Energy Management; Battery Interface - Nokia 3555 Service Manual

RM-257; RM-270; RM-277
System Module

Energy management

Battery interface

The phone is powered by a 3-pole BL-5C S-pack 1020 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 22 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 3-pole connector.
• 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
This phone is charged through the smaller Nokia standard interface (2.0 mm plug). The wider standard
charger (3.5 mm) can be used together with the CA-44 charger adapter.
Figure 23 Small (left) and wide (right) charger plugs
Charging is controlled by energy management, and external components are needed to protect the baseband
module against EMC, reverse polarity and transient frequency deviation.
Issue 1 COMPANY CONFIDENTIAL Page 5 –9
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