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UCC28070: Current sense w/o trance

Kuramochi Tadahiko
Guru 28715 points

Part Number: UCC28070

Hi,

Using transformer is recommended for current sense on the datasheet.

My customer hopes to realize current sense without transformer on the UCC28070.

Is it possible?

Best Regards,

Kuramochi

  • 0
    TI__Mastermind 34465 points
    Hello Kuramochi,
    Most of the applications and references designs use a current transformer for sensing the inductor current but it is possible to use resistive sensing.
    You can place a small resistor between the source and ground of each boost FETs and use a high speed OPAMP to amplify these current sense signals.

    Regards
    John
  • 0 in reply to John Griffin1
    Guru 28715 points
    John-san,

    Thank you for your support.

    I have an additional question.

    >You can place a small resistor between the source and ground of each boost FETs and use a high speed OPAMP to amplify these current sense signals.

    Can the CSA/B pin of UCC28070 receive output of current sense opamp directly?
    Please let me know if there is an application note for this usage.

    Best Regards,
    Kuramochi
  • 0 in reply to Kuramochi Tadahiko
    TI__Mastermind 34465 points

    5618.TIDA-0130A(001)_Sch.PDFHi Kuramochi-san,

    That is correct. You do not need to use an opamp .

    You  can connect the sense voltage directly to the opamp but you will need about 3V for the full scale range.

    This will result in a lot of power dissipation in the sense resistor.

    There is no app note for this procedure but attached is a reference design for a 300W application.