Figure 64 Battery pin order
The battery temperature is estimated by measuring separate battery temperature NTC via the BTEMP line.
This is located on the main PWB, at the place where the phone temperature is closest to the battery
temperature.
Battery connector
The battery connector is a blade connector. It has three blades;
•
BSI (Battery size indicator)
•
GND (Ground)
•
VBAT (Battery voltage)
Figure 65 Blade battery connector
Charging
This phone is charged through the micro USB connector. The phone supports dedicated, host or hub chargers.
Charging is controlled by energy management, and external components are needed to protect the baseband
module against EMC, reverse polarity and transient frequency deviation.
Backup battery
When the main battery is not attached EM ASIC (N2200) goes in backup mode using back-up battery that
supplies voltage to RTC in EM ASIC (N2200).
Normal and extreme voltages
Energy management is mainly carried out in the two Application Specific Integrated Circuits (ASICs) BETTY
and AVILMA. These two circuits contains a number of regulators. In addition there are some external
regulators too.
In the table below normal and extreme voltages are shown when a BL-4D battery is used.
Table 10 Nominal voltages
Voltage
Voltage [V]
Condition
General Conditions
Nominal voltage
3.700
Lower extreme voltage
3.145
Higher extreme voltage
(fast charging)
4.230
RM-555
System Module and User Interface
Page 6 –10
COMPANY CONFIDENTIAL
Issue 1
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