BQ76940: Under temperature during charge (UTC) not tripping

Correction: BQ76940/BQ78350 chipset

Please check TRM, 3.7.3.

The gauge will only turn off the charge FET, if SafetyStatus()[UTC] = 1 (not just SafetyAlert()[UTC]).

Note that the gauge will turn on the charge FET even if SafetyStatus()[UTC] = 1, if there's a significant discharge current present so that the charge FET body diode is protected.

SafetyStatus A+B (high) UTC is 1, Operation Status A CHG is on, and it is charging at 98 mA.

I tried to attach a screen shot, but was not successful.

Spencer

What's the voltage on the AFE CHG pin?

I will have to dig into the battery to get that.

For what it's worth, I am able to toggle the FETs off and on with the enable pin. And Operation Status A CHG indication does follow when the CHG/DSG FETs are on or off - as well as the charge current that is applied to the pack.

What bq78350 firmware are you running?

bq78350_R1 1e9b_1_03

I just loaded 1e9b_3_00

Same issue. Also (probably related) this issue applies to the Over Temperature Charge. No cut off.

I get the UTC or OTC flag depending on the test, and the SS flag, yet the CHG flag remains on (as well as the FET).

Please attach a screenshot of all byte registers so that I can see what flags are actually set.

I hope this zooms out OK.  Let me know

Please enable the OTFET bit. I know that the TRM doesn't list UTC for this bit but the FW code requires OTFET = 1 for the CHG FET to turn off if UTC = 1 (not just OTC).