User Guide

2118 (RH-77)
Baseband Description and Troubleshooting Nokia Customer Care
Page 20 ©2005 Nokia Corporation Company Confidential Issue 01 04/2005
If the charger is accepted and identified, the appropriate charging algorithm is initiated.
Figure 13: Charging circuit
Charge Control
In active mode, charging is controlled by the UEMC’s digital part. Charging voltage and
current monitoring is used to limit charging into safe area. For this reason, the UEMC has
the following programmable charge cut-off limits:
• VBATLim1=3.6 V (Default)
• VBATLim2L=5.0 V
• VBATLim2H=5.25 V
VBATLim1, 2L, 2H are designed with hystereses. When the voltage rises above VBATLim1,
2L, 2H+ charging is stopped by turning the charging switch off. No change is done in
operational mode. After the voltage has decreased below VBATLim-, charging restarts.
There are two PWM frequencies in use depending on the type of the charger. A 2-wire
charger uses a 1 Hz, while a 3-wire charger uses a 32Hz. The duty cycle range is 0% to
100%. The maximum charging current is limited to 1.2 A.
Figure 14: Charging circuity at the battery
Audio
The audio control and processing is provided by UEMC, which contains the audio codec,
and the UPP, which contains the MCU and DSP blocks. These blocks handle and process
the audio data signals.
The baseband supports three microphone inputs and two earpiece outputs. The
microphone inputs are MIC1, MIC2, and MIC3. MIC1 input is used for the mobile
terminal's internal microphone; MIC2 input is used for headsets (HDB-4). MIC3 is not
used. Every microphone input can have either a differential or single-ended AC
connection to UEMC circuit. The internal microphone (MIC1) and external microphone
(MIC2) for Pop-port
TM
accessory detection are both differential. The microphone signals
from different sources are connected to separate inputs at UEMC. Inputs for the
________
F100
0
2
1.5A
L1002
X102
1
42R/100MHz
"VCHARIN"
CHARGER(4:0)
V100
C106
1n0
R200
.22 Ohms
N10
UEM Pins
M10
C201
1uF
C202
10nF
VBAT