Energy Management; Battery And Charging - Nokia 300 Service Manual

RM-781
System Module
Key component placement
Please refer to the L1/L2 Service Schematics.
System module block diagram

Energy management

Battery and charging

Battery
The phone is powered by a 3-pole battery (Li-Ion). The three poles of the battery 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 9 Battery pin order
The battery temperature is estimated by measuring separate battery temperature NTC via the BTEMP line of
EM ASIC. This resistor is located on the main PWB, at a place where the phone temperature is closest to the
battery temperature.
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