BQ2084-V140_14 Datasheet, PDF (19/64 Pages) Texas Instruments – SBS v1.1-COMPLIANT GAS GAUGE FOR USE WITH THE bq29312

bq2084-V140
www.ti.com
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Activation
The display may be activated at any time by a high-to-low transition on the DISP input. This is usually
accomplished with a pullup resistor and a pushbutton switch. Detection of the transition activates the display and
starts a 4-s display timer. Reactivation of the display requires that the DISP input return to a logic-high state and
then transition low again. The second high-to-low transition can be detected only after the display timer expires.
If unused, the DISP input must be pulled up to VCC. If the EDV0 bit is set, the bq2084-V140 disables the LED
display.
Display Modes
In relative mode, each LED output represents 20%, 25%, or 33% of the RelativeStateOfCharge() value. In
absolute mode, each LED output represents 20%, 25% or 33% of the AbsoluteStateOfCharge() value. Table 7
shows the display options for 5 LEDs, for 4 LEDs, Table 8 and Table 9 for 3 LEDs. In either mode, the
bq2084-V140 blinks the LED display if RemainingCapacity() is less than Remaining CapacityAlarm(). The
display is disabled if EDV0 = 1.
Table 7. Display Mode for Five LEDs
CONDITION
RELATIVE OR ABSOLUTE
StateOfCharge()
EDV0 = 1
<20%
≤20%, < 40%
≤40%, < 60%
≤60%, < 80%
≤80%
LED1
OFF
ON
ON
ON
ON
ON
FIVE-LED DISPLAY OPTION
LED2
OFF
OFF
ON
ON
ON
ON
LED3
OFF
OFF
OFF
ON
ON
ON
LED4
OFF
OFF
OFF
OFF
ON
ON
LED5
OFF
OFF
OFF
OFF
OFF
ON
Table 8. Display Mode for Four LEDs
CONDITION
RELATIVE OR ABSOLUTE
StateOfCharge()
EDV0 = 1
<25%
≤25%, < 50%
≤50%, < 75%
≤75%
FOUR-LED DISPLAY OPTION
LED1
OFF
ON
ON
ON
ON
LED2
OFF
OFF
ON
ON
ON
LED3
OFF
OFF
OFF
ON
ON
LED4
OFF
OFF
OFF
OFF
ON
Table 9. Display Mode for Three LEDs
CONDITION
RELATIVE OR ABSOLUTE
StateOfCharge()
EDV0 = 1
<34%
≤34%, < 67%
≤67%
THREE-LED DISPLAY OPTION
LED1
OFF
ON
ON
ON
LED2
OFF
OFF
ON
ON
LED3
OFF
OFF
OFF
ON
LI-ION PROTECTION
The bq2084-V140 along with the bq29312 provides protection for Li-ion batteries, as shown in Table 10. The
bq2084-V140 measures temperature and current and uses the bq29312 to measure individual cell voltage. The
bq2084-V140 uses this information to determine protection requirements and control the safety FETs or SAFE
output as necessary. It is recommended that the bq2084-V140 protection control be validated by two successive
measurements by setting VOD=1 in Misc Configuration.
Submit Documentation Feedback
19