A direct AC LED driver with high power factor without the use of passive components

Dayal, Rohan; Modepalli, Kumar; Parsa, Leila

doi:10.1109/ecce.2012.6342248

Cited by 40 publications

(22 citation statements)

References 7 publications

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“…As a consequence, the PF and THD of the proposed LED driver are efficiently improved. Furthermore, there are no current glitches due to a soft turn on of the switch MOS because of a slow change of the reference voltage of the SR2, then the disadvantages (such as decrease the quality of lighting due to blink, shortening of the LED lifetime, and degrading of the THD due to severe current distortion, which in turn degrade the PF) caused by the hard switching operation as encountered in [5] are no longer exist. It can also be seen that the input current is relatively insensitive with a large fluctuation of the input voltage by using two CLCs.…”

Section: Simulation and Experimental Resultsmentioning

confidence: 99%

“…Most of them use a bulky transformer and electrolytic capacitors which shorts the lifetime of LED module and cannot be integrated inside the chip. Then, some researchers have been trying to design AC directly-controlled LED drivers which eliminate totally transformer and electrolytic capacitors [5,6]. In the design presented in [5], the design gains a high PF and improves THD; however, it may results in a current glitch due to hard switching operation that degrades the THD due to severe current distortion which then degrade PF [1].…”

Section: Introductionmentioning

confidence: 99%

“…Then, some researchers have been trying to design AC directly-controlled LED drivers which eliminate totally transformer and electrolytic capacitors [5,6]. In the design presented in [5], the design gains a high PF and improves THD; however, it may results in a current glitch due to hard switching operation that degrades the THD due to severe current distortion which then degrade PF [1]. With the design in [6], although the glitch phenomenon is eliminated due to the use of a soft-switching mechanism, it owns another shortcoming of the change of reference voltage level if the input voltage changes.…”

Section: Introductionmentioning

confidence: 99%

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Multi-string AC-powered LED driver with current regulation reduction based on simple circuitry

Seo¹,

Nguyen

Jung

et al. 2014

IEICE Electron. Express

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In this letter, a new simple circuitry LED driver with current reduction is proposed, realized and experimentally validated. The proposed circuit comprises with very few components intended for making a costeffective and compact design while still shows a high performance. The circuit reduces non-conducting time of LEDs to enhance power factor (PF) and total harmonic distortion (THD). The flicker can also be relatively reduced. By using current limiter cells, lighting variation is eliminated with respect of the variation of AC input voltage. A worst case of a 4 W with only two LED-strings driver is implemented and tested by using a 1 um 650 V-BCDMOS high voltage process to verify advantageous characteristics of the suggested scheme. Experimental results demonstrate a PF of 0.97 with a THD of 24.62% and an efficiency of 87.1% at a 220 V AC supply.

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Section: Simulation and Experimental Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multi-string AC-powered LED driver with current regulation reduction based on simple circuitry

Seo¹,

Nguyen

Jung

et al. 2014

IEICE Electron. Express

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show abstract

“…Due to its properties of low lost, high PF and high efficiency, the technology has been widely implemented in commercial lamps. Based on the topology, several improvements have been found in the literature, in [6], [7], and [8], soft self-commutating technology is introduced instead of hard switching for lower THD. In [9], single reference and twin-switch topology is implemented for better noise rejection and adjustable current ratio.…”

Section: Introductionmentioning

confidence: 99%

“…However, in conventional AC-direct multiple string LED drivers, represented by [6], [7] and [9], the current regulation level is fixed. The LED driver described in [10] proposed a variable current level, but only for dimming functions.…”

Section: Introductionmentioning

confidence: 99%

Line voltage compensation technology for AC-direct multiple-string LED drivers

Lai

2015

IEICE Electron. Express

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An AC-mains voltage compensation technology for variable load multiple-string LED drivers is presented. By forming a closed loop control of the multiple reference voltages and by introducing an external compensation resistor, the output luminance is well compensated in case of line voltage variations. The proposed technology along with the accompanied AC-direct multiple-string LED driver were integrated in an 1 µm trenchisolated BCD process and tested with a three-string prototype. With very few external components used, the line regulation character of the LED driver is highly optimized by the proposed technology. The experimental results show that within 15% AC-mains voltage tolerance, the output luminance deviation is restrained to 2.0% (1.5%) under 10 W, 110 V/AC (220 V/AC), 50 Hz conditions.

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Experimental verification of a linear AC LED driver with a light flicker compensating circuit and high power factor operation by modulating the current regulator

Noge

2019

Electrical Engineering Japan

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This article proposes a linear PFC regulator with a light flicker compensating circuit for LED lighting applications. The proposed circuit is small in size because it includes no reactors or electrolytic capacitors. The light flicker compensating circuit, which is connected in parallel to the LED string, consists of four ceramic capacitors and diodes. These capacitors are operated in series in the charge state and in parallel in the discharge state by using a diode network circuit. Therefore, an external controller and large capacitors are not required. The proposed circuit is experimentally validated using a 9 W prototype. From the experimental results, it is found that the power fluctuation of the LED string is less than the JIS and JLMA limitations, and the power factor is 0.95. In addition, the power loss is analyzed at an efficiency of 89.4% for the prototype circuit. Also, by modulating the current regulator, sinusoidal input current can be achieved. The second proposed circuit is experimentally validated using a 7.5 W prototype, and the power factor and input current distortion are found to be 0.999 and 2.1%, respectively.

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A direct AC LED driver with high power factor without the use of passive components

Cited by 40 publications

References 7 publications

Multi-string AC-powered LED driver with current regulation reduction based on simple circuitry

Multi-string AC-powered LED driver with current regulation reduction based on simple circuitry

Line voltage compensation technology for AC-direct multiple-string LED drivers

Experimental verification of a linear AC LED driver with a light flicker compensating circuit and high power factor operation by modulating the current regulator

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