Robust LED backlight driver with low output voltage drop and hig output current accuracy

Liao, Tse-Ju; Chen, Chern‐Lin

doi:10.1109/icset.2008.4746973

Cited by 10 publications

(2 citation statements)

References 3 publications

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“…Various approaches for driving LEDs are available in the literature, such as in alternate [ 16 ] and direct current [ 17 , 18 ]. An experimental comparison is also presented here.…”

Section: Introductionmentioning

confidence: 99%

An Instrument for the Characterization and Calibration of Optical Sensors

Gastasini

Capecci

Lupi

et al. 2021

Sensors

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This paper presents the development of a hardware/software system for the characterization of the electronic response of optical (camera) sensors such as matrix and linear color and monochrome Charge Coupled Device (CCD) or Complementary Metal Oxide Semiconductor (CMOS). The electronic response of a sensor is required for inspection purposes. It also allows the design and calibration of the integrating device to achieve the desired performance. The proposed instrument equipment fulfills the most recent European Machine Vision Association (EMVA) 1288 standard ver. 3.1: the spatial non uniformity of the illumination ΔE must be under 3%, and the sensor must achieve an f-number of 8.0 concerning the light source. The following main innovations have achieved this: an Ulbricht sphere providing a uniform light distribution (irradiation) of 99.54%; an innovative illuminator with proper positioning of color Light Emitting Diodes (LEDs) and control electronics; and a flexible C# program to analyze the sensor parameters, namely Quantum Efficiency, Overall System Gain, Temporal Dark Noise, Dark Signal Non Uniformity (DSNU1288), Photo Response Non-Uniformity (PRNU1288), Maximum achievable Signal to Noise Ratio (SNRmax), Absolute sensitivity threshold, Saturation Capacity, Dynamic Range, and Dark Current. This new instrument has allowed a camera manufacturer to design, integrate, and inspect numerous devices and camera models (Necta, Celera, and Aria).

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“…Various approaches for driving LEDs are available in the literature, such as in alternate [ 16 ] and direct current [ 17 , 18 ]. An experimental comparison is also presented here.…”

Section: Introductionmentioning

confidence: 99%

An Instrument for the Characterization and Calibration of Optical Sensors

Gastasini

Capecci

Lupi

et al. 2021

Sensors

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“…However, there is a main drawback because of undesired power losses in metal oxide semiconductor field effect transistors (MOSFETs) [26, 27]. Aside from this, as the MOSFET operates in the saturation region, the channel would be modulated because of too much voltage across between the drain and source of the MOSFET, and hence, together with the parasitic inductances, would tend to make the output current oscillate [28, 29]. Furthermore, as generally acknowledged, the less current in the LED is, the less the forward voltage drop of the LED.…”

Section: Introductionmentioning

confidence: 99%

Light‐emitting diode driver with low‐frequency ripple suppressed and dimming efficiency improved

Hwu

Lai

2014

IET Power Electronics

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In this study, a single-stage power-factor-corrected flyback converter is used as the main power stage, which is controlled by a critical mode control integrated circuit and is used to drive light-emitting diode (LED) strings. Since the output voltage of this converter possesses a double line frequency ripple, one energy-recycling circuit without any control is added to render the instantaneous output power close to the instantaneous input power, so as to reduce the energy stored/ released in the output capacitor and hence to reduce the output voltage ripple of the double line frequency. Accordingly, the effect of the low-frequency voltage ripple on the colour, luminance, life and stability of the LED can be reduced. For the dimming circuit to be considered, the gate voltage detecting circuit is employed herein so as to achieve efficiency improvement in LED dimming. Based on the dimming command and the variation in gate voltage, the voltage reference command for the flyback converter is dynamically adjusted so as to make the voltage across the metal oxide semiconductor field effect transistor reduced as the LED string is dimmed up/down and hence to increase the efficiency of the overall system.

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