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WEBENCH® Tools/UCC28C40: Transformer core selection

Part Number: UCC28C40
Other Parts Discussed in Thread: UCC28C44, , PMP8861, PMP8380, UCC2897A

Tool/software: WEBENCH® Design Tools

I have designed DCDC converter using UCC28C44 & UCC28C40 IC. I took help of WEBENCH. Here the transformer details, like Lp, turns ratio etc  are given but core size (type, make, part no) is not given, can you pls help me with this.

transformer parameters as well as surge suppressor components are dependant on transformer core size. hence its important to know the core size considered while designing in WEBENCH.

specification: input 18V to 80VDC & output 24V, 5A, 120W

  • If you would like to design the transformer by yourself or to understand how a transformer in a DC DC converter is designed, I suggest to start to work on the steps generally found in a power electronics book.

    If you will ask a transformer vendor to design and build samples for you, you can simply send the Webench generated transformer specs to the vendor - they will help you the design and build the samples. In addition to the specifications you listed, please also include the switch frequency when you ask a vendor to help the transformer design and build the samples.

  • Dear sir,

    We have many vendors supplying the transformers. We ourselves have would transformer for development purposes. WEBENCH has given few parameters of the transformer like, Lp, ratio etc but they have not specified the core size. Core size is the basic on which the transformer is designed. If we receive the core size, Np & Ns our problem will be solved.

    There are few components, which depend on core size, Np & Ns. Since these components are defined in WEBENCH, I am sure some core size Ns & Np, would have been considered in the software

    Looking forward to receive these inputs to implement the design


    Sachin Alaspurkar 

  • Hi,

    I went to the UCC28C40 webench. It looks different designs may have different options on how many different transformer options.

    One case with DC-DC is the webench provides two off-shelf parts with vendors names and part numbers. As these are off-shelf parts with part numbers, the core shape should be ok to obtain from the vendors.

    On another case of AC-DC, there are many options with core info.

    In your case, if you can get the transformer part numbers, can you ask the vendor to provide you samples and specs of that transformer so you can find what core is used?

    As there are many possible designs, off-shelf transformers can would be first choice, then they will be listed, and only a few can be listed.

    What are your design specs, can you show your webench design so I can input your design specs into the webench to see what I can get?

  • I have created another case as below, which shows many options of transformers with core info. Can you please provide your design info like the below so I can input them into the webench to see what I can get?

  • The image you have shared are for 12W supply, we are designing for 120W supply with below specifications:
    input 18V to 80VDC & output 24V, 5A
    we wish to have the 120W transformer information as shared by you for 12W supply. we are unable to get this specification from WEBENCH
    TI has a reference design for 120W, PMP8861 & PMP8380. we only need to change the output voltage and current values. Input can be as per reference design
    We are looking forward to getting a transformer design for 24V, 5A (120W),  from you.
  • Hi,

    What you are asking is with very wide input voltage range, The Webench is not able to cover such application at moment.

    Per your mentioned two ref designs, they are using UCC2897A. I went Webench with UCC2897A, but it is again due to your very wide input voltage, it cannot provide a transformer.

    It is not a support that can be done on E2E or on Webench for your input specs. I suggest you contact your local TI office to request a reference design.

    If you want to look into the two mentioned ref designs, please also contact your TI sales office to request a board. The transformers used in these two designs are designed and built by Pulse Engineering.

    This transformer design will be involved and complicated it should go through your local TI office instead of the E2E.

    Please go to contact your local TI office. I close this thread.

  • Dear Sir,

    Can i have contact of Pulse Engineering. I will share WEBENCH design with them and see if they can design transformer for us. The input range of our design is same as of reference design, hence i expected WEBENCH to suggest us the core and other relevant details of transformer.

    i am unable to contact local TI office, as the contact numbers are not valid or they do not respond. Can you pls help me there contact or email

  • Hi,

    This link is for Pulse Engineering contact

    Where is your geographic location? Can you send to me a message on your design need through So I can forward your request to a proper group?

    I am closing this thread and additional support will be on email.

  • Dear sir,

    I have mailed you information as requested by you



  • Awaiting solution from TI. its now almost 16 days.

    pls expedite

    Request you to kindly share contact details of TI, India. The contact numbers on your website are not valid


    Sachin Alaspurkar

  • The email communication has been established. Please continue on email. Your support request cannot be made on E2E. This thread needs to close.