Hello~
I have a question for Safety timer duration of BQ24166.
Test conditions are
1.Initial battery voltage for charging start --> 3.31V
2.Charging mode start --> USB100 (IUSB3 = IUSB2 = IUSB1 = "0", and /CE = "0")
3. Power input source is USB port of PC.
Test results are
1.Battery voltage --> Starting from 3.31V to termination at 3.85V
2.Charging current variation --> Starting from 114mA to termination at 107mA
3.Termination time --> Charging termination after 12hours and 12minutes
In view of the overall behavior that you see is stopped by the Safety Timer (as I expected).
However, real Safety Timer duration was 2 times longer than the default 6 hours.
Below contents are from BQ24166's datasheet.
"When USB100 mode is selected, termination is disabled."
"SAFETY TIMER
At the beginning of charging process, the bq24165/6/7 starts the 6 hour safety timer. This timer is active during the entire charging process. If charging has not terminated before the safety timer expires, the charge cycle is terminated and the battery FET is turned off. To clear the safety timer fault, charging must be resumed by using CE1 and CE2 (bq24165) or CE(bq24166/7) or High Impedance mode or a new charge cycle started by VSUPPLY POR or battery remove and replace.
During the fast charge (CC) phase, several events increase the timer duration by 2X.
1. The system load current reduces the available charging current.
2. The input current needed for the fast charge current is limited by the input current loop.
3. The input current is reduced because the VINDPM loop is preventing the supply from crashing.
4. The device has entered thermal regulation because the IC junction temperature has exceeded TJ(REG).
5. The CEx bits are reducing ICHARGE or VBAT.
6. The battery voltage is less than VBATSHORT.
7. The battery has entered the JEITA WARM or COLD state via the TS pin (bq24166/6) or CE1/CE2 (bq24165)configuration."
According to the above information, as I think, my test condition & result is not a condition that meets the criteria for "Timer duration by 2X".
Would you please clarify for this behavior??
Thanks... C.W. :)
