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BQ77915: Under Voltage Cutoff issue

Part Number: BQ77915
Other Parts Discussed in Thread: TEST

Hi we have BQ7791501 based BMS under production and facing major issue of under voltage cutoff/threshold, which is mentioned as 2800mV in Datasheet but in actual we are getting different UV cutoff in different boards, we tested 100+ boards but getting same issue.

Earlier at R&D time, everything worked fine, All cuttoff's were ok, UV cutoff was around 2770, 2780,2800mV, but now we are getting it 2850, 2880 & upto 2940mV also.

We are using Auto grade parts.

We want to know which part can affect Under Voltage cutoff.

Why we are getting UV cutoff at 2940mV?

We are using recommended circuit only, please help to diagnose problem & provide solution as soon as possible.

Regards

  • Hi Pankaj,

    Can you describe how you are testing the UV cutoff? Can you verify that all of your devices are BQ7791501? What do you mean by Auto grad parts?

    Best regards,

    Matt

  • Hi,

    Yes, all parts are same BQ7791501. We are using 5A Load(DC Electronic Load).

    Auto Grade parts means Automotive parts.

  • Hi Pankaj,

    There is no automotive grade version of the BQ77915. TI automotive devices will have -Q1 in the part name. However, I do not think this is relevant to the issue.

    Can you describe your test in a little more detail? For example, are you forcing the same voltage on all cell inputs, are you forcing one cell input low, or do you have cells connected and are discharging with the load? If the latter, how are you measuring the voltages on each cell?

    Regards,

    Matt