Multiple String LED Driver With Flexible and High-Performance PWM Dimming Control

Tahan, Mohammad; Hu, Tingshu

doi:10.1109/tpel.2017.2655884

Cited by 40 publications

(10 citation statements)

References 18 publications

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“…LED illuminance is related to the forward current. Due to the non-linear relationship between its voltage and current, a small voltage variation may cause dramatic change of the forward current, thereby leading to a change in LED illuminance [18]. Therefore, to better control LED illuminance and fully realize its energy-saving, it is necessary to control a constant current driver using the corresponding dimming method to drive the LED [3], [6], [19], [20].…”

Section: Introductionmentioning

confidence: 99%

Full-Range LED Dimming Driver With Ultrahigh Frequency PWM Shunt Dimming Control

Wang

Hou

et al. 2020

IEEE Access

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This paper explores an ultrahigh dimming frequency Light-Emitting Diode (LED) pulse width modulation (PWM) shunt dimming driver that achieves the full-range dimming. Firstly, the dimming frequency is improved to 20kHz for avoiding flicker and audible noise in high dimming requirements application, such as film and television shooting. Secondly, this paper reduces dimming ratio loss at ultrahigh dimming frequency by removing output capacitor. As a result, given 1% dimming ratio is achieved. Subsequently, for improving LED current square waveform at ultrahigh dimming frequency, it is necessary to suppress parasitic oscillation at the falling edge in LED current. Therefore, this paper proposes a method which connects a fast recovery diode with LED in series. In such way, parasitic oscillation at the falling edge in LED current is suppressed. Meanwhile, linear dimming performance is improved such as dimming linearity of low ratio and circuit reliability. Finally, a 120 W experimental prototype is built to drive an LED array comprising 9 LEDs in parallel and 15 LEDs in series. The switching frequency and dimming frequency of prototype are 500 kHz and 20 kHz, respectively. In addition, it achieves full dimming range of 1% to 99.99%. INDEX TERMS Output capacitance, PWM shunt dimming, ultrahigh dimming frequency, full-range dimming, parasitic parameters.

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Section: Introductionmentioning

confidence: 99%

Full-Range LED Dimming Driver With Ultrahigh Frequency PWM Shunt Dimming Control

Wang

Hou

et al. 2020

IEEE Access

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“…The AC input current is highly distorted from its sinusoidal shape and gets worse with an increasing level of phase angle or dimming [14, 15, 18]. The AC mains current is highly pulsating and barely meets the harmonic regulations according to the IEC 61000‐3‐2 for power >25 W. Few more dimming operations are reported in [19–21]. A non‐isolated SEPIC‐based LED power supply operating in critical conduction mode (CrCM) is reported in the literature [22].…”

Section: Introductionmentioning

confidence: 99%

Novel distortionless dimming in high power LED lighting using isolated SEPIC converter

Pal

Singh

Shrivastava

2020

IET power electron.

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“…Therefore, the LED current experiences high peaks, reaching twice the value of the nominal current. Using this technique a bulky output capacitor is needed, which reaches 2000 μF [33]. Other techniques can be found in the literature, as for example the TRIAC-Dimmable LED driver [34,35].…”

Section: Introductionmentioning

confidence: 99%

Analysis, design, and experimentation of the active hybrid‐series‐parallel PWM dimming scheme for high‐efficient off‐line LED drivers

Abdelmessih

Alonso

Costa

2019

IET Power Electronics

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This study presents a high power factor (PF) light-emitting diode (LED) driver featuring a pulse width modulation (PWM) dimming technique. The integrated buck-flyback-buck converter (IBFBC) is built by connecting a buck converter to the integrated buck-flyback converter's output. The IBFBC ensures a constant output current regulation as well as high PF at all dimming ratios. The purpose of the output buck converter is to clear up the discontinuous power operation created by the PWM dimming. This occurs when the buck converter absorbs the output power, at LED switched-off, and sends it back to the input. Thus, the IBFBC maintains the operational enhancement shown by the hybrid-series-parallel (HSP)-PWM technique, ensuring greater efficiency. This study explains the operating principles of the IBFBC using circuit diagrams as well as an average model for the entire converter. Moreover, the study presents a mathematical analysis of the IBFBC power flow. It provides guidance on how to select the optimum value for the output buck inductance. A 230 V, 50 Hz input, 160 V output, 100 W AC-DC converter operating at 100 kHz has been implemented. The prototype is fully tested to demonstrate the active HSP-PWM technique. An efficiency ranging 50-86% corresponding to the dimming ratio of 5-100% is reached, where 5% dimming refers to an output power of 4 W.

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Multiple String LED Driver With Flexible and High-Performance PWM Dimming Control

Cited by 40 publications

References 18 publications

Full-Range LED Dimming Driver With Ultrahigh Frequency PWM Shunt Dimming Control

Full-Range LED Dimming Driver With Ultrahigh Frequency PWM Shunt Dimming Control

Novel distortionless dimming in high power LED lighting using isolated SEPIC converter

Analysis, design, and experimentation of the active hybrid‐series‐parallel PWM dimming scheme for high‐efficient off‐line LED drivers

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