BQ27426 Thermistor

Dan Cristy

Other Parts Discussed in Thread: BQ27426, BQ24072T

Hi Team –

Posting this on customer’s behalf.

Planning to use a bq24072T to charge a single Li-Ion cell, along with a bq27426 fuel gauge for monitoring. Both devices have a thermistor input for one located in the battery pack.

Is there a way to avoid putting a separate thermistor in the battery pack for each device?

The thermistor current is sourced internally from the fuel gauge and externally for the charger, so simply using a single thermistor with both inputs connected to it doesn’t appear to work.

Alternately, do you have any recommendations for a fuel gauge that doesn’t require a thermistor?

Thank you,

over 7 years ago

0 Dominik Hartl11 over 7 years ago

TI__Guru 54076 points

Hello,

The bq27426 has an internal temperature sensor so if the gauge is close to the cell this may be an option. All fuel gauges require temperature information. The bq27426 has the most flexibility: You can use an external thermistor, the internal temperature sensor or you can write the temperature data periodically from a host uC (if this one has the temperature data).

Regards,
Dominik.

0 Dan Cristy over 7 years ago in reply to Dominik Hartl11

TI__Intellectual 2615 points

Hi Dominik -

That's a good suggestion. How close would the gauge have to be to the cell? I couldn't find information on this in the datasheet.

Thanks!

0 Dominik Hartl11 over 7 years ago in reply to Dan Cristy

TI__Guru 54076 points

Dan,

As long as the gauge is within a few (+/-5) degrees C of the cell it should be ok.

.Dominik.

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BQ27426 Thermistor