• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 238 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS272C45: off state charge

Miroslav Mrdjan
Prodigy 175 points
Part Number: TPS272C45


Hello,

We are facing a strange behavior of HS switch. When it is turned off, without any capacitor at the output, it sparks after we leave it off for a ~minute.

We take a wire, and do the short connection between output and ground and we see a small spark.

Then we took LEDs, and when connected they blink very short, until output is "discharged???". If you try it again in a few seconds nothing happens. Only if you leave it for a minute or more.

Do you have any idea what is the reason of this?

Best regards,
Miroslav

  • 0
    TI__Mastermind 35745 points

    Miroslav,

    On the output in the off-state, there is a pull-up from VS to OUT that is approximately 150kOhm (see Rpu_OL in the datasheet). I am guessing in your case the pull-up is forming an RC circuit with the capacitance on the output and slowly charging the voltage to a state that turns on the LED.

    The open load detection resistor is enabled/disabled with DIAG_EN. Could you try to make DIAG_EN go low and still see if the issue persists?

    Thanks and Best Regards,
    Tim

  • 0 in reply to Timothy Logan
    Prodigy 175 points

    Hello Timothy,

    DIAG_EN is always low and outputs with open load. This would be true if we would have capacitor at the output. But there isn't.

    Even if some parasitic capacitance is there, but the energy we can see is not realistic for parasitic capacitance.

    Now we are testing if there are some false noise on Enable inputs that could trigger this. Will keep you updated.

    Best regards,
    Miroslav