HCMS-2913 datasheet(16/16 Pages) AVAGO

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Appendix E. Display Brightness

Two ways have been shown to control the brightness

of this LED display: setting the peak current and setting

the duty factor. Both values are set in Control Word 0.

To compute the resulting display brightness when both

PWM and peak current control are used, simply multi-

ply the two relative brightness factors. For example, if

Control Register 0 holds the word 1001101, the peak

current is 73% of full scale (BIT D5 = L, BIT D4 = L) and

the PWM is set to 60% duty factor (BIT D3 = H, BIT D2

= H, BIT D1 = L, BIT D0 = H). The resulting brightness is

44% (.73 x .60 = .44) of full scale.

The temperature of the display will also affect the LED

brightness as shown in Figure 5.

Appendix F. Reference Material

Application Note 1027: Soldering LED Components

Application Note 1015: Contrast Enhancement Techniques

for LED Displays

Figure 5.

YELLOW

HER/ORANGE

0.2

-55

TA – AMBIENT TEMPERATURE – °C

3.0

2.6

2.2

1.8

1.4

1.0

0.6

-15

-35

GREEN

AlGaAs

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AV02-0699EN - September 18, 2007

HCMS-2913 Datasheet(PDF) 16 Page - AVAGO TECHNOLOGIES LIMITED