BQ27500 Datasheet, PDF (28/39 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge

bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785 – SEPTEMBER 2007
POR
www.ti.com
Exit From HIBERNATE
(Communication Activity
AND
Comm address is for bq27500/1)
OR
Battery Removed
(Control Status
[ HIBERNATE] is set to.0
BAT INSERT CHECK
Check for battery insertion
from HALT state.
No gauging
ICC = Sleep
Flags [BAT_DET] =0
Entry to NORMAL
Flags [ BAT_DET] =1
Exit FromNORMAL
Flags [ BAT_DET] =0
HIBERNATE
Disable all bq8032
subcircuits except GPIO.
Set /BAD_GD to “high”
status
ICC = Hibernate
Wakeup From HIBERNATE
Communication Activity
AND
Comm address is NOT for bq27500/1
NORMAL
Fuel gauging and data
updated every 1s,
ICC = Normal
Exit From SLEEP
| AverageCurrent ( ) | >Sleep Current
OR
Current is Detected above IWAKE
Entry to SLEEP
Operation Configuration[SLEEP] =1
AND
|AverageCurrent( )| ≤ Sleep Current
Exit From SLEEP
Flags [BAT_DET] =0
Entry To HIBERNATE
Host has set Control Status
[HIBERNATE] =1
OR
VCELL < Hibernate Voltage
SLEEP
Fuel gauging and data
updated every 60 seconds
ICC = Sleep
Figure 5-2. Power Mode Diagram
5.7.4 HIBERNATE MODE
HIBERNATE mode should be used when the system equipment needs to enter a very low-power state,
and minimal gauge power consumption is required. This mode is ideal when a system equipment is set to
its own SLEEP, HIBERNATE, or SHUTDOWN modes.
To enter HIBERNATE mode, either the system must set the [HIBERNATE] bit of the CONTROL STATUS
register OR the cell voltage must fall below Hibernate Voltage. The gauge will remain in HIBERNATE
mode until the battery is removed, or the system issues a direct I²C command to the gauge. I²C
Communication that is not directed to the gauge will not wake the gauge.
It is important that BAT_GD be set to disable status (no battery charging/discharging). This prevents a
charger application from inadvertently charging the battery before an OCV reading can be taken. It is the
system’s responsibility to wake the bq27500/1 after it has gone into HIBERNATE mode. After waking, the
gauge can proceed with the initialization of the battery information (OCV, profile selection, etc.)
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FUNCTIONAL DESCRIPTION
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