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CCS/BQ76940: Can we connect the AFE to battery out-of-order

kai nan
Prodigy 60 points
Part Number: BQ76940

Tool/software: Code Composer Studio

 As Normal  we connect the AFE to battery: Cell 1--> Cell 2 -->Cell 3--> Cell 4...........-->Cell 12 --Cell 13 or uesing a connector for connect

But Now  we want to change the attended mode to Solder Nickel connect AFE to battery which will change the  sequence and it will cost more time to finish the connect

1.  For Sequence:  can we change to :2,4,6,7,8,9,10,11,12,13 in the end connect 1,3,5  or

                                                                    1,2,3,4,5,6,7,9,11,13 in the end connect 8,10,12

2. For the attended mode: can we change to solder instead of connector？

thank you so much

  • 0
    TI__Guru 54715 points
    Hi Nan,
    The bq76940 was designed for random cell connection, but no special specifications were included in the data sheet. In general we found it worked well, but there are many combinations of sequences. The total BMS circuit can load the cells and potentially overstress inputs. Some users have reported damage on assembly. One area to consider is shown in www.ti.com/.../slua749a.pdf figure 21. Battery- should be connected first.
    Since your proposals have relatively small steps in cells, you may find that the proposed sequences are fine. The voltage of the node between 2 cells will be divided by the capacitors, or biased by the external diode at the intermediate power pins.
    In general connections should work well when soldered. Soldering generally allows time for the capacitor network to charge before the next terminal is connected. Select and validate a sequence suitable for your operation.
  • 0 in reply to WM5295
    Prodigy 60 points

    thank you so much 

    as i check the sample, when the sequence is cell 1. cell 3, cell 5 and then cell 2, cell 4, cell 6, cell 7......cell 13 , the AFE could  work 

    but if i change the sequence to Cell 2, Cell 4, Cell 6 , Cell 7.....Cell 13 and then Cell 1 ,Cell 3, Cell5 the AFE could not work and should reset ,then it works.

  • 0 in reply to WM5295
    Prodigy 60 points

    As Some users have reported damage on assembly, is there any suggestion for this .

    As now we bulid the samples 10Pcs there are 3Pcs damage for IC damage

    can we add bead in the battery Line?

  • 0 in reply to kai nan
    TI__Guru 54715 points
    Hi Nan,
    You should be able to add beads to the signal lines to the IC, they may not be sufficient to suppress all transients though. Inspect what is being damaged, see ideas in www.ti.com/.../slua749