LED backlight power system with auto-tuning regulation voltage for LCD panels

Tseng, S.-Y.; Lin, Shian-Jyh; Lin, Hsin-Chiung

doi:10.1109/apec.2008.4522775

Cited by 11 publications

(8 citation statements)

References 7 publications

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“…Several LED drivers have been studied to improve the power efficiency using the lowest channel selection technique, [5][6][7][8][9][10][11][12][13][14] which adjusts the output voltage considering the minimum voltage margin of the current regulator. However, this technique can lead to a critical problem in LED drivers, namely, that the current of multichannel LED strings may not be accurately regulated when the output voltage fluctuates due to the load variation.…”

Section: Introductionmentioning

confidence: 99%

A fast transient LED driver with adaptive frequency control according to load variation for large‐sized LCD backlights

2017

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A fast transient light‐emitting diode (LED) driver is proposed for large‐sized liquid crystal display TV backlights in attempt to shorten the recovery time and to reduce the voltage fluctuation, while maintaining a high power efficiency. The direct current‐direct current (DC–DC) converter in the proposed LED driver accurately detects the load variation using the dimming data and then adjusts the slew rate and operating frequency according to the detected load variation. Thus, it rapidly controls the turn‐on time of the power switch and then controls the inductor current so that the output of the proposed LED driver can be accurately regulated during the load transient time. To verify the performance of the proposed LED driver, a DC–DC converter and an expandable LED current controller were fabricated using a 0.35‐μm bipolar–complementary metal–oxide–semiconductor (CMOS)–double‐diffused metal–oxide–semiconductor (DMOS) process technology and assembled with 48 LED channels for measurement. The measurement results show that the proposed LED driver improves the recovery time and voltage fluctuation by 45.1% and 45.6%, respectively. In addition, it achieves a maximum power of 115.2 W and a maximum power efficiency of 89.2%. Therefore, the proposed LED driver is suitable for high‐end applications such as large‐sized LED TV backlight modules.

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Section: Introductionmentioning

confidence: 99%

A fast transient LED driver with adaptive frequency control according to load variation for large‐sized LCD backlights

2017

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“…As is generally acknowledged, a key technology of an LED driver is a DC-DC converter which has been based on an analog control scheme [1], [2]. The analog control systems should require too much complex hardware circuit even though these systems have two principal merits such as a low cost design and a wide system bandwidth [3].…”

Section: Introductionmentioning

confidence: 99%

Fully digitalized switch-mode LED driver without ADC

Park

Yoon

2014

2014 International SoC Design Conference (ISOCC)

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A digitalized switch-mode LED driver is implemented using a O.35f.1m high voltage process, which featured by no use of any ADCs. The comparison result between the output current and the desired current causes the counter to increase or decrease its binary value which determines the duty ratio of the PWM signal. This PWM signal controls switching devices. A delay routine added in the counter prevents oscillation of the counter value owing to a high speed clock.

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“…Although this approach offers a higher operating efficiency compared to its linear counterpart, it has a higher component count and cost. For LED drivers employing linear current regulators, the drive voltage is typically provided by a switch-mode preregulator [10], [13], as shown in Fig. 2.…”

Section: Introductionmentioning

confidence: 99%

LED Driver With Self-Adaptive Drive Voltage

Jovanovic

2008

IEEE Trans. Power Electron.

292

109

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Abstract-This paper presents an LED driver circuit consisting of multiple linear current regulators and a voltage preregulator with adaptive output voltage. In the proposed driver, the output voltage of the preregulator is always self-adjusted so that the voltage across the linear current regulator of the LED string with the highest voltage drop is kept at the minimum value that is required to maintain the desired string current. Because the linear current regulators in this driver operate with the minimum voltages, the driver efficiency is maximized. The performance of the proposed driver was experimentally verified on a four-string LED setup with eight white LEDs in each string. The measured efficiency improvement of the linear current regulators was approximately 15% compared to the corresponding implementation with a constant preregulator voltage.Index Terms-Adaptive drive voltage, LED driver, linear current regulator, sequential pulsewidth modulation (PWM) dimming.

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LED backlight power system with auto-tuning regulation voltage for LCD panels

Cited by 11 publications

References 7 publications

A fast transient LED driver with adaptive frequency control according to load variation for large‐sized LCD backlights

A fast transient LED driver with adaptive frequency control according to load variation for large‐sized LCD backlights

Fully digitalized switch-mode LED driver without ADC

LED Driver With Self-Adaptive Drive Voltage

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