) PWM converter, and the design, the simulation and experiment are performed. As a result, it could confirm that the proposed PWM converter is the lighting equipments for LED drive which can alternate the existing 60W class incandescent bulbs and it has the high drive performance of the efficiency 80% and over, the power factor 0.95 and over under the normal voltage 220V. Finally, total harmonic distortion(THD) is gratified with a standard[1] of the lighting equipments and the durability is evaluated as the high reliablilty of 150,000 hours and over.

• Journal of Power Electronics
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• 제18권2호
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• pp.640-650
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• 2018

A TRIAC dimmable LED driver with a wide tuning range and a two-stage uniform dimming scheme is proposed in this paper. To solve the restricted dimming range problem caused by the limited conduction ratio of TRIAC dimmers, a conduction ratio compensation technique is introduced, which can increase the output current up to the rated output current when the TRIAC dimmer turns to the maximum conduction ratio. For further optimization, a two-stage uniform dimming diagram with a rapid dimming curve and a slow dimming curve is designed to make the LED driver regulated visually uniform in the whole adjustable range of the TRIAC dimmer. The proposed control chip is fabricated in a TSMC $0.35{\mu}m$ 5V/650V CMOS/LDMOS process, and verified on a 21V/500mA circuit prototype. The test results show that, in the 90V/60Hz~132V/60Hz ac input range, the voltage linear regulation is 2.6%, the power factor is 99.5% and the efficiency is 83%. Moreover, in the dimming mode, the dimming rate is less than 1% when the maximum dimming current is 516mA and the minimum dimming current is only about 5mA.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.210-212
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• 2018

A new switching mode has been proposed to obtain high power factor and low THD in single stage AC-DC converter. The conventional voltage mode control in critical conduction mode distorts input current shape with poor THD in flyback topology. Once TRIAC dimmer is connected, visible flicker in the LED lamp is easily detected due to a lack of TRAIC holding current near the input voltage zero cross. The newly proposed method can shape the input current by providing a desired reference voltage so that low THD is obtained by ideal sinusoidal input current in case of no dimmer connection and flat input current performs good TRIAC dimmer compatibility in phase-cut dimming condition. To confirm the validity of the proposed method, theoretical analysis and experimental result from 8W dimmable LED lighting system are presented.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2011년도 추계학술대회
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• pp.360-363
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• 2011

카메라 촬영시 LED방송조명 등기구를 조도 디밍하는 경우에 카메라 셔터속도가 빨라 질 경우, 카메라가 신호를 감지하며 카메라 영상에 플리커 현상이 생기게 된다. 그 현상을 없어지게 하기 위하여 LED 디머의 PWM속도를 충분히 높여주어서 카메라 셔터속도가 빨라져도 어느 정도 범위에서 감지하지 못하도록 하였다.

• 한국인터넷방송통신학회논문지
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• 제13권4호
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• pp.47-53
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• 2013

현재 조명의 효율화 및 제어시스템 개선을 통해 에너지절감을 추진한다는 계획을 수립하고 조명자체의 고효율화와 조명제어시스템의 성능 향상을 통해 에너지 절감을 추구하는 노력이 한층 강화될 것으로 보인다. 조명시스템에서 LED를 광원으로 사용할 경우 기존 대비 약 50% 이상의 고효율 조명 구현이 가능하다. 본 논문은 LED 디지털 조명을 제어하기 위해 USN을 활용해 유무선 통신을 지원하는 스마트 디머 와 스마트 스위치를 적용한 LEMS(Lighting Energy Management System)를 개발했다. 이 시스템은 유/무선 네트워킹 장치 및 시스템 S/W를 통해 실내외 조명 및 경관 조명을 포함한 특수 목적 등을 효율적이고 신뢰성 있게 제어 한다. 본 시스템은 LED조명의 Digital System Lighting을 통한 USN 원격통합제어기능 및 에너지 효율성을 증대하여 실내외의 조명에너지 사용량을 최소화 하고, 웹 또는 스위치를 통해 조명 에너지 사용량을 사용자가 측정하여 조명 사용량을 피드백 할 수 있게 하는 참여형 시스템이다.