BQ27500-V120 Datasheet, PDF (26/36 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge

bq27500-V120
System-Side Impedance Track™ Fuel Gauge
SLUS880 – OCTOBER 2008
POR
www.ti.com
Exit From HIBERNATE
Battery Removed
Exit From HIBERNATE
Communication Activity
AND Comm address is for bq27500
bq27500 clears Control Status
[HIBERNATE] = 0
Recommend Host also set Control
Status [HIBERNATE] = 0
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
Exit From SLEEP
Flags [BAT_DET] = 0
HIBERNATE
Disable all bq 27500
subcircuits except GPIO .
Negate /BAT _GD
Wakeup From HIBERNATE
Communication Activity
AND
Comm address is NOT for bq27500
Entry to SLEEP+
Operation Configuration[SLEEP] = 1
AND
Control Status[SNOOZE] = 1
AND
| AverageCurrent( ) | ≤ Sleep Current
Entry to SLEEP
Operation Configuration[SLEEP] = 1
AND
| AverageCurrent( ) | ≤ Sleep Current
AND
Control Status[SNOOZE] = 0
Exit From WAIT_HIBERNATE
Cell relaxed
AND
| AverageCurrent() | < Hibernate
Current
WAIT_HIBERNATE
OR
Cell relaxed
AND
V_CELL < Hibernate Voltage
Fuel gauging and data
updated every 20 seconds
/BAT _GD unchanged
System Shutdown
Entry to SLEEP+
Control Status[SNOOZE] = 0
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
Exit From SLEEP+
Any communication to the gauge
OR
| AverageCurrent( ) | > Sleep Current
OR
Current is Detected above IWAKE
SLEEP+
Fuel gauging and data
updated every 20 seconds
Both LFO and HFO are ON
Entry to SLEEP+
Control Status[SNOOZE] = 1
SLEEP
Fuel gauging and data
updated every 20 seconds
(LFO ON and HFO OFF )
Exit From SLEEP
(Host has set Control Status
[HIBERNATE] = 1
OR
VCELL < Hibernate Voltage
System Sleep
Figure 5-1. Power Mode Diagram
5.7.2 NORMAL MODE
The fuel gauge is in NORMAL mode when not in any other power mode. During this mode,
AverageCurrent( ), Voltage( ) and Temperature( ) measurements are taken, and the interface data set is
updated. Decisions to change states are also made. This mode is exited by activating a different power
mode.
Because the gauge consumes the most power in NORMAL mode, the Impedance Track™ algorithm
minimizes the time the fuel gauge remains in this mode.
26
FUNCTIONAL DESCRIPTION
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