BQ27500_08 Datasheet, PDF (28/39 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge

bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785D – SEPTEMBER 2007 – REVISED APRIL 2008
POR
Exit From HIBERNATE
Battery Removed
Exit From HIBERNATE
Communication Activity
AND Comm address is for
bq27500/1
bq27500/1 clears Control Status
[HIBERNATE] = 0
Recommend Host also set Control
Status [HIBERNATE] = 0
HIBERNATE
Disable all bq27500/1
subcircuits except GPIO.
Negate BAT_GD
Wakeup From HIBERNATE
Communication Activity
AND
Comm address is NOT for
bq27500/1
BAT INSERT CHECK
Check for battery insertion
from HALT state.
No gauging
Flags [BAT_DET] = 0
Entry to NORMAL
Flags [BAT_DET] = 1
Exit From NORMAL
Flags [BAT_DET] = 0
NORMAL
Fuel gauging and data
updated every 1s
Entry to SLEEP
Operation Configuration [SLEEP] = 1
AND
| AverageCurrent( )| ≤ Sleep Current
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Exit From SLEEP
Flags [BAT_DET] = 0
Exit From WAIT_HIBERNATE
Cell relaxed
AND
| AverageCurrent() | < Hibernate
OR
Cell relaxed
AND
VCELL < Hibernate Voltage
WAIT_HIBERNATE
Fuel gauging and data
updated every 20 seconds
BAT_GD unchanged
Exit From WAIT _HIBERNATE
Host must set Control Status
[HIBERNATE] = 0
AND
VCELL > Hibernate Voltage
Exit From SLEEP
| AverageCurrent( )| > Sleep Current
OR
Current is Detected above IWAKE
SLEEP
Fuel gauging and data
updated every 20 seconds
System Shutdown
Exit From SLEEP
(Host has set Control Status
[HIBERNATE] = 1
OR
VCELL < Hibernate Voltage
Figure 5-2. Power Mode Diagram
5.7.4 HIBERNATE MODE
HIBERNATE mode should be used when the system equipment needs to enter a low-power state, and
minimal gauge power consumption is required. This mode is ideal when a system equipment is set to its
own HIBERNATE, SHUTDOWN, or OFF modes.
Before the fuel gauge can enter the HIBERNATE mode, the system must set the [HIBERNATE] bit of the
CONTROL_STATUS register. The gauge waits to enter HIBERNATE mode until it has taken a valid OCV
measurement and the magnitude of the average cell current has fallen below Hibernate Current. The
gauge can also enter HIBERNATE mode if the cell voltage falls below Hibernate Voltage, and a valid
OCV measurement has been taken. The gauge remains in HIBERNATE mode until the system issues a
direct I²C command to the gauge or a POR occurs. I²C communication that is not directed to the gauge
does not wake the gauge.
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FUNCTIONAL DESCRIPTION
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