AN2042

Commercial LEDs

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Figure 4.

C.I.E. chromaticity diagram

3

Commercial LEDs

In the last years, light emitting diodes can be chosen from a wide variety of products

designed to meet specific needs to provide more efficient, longer life time alternatives to

traditional incandescent lamps.

They are manufactured of GaN and related compounds of AlGaN and InGaN due to the

wide bandgap, which allows emission of light ranging from the red to the ultraviolet (UV)

wavelength. Blue and green LEDs are of special interest and are being used in a wide range

of applications from outdoor video displays to automotive and cell phone backlights. LEDs

for solid-state white lighting offer high efficiency, long lifetime and a high degree of design

flexibility for a variety of lighting applications.

Thanks to new solid state technology, it now delivers from 25 to more then 120 lm/W in white

and comparable light output in other colors. In Table 2 are listed the main specifications for

typical commercial high efficiency LEDs are listed, while Figure 5 shows a typical V-I

characteristic for a high efficiency LED.

Table 2.

Typical characteristic for commercial LEDs (from Luxeon)

Color

Operating

voltage (V)

Operative forward current

(mA)

Dominant wavelength/

color temperature

Typical luminous flux (lm)

White

3.42

350

5500 K

18

Blue

3.42

350

470 nm

5

Cyan

3.42

350

505 nm

30

Green

3.42

350

530 nm

25

Amber

2.85

350

590 nm

20

Red

2.85

350

625 nm

25