User's Guide

xE922-3GR Hardware User Guide
1VV0301272 Rev.0.8 2017-01-05
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Reserved. Page 51 of 112
7. Battery management
The xE922-3GR chipset supports an (optional) complete battery management solution based on external
charger IC interfacing by the following dedicated charging control lines.
PAD
Signal
I/O
descriptions Type
AN14
CHG_RST_OUT
O
External Charger Reset
AB21
CHG_INT_IN
I
Charger IRQ
AN16
CHG_POK_IN
I
Charger Power OK indication
AV16
FG_IBATP
I
Battery Fuel Gauge Positive
AT16
FG_IBATN
I
Battery Fuel Gauge Negative
AM19
ADC_VBATMEAS
I
Battery measurement ADC
AC18
CHG_I2C_SCL
I/O
Charger I2C Clock
CMOS 1.8V
AE18
CHG_I2C_SDA
I/O
Charger I2C Data
CMOS 1.8V
AL18
ADC_IN0
AI
Analog to Digital converter (MEAS0 Batt ID)
Analog
AK19
ADC_IN1
AI
Analog to Digital converter (MEAS1 Batt Temp)
Analog
The battery management system foresees in the following main functions:
· Battery voltage/capacity monitoring (fuel gauge)
· Battery charger interface (I2C bus, predefined IO’s)
7.1. Coulomb counter
The coulomb counter is a current integration method to improve the battery state of charge, while combined
with VBATMEAS voltage monitoring. Below figure shows the required connections, where the biderectional
battery current is sensed across a shunt resistor (low side sensing, typ. 20 mOhm).
Always connect the sense resistor to the negative (ground) side of the battery. Positive side battery sensing is
not supported and will damage the chip.