BQ34z100-G1 Design Energy

Jeff Lam55

Other Parts Discussed in Thread: BQ34Z100-G1

Hi,

I have a question regarding the design energy parameter for the battery gauge. Our design uses a 1S4P Li-ion battery. Each cell is 3.7V, 3Ah so the total design energy is = 3.7V * (3Ah*4) = 44400mWh. However, this seems to exceed the max input for the Design Energy field.

Looking through the datasheet, I found that there is a field called the Design Energy scale. I think by changing the design energy scale to 2 should fix my problem:

Design Energy Scale = 2

Design Energy = 22200

The actual reading for reserve energy, avg power last run, user rate will need to be multiply by the design energy scale (2) as well.

Please let me know if I am understanding the document correctly. Thank you so much!

over 9 years ago

0 ThomasCosby over 9 years ago

TI__Guru 73830 points

The Design Energy is entered at a single cell level on the bq34z100-G1 device, so your Design Energy will be 11100mWh. The Design Energy Scale is also available and it works as you described.

0 Jeff Lam55 over 9 years ago in reply to ThomasCosby

Intellectual 420 points

Thank you for your quick response.

So even the battery cells are connected to the gauge in parallel. I should enter the design energy = 11100mWh and design capacity = 3000mA?

If that's true, should I set VOLSEL bit high so the gauge knows there is more than one cell? Also, I can only enter the number of series cells but not parallel cell?

0 ThomasCosby over 9 years ago in reply to Jeff Lam55

TI__Guru 73830 points

I am sorry. I am so used to seeing users use multi-cell, the I did not notice that yours was 4P. You are correct that the Design Energy will be 44400mWh and you can use scaling to set it to 22200mWh.

0 Jeff Lam55 over 9 years ago in reply to ThomasCosby

Intellectual 420 points

Great. Thank you for the clarification.

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BQ34z100-G1 Design Energy