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RH-27
Troubleshooting - Baseband
CCS Technical Documentation
Page 20
©
2003
Nokia Corporation Confidential
Issue 1 11/2003
Figure 7: Charging circuit
Charge Control
In active mode, charging is controlled by UEM's digital part. Charging voltage and cur-
rent monitoring is used to limit charging into safe area. For that reason, UEM has pro-
grammable charging cut-off limits:
VBATLim1=3.6 V (Default)
VBATLim2L=5.0 V and
VBATLim2H=5.25 V.
VBATLim1, 2L, 2H are designed with hystereses. When the voltage rises above VBATLim1,
2L, 2H+ charging is stopped by turning charging switch OFF. No change in operational
mode is done. After voltage has decreased below VBATLim- charging re-starts.
There are two PWM frequencies in use depending on the type of the charger: two-wire
charger uses a 1Hz and a three-wire charger uses a 32Hz. Duty cycle range is 0% to
100%. Maximum charging current is limited to 1.2 A.
Figure 8: Charging circuit at battery
Audio
The audio control and processing in RH-27 is supported by UEM, which contains the
audio codec, and UPP, which contains the MCU and DSP blocks, handling and processing
the audio data signals.
The baseband supports three microphone inputs and two earpiece outputs. The micro-
phone inputs are MIC1, MIC2, and MIC3. MIC1 input is used for the phone's internal
CHARGER(4:0)
________
F100
0
2
1.5A
L100
2
X102
1
42R/100MHz
"VCHARIN"
V100
22p
C110
C106
1n0
R200
.22 Ohms
N10
UEM Pins
M10
C237
1uF
C202
10nF
VBAT