BQ27750: Common design with BQ25896

Maciej Przybecki

Part Number: BQ27750

I have successfully implemented BQ25896 design for my 1-cell 18650 Li-Ion batterry. Now I'd like to implement more precise battery charge/discharge metering using battery gauge chip BQ27750.

I'm just wondering how to properly implement NTC component? Should I use both of them on my cell or should I leave one not connected ?

over 6 years ago

0 Nabil M over 6 years ago

TI__Intellectual 1840 points

In order for the gauge to operate accurately, accurate measurement of the cell's temperature is desirable - this is what the external temp sensor is for. You can read this external temperature value via I2C from the gauge and possibly use that reading to regulate the charger's behavior.

0 Maciej Przybecki over 6 years ago in reply to Nabil M

Prodigy 100 points

How can I "regulate the charger's behavior" using temperature readings from gauge ? I read BQ29896 documentation and found no way to set up temperature by I2C registry.

0 Nabil M over 6 years ago in reply to Maciej Przybecki

TI__Intellectual 1840 points

You're right there isn't really way in this case. You can try depending on the internal sensor of the gauge solely and seeing how the accuracy is vs. with the external temp sensor, and based on the results decide what is satisfactory to you.

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BQ27750: Common design with BQ25896