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UCC28750: design troubleshooting

Anand Vartak
Prodigy 10 points
Part Number: UCC28750

Tool/software:

I have implemented a design based on TI web bench design. i am getting 0 V output.

attached is the web bench design, my schematic and transformer test report. please help to troubleshoot.


2818.design files.zip

  • 0
    TI__Guru* 85616 points

    Hello,

    I reviewed your files which is the Webench schematic and your schematic; as well as, the transformer specs of your design.

    Your schematic and your aux widing is not connected correctly.  Please correct it so it matches the Webench schematic.

    Also make sure your transformer turns ratios and magnatizing inductances match what Webench suggested within +/-5 %.

    Regards,

  • 0 in reply to Mike O'
    Prodigy 10 points

    Hello Mike,

    As per your suggestion I corrected the connection. the turns ratio and magnetizing inductance is matching Webench suggested within +/-5 %.

    I have measured the on pins with respect to ground as follows

    pin 2 -  1-1.8 vdc

    pin 3 - 0.9 to 1.1 vdc

    pin 4- 2.9 vdc

    pin 5 - 11.5 vdc

    the output is still 0.

    Regards

  • 0 in reply to Anand Vartak
    TI__Guru* 85616 points

    Hello,

    I could not find a Webench tool for this product.  Can you share the link?

    Your transformer turns ratio might be off.  You can check it with the excel design tool.

    https://www.ti.com/tool/download/UCC28750-CALC

    If the transformer turns ratio is O.K. you then should study VDD, CS, FB, FLT and Vout with an oscillsope to determine why the output is not comming up into regulation.

    Thank you for interest in Texas Instruments (TI) products.  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.

    Regards,