Figure 74 Illumination block diagram
Light segments
8 different light segments are used for illumination, each having 1-4 parallel connected LEDs (see the figure
below). Parallel connected LEDs which are in the same LED driver output branch have a serial resistor to even
their currents. As ITU and S60 keyboard backlights are controlled by the Ambient Light Sensor (ALS) they are
turned ON only in dark ambient light.
RM-484 has a self-emissive AM-OLED display, therefore it does not need LEDs for backlighting.
RM-484; RM-485; RM-486
System Module and User Interface
Issue 1 COMPANY CONFIDENTIAL Page 8 –23
Copyright © 2009 Nokia. All rights reserved.
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