BQ34110: technical support for BQ34110

May

Part Number: BQ34110
Other Parts Discussed in Thread: TMS320F280049

Hi Team,

Good day, we have received query from customer and they want to drive TS pin of BQ34110 from DAC output of TMS32F280049.

They want to remove the NTC from TS pin and directly drive TS pin by DAC. Is this possible?

The customer also want to know the internal structure of the TS pin of the device.

Thank you and looking forward for your kind response.

Regards,

Maynard

over 4 years ago

0 Wyatt Keller over 4 years ago

TI__Guru** 105760 points

Hello Maynard,

This would be hard to correlate within the gauge, the firmware uses a polynomial fit to calculate the temperature based on the voltage on the TS pin. There's a 5Kohm pulldown internally. If the DAC supplies the same voltages the thermistor network would then it could work.

They can also use the internal thermistor instead.

Sincerely,

Wyatt Keller

0 Olus Onder CAGLAR over 4 years ago in reply to Wyatt Keller

Prodigy 30 points

Hello Wyatt,

In my design, i have two series 12V batteries and i have to measure each battery's temperatures individually, process inside the mcu for various uses and drive the BQ34110 TS pin for fuel gauging. I observed that, BQ34110 samples TS pin for 140 ms in every 2 seconds with a 5k pull-down resistor. In this case TMS320F280049' s buffered DAC's can drive TS pin directly.

Can you please confirm and comment for my above ideas ?

Best Regards,

Oluş Önder Çağlar

0 Wyatt Keller over 4 years ago in reply to Olus Onder CAGLAR

TI__Guru** 105760 points

Hello Maynard,

I would not recommend using a DAC to try to correlate temperature with voltage, unless like I posted earlier you can replicate the voltage on the TS pin exactly so the gauge can't tell the difference.

I think this configuration will be hard to achieve successfully.