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bq2057C support 8V CV regulation

Paul Yeh
Genius 16125 points
Other Parts Discussed in Thread: BQ2057, BQ2057C, BQ2057W, BQ2057T

Hi all,

My customer use panasonic battery(2S1P) but its CV voltage is 8V. And due to they are familiar with bq2057 series so they would like to use bq2057C with external BAt resistor divider to implement this specification.

can you advise is it ok or any concern from you?

Thanks

Thanks

  • 0
    TI__Genius 16125 points

    Hi Expert,

    I still don't get any feedback now and my customer is pushing the possibility of this application for bq2057C.

    could I have your answer today.

    thanks

  • 0 in reply to Paul Yeh
    TI__Guru 56650 points

    I don't see any problem. But, this is a legacy part. Please order an EVM and test it before doing real project.

    Also, bq2057W supports 8.4V output and pin to pin compatible with bq2057C.

  • 0 in reply to Wang5577
    TI__Genius 16125 points
    Hi Wang,
    Customer needs 8V battery , so bq2057W is not ok for this design. and in datasheet page11, only mentioned bq2057T and bq2057W can add voltage divider between positive and negative terminals. but didn't mention bq2057c can do the same thing. that's why customer is asking?

    And from another E2E discussion, e2e.ti.com/.../38095 (it should not use external resistor divider for bq2057c because of the internal logic, for example, SLEEP comparator will be wrong.) That's why I need to double confirmation?
    Thanks
  • 0 in reply to Wang5577
    TI__Expert 3260 points

    Hi Wang,

    In addition to Paul's comment, BQ2057 will be used in the backup power unit for server.

    Could you please help us to verify this by this week? since our customer will be making the decision of whether to adopt our solution or not by this week. We need solid answer to ensure BQ2057C is perfectly capable of 8.0V output level to convince our customer.

    And of course, in the mean while we will be testing this on the EVM board, and will let you know the result within two days. Please support us to win this socket.

    Thank you very much.

    Best regards,
    Wei-Hao | Analog FAE TITL

  • 0 in reply to Wei-Hao Chen (TW-FAE)
    TI__Genius 14890 points
    Paul,

    Why does the customer want to use the bq2057C instead of the bq2057W? I am working with the design team to look into using the C version at 8V.

    Regards,

    Dick
  • 0 in reply to Dick Stacey
    TI__Genius 16125 points
    Hi Dick,
    Due to customer needs to support 8V battery voltage, so I think bq2057W can't support it with datsheet figure7 application circuit.
    If bq2057W can support thn of course, we can suggest this part.
    Please advise then we can feedback to customer.
    Thank you and Regards
  • 0 in reply to Paul Yeh
    TI__Genius 14890 points
    Paul,

    Figure 7 shows "bq2057", but the text above that in the "voltage regulation phase" discussion specifically calls out the bq2057T or bq12057W as being able to use the voltage divider to be able to set a nonstandard voltage. The T and W version are not available in all package types.

    Regards,

    Dick
  • 0 in reply to Dick Stacey
    TI__Expert 3260 points

    Hi Dick,

    We understand that BQ2057T and BQ2057W are able to set a nonstandard voltage, however based on the equation and simplified function block diagram, the outputvoltage regulation level can only be adjusted to higher voltage level than the original VOUT(REG) that specified in the data sheet. i.e. 8.2 or 8.4V. 

    That is why we are thinking of using BQ2057 or BQ2057C with external voltage divider to achieve output regulation voltage of +8.0V.

    Thanks.

    Best Regards,

    Wei-Hao