BQ24079: Temperature Range window

Jake Salmi

Part Number: BQ24079

Hi folks -

I'm looking for a way to decrease the temperature range of a design using BQ24079 to 5C-40C. In the datasheet, we include equations and calculations to _widen_ the temperature range. Is there a circuit or some other trick to restrict the range? Perhaps with a different NTC?

Thanks,
Jake

over 5 years ago

0 Raheem over 5 years ago

TI__Mastermind 21590 points

Hello Jake,
Do you mean -5C to 40C?

0 Jake Salmi over 5 years ago in reply to Raheem

TI__Expert 7055 points

No, +5C to +40C.

Thanks,

Jake

0 Raheem over 5 years ago in reply to Jake Salmi

TI__Mastermind 21590 points

Hello Jake,
Take a look at the BQ24079T. It has a voltage based thermistor monitoring.

0 Jake Salmi over 5 years ago in reply to Raheem

TI__Expert 7055 points

Would it be possible to use a different NTD? 20k or 100k perhaps? Changing the charger at this point of the project is highly undesirable.

0 Raheem over 5 years ago in reply to Jake Salmi

TI__Mastermind 21590 points

Jake,
Only the 103AT-2 is recommended with this device. You can extend the range but not reduce it due to the bias current and the internal comparator thresholds. The BQ24079T is pin to pin compatible with the BQ24079. Only change that would be needed is a routing change if that is possible at the stage of the project.

0 Jake Salmi over 5 years ago in reply to Raheem

TI__Expert 7055 points

What specifically is the routing change required?

0 Raheem over 5 years ago in reply to Jake Salmi

TI__Mastermind 21590 points

Jake,

You'll need to add 2 resistors as shown below and connect to VIN.

Power management

Power management forum

BQ24079: Temperature Range window