Using the BQ76PL536 for a flexible 10S to 14S BMS design

Tobias Mueller

Other Parts Discussed in Thread: BQ76PL536

Dear Engineers,

we're working on a flexible BMS solution with a cell count reaching from 10S to 14S (with a stack of 3 bq76PL536). We just received the evaluation board, but before connecting cells to it, I need to know how to distribute the cells. The datasheet sais bq76PL536 is made for 3 to 6 cells.

Does that mean, let's say for a 13S configuration, I have to have a 4 - 4 - 5 or a 6 - 4 - 3 configuration (or such similar patterns). Or can I just straight forward connect 6 cells to lower bq76PL536, 6 cells to the middle bq76PL536, and 1 cell to the top bq76PL536?

Thanks and best regards,

Tobias

over 12 years ago

0 Tobias Mueller over 12 years ago

Prodigy 130 points

Dear,

I really need support on that issue. I've drawn a picture to show the challange.

We need to flexible with the cell count and support 10S to 14S.

Thanks and best regards,

Tobias

0 Tom Messick over 12 years ago

Prodigy 90 points

Each bq76PL536 must have at least 3 cells. Look at the section "3 to 6 Series Cell Configuration" in the data sheet.

tom

0 Tobias Mueller over 12 years ago in reply to Tom Messick

Prodigy 130 points

okay, lets assume the middle device will only have 3 cells, then it's no problem to tie its cell-voltage terminals 4-6 together with top of cell 3? Can I setup an indiviual cell count for each device?

Thanks and best!

Tobias

0 Roger Hwang over 12 years ago in reply to Tobias Mueller

TI__Genius 10785 points

You can have any combination but two things to consider.

1. 3S and above.

2. POR spec is 5V and UVLO is 5.6V. It means that your total cell voltage should be around 6V. Datasheet recommend VBAT is 7.2V. IC will function at 6V but may not meet the datahsset spec.

You can have any combinations to make 10S and 14S with 3ICs.

for 10S, I recommend two ICs if you can.

0 Roger Hwang over 12 years ago in reply to Tobias Mueller

TI__Genius 10785 points

Go see fig4 in the datasheet. It will show you how to connect cells.

If you have 4S as example, then you will connect cell4, cell5 and cell6 together.

IF you have 3S config then you will connect Cell3, cell4, cell5 and cell6 together.

You also need to config each IC to right cell counts. If not then you will get the COV and CUV faults.

0 Tobias Mueller over 12 years ago in reply to Roger Hwang

Prodigy 130 points

Thank you very much for explenation. I managed to get the EVM working.

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Using the BQ76PL536 for a flexible 10S to 14S BMS design