BQ27742-G1 Datasheet, PDF (31/46 Pages) Texas Instruments – Single-Cell Li-Ion Battery Fuel Gauge with Programmable Hardware Protection

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bq27742-G1
SLUSBV9C – MARCH 2014 – REVISED FEBRUARY 2016
Typical Applications (continued)
Table 11. Key Data Flash Parameters for Configuration (continued)
NAME
Design Energy Scale
Reserve Capacity
Design Voltage
Cycle Count Threshold
DEFAULT
1
0
3800
900
Device Chemistry
0354
Load Mode
Load Select
Qmax Cell 0
V at Chg Term
Terminate Voltage
Ra Max Delta
Charging Voltage
Taper Current
Taper Voltage
Dsg Current Threshold
Chg Current Threshold
Quit Current
Avg I Last Run
1
1
1000
4350
3000
43
4350
100
100
60
75
40
–299
Avg P Last Run
–1131
Sleep Current
15
Shutdown V
0
T1 Temp
0
T2 Temp
10
T3 Temp
45
UNIT
—
mAh
mV
mAh
hex
—
—
mAh
mV
mV
mΩ
mV
mA
mV
mA
mA
mA
mA
mW
mA
mV
°C
°C
°C
RECOMMENDED SETTING
Set to 10 to convert all power values to cWh or to 1 for mWh. Design Energy is
divided by this value.
Set to desired runtime remaining (in seconds/3600) * typical applied load
between reporting 0% SOC and reaching Terminate Voltage, if needed.
Set to nominal cell voltage per manufacturer datasheet.
Set to 90% of configured Design Capacity
Should be configured using TI-supplied Battery Management Studio software.
Default open-circuit voltage and resistance tables are also updated in conjunction
with this step. Do not attempt to manually update reported Device Chemistry as
this does not change all chemistry information! Always update chemistry using
the appropriate software tool (that is, BMS).
Set to applicable load model, 0 for constant current or 1 for constant power.
Set to load profile which most closely matches typical system load.
Set to initial configured value for Design Capacity. The gauge will update this
parameter automatically after the optimization cycle and for every regular Qmax
update thereafter.
Set to nominal cell voltage for a fully charged cell. The gauge will update this
parameter automatically each time full charge termination is detected.
Set to empty point reference of battery based on system needs. Typical is
between 3000 and 3200 mV.
Set to 15% of Cell0 R_a 4 resistance after an optimization cycle is completed.
Set based on nominal charge voltage for the battery in normal conditions (25°C,
etc). Used as the reference point for offsetting by Taper Voltage for full charge
termination detection.
Set to the nominal taper current of the charger + taper current tolerance to ensure
that the gauge will reliably detect charge termination.
Sets the voltage window for qualifying full charge termination. Can be set tighter
to avoid or wider to ensure possibility of reporting 100% SOC in outer JEITA
temperature ranges that use derated charging voltage.
Sets threshold for gauge detecting battery discharge. Should be set lower than
minimal system load expected in the application and higher than Quit Current.
Sets the threshold for detecting battery charge. Can be set higher or lower
depending on typical trickle charge current used. Also should be set higher than
Quit Current.
Sets threshold for gauge detecting battery relaxation. Can be set higher or lower
depending on typical standby current and exhibited in the end system.
Current profile used in capacity simulations at onset of discharge or at all times if
Load Select = 0. Should be set to nominal system load. Is automatically updated
by the gauge every cycle.
Power profile used in capacity simulations at onset of discharge or at all times if
Load Select = 0. Should be set to nominal system power. Is automatically
updated by the gauge every cycle.
Sets the threshold at which the fuel gauge enters SLEEP Mode. Take care in
setting above typical standby currents else entry to SLEEP may be
unintentionally blocked.
If auto-shutdown of fuel gauge is required prior to protect against accidental
discharge to undervoltage condition, set this to desired voltage threshold for
completely powering down the fuel gauge. Recovery occurs when a charger is
connected.
Sets the boundary between charging inhibit/suspend and charging with T1-T2
parameters. Defaults set based on recommended values from JEITA standard.
Sets the boundary between charging with T1-T2 or T2-T3 parameters. Defaults
set based on recommended values from JEITA standard.
Sets the boundary between charging with T2-T3 or T3-T4 parameters. Defaults
set based on recommended values from JEITA standard.
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