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UCC28070: PIN #1, PIN #14, PIN #17 MULTIPLE SIGNALS

Eddie Loy
Intellectual 850 points
Part Number: UCC28070

UCC28070 IPFC CONTROLLER IC

PICTURE 1)  THIS IS A CAPTURED SIGNAL OF PIN #1 (USING THE STOP FEATURE OF THE OSCILLOSCOPE) FROM PIN #1.

PICTURE 2)  THIS IS THE SAME WAVEFORM AS PICTURE 1 AFTER I CLICKED THE HORIZONTAL OF THE SCOPE. 

PICTURE 3)  THIS IS A CAPTURED SIGNAL OF PINS 14 & 17  (USING THE STOP FEATURE OF THE OSCILLOSCOPE). 

PICTURE 4)  THIS IS THE SAME WAVEFORM AS PICTURE 14 & 17 ( AFTER I CLICKED THE HORIZONTAL OF THE SCOPE).

THESE ARE THE ONLY THREE PINS THAT ARE ACTING THIS WAY.  I HAVE USED THE TRIGGER ADJUSTMENT, BUT THESE SIGNALS WOULD NOT CHANGE.

QUESTION 1)  HAT WOULD CAUSE THESE MULTIPLE SIGNALS TO APPEAR?

QUESTION 2)  WHAT PIN NUMBER(S) ARE ASSOCIATED WITH THESE SIGNALS?

I NEED YOUR EXPERT ADVICE ON HOW TO RESOLVE THE ISSUE.

 

LOOKING FORWARD TO YOUR RESPONCE.

  • 0
    Intellectual 850 points

    PICTURE 1)  THIS IS A CAPTURED SIGNAL OF PIN #1 (USING THE STOP FEATURE OF THE OSCILLOSCOPE) FROM PIN #1.

    PICTURE 2)  THIS IS THE SAME WAVEFORM AS PICTURE 1 AFTER I CLICKED THE HORIZONTAL OF THE SCOPE. 

  • 0 in reply to Eddie Loy
    TI__Mastermind 31580 points

    Hi Eddie

    The issue with your waveforms is the trigger setup on your oscilloscope, it could be the source signal that you are use for the trigger or the trigger level position.

    I suggest triggering the scope on the signal that you want to view and adjust the trigger level to try and get a stable image.

    You have a number of posts regarding the waveforms that you are seeing on the UCC28070, my best advice is that you get the UCC28070 EVM from ti.com and use that to compare the waveforms with your board. That way you will learn to recognise the correct waveforms on each pin during normal operation.

    Regards

    Peter

  • 0 in reply to Peter Meaney
    Intellectual 850 points

    "The issue with your waveforms is the trigger setup on your oscilloscope, it could be the source signal that you are use for the trigger or the trigger level position."

    THANK YOU FOR THE ABOVE DIRECTION.  I FINALLY SAW THE OUTPUT SIGNAL.

  • 0 in reply to Eddie Loy
    Intellectual 850 points

    YOUR PREVIOUS STATEMENT:

    "You have a number of posts regarding the wave-forms that you are seeing on the UCC28070, my best advice is that you get the UCC28070 EVM and use that to compare the wave-forms with your board. That way you will learn to recognize the correct wave-forms on each pin during normal operation."

    Reply To Statement ) Yes, I have posted several times wave-forms and associated voltages. What I was expecting were answers regarding the validity of the wave-forms and associated voltages. What I did not expect was an answer from a document reader who states that his best advice is that I go buy a evaluation board and learn to recognize the correct wave forms on each pin during normal operation.

    Did you read your reply? I did and I was appalled that an engineer would make such a statement. An engineer who is unsure of the answer, would state such and reply that he would speak with another engineer that had more experience with this particular product that could answer the CUSTOMERS questions.

    I was not expecting the engineer to reply that he does not know the answer and for the customer to go figure it out himself by purchasing an evaluation module, “Mouser $102.50)”, so the customer could figure out what the correct signals are. So, where is the need of customer service?

    TI developed the above referenced evaluation board and should, but maybe not, have the correct signal wave-forms that was gathered at the completion of the above evaluation board in support of the mass manufacturing of them.

    These wave-forms should have already been made available to the TI E2E Engineers in support of both the engineers and customers.

     

    Lets look at the definition of “customer service”. Oxford dictionary states:

    “the assistance and advice provided by a company to those people who buy or use its products or services.”

    What does that mean? If no customers buy the company's products, the company dissolves and therefore no need for customer service support.  If the company's customer service does not support the customers, the company dissolves.

    I hope that you read this and at least dwell on it for a couple of minutes and realize:

    [Your position within the company burdens you with a great responsibility to the company and equal responsibility to the company's customers.]



    Thank You

    Eddie H. Loy, Jr

  • 0 in reply to Eddie Loy
    TI__Mastermind 31580 points

    Hi Eddie,

    I suggested obtaining the EVM as you had many questions on the waveforms on each pin and I believe its the best way to support your queries.

    The waveforms for pins 13 and 14 look good, these are the gate drive outputs. Pin is the CDR pin and this controls the dithering, rate of change of the switching frequency for improved EMI.

    Figure 29 in the datasheet on page 37 also shows the gate drive waveforms from the EVM.

    Regards

    Peter