BQ24161B_15 Datasheet, PDF (19/52 Pages) Texas Instruments – bq2416xx 2.5A, Dual-Input, Single-Cell Switched-Mode Li-Ion Battery Charger with Power Path Management and I2C Interface

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bq24160, bq24160A, bq24161
bq24161B, bq24163, bq24168
SLUSAO0F – NOVEMBER 2011 – REVISED JULY 2014
Feature Description (continued)
6. The battery voltage is less than VBATSHORT.
7. The battery has entered the JEITA WARM or COLD state via the TS pin
During these events, the timer is slowed by half to extend the timer and prevent any false timer faults. Starting a
new charge cycle by VSUPPLY POR or removing/replacing the battery or resuming a charge by toggling the CE
or HZ_MODE bits, resets the safety timer. Additionally, thermal shutdown events cause the safety timer to reset.
In addition to the safety timer, the bq24160/1/1B/3 contain a watchdog timer that monitors the host through the
I²C interface. Once a read/write is performed on the I²C interface, a 30-second timer (t_WATCHDOG) is started. The
30-second timer is reset by the host using the I²C interface. This is done by writing a “1” to the reset bit
(TMR_RST) in the control register. The TMR_RST bit is automatically set to “0” when the 30-second timer is
reset. This process continues until the battery is fully charged or the safety timer expires. If the 30-second timer
expires, the IC enters DEFAULT mode where the default register values are loaded, the safety timer restarts at
27 minutes and charging continues. The I²C may be accessed again to reinitialize the desired values and restart
the watchdog timer. The watchdog timer flow chart is shown in Figure 12.
Start Safety Timer
Yes
Safety timer expired?
No
Charge Done?
ICHG < ITERM
No
Yes ^{STAT = Hi}
Update STAT
bits
No
I2C Read/Write
performed?
Yes
Start 30 second
watchdog timer
Safety timer
fault
Charging suspended
Enter suspended
mode
Fault indicated in
STAT registers
Charge Done?
ICHG < ITERM
Yes ^{STAT = Hi}
Update STAT
bits
No
Safety timer expired?
No
Yes
Safety timer
fault
Reset 30 second
watchdog timer
30s timer expired?
Yes
Charging suspended
Fault indicated in
STAT registers
No
Yes
No
Received SW watchdog
RESET?
Reset to default
values in I2C
register
Restart 27min
safety timer
Figure 12. The Watchdog Timer Flow Chart for bq2416xx
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