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TPS40090EVM-001: Why can’t I measure the same CLOSED LOOP BODE PLOT in TPS40090EVM-001?

Jun
Prodigy 30 points
Part Number: TPS40090EVM-001

Tool/software:

The following are the measurement tools I use.

Is there an error in the measurement connection method? Or is there another problem? 

Measurement circuit:TPS40090EVM-001
Measuring Bode Plot equipment: Venable Model 6305
Power supply: Chroma 62012P-80-60  
Load: electronic load  C.C : 10A
Vin : 12V Vo :1.37V  Iout : 10A

thank you for your answer


  • 0
    TI__Expert 4970 points

    Hello,

    You are injecting 100 mV between FB and VOUT which is a lot of current for the converter to match. I would recommend setting the injection level to 10mV and see if that helps the bode plot.

    If this does not help, please send pictures of the connection from the injection isolation transformer and the oscilloscope probes.

    Regards,

    Maha

  • 0 in reply to Maha Noor
    Prodigy 30 points

    Hello ,

    Thank for your reply.

    I will change it to 10mv and do it again,
    But there is still no improvement.
    The injection isolation transformer is connected using BNC to alligator clips.

    Best Regards , Jun
     
  • 0 in reply to Jun
    Prodigy 30 points

    Hi ,

    Later I found out that there was a problem with the 1:1 transformer, so I replaced it and the problem was solved.
    Thank you very much for your help.
    Vin = 10V Io = 5A
  • 0 in reply to Jun
    TI__Expert 4970 points

    Hi Jun,

    I am happy the problem was resolved. I will be closing this thread.

    Regards,

    Maha