BQ24187 Datasheet, PDF (19/44 Pages) Texas Instruments – 1A USB-OTG Support

Not Recommended for New Designs
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Device Functional Modes (continued)
Start Safety Timer
bq24187
SLUSBM0 – APRIL 2014
Safety timer expired? ^Yes
No
Charge Done?
I_CHG < I_TERM
No
Yes ^{STAT = Hi}
Update STAT
bits
No
I²C Read/Write
performed?
Yes
Start watchdog timer
Safety timer
fault
Charging suspended
Enter suspended
mode
Fault indicated in
STAT registers
Charge Done? ^Yes
I_CHG < I_TERM
STAT = Hi
Update STAT
bits
Reset watchdog timer
No
Yes
Safety timer expired?
Safety timer
fault
No
WD timer expired?
Yes
Charging suspended
Enter suspended
mode
Fault indicated in
STAT registers
No
Yes
No
Received
software watchdog
RESET?
Reset to default
values in I²C
register
Restart 40 min
safety timer
Figure 9. The Watchdog Timer Flow Chart For Bq24187
8.4.1.1.9 LDO Output (DRV)
The bq24187 contains a linear regulator (DRV) that is used to supply the internal MOSFET drivers and other
circuitry. Additionally, DRV supplies up to 10mA external loads to power the STAT LED or the USB transceiver
circuitry. The maximum value of the DRV output is 5.3V so it ideal to protect voltage sensitive USB circuits. The
LDO is on whenever a supply is connected to the input of the bq24187. The LDO is on whenever a supply is
connected to the input of the bq24187. The DRV is disabled under the following conditions:
1. V_SUPPLY < UVLO
2. V_SUPPLY < V_BAT + V_SLP
3. Thermal Shutdown
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