Abstract

Light-emitting diode (LED) video displays enclose thousands of LEDs which create the resulting image. LED intensity is regulated using pulse width modulation (PWM). Though the individual LED current is small, the total current consumed is large. Simultaneous switching of a large number of LEDs dimmed by PWM can cause serious electromagnetic interference (EMI). Three LED PWM dimming techniques have been studied for potential EMI. Techniques represent different current pulse positioning in time: the aim of study was to compare the spectrum of current produced in LED video display power supply circuits when discussed techniques are used for pixel intensity control. It was assumed that the produced EMI is proportional to the power supply current. The power supply filter and transient load decoupling capacitors were not taken into account. The uniform and nonuniform pixels' intensities distribution within an image were assumed. Spectrum has been studied on a single pixel and the video display tile containing 16×32 LEDs. Resulting time diagrams and frequency responses are presented. The results indicate that, despite expected significant advantage of binary PWM methods, in realistic case all methods' performance is similar.

© 2012 IEEE

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References

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  1. N. D. Lamontagne, "The shape of displays to come," Photonics Spectra 42, 76-77 (2008).
  2. P. Pihos, "Full-color video LED billboards feel the impact of alternative technologies," LEDs Mag. 8, 29-31 (2006).
  3. N. Shlayan, R. Venkat, P. Ginobbi, G. Mercier, "A novel RGBW pixel for LED displays," Proc. Int. Conf. on Syst. Eng. (2008) pp. 407-411.
  4. E. F. Schubert, Light-Emitting Diodes (Cambridge Univ. Press, 2003).
  5. A. Zukauskas, M. S. Shur, R. Gaska, Introduction to Solid-State Lighting (Wiley-Interscience, 2002).
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  8. “LVS-P16 module description” RGG Electronics (2010) http://www.rggled.com/index.php?s_id=70&lang=en.
  9. W. Kurdthongmee, "Design and implementation of an FPGA-based multiple-colour LED display board," Microprocessors and Microsyst. 29, 327-336 (2005).
  10. Artistic Licence LtdLondonU.K.“An overview of the electronic drive techniques for intensity control and colour mixing of low voltage light sources such as LEDs and LEPs,” Appl. note 011 (2002).
  11. L. Svilainis, "LED brightness control for video display application," Displays 29, 506-511 (2008).
  12. C. A. Poynton, "Gamma and its disguises," J. Soc. Motion Picture and TV Eng. 102, 1099-1108 (1993).

2008 (3)

N. D. Lamontagne, "The shape of displays to come," Photonics Spectra 42, 76-77 (2008).

L. Svilainis, "LED PWM dimming linearity investigation," Displays 29, 243-249 (2008).

L. Svilainis, "LED brightness control for video display application," Displays 29, 506-511 (2008).

2006 (2)

P. Pihos, "Full-color video LED billboards feel the impact of alternative technologies," LEDs Mag. 8, 29-31 (2006).

M.-C. Kim, "Optically adjustable display color gamut in time-sequential displays using LED/Laser light sources," Displays 27, 137-144 (2006).

2005 (1)

W. Kurdthongmee, "Design and implementation of an FPGA-based multiple-colour LED display board," Microprocessors and Microsyst. 29, 327-336 (2005).

1993 (1)

C. A. Poynton, "Gamma and its disguises," J. Soc. Motion Picture and TV Eng. 102, 1099-1108 (1993).

Displays (3)

M.-C. Kim, "Optically adjustable display color gamut in time-sequential displays using LED/Laser light sources," Displays 27, 137-144 (2006).

L. Svilainis, "LED PWM dimming linearity investigation," Displays 29, 243-249 (2008).

L. Svilainis, "LED brightness control for video display application," Displays 29, 506-511 (2008).

J. Soc. Motion Picture and TV Eng. (1)

C. A. Poynton, "Gamma and its disguises," J. Soc. Motion Picture and TV Eng. 102, 1099-1108 (1993).

LEDs Mag. (1)

P. Pihos, "Full-color video LED billboards feel the impact of alternative technologies," LEDs Mag. 8, 29-31 (2006).

Microprocessors and Microsyst. (1)

W. Kurdthongmee, "Design and implementation of an FPGA-based multiple-colour LED display board," Microprocessors and Microsyst. 29, 327-336 (2005).

Photonics Spectra (1)

N. D. Lamontagne, "The shape of displays to come," Photonics Spectra 42, 76-77 (2008).

Other (5)

Artistic Licence LtdLondonU.K.“An overview of the electronic drive techniques for intensity control and colour mixing of low voltage light sources such as LEDs and LEPs,” Appl. note 011 (2002).

“LVS-P16 module description” RGG Electronics (2010) http://www.rggled.com/index.php?s_id=70&lang=en.

N. Shlayan, R. Venkat, P. Ginobbi, G. Mercier, "A novel RGBW pixel for LED displays," Proc. Int. Conf. on Syst. Eng. (2008) pp. 407-411.

E. F. Schubert, Light-Emitting Diodes (Cambridge Univ. Press, 2003).

A. Zukauskas, M. S. Shur, R. Gaska, Introduction to Solid-State Lighting (Wiley-Interscience, 2002).

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