BQ28Z610: sluua65d - question about the formula for balance constant

Maurizio Bonelli

Part Number: BQ28Z610

Hello

at page 42 of the BQ28Z610 TR, SLUUA65D–April 2014–Revised January 2020, the formula for the formula for Bal Time/mAh is:

Bal Time/mAh Cell x = 3600 mAs/(DUTY × (1000 mV / 1 V) × VCELL/(RVCx + Rcb))

It is different from SLUUA65C and it's OK, but what does the term 1000 mV/1V mean? (1000mV /1V) is 1 then that formula can be re-written in the form:

Bal Time/mAh Cell x = 3600 mAs/(DUTY × (1) × VCELL/(RVCx + Rcb))

and I am not sure it is correct, its results are 1 thousands different from the same values calculated with previous editions.....

It might it stay for 1000/1 -> 1000?

Please clarify

Maurizio

PS: I've tried to send a feedback but the feedback link in the pages footer is not working.

over 3 years ago

0 Andy Liu (BMS) over 3 years ago

TI__Guru 52115 points

See the discussions in the following thread.

https://e2e.ti.com/support/power-management/f/196/t/729065

Andy

0 Maurizio Bonelli over 3 years ago in reply to Andy Liu (BMS)

Expert 1400 points

Yes Andy,

I have used that..... but my question was different.

what the hell does "1000 mV/1V" mean? it is 1000 or it is 1? the end result is a lot different, absolutely 1 thousand times different!

Maurizio

PS: I would have send the feedback by the document feedback link in the sluua65d footer, unfortunately it was not working ....

0 Dominik Hartl11 over 3 years ago in reply to Maurizio Bonelli

TI__Guru 51346 points

It means 1000 if VCell is in [V] and R is in [Ohm]. Because the resulting current would then be in [A] and to make this mA (for the Bal Time / [mAh]), you'll have to multiply this by 1000.

Bal Time/mAh Cell x = 3600 mAs/(DUTY × (1000) × VCELL/(RVCx + Rcb))

0 Maurizio Bonelli over 3 years ago in reply to Dominik Hartl11

Expert 1400 points

Thanks,

that's ok, then!

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BQ28Z610: sluua65d - question about the formula for balance constant