Energy Management; Battery And Charging; Normal And Extreme Voltages - Nokia RM-701 Service Manual

RM-701
System Module

Energy management

Battery and charging

BL-4J battery
The phone is powered by a 3-pole BL-4J 1200 mAh battery. The three poles are named VBAT, BSI and GND
where the BSI line is used to recognize the battery capacity. This is done by means of an internal battery pull
down resistor.
Figure 59 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)
The BSI line is used to recognize the battery capacity by a battery internal pull down resistor.
Charging
The phone can be charged through the dedicated charger interface or through the micro USB interface.
Charging is controlled by energy management, and external components are needed to protect the baseband
module against EMC, reverse polarity and transient frequency deviation.
Charging a dead battery
It may take up to several minutes before the phone indicates that it is charging if the battery is dead.

Normal and extreme voltages

Energy management is mainly carried out in the EM ASIC (N2200). that contains a number of regulators. In
addition there are also some external regulators.
In the table below normal and extreme voltages are shown when a BL-4J battery is used.
Table 9 Nominal voltages
Voltage Voltage [V] Condition
General Conditions
Nominal voltage 3.700
Lower extreme voltage 3.5
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