User Guide

Table 20 LED driver control signals

From Voltage Function

GenOut1 EM ASIC N2300 0V / 1.8V EL ON (1.8V)/OFF (0V)

PWM EM ASIC N2300 PWM 0%-100%, 1.8V Current PWM control (16

steps)

ALS interface

Ambient Light Sensor (ALS) is located on UI flex in the upper part of the phone. It consists of the following

components:

• lightguide (part of the front cover)

• photo detector (V8004 in 1YC)

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 IC, which is internally temperature-compensated.

The supply voltage for the ambient light sensor is coming from VAUX via a switch N4404 controlled by EM

ASIC N2300 Genio2 GenOUT2.

The output from ALS is current, which is fed to the resistor R2206. N2200 reads the light sensor (LS) results,

voltage over resistor R2206 ALS calibration is not possible in the service points.

ALS is serviced by replacing faulty phototransistors.

See ALS interface figure.

RM-208

System Module Nokia Customer Care

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