Table 15 LED driver control signals
From To Voltage Function
GenOut 1 N2300 V4405 0V/1.8V S60 LED control
Genout 0 N2300 V4404 0V/1.8V ITU LED control
Typically, keyboard LEDs are turned ON only in dark ambient light conditions. The ITU keymat LEDs are
extinguished when the device detects that the slide has been closed.
ALS interface
Ambient Light Sensor (ALS) is located in the upper part of the phone. It consists of the following components:
• lightguide (part of the front cover)
• phototransistor (V4400) + resistor (R4401)
• NTC + resistors (R4400, R4402, R4403)
• EM ASIC (N2200)
Information on ambient lighting is used to control the backlights of the phone:
• Keypad lighting is switched on only when the environment is dark / dim
• Display backlights are dimmed, when the environment is dark / dim
The ambient light sensor itself is a photo transistor, which is temperature-compensated by an external NTC
resistor. N2200 reads the light sensor (LS) and temperature (LST) results.
ALS calibration is not possible in the service points. ALS is serviced by replacing faulty phototransistors.
RM-91; RM-92
System Module Nokia Customer Care
Issue 1 COMPANY CONFIDENTIAL Page 9 –21
Copyright © 2006 Nokia. All rights reserved.
To Next Page
Loading...
