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TPS5450: reverse current at power off

Shinichi Inoue
Guru 21626 points
Part Number: TPS5450

Dear Specialists,

My customer is testing TPS5450 and has a question.

I would be grateful if you could advise.

---

When power is off, 5V output seems to be dischaged to 24V input.

Is there any problem?

Or is additional circuit needed? 

---

I appreciate your great help in advance.

Best regards,

Shinichi

inquiry about TPS5450.xlsx

  • 0
    TI__Guru 72315 points
    In general it is not a good idea to let the output discharge into the input.
    The current path is through the internal body diode of the power MOSFET.
    The current through this path can cause unexpected issues.
    If this conditions is found is your application, then a Schottky diode between VOUT
    and VIN pins, with cathode to VIN, would be prudent.
  • 0 in reply to Frank De Stasi
    Guru 21626 points

    Hi Frank,

    Thank you for your reply.

    I understand external schottky diode is needed in some cases,

    I'll share your suggestion with the customer.

    In addition, I responded to consider the output discharge circuit.

    I appreciate your great help.

    Best regards,

    Shinichi