BQ2084-V133 Datasheet, PDF (58/64 Pages) Texas Instruments – SBS v1.1-COMPLIANT GAS GAUGE FOR USE WITH THE bq29312

bq2084-V133
SLUS640A – JUNE 2005 – REVISED JUNE 2005
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Discharge Detection Current
Discharge Detection Current (DF 0x115-0x116) sets the threshold in milliamperes for detecting discharge
current. This is a signed value and is negative. This threshold is used for detecting cross-conduction and
determining that the charge FET should be turned on during discharge to reduce IR losses.
FET Fail Charge Current
FET Fail Charge Current (DF 0x125-0x126) sets the threshold in milliamperes for detecting current in a charge
FET which is turned off. This is a signed value and is positive.
FET Fail Discharge Current
FET Fail Discharge Current (DF 0x127-0x128) sets the threshold in milliamperes for detecting current in a
discharge FET which is turned off. This is a signed value and is negative.
FET Fail Time
FET Fail Time (DF 0x129) sets the time in seconds that current must be detected in a FET which is turned off, in
order to determine that the FET has failed.
Terminate Voltage
Terminate Voltage (DF 0x67-0x68) sets the threshold below which the Terminate Discharge Alarm bit is set. The
alarm is cleared when the voltage rises above this threshold, if the CVUV bit in Pack Status is not set.
Offsets and Limits
Temperature offset
Temperature offset (DF 0xd6) contains a signed offset for the pack's temperature measurements, in degrees
C/10. It is set at board test during pack calibration.
Board offset
Board offset (DF 0xd7), contains a signed offset for the pack's coulomb counter measurements. If used, it is set
at board design time.
Current Deadband
Current Deadband (DF 0x7b), sets the threshold in mA below which a current measurement is not detected.
Shutdown Voltage
Shutdown Voltage (DF 0x7c-0x7d) sets the pack voltage below which the pack's electronics, including the
bq2084-V133, is shut down to conserve power. All FETs are turned off by the AFE.
APPLICATION INFORMATION
Figure 7 shows a typical bq2084-V133-based battery pack application. The circuit consists of the bq29312 AFE
IC, bq29400 second-level protection IC, LED, temperature measurement network, data flash connections, serial
port, and the sense resistor. The data flash stores basic battery pack configuration information and measurement
calibration values. The data flash must be programmed properly for bq2084-V133 operation.
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