User Guide

Energy management

Battery and charging

BL-4U battery

The phone is powered by a 3-pole BL-4U battery S-pack 1000 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 46 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.

RM-412; RM-413

System Module and User Interface

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