BQ25798: BQ25798 cut-off current accuracy problem

Hi Q,

All of our higher current chargers require that the charge current setting be reduced for highest ITERM and ICHG accuracy.  At lower ICHG settings, we turn off a portion of the battery FET to make it more resistive and therefore provide more accurate current measurement.  Per below, the BQ25798 current setting must be below 1A for highest accuracy.

I do not have data for ITERM=80mA but it will be slightly worse than the +/-20% shown for ITERM=120mA shown above.

Regards,

Jeff

HI  ti team.

          When I set the charging current to 3.2A and the charging cutoff current to 80mA, the accuracy of the charging cutoff current will be worse than 80mA±20%. So I need to define the accuracy of the charging cutoff current to what is reasonable? (I used the data of BQ25798 or BQ4050 log, and the measured charging cutoff current reached about 180mA, which exceeded the cutoff current specification defined in the datasheet of BQ25798.) I could not find the corresponding documents to prove whether my test data was reasonable.      

Hi Q,

If the host changes ICHG < 1A once the charger reports taper charger and/or measured IBAT current < 1A, ITERM accuracy will be slightly higher than the +/-20% listed in the datasheet for ITERM=120mA (see excerpt above).  I do not have data for ITERM=80mA but I estimate it to be +/-30%.

Regards,

Jeff

HI  ti team.

            But my charging current is 3.2A, not less than 1A, in this case set 80mA cut-off current can also achieve 80mA±30% accuracy?