User Guide

PAMS Technical Documentation System Module & UI
NHM-8NX
Issue 1 05/02 ãNokia Corporation Page 29
The keyboard light consists of 2 TBSF yellow/green LED's, which are placed under the
keyboard and use the light guide to distribute the light
LED driver circuit
The LED drivers for LCD & Keyboard backlight are shared as shown below in Figure 4
Shared LED driver circuit for LCD and Keyboard backlight.The driver circuit is controlled
by the UEM output pin [DLIGHT] and drive current is 15mA pr. LED. By appropriate SW
the driver can be PWM controlled for dimming purpose.
Figure 3: Shared LED driver circuit for LCD and Keyboard backlight
LCD cell
Figure 4: Complete overview of LCD module
Metal frame
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LCD Glass
Lightguide
Domesheet