BQ27350 Datasheet, PDF (23/33 Pages) Texas Instruments – Single Cell Li-Ion Battery Manager With Impedance Track Fuel Gauge Technology

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bq27350
Single Cell Li-Ion Battery Manager
With Impedance Track Fuel Gauge Technology
SLUS754 – MARCH 2007
Exit From HIBERNATE
Interface activity
OR
Current is Detected above IWAKE
OR
Device reset
HIBERNATE
Gas gauging and data
updating is OFF
NORMAL
Gas gauging and data
updated every1s,
ICC = Normal
Entry to SLEEP
PkCfg[SLEEP] =1
AND
| AverageCurrent( ) |≤ SleepCurrent
AND
[( If PkCfg[BUSLOW] = 1 for
t BUSLOW ≥ 5 seconds)
OR
(PkCfg[BUSLOW] = 0 )]
Exit From SLEEP
|AverageCurrent( )| > SleepCurrent
OR
Current is Detected above IWAKE
OR
Interface Activity when
PkCfg[BUSLOW] = 1
Exit From SHUTDOWN
2s after both charger is attached
AND
Protection FETs close/are closed
SHUTDOWN
Gas gauging and data
updating is OFF
ICC = Hibernate
Entry to HIBERNATE
PkCfg[HIBERNATE] = 1
AND
Entry to SLEEP still conditions met
SLEEP
Gas gauging and data
Updating every 5 seconds
ICC = Sleep
Exit From PRE_SHUTDOWN
Interface activity
OR
Current is Detected above IWAKE
OR
Device reset
I_CC = 0
Entry to SHUTDOWN
No Charger Present
Entry to PRE_SHUTDOWN
PkCfg [SHUTDOWN] = 1
PRE_SHUTDOWN
Gas gauging and data
updating is OFF
DSG FET Turned OFF
SE pin = High
ICC = Hibernate
Figure 5-1. Power Mode Diagram
5.6.1 NORMAL MODE
The gas 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.
5.6.2 SLEEP MODE
SLEEP mode is entered when (1) AverageCurrent( ) is below a programmable level Sleep Current and
(2) if the [BUSLOW] bit of Pack Configuration( ) is set and the data bus (both SCL and SDA low pins) is
low for 5s. [SLEEP] bit of Control Status( ) is set when the bq27350 enters SLEEP mode. Once entry to
SLEEP has been qualified, but prior to entry to sleep mode, the bq27350 performs an ADC autocalibration
to minimize offset. Entry into SLEEP mode can be disabled by setting the [SLEEP] bit of Pack
Configuration( ), where "0" = disabled and "1" = enabled. During SLEEP mode, the bq27350 periodically
wakes to take data measurements and update the data set, after which it then returns directly to SLEEP.
The bq27350 exits SLEEP if any entry condition is broken, a change in protection status occurs, or a
current in excess of I_WAKE through R_SENSE is detected.
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FUNCTIONAL DESCRIPTION
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