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

• Proceedings of the KIPE Conference
• /
• 2009.11a
• /
• pp.280-282
• /
• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.6
• /
• pp.73-80
• /
• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.4
• /
• pp.16-23
• /
• 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.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.11 no.5
• /
• pp.586-592
• /
• 2018

In this paper, HIC with various functions is proposed for the design 140W LED power control circuit. The proposed HIC integrates constant voltage/constant current circuit, short circuit protection circuit, internal constant voltage circuit, and dimmer circuit, thereby reducing the horizontal length of the PCB by 16% comparing with the conventional system. Through various experiments, we verified the performance of each block implemented inside of HIC with numerical results. (Constant voltage variation ratio: 2.9%, dimmer circuit duty variation within 5%, stable short protection at 720 mA) Since the PCB area can be significantly reduced by applying the proposed HIC. It is possible to reduce the PCB manufacturing time which takes up most of the manufacturing time, however, It is expected that the faulted power module can be replaced without replacing the whole PCB, so that maintenance / repair can be made easier.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.2
• /
• pp.84-94
• /
• 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
• /
• v.18 no.2
• /
• pp.640-650
• /
• 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.

• Proceedings of the KIPE Conference
• /
• 2018.07a
• /
• pp.210-212
• /
• 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.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2011.11a
• /
• pp.360-363
• /
• 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.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.4
• /
• pp.47-53
• /
• 2013

Nowadays, Advanced country have devised a plan energy-saving through lighting effectiveness and increasing performance of lighting control system. If it uses the LED as a source of light then conserve electricity by 50%. This paper implement LEMS(Lighting Energy Management System) that applicate and Smart Dimmer and Smart Switch that control the digital LED light, support wired-wireless communication using USN(Ubiquitous Sensor Network). This system of validity and reliability control special purpose lamp including indoor and outdoor lighting and landscape lighting effectively. It minimize the use of indoor and outdoor lighting energy by USN remote integral control function of Digital System Lighting of LED and increase effectiveness of energy and is a collaborative system that can feedback the use of electricity by measurement itself through Web and Switch.