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PWMxA output limited to 100mV

user4565873
Expert 1250 points

Other Parts Discussed in Thread: TMDSCNCD280049C

Hello all,

When branching our eval card to a motor, we had what we think is a shortcut between 3.3V and Ground.

We witness a square signal of around 100mv on our "TOP" PWMs (PWM1-2-3 A) instead of the regular 0-3.3V PWM signal. The "BOTTOM3 (èB) signal work perfectly.

I try and branch my ePWM7 then to see if it could wotk out... Same result on the ePWM 7.

Can you explain why the ePWM 7 is also not functioning?

Does it confirm a shortcut between 0 and 3.3V? 

Do you think we can find a way to make it operate again?

Thank you

PA

 

  • 0
    TI__Guru 71526 points

    Hello,

    You did not identify the EVAL card you are using.  Please provide the part number and description.

    Thank you,

    ~Leonard 

  • 0 in reply to LeonardEllis
    Expert 1250 points

    Sorry i was lost in my thoughts...

    We use the TMDSCNCD280049C F280049C controlCARD Evaluation Module.

    We encounter 2 possible shortcuts but without any power current going through:

    - our LEMs were wired with the ref value set to the Ground.

    - the IGBT drivers are driven by a 5V insteda of our 3.3V.

    My questions are mostly:

    - does the description that i provided in previous post confirm a shortcut on the PWMX-B ?

    - Is it "normal"  that even not used PWMx-B are affected?

     

    Thank you,

    PA.

  • 0 in reply to user4565873
    TI__Guru 52200 points
    If there is extra current being drawn out of the device, many things including other GPIOs can be affected. If the device is damaged due to drawing too much current, I do not think there is anyway to restore the internals.

    Sorry to hear this. Make sure you always power the device with a clean voltage on the VDD VDDIO and GND pins, and follow the maximum current limitations on the GPIOs.

    Nima