BQ27520-G2 Datasheet, PDF (17/47 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge With Integrated LDO

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bq27520-G2
SLUSAB7A – MARCH 2011 – REVISED AUGUST 2011
4.1.1.21 StateofHealth( ): 0x28/0x29
0x28 SOH percentage: this read-only function returns an unsigned integer value, expressed as a
percentage of the ratio of predicted FCC(25°C, SOH LoadI) over the DesignCapacity(). The FCC(25°C,
SOH LoadI) is the calculated full charge capacity at 25°C and the SOH LoadI which is specified in the
data flash. The range of the returned SOH percentage is 0x00 to 0x64, indicating 0 to 100%
correspondingly.
0x29 SOH Status: this read-only function returns an unsigned integer value, indicating the status of the
SOH percentage. The meanings of the returned value are:
• 0x00: SOH not valid (initialization)
• 0x01: Instant SOH value ready
• 0x02: Initial SOH value ready
– Calculation based on uncompensated Qmax
– Updated at first grid point update after cell insertion
• 0x03: SOH value ready
– Utilize the updated Qmax update
– Calculation based on compensated Qmax
– Updated after complete charge and relax is complete
• 0x04-0xFF: Reserved
4.1.1.22 CycleCount( ): 0x2a/0x2b
This read-only function returns an unsigned integer value of the number of cycles that the active cell has
experienced with a range of 0 to 65535. One cycle occurs when accumulated discharge ≥ CC Threshold.
The gauge maintains a separate cycle counter for both cell profiles and will reset to zero if the insertion of
a new pack has been detected.
4.1.1.23 StateOfCharge( ): 0x2c/0x2d
This read-only function returns an unsigned integer value of the predicted remaining battery capacity
expressed as a percentage of FullChargeCapacity( ), with a range of 0 to 100%.
4.1.1.24 NormalizedImpedanceCal( ): 0x2e/0x2f
This read-only function returns an unsigned integer value of the calculated normalized impedance to 0°C
at the current Depth of Discharge, with the unit of mΩ.
4.1.1.25 InstantaneousCurrent Reading( ) 0x30/0x31
This read-only function returns a signed integer value that is the instantaneous current flow through the
sense resistor. The conversion time is 125ms. It is updated every 1 second. Units are mA.
4.1.1.26 DataLogIndex( ): 0x32/0x33
In Data Logging Mode, this read-only register returns an unsigned integer that increments for every new
coulomb counter sample placed in the data FIFO and decrements for each sample read by the host from
DataLogBuffer(). The index saturates at 30 counts to prevent rollover of the FIFO and subsequent data
samples are discarded. Data logging is controlled by the ENABLE_DLOG and DISABLE_DLOG
subcommands while status is provided by the CONTROL_STATUS[DLOGEN] bit.
4.1.1.27 DataLogBuffer( ): 0x34/0x35
In Data Logging Mode, this read-only register returns a 16-bit signed coulomb counter value in mA.
Access to data is provided by a 30 sample FIFO with the number of samples available from
DataLogIndex(). If the FIFO is empty, this value returned is 0x7FFF.
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GENERAL DESCRIPTION
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