
RH-27
Troubleshooting - Baseband
CCS Technical Documentation
Page 18
©
2003
Nokia Corporation Confidential
Issue 1 11/2003
pack on the BSI line indicates the battery size. NTC-resistor inside the battery measures
the battery temperature on the BTEMP line.
Temperature and capacity information are needed for charge control. These resistors are
connected to BSI and BTEMP pins of battery connector. Phone has 100 kW pull-up resis-
tors for these lines so that they can be read by A/D inputs in the phone.
Figure 4: BLD-3 battery pack pin order
Figure 5: Interconnection diagram inside the battery pack
Charging circuitry
The UEM ASIC controls charging depending on the charger being used and the battery
size. External components are needed for EMC, reverse polarity and transient protection
of the input to the baseband module. The charger connection is through the system con-
nector interface. The RH-27 baseband is designed to support DCT3 chargers from an
electrical point of view. Both 2- and 3-wire type chargers are supported. However, as
mention above, three wire chargers are treated as two.
1 (+)
2(BSI)
3(BTEMP)
4(GND)
Overcharge /
Overdischarge
protection
VBATT
BSI
BTEMP
EMC
Li-Ion