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[IEEE 2019 IEEE 4th International Future Energy Electronics Conference (IFEEC) - Singapore, Singapore (2019.11.25-2019.11.28)] 2019 IEEE 4th International Future Energy Electronics Conference (IFEEC) - Design and Implementation of Active Bleeder for TRIAC Dimmable LED Driver
摘要： In this paper, implementation of active bleeder for TRIAC dimmable LED driver is presented. The insufficient holding current problem occurs when LED driver is connected to TRIAC dimmer, causing TRIAC dimmer misfire and LED flicker. Therefore, a bleeder circuit is parallel-connected to provide TRIAC enough holding current. In the bleeder, the resistor is usually used to control the amount of current through the bleeder, and cause high power loss on the resistor. A bleeder circuit with an inductor, a capacitor and switches is used to provide TRIAC dimmer extra current to reduce the power dissipation by using a resistor. Finally, the hardware type of the bleeder circuit with input voltage of 90~135V is implemented, and able to applied on the TRIAC dimmable 7.2W LED driver. The bleeder can provide enough holding current, widening the conducting angle of TRIAC dimmer with no flicker and misfire occur.
关键词： LED driver,Flyback,bleeder circuit,TRIAC dimmer
更新于2025-09-19 17:13:59
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[IEEE 2018 IEEE International Conference on Information and Automation for Sustainability (ICIAfS) - Colombo, Sri Lanka (2018.12.21-2018.12.22)] 2018 IEEE International Conference on Information and Automation for Sustainability (ICIAfS) - A Robust Driver for RGB LEDs
摘要： For running applications based on RGB LEDs, a dc-dc buck converter associated with linear control is mostly used to manage the constant current of LED. In this paper, the driver to run RGB LEDs gives 180 mA constant outputs current and a PWM control scheme has been utilized, which determines the desired brightness levels with a dimming frequency of 10000 Hz. Previously there used to be a dimming option for dimming each array of LED color, through the dimming controller circuit; approximately 93%, 90% 93% efficiencies, were found for the green, red and blue color LEDs’ arrays respectively. A digital controller based on PID controller has been created, with the option of using digital dimming by using current mirroring with a transistor (for the intent of switching system). The proposed LED driver system contains the constant source of current to maintain the small drive voltage across the LEDs which lead in the reduction of power dissipation in the transistor, i.e., NPN, which eventually increases the efficiency of the whole system in return. With the application of the 12V supply voltage, the efficiencies of RGB LEDs are found up to 98.94%, 99.37%, and 99.37% correspondingly.
关键词： RGB LED Driver,DC-DC Converter,Digital Controller
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Conference on Mechatronics and Automation (ICMA) - Tianjin, China (2019.8.4-2019.8.7)] 2019 IEEE International Conference on Mechatronics and Automation (ICMA) - The Application Research of Soft Starting Technology in Marine LED Lighting System
摘要： In this paper, for the problem that the LED lighting equipment affects the normal operation of the power supply equipment in ship due to the excessive starting current at the power-on moment, a soft-start technology scheme for LED power supply is proposed. The scheme is analyzed and compared in the marine LED lighting system. The application of technology solve the adverse effects of the LED lighting equipment on the power distribution system during the startup process, and conclude that the soft start technology has an improved effect on LED lighting system.
关键词： Inrush current,LED driver,instantaneous trip,zero-crossing trigger,soft start
更新于2025-09-16 10:30:52
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A Multi-Phase Switched-Capacitor Converter for Fully Integrated AMLED Micro Display System
摘要： A fully-integrated switched-capacitor (SC) DC-DC converter is designed for powering up an active-matrix light-emitting diode (AMLED) micro-display system. Stacking-transistor technique with three voltage conversion ratios is utilized to handle the lithium-ion battery range of 2.6 V to 4.2 V and to reduce the switching loss. A 101-phase interleaving scheme is adopted such that (1) output voltage ripple ΔVO is significantly reduced; (2) no external output capacitor is needed; and (3) SC power-cells are physically cascaded to encircle the LED array and drivers to reduce conduction loss. Two test chips were designed in 0.18 μm 1P6M CMOS technology. The first chip is a test chip consisted of the SC converter only. The output voltage is 4.2V and the measured maximum ΔVO is 52 mV. The measured power density is 74.4 mW/mm2, peak efficiency is 81%, and maximum output power is 258 mW. The second chip is a system chip integrating the SC converter with the AMLED array and drivers using flip-chip packaging. The converter delivers a maximum power of 216 mW with a 78% peak efficiency in the SC mode and a 91% peak efficiency in the linear regulator mode.
关键词： AMLED,micro-displays,voltage regulator,LED driver,active matrix,SC converter,DC-DC converter,μ-displays,multiphase interleaving,battery-connected,switched-capacitor converter
更新于2025-09-16 10:30:52
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[IEEE IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society - Lisbon, Portugal (2019.10.14-2019.10.17)] IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society - Comparative Analysis between the Half Brige Resonant LLC and Buck Converters as the Power Stage of an LED Driver
摘要： This paper presents a comparative analysis between the Buck Converter and the LLC Resonant Converter working as LED drivers. These converters are placed after a Power-Factor-Correction (PFC) stage, in order to work as the Power-Control (PC) stage of two-stage LED drivers. The main objective of this study is to evaluate these converters in terms of efficiency, volume and cost using different switching frequencies supplying an LED load of 180W. The methodology used theoretical losses calculation and industrial feedback in order to compare the proposed converters. The Buck converter was evaluated under 33kHz, 60kHz and 100kHz, and the LLC Resonant converter was evaluated under 100kHz, 140kHz, 180kHz, and 220kHz. Both converters were dimmed from 100% to 20%.
关键词： LED Driver,Resonant Converter,LLC
更新于2025-09-16 10:30:52
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[IEEE 2019 International Symposium on Electromagnetic Compatibility - EMC EUROPE - Barcelona, Spain (2019.9.2-2019.9.6)] 2019 International Symposium on Electromagnetic Compatibility - EMC EUROPE - Modeling of conducted EMI noise in an Automotive LED Driver Module with DC/DC Converters
摘要： When transferring power from source to LED matrix, the electromagnetic interference (EMI) noise is generated. Moreover, the dc-dc converter with switching operation contains a wide range of harmonics. Therefore, it is important to predict the EMI noise in an automotive LED driver module. In this study, we firstly simulated conducted noise from the automotive LED driver module. The ringing noise of the dc-dc converter has been analyzed and simulated by using a circuit simulation. In order to simulate conducted EMI noise, parasitic components of power transfer line trace, passive components such as capacitor and inductor, active components such as diode and switching device, cable between PCB board and LED matrix, and connector in the LED driver module are considered. The simulation and measurement setup for conducted emissions are directed by CISPR 25 standard.
关键词： LED Driver,LDM,EMI,Conducted Emission,dc-dc Converter
更新于2025-09-16 10:30:52
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Inductive decoupling-based multi-channel LED driver without electrolytic capacitors
摘要： Light-emitting diode (LED) drivers in outdoor street lighting applications suffer from short-lifetime because of the prolonged exposure to harsh environmental conditions such as high operating temperature, high humidity etc. A long-lifetime multi-channel LED driver consisting of front-end AC–DC boost power factor correction (PFC) converter followed by a DC–DC power conversion stage with dimming capability for LED-based street light is proposed in this study. This LED driver uses an inductor-based auxiliary decoupling circuit at the output of the AC–DC converter for mitigating the double-line-frequency power ripple present in the DC bus. The inductive ripple power storage circuit has a longer lifetime than a conventional capacitive storage circuit which is usually implemented by electrolytic capacitors. A digital control method is proposed to realise the decoupling control along with PFC control by a single non-digital signal processor micro-controller ST STM32F103RBT6. The proposed LED driver for street lighting is analysed and validated on a 150?W test setup. A comparison of active decoupling AC–DC converters for eliminating secondary-harmonic power ripple is displayed.
关键词： inductive decoupling,electrolytic capacitors,street lighting,LED driver,power factor correction
更新于2025-09-16 10:30:52
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Adaptive Peak Average Current Control LED Driver for Automotive Lighting
摘要： This letter describes a new average current control dc–dc LED driver suitable for automotive pixel (matrix) lighting. Current is sensed only on an integrated high side switch and peak current is controlled to achieve required average output current independent of tolerances of components and parameters other than the current sensing itself. Fast reaction to output voltage changes required by the pixel light operation is achieved by using a constant ripple control with an off time inversely proportional to the output voltage.
关键词： Average current control,dc–dc LED driver,LED lighting,matrix light,pixel light
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE Energy Conversion Congress and Exposition (ECCE) - Baltimore, MD, USA (2019.9.29-2019.10.3)] 2019 IEEE Energy Conversion Congress and Exposition (ECCE) - A Multiplexing Off-Line LED Driver Achieves High Power Factor and Flicker-Free Operation
摘要： Although a single-stage off-line LED driver can achieve low cost and high efficiency, the notorious double-line-frequency flicker issue with a single-stage LED driver limits its usage in high-quality lighting applications. To solve lighting flicker, multiplexing operation is proposed in this paper. One switching cycle is further divided into two portions, namely phase one and phase two, which produces a main output voltage and an opposite ripple voltage. The main and the opposite ripple voltage are connected in series to form the LED voltage, which is a DC because of ripple cancellation. Therefore, a DC LED current can be produced and achieves flicker-free LED driving performance. A 7.5W experimental prototype had been built and tested to verify the design concept.
关键词： power factor correction,ripple cancellation,multiplexing operation,flicker-free,LED driver
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE Energy Conversion Congress and Exposition (ECCE) - Baltimore, MD, USA (2019.9.29-2019.10.3)] 2019 IEEE Energy Conversion Congress and Exposition (ECCE) - Resonant Switched-capacitor Auxiliary Circuit for Active Power Decoupling in Electrolytic Capacitor-less AC/DC LED Drivers
摘要： This paper introduces an auxiliary circuit that is used to buffer double-line-frequency ripple power and form electrolytic capacitor-less single-phase AC/DC LED drivers. The proposed auxiliary circuit is implemented by a resonant switched capacitor circuit behaving as a gyrator circuit, namely a voltage-dependent current source. The output current of the auxiliary circuit is regulated with constant on-time and hysteresis control schemes. Comparing with other alternative methods, the proposed auxiliary circuit has less power loss due to its zero-current switching (ZCS) operation, and includes smaller passive components because of its higher operating frequency (about 3 MHz). An LED driver prototype with the proposed auxiliary circuit is built, and the experimental results are given to verify the proposed topology and the parameter design.
关键词： resonant switched-capacitor circuit,ac–dc power conversion,electrolytic capacitor less,LED driver,ripple power decoupling
更新于2025-09-12 10:27:22