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TPS63031: Disconnect at shut down

Stefan Lintner
Expert 4255 points
Part Number: TPS63031

Hi,

I have a question regarding the "Load Disconnect During Shutdown" feature. Input voltage is 5V, output voltage is 3.3V. When i shut down the device Vin is 0V but the output voltage is still at 3.3V due to an external source. Can this voltage at the output during shutdown influence the input side of the converter?

Am i safe to assume that as long as EN is GND the input side can not be influenced by the output side?

"The device is put into operation when EN is set high. It is put into a shutdown mode when EN is set to GND. In shutdown mode, the regulator stops switching, all internal control circuitry is switched off, and the load is disconnected from the input."

Thank you!

BR,
Stefan

  • 0
    TI__Guru 58225 points
    Hello Stefan,

    As the device does not have a supply voltage anymore, it is not really in shutdown, it is in UVLO instead. There will be some current going into VOUT of the device because of the FB divider inside the IC which is not disabled during shutdown.

    What is applied to VIN during this time and which voltage do you expect there? Is the 0V on VIN a short to GND or is the input side open and high impedance?

    I want to test your case in the lab but need to fully understand your use case first.
  • 0
    TI__Expert 7925 points
    Hi Stefan,

    Does this resolve your question?

    Best regards,
    Milos