Datasheet

Exit From SLEEP
Pack Configuration [SLEEP] = 0
OR
| AverageCurrent( ) | > Sleep Current
OR
Current is Detected above I
WAKE
Exit From SLEEP
Fuel gauging and data
updated every 1s
NORMAL
Disable all bq27541
subcircuits except GPIO.
HIBERNATE
Entry to SLEEP
Pack Configuration [SLEEP] = 1
AND
| AverageCurrent( ) |≤ Sleep Current
Wakeup From HIBERNATE
Communication Activity
AND
Comm address is NOT for bq27541
Exit From HIBERNATE
V
CELL
< POR threshold
POR
Exit From WAIT_HIBERNATE
| AverageCurrent() | < Hibernate
Current
OR
(Supports SE pin shutdown function)
AND
System Shutdown
Exit From WAIT_HIBERNATE
Exit From HIBERNATE
Communication Activity
OR
bq27541 clears Control Status
[HIBERNATE] = 0
Recommend Host also set Control
Status [HIBERNATE] = 0
WAIT_HIBERNATE
Fuel gauging and data
updated every 20 seconds
System Sleep
FULLSLEEP
Exit From
Any
Communication
Cmd
V
CELL
< Hibernate Voltage
Host has set Control Status
[HIBERNATE] = 1
Cell relaxed
| AverageCurrent() | =>Hibernate
Current
OR
Cell not relaxed
Note: Control Status [FULLSLEEP]
is cleared if Full Sleep Wait Time
<= 0
Fuel gauging and data
updated every 20 seconds
SLEEP
In low power state of SLEEP
mode. Gas gauging and data
updated every 20 seconds
FULLSLEEP
FULLSLEEP Count Down
WAITFULLSLEEP
Entry to FULLSLEEP
If Full Sleep Wait Time = 0,
Host must set Control Status
[FULLSLEEP]=1
Entry to WAITFULLSLEEP
If Full Sleep Wait Time > 0,
Guage ignores Control Status
[FULLSLEEP]
Entry to FULLSLEEP
Count <1
Exit From WAITFULLSLEEP
Any Communication Cmd
bq27541-G1
www.ti.com SLUSAL6C –NOVEMBER 2011–REVISED OCTOBER 2012
Figure 3. Power Mode Diagram
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.
SLEEP MODE
SLEEP mode is entered automatically if the feature is enabled (Pack Configuration [SLEEP]) = 1) and
AverageCurrent( ) is below the programmable level Sleep Current. Once entry into SLEEP mode has been
qualified, but prior to entering it, the bq27541-G1 performs an ADC autocalibration to minimize offset.
While in SLEEP mode, the fuel gauge can suspend serial communications as much as 4ms by holding the comm
line(s) low. This delay is necessary to correctly process host communication, since the fuel gauge processor is
mostly halted in SLEEP mode.
During the SLEEP mode, the bq27541-G1 periodically takes data measurements and updates its data set.
However, a majority of its time is spent in an idle condition.
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Product Folder Links: bq27541-G1