BQ27425-G1 Datasheet, PDF (21/32 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge With Integrated Sense Resistor

bq27425-G1
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SOCI_Delta
Enable Condition
SOCI_Delta ≠ 0
State Change
Battery
Removal
SOCI_Delta ≠ 0
[BIE] bit is set in
OpConfig
SLUSAI6 – NOVEMBER 2011
Table 9. SOC_INT Function Definition
Pulse Width
1ms
1ms
1ms
Description
During charge, when the StateOfCharge() reaches greater than or equal to (≥) the
defined SOC_INT intervals. The intervals are defined as 100% and 100% – n ×
SOCI_Delta.
During discharge, when the StateOfCharge() reaches less than (<) the defined
SOC_INT intervals. The intervals are defined as 0% and 100% – n × SOCI_Delta.
n: Integer value starting from 0.
For SOCI_Delta = 10%, the SOC_INT intervals are 0%, 10%, 20%, ….. 90%, and
100%.
When there is a state change including charging, discharging, and relaxation.
When battery removal is detected by BIN pin.
Battery Detection (BIN)
The host is responsible for battery detection by setting the [BAT_DET] bit to trigger INITIALIZATION mode. The
function of OpConfig[BIE] bit is described in Table 10. When battery insertion is detected and INITIALIZATION
mode is completed, the bq27425 runs in NORMAL mode to start Impedance Track™ fuel gauging. When battery
insertion is not detected, fuel gauging is stopped.
OpConfig[BIE]
1
0
Table 10. Battery Detection
Battery Insertion Requirement
(1) Host drives BIN pin from logic high to low
to signal battery insertion.
or
(2) A weak pull-up resistor can be used
(between BIN and VCC pin). When battery
pack with pull-down is connected, it can
generate a logic low to signal battery
insertion.
Host sends BAT_INSERT subcommand to
signal battery insertion.
Battery Removal Requirement
(1) Host drives BIN pin from logic low to high to
signal battery removal.
or
(2) When battery pack with pull-down is removed,
the weak pull-up resistor can generate a logic high
to signal battery removal.
Host sends BAT_REMOVE subcommand to signal
battery removal.
TEMPERATURE MEASUREMENT
The bq27425 measures temperature using an on-chip temperature sensor. Alternatively if [WRTEMP] = 1, the
host sends temperature data to the gauge with the initial default setting at 25°C. Regardless of [WRTEMP]
setting, the fuel gauge uses temperature data in Temperature() command for fuel gauging.
Over-Temperature Indication: Charge
If during charging, Temperature( ) reaches the threshold of OT Chg (default = 55°C) for a period of OT Chg
Time (default = 2 seconds) and AverageCurrent( ) > Chg Current Threshold (default = DesignCapacity / 13.3),
then the [OTC] bit of Flags( ) is set. When Temperature() falls to OT Chg Recovery (default = 50°C), the [OTC]
of Flags() is reset.
Over-Temperature Indication: Discharge
If during discharging, Temperature( ) reaches the threshold of OT Dsg (default = 60°C) for a period of OT Dsg
Time (default = 2 seconds) , and AverageCurrent( ) ≤ -Dsg Current Threshold (default = DesignCapacity
/16.7 ) , then the [OTD] bit of Flags( ) is set. When Temperature( ) falls to OT Dsg Recovery (default = 55°C),
the [OTD] bit of Flags( ) is reset.
Copyright © 2011, Texas Instruments Incorporated
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