BQ27000 Datasheet, PDF (7/29 Pages) Texas Instruments – SINGLE CELL Li-Ion AND Li-Pol BATTERY GAS GAUGE IC FOR PORTABLE APPLICATIONS (bqJUNIOR)

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bq27000, bq27200
SLUS556B – SEPTEMBER 2004 – REVISED NOVEMBER 2004
FUNCTIONAL BLOCK DIAGRAMS
bq27000
VCC 2
Bandgap,
Reference
and Bias
Temperature
Compensated
Precision Oscillator
Clock
Generator
EEPROM
System I/O
and Control
5 HDQ
9 GPIO
SRP 8
SRN 7
Autocalibration
and
Autocompensating
Coulomb Counter
SCPU
RAM
10 RGM
1 ^RBI
BAT 6
Temperature
Sensor
ADC
3 VSS
UDG−03040
bq27200
VCC 2
Bandgap,
Reference
and Bias
SRP 8
SRN 7
Autocalibration and
Autocompensating
Coulomb Counter
Temperature
Compensated
Precision Oscillator
Clock
Generator
EEPROM
SCPU
RAM
System I/O
and Control
4 SCL
5 SDA
9 GPIO
10 RGM
1 RBI
BAT 6
Temperature
Sensor
ADC
3 VSS
UDG−04123
FUNCTIONAL DESCRIPTION
The bqJUNIOR determines battery capacity by monitoring the amount of charge input to or removed from a
Li-Ion or Li-Pol battery. The bqJUNIOR measures discharge and charge currents, monitors the battery for low
voltage thresholds, and compensates for self-discharge, aging, temperature, and discharge rate. Current is
measured across a small value series resistor between the negative terminal of the battery and the pack ground
(see R_S in Figure 3). Available capacity is reported with a resolution of 0.00357/R_S mAh. Time-To-Empty
reporting in minutes at standby, peak, actual, and at-rate currents allows the requirements for host-based
calculations to be greatly reduced or eliminated; reading a single register pair provides useful and meaningful
information to the end user of the application.
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