• Title/Summary/Keyword: LED Driver

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Overview of Classification and Characteristics of Recent LED drive IC (최근의 LED 구동 IC의 종류 및 특성)

  • Han, Soo-Bin;Park, Suck-In;Song, Eu-Gine;Jeoung, Hak-Guen;Jung, Bong-Man;Kim, Gue-Duk
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2008.10a
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    • pp.105-107
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    • 2008
  • LED driver is important for reliable LED lighting system. A variety of ICs for LED driver are supplied by almost all semiconductor company The types and performances are too diverse to collect proper IC and use efficiently. This paper classifies driver IC according to the usage for each application area and the circuit topology. Finally, the paper shows several representative ICs for main applications with notice of important performance.

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Third Harmonic Injection Circuit to Eliminate Electrolytic Capacitors in Light-Emitting Diode Drivers

  • Yoo, Jin-Wan;Jung, Kwang-Hyun;Jeon, In-Ung;Park, Chong-Yeun
    • Journal of Electrical Engineering and Technology
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    • v.7 no.3
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    • pp.358-365
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    • 2012
  • A new third harmonic injection circuit for light-emitting diode (LED) drivers is proposed to eliminate electrolytic capacitors and thereby extend the lifetime of LED drivers. When a third harmonic current is injected to the input current of the LED driver, the required capacitance of the driver can be reduced. The proposed circuit can control an injection ratio and has simple circuitry. The synchronous third harmonic is generated by a phase locked loop (PLL), a 1/3 counter, and op-amps and applied to a power factor correction circuit. Thus, the storage capacitor can install film capacitors instead of the electrolytic capacitor. The value of storage capacitance can be reduced to 78% compared to an input power factor of 100%. The proposed circuit is applied to the 80W prototype LED driver to experimentally verify the performances.

Study of Single Stage PFC CCM Flyback Converter (연속모드 단일단 PFC 플라이백 컨버터의 연구)

  • La, Jae Du
    • Journal of IKEEE
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    • v.23 no.2
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    • pp.407-412
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    • 2019
  • Many industrial regions has used and extended the application of LED driver because of many advantage. Specially, due to the simplicity, miniaturization and power density, the flyback converter is selected by a lot of power engineer. Also, the electrolytic capacitor in this converter is used for the constant DC voltage of the converter because of the sufficient capacitance and the economic price. However, because of the characteristics of the electrolytic capacitor and ripple currents on the converter. the expected lifetime of the LED driver is more and more shorted. In this paper, a single-stage CCM PFC flyback converter with the film capacitor is suggested to extended the lifetime of the LED driver. In addition, the proposed converter with the LC filter is decreased the ripple current of the converter output.

Implementation of Visible Light Communication System Modulated by a Switching Driver Circuit of Lighting LED (조명용 LED의 스위칭 구동 회로로 변조되는 가시광 통신 시스템의 구현)

  • Cho, Sang-Ho;Han, Sang-Kyoo;Roh, Chung-Wook;Hong, Sung-Soo;Jang, Byung-Jun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.8
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    • pp.905-910
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    • 2010
  • In this paper, visible light communication(VLC) system modulated by a switching driver circuit of lighting light emitting diode(LED), not only for illumination but also for optical wireless communication, is implemented. Presented system could overcome the drawbacks of prior linear modulation technique such as low efficiency, heat generation, and limits to realization of high power lighting LED. Experimental results from the realized digital audio system are presented to confirm the superiority of the proposed circuit. Our prototype achieves a transmission data rate of 10 Mbps with a radius of 1.5 meters using 20 W output power, and the signals were detected successfully.

Analysis and Experiment of Peak Current Controlled Buck LED Driver

  • Kim, Marn-Go;Jung, Young-Seok
    • Proceedings of the KIPE Conference
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    • 2011.07a
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    • pp.68-69
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    • 2011
  • Realistic amounts of time delay are found to have significant effects on the average output LED current and on the critical inductor value at the boundary between the two conduction modes. Especially, the time delay can provide an accurate LED current for the peak current controlled (PCC) buck converter with a wide input voltage. Experimental results are presented for the PCC buck LED driver with constant-frequency controller.

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A Fast-Switching Current-Pulse Driver for LED Backlight (LED 백라이트를 위한 고속 스위칭 전류-펄스 드라이버)

  • Yang, Byung-Do;Lee, Yong-Kyu
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.7
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    • pp.39-46
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    • 2009
  • A fast-switching current-pulse driver for light emitting diode (LED) backlight is proposed. It uses a regulated drain current mirror (RD-CM) [1] and a high-voltage NMOS transistor (HV-NMOS). It achieves the fast-response current-pulse switching by using a dynamic gain-boosting amplifier (DGB-AMP). The DGB-AMP does not discharge the large HV-NMOS gate capacitance of the RD-CM when the output current switch turns off. Therefore, it does not need to charge the HV-NMOS gate capacitance when the switch turns on. The proposed current-pulse driver achieves the fast current switching by removing the repetitive gate discharging and charging. Simulation results were verified with measurements performed on a fabricated chip using a 5V/40V 0.5um BCD process. It reduces the switching delay to 360ns from 700ns of the conventional current-pulse driver.

Design of a New Thermal shut Down Protection Circuit for LED Driver IC Applications (LED 구동회로를 위한 새로운 과열방지회로 설계)

  • Heo, Yun-Seok;Jung, Jin-Woo;Park, Won-Kyoung;Song, Han-Jung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.12
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    • pp.5832-5837
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    • 2011
  • In this paper, we designed a thermal shutdown block for LED applications using a 1 ${\mu}m$ CMOS process. The proposed thermal shutdown protection circuit has been designed with a shut-off temperature of $120^{\circ}C$ and a restart temperature of $90^{\circ}C$ which are suitable conditions for LED driver IC. Also, we got SPICE simulation results of the circuit about process variation of the semiconductor fabrication. From simulation data, process variation rate of the proposed circuit are within 7 % which are good results compared with conventional BJT current mirror type circuit. Finally, we confirmed that the thermal shutdown circuit has good thermal protection function within a LED driver IC.

Analysis of Buck-Boost Converter for LED Drive (LED 구동을 위한 승강압 DC/DC 컨버터에 관한 연구)

  • Joe, Wi-Keun;Kim, Yong;Lee, Dong-Hyun;Cho, Kyu-Man;Lee, Eun-Young
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.967_968
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    • 2009
  • For lighting application, high-power LED nowadays is driven at 350mA and a sensing resistor is used to provide feedback for LED-current regulation. This method adds an IR drop at the output branch, and limits power efficiency as LED current is large and keeps increasing. In this paper, a power efficient LED-current sensing circuit is proposed. The circuit does not use any sensing resistor but extracts LED-current information from the output capacitor of the driver. Controlling the brightness of LEDs requires a driver that provides a constant, regulated current. In one case, the converter may need to step down the input voltage, and, in another, it may need to boost up the output voltage. These situations often arise in applications with wide-ranging ""dirty"" input power sources, such as automotive systems. And, the driver topology must be able to generate a large enough output voltage to forward bias the LEDs. So, to provide this requirements, 13W prototype Buck-Boost Converter is used.

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A Comparison of Constant Current and Constant Voltage Control in LED Driver (LED driver에서의 정전류 및 정전압 제어의 비교 연구)

  • Han, Soo-Bin;Park, Suck-In;Jung, Hak-Kun;Song, Eu-Gine;Jung, Bong-Man
    • Proceedings of the KIPE Conference
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    • 2010.07a
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    • pp.83-84
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    • 2010
  • This paper reviews the performance difference between constant voltage control and constant current control in LED driver. Simulations of both control methods are performed for performance comparison especially with temperature variation. The results show that constant current control method is inherently better than constant voltage control for LED drive.

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Independently-Controlled Dual-Channel LED Driver using LLC Resonant Converter (LLC 공진형 컨버터를 이용한 독립제어 가능한 2 채널 LED 구동회로)

  • Hwang, Min-Ha;Choi, Yoon;Han, Sang-Kyoo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.2
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    • pp.142-149
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    • 2012
  • The independently regulated dual-output LLC resonant converter using only one power stage and one control IC is proposed in this paper. The conventional dual-output LLC resonant converter requires the extra non-isolated DC/DC converter to obtain the tightly regulated slave output voltage, which results in the low power conversion efficiency and high production costs. On the other hand, since the proposed converter controls the master and slave output voltages by pulse width modulation(PWM) and pulse frequency modulation(PFM), it can achieve tightly regulated dual output voltages without the additional non-isolated DC/DC converter. Therefore, it features a high efficiency and low cost. To confirm the validity of the proposed converter, theoretical analysis and experimental results from a 40W LED driver prototype are presented.