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TPS65130　ABSOLUTE　FBN

T Kishi
Genius 4425 points
Other Parts Discussed in Thread: TPS65130

Hello

My customer has a question about TPS65130 absolute FBN.Please let me consult.

Absolute FBN is written in DataSheet at -0.3V.but my customer says,

When the power is turned off,FBN drops to -0.7V.Please look at the waveform of the attached file.

This wavefom,When the power is off,Vout=-5.0V,it becomes VREF=0V.

Therefore FBN is I think is to be a -V.But it to drop to -0.7V is correct? it is not correct?

Please teach me about it.

Regards

 8726.TPS65130.pdf

  • 0
    TI__Guru 65450 points
    Hello T Kishi,
    The value on FBN is just defined when the IC is turned on and then it should be 0V. GND level is the reference level for the negative output. When the IC is turned off, the reference voltage is off and therefore FBN might go negative as long as the output is not discharged.
    Best regards,Brigitte
  • 0 in reply to Brigitte
    Genius 4425 points
    Hello BrigitteThank you for reply.
    As expected,i'm there is a possibility that the fall to a nagative voltage at FBN.
    Device is no problem even if the voltage falls to -0.7V? Or should be added the discharge circuit?
    Best Regards,T Kishi
  • 0 in reply to T Kishi
    TI__Guru 65450 points
    Hello T Kishi,Please excuse the late response.
    The part clamps to the negative voltage and as long as the current causing this negative voltage is coming from the feedback divider, the IC will not get damaged.
    Do you have anything else connected to FBN than the feedback divider and the feedforward parts?
    Best regards, Brigitte
  • 0 in reply to Brigitte
    Genius 4425 points

    Hi Brigitte

    Thank you for replay.

    I was relieved "No damege".

    And condition of my customer is attachment.

    Regurd

    T Kishi

    TPS65130.pdf

  • 0 in reply to T Kishi
    TI__Guru 65450 points
    Hello T Kishi,
    Thank you for the setup. There is no additional circuit attached to the FBN pin, so the negative voltage when the output is turned off will not damage the part.
    Best regards,Brigitte