Normal And Extreme Voltages - Nokia RM-645 Service Manual

RM-645
System Module
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-5CT battery is used.
Voltage
Nominal voltage
Lower extreme voltage
Higher extreme voltage
(fast charging)
Vmstr+
Vmstr-
Sw shutdown
Sw shutdown
Vcoff+
Vcoff-
Issue 1
Table 10 Nominal voltages
Voltage [V]
General Conditions
3.700
3.5
4.2
HW Shutdown Voltages
2.1 ± 0.1
1.9 ± 0.1
SW Shutdown Voltages
3.1
3.2
Min Operating Voltage
2.9 ± 0.1
2.7 ± 0.1
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Condition
Off to on
On to off
In call
In idle
Off to on
On to off
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