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UCC28700: Schematic Review

Part Number: UCC28700
Other Parts Discussed in Thread: PMP10344

Hi I made a design by using UCC28700 to make a 12VDC 0.5A output power supply from 120-480VAC input range. Could you help review for me?



  • Hi Jane,

    I have asked one of applications engineers to review the post and you should see an answer shortly.


  • Jane,

    thanks for the interest here. For a schematic review please allow up to 2 weeks as this can be quite involved. I have a few questions to make this a valuable exercise.
    1) Can you provide full power supply spec like input voltage range, output voltage, max output current, etc. ? some of that info looks to be included but if you have more details here that would help a lot.
    2) Can you provide the transformer spec? if not can you provide number of turns for primary, aux, and secondary as well as magnetizing inductance?
    3) did you use the design calculator tool for these component selections? can you send us your calculator tool with your values filled in?

  • Hi John,

    Thank you for reply!

    1) the input voltage range is 120VAC - 480VAC; output is 12VDC; max output current 0.7A

    2) I refer WURTH`s 750817930 specs but made a change as I only need one secondary. attached both datasheets. 

    3) No I didn`t use design calculator tool. I refered a demo design I found online (PMP10344_REVC)  attached as well. Do you have a calculator tool to suggest?

    Thanks a lot!

    Jane480VAC-12VDC Transformer.pdf2860.750817930r00.pdf7750.PMP10344_REVC.pdf

  • Jane,
    thanks for your reply. the design calculator is in the "tools and software" tab of the UCC28700 product folder online here:
    You have your choice of excel or Mathcad.
    Can you work through that and see if you have any specific questions after? We use this tool when we do our designs as well.
  • HI John,

    It's frustrating... I entered the 120-480VAC on the page you sent me and then click <Open Design> button, then the WEBENCH would automatically change my input voltage spec to 120-480V DC... so it will pick a MOSFET with 700V. If I change the spec to 680VDC (DC voltage after rectifier of 480VAC), then the design came out without this controller UCC28700.