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TPS65217C: LDO3/LDO4 is not disabled even though PWR_EN pin is pulled "Low"

Kaka
Guru 24520 points
Other Parts Discussed in Thread: TPS65217

Hi community member, 

Please let me confirm the following question.

[Question]

  The output power of LDO3 and LDO4 of TPS65217 were not disabled even though PWR_EN pin was pulled "Low" (i.e. OFF mode).

  I confirmed this phenomenon on BeagleBone Black board.  Just in case, I show the URL of schematics as below.

https://github.com/CircuitCo/BeagleBone-Black/blob/master/BBB_SCH.pdf?raw=true

  Would you please provide your advice for this phenomenon in order to solve?

If you have any questions, please let me know.

Best regards.

Kaka

  • 0
    Guru 24520 points

    Hi community member,
    Would you please provide your advice for my question?

    Also, we did some tests with some power source by using BBB board.  As a result, it seems that this phenomenon will be occurred in case of using USB power and battery.

    When I used the 5V DC power for AC pin, this phenomenon did not occurred.
    In case of using USB power, LDO3 output the 0.16V even though PWR_EN pin is pulled low. In addttion, LDO3 output the 1.40V with battery.

    Best regards.
    Kaka

  • 0 in reply to Kaka
    TI__Expert 3740 points

    Kaka,

     

    What is the voltage of the system pin when the power enable is pulled low?

     

    Janice

  • 0 in reply to Janice Escobar
    Guru 24520 points

    Hi Janice,
    Thank you for response.

    I re-checked the System pin when the power enable pin is pulled low, the output voltage of sys pin was 1.1V.

    Best regards.
    Kaka

  • 0 in reply to Kaka
    TI__Expert 3740 points

    Kaka,

    Thank you for validating that for me. Does this issue still occur when all loads are removed from the device? It could be that the power is flowing back from elsewhere on the platform, causing the LDOs to float at odd voltages even in off state. I am currently working on recreating this in our lab to better diagnose this issue you are seeing.

    Janice

  • 0 in reply to Janice Escobar
    Guru 24520 points
    Hi Janice,

    Thank you for your comments.
    We do not have answer for your question because it can not destroy the beaglebone black.
    In addition, your reproducing test is very helpful for us. If you have any update for this issue, please share it with us.

    Best regards.
    Kaka