BQ76972: Regarding the timing of ADC conversion in AFE

SAI VARUN PENDELA

Part Number: BQ76972

Tool/software:

In the Technical Reference Manual, it was mentioned that in NORMAL ADC MODE, measurement time for each slot will take around 3ms. What are all process involved in that 3ms?

MUX1 and MUX2 are responsible for what?

4 months ago

0 Luis H. S. 4 months ago

TI__Mastermind 42060 points

Hello Sai,

See the following article to see how the measurement scheduled works.

Improving voltage measurement accuracy in battery monitoring systems

Best Regards,

Luis Hernandez Salomon

0 SAI VARUN PENDELA 4 months ago in reply to Luis H. S.

Prodigy 100 points

Hi Luis,

Thank you for your quick reply.

I have gone through the documentation that you have shared.

But in that document, I haven't found the process that is involved in the 3ms slot allocated for each channel. Can you please tell me if it is a normal ADC conversion why does 3ms time is needed?

And I also want to know about the MUX1 & MUX 2 in the block diagram.

Best Regards,

SAI VARUN

0 SAI VARUN PENDELA 4 months ago in reply to Luis H. S.

Prodigy 100 points

Hi Luis,

Thank you for your quick reply.

I have gone through the documentation that you have shared.

But in that document, I haven't found the process that is involved in the 3ms slot allocated for each channel. Can you please tell me if it is a normal ADC conversion why does 3ms time is needed?

And I also want to know about the MUX1 & MUX 2 in the block diagram.

Best Regards,

SAI VARUN

0 Luis H. S. 4 months ago in reply to SAI VARUN PENDELA

TI__Mastermind 42060 points

Hello Sai,

SAI VARUN PENDELA said:
But in that document, I haven't found the process that is involved in the 3ms slot allocated for each channel. Can you please tell me if it is a normal ADC conversion why does 3ms time is needed?

The part uses a delta-sigma ADC that takes measurements at a high frequency for a period of 3-ms. The reported result is the averaged value within the 3-ms. The device has a setting to make this time slot shorter, by making it 1.5-ms instead. This is the FASTADC bit.

SAI VARUN PENDELA said:
And I also want to know about the MUX1 & MUX 2 in the block diagram.

One is for the ADC measurement, the second is for comparator measurements.

Best Regards,

Luis Hernandez Salomon

0 SAI VARUN PENDELA 4 months ago in reply to Luis H. S.

Prodigy 100 points

Hi Luis,

Luis H. S. said:
The reported result is the averaged value within the 3-ms.

It means that the device has a filter which will give an average of multiple samples.

Can you tell me how many samples are averaged in one time slot of 3ms and time slot of 1.5ms?

Is there any possibility to fix the number of samples to be averaged by us?

Best Regards,

SAI VARUN

0 Luis H. S. 4 months ago in reply to SAI VARUN PENDELA

TI__Mastermind 42060 points

Hello Sai,

In essence, it does do some filtering due to how the ADC samples the voltage.

I believe it is sampled at a frequency of ~250ish kHz. I forget the exact value.

This is a fixed frequency and the number of samples cannot be changed for the voltage measurements.

Best Regards,

Luis Hernandez Salomon

0 SAI VARUN PENDELA 4 months ago in reply to Luis H. S.

Prodigy 100 points

Hello Luis,

Can I get any document where all these things are clearly mentioned for my reference?

Best Regards,

SAI VARUN

0 Luis H. S. 4 months ago in reply to SAI VARUN PENDELA

TI__Mastermind 42060 points

Hello Sai,

I do not believe there is an exact location. For performance checks, see the datasheet. With in-depth details as to how the device operates, see the Technical Reference Manual.

Best Regards,

Luis Hernandez Salomon

Power management

Power management forum

BQ76972: Regarding the timing of ADC conversion in AFE