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DRV8302: Guidelines on setting Vsense.

John Linehan18
Prodigy 20 points

Part Number: DRV8302
Other Parts Discussed in Thread: TPS54160

I could not find specific instructions for setting Vsense in the datasheet. I am reviewing a design that uses a 5.36K/1K resistive divider between control voltage and ground to set the feedback level at Vsense. What are the rules/constraints for setting the feedback value?  I have a failed return that provides 8.25V at PH. Can I deduct that Vsense is OC or that I have internal damage?

 

  • 0
    TI__Guru** 114905 points
    Hi John,

    There is much more information about the buck converter here: www.ti.com/.../slvsb56c.pdf

    This is the full TPS54160 datasheet.

    We will contact the buck converter team for more specific details. Please let us know if you have any additional questions.
    From your description, you are trying to achieve a 5V output. Is that correct?
    What is the VIN voltage?
    What is the EN voltage?
  • 0 in reply to Rick Duncan
    Prodigy 20 points

    Rick,

    Thanks for the buck converter link, that was helpful, lots of good info there.

    Yes, we are trying to achieve 5V and we do get that on a production board.

    We received a return however that is reporting current offset fault. Normally my current offset is at 2.5V, but this one is measuring 1.6V. I then noticed that my 5V is not 5V but at 8.25V. Vsense, which is at 0.8V on a normal board, is showing 1.29V. Makes sense from the resistive divider perspective but looks like the internal reference is off.

    Anything external to the device that could cause this?

    Any event that might cause it.

    VIN (PVDD) is 12V to 20V depending on load.

    The EN_BUCK is open circuit.

    The EN_GATE pin is pulled low with a 1K to ground unless driven by the controlling processor to 3.3V.

  • 0 in reply to John Linehan18
    TI__Guru** 114905 points
    Hi John,

    The buck converter group has been notified and should reply next. If you do not hear back from them in a day or two, please feel free to ping me.
  • 0 in reply to Rick Duncan
    TI__Guru**** 191445 points
    The resistor divider sets the output voltage. The converter duty cycle is controlled so that the out put is correct when VSENSE = 0.8 V. Sounds like you either have a faulty error amp, faulty reference or some external voltage is forcing 8.35 V on your output. Can you post your schematic?