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UCC21521: PSFB converter design using UCC21521 + UCC28950

Umang Butani
Prodigy 160 points
Part Number: UCC21521
Other Parts Discussed in Thread: UCC28950, , UCC21551, UCC21520, UCC21530

Tool/software:

Hello, 
For one of our customer we are designing power converter module using PSFB topology. 
Control IC we are considering as of now is UCC28950. 

As I was reviewing/studying literature of UCC28950 from ref design https://www.ti.com/tool/UCC27714EVM-551

In that for mosfet control circuit there has been used of two different ICs, TI is driving mosfet using ISO7240MDW + UCC27714D combination. but as I have searched on your portfolio and its seems that UCC21521 can work standalone for Isolation + Mosfet driver. 

Do you think am I missing something here? 

Please let me know if that's possible or not?

Also, Some non-reel parts of UCC21521 are NRND, Will UCC21521 be obsolete in near future? 

Regards, 
Umang Butani

  • 0
    TI__Expert 8686 points

    Hi Umang,

    Thank you for your interest in our products!

    It looks like the UCC27714EVM is using the digital isolator as an isolation for the control signal. Our isolated gate drivers will have the isolation between the control side and the power side built in internally.

    Umang Butani said:
    Also, Some non-reel parts of UCC21521 are NRND, Will UCC21521 be obsolete in near future?

    Correct, the newer generation of this device is UCC21551.

    Here is the link to the product page: https://www.ti.com/product/UCC21551 

    The UCC21551 EVM is found here: https://www.ti.com/tool/UCC21551CQEVM-079 

    For reference designs, you can refer to UCC21520 reference designs found here: https://www.ti.com/product/UCC21520#reference-designs 

    UCC21551 is mostly p2p with UCC21520 so these reference designs will be helpful to refer to when designing your application.

    Please feel free to ask any additional questions below if needed.

    Regards,

    Hiroki

  • 0 in reply to Hiroki Honda
    Prodigy 160 points

    Dear Hiroki, 
    Yes, Based on datasheet of UCC21551, Primary side VCCI max can go upto only 6V, because of this INA and INB will be limited to maximum of 6VDC only, where output signal of UCC28950 OUTA to OUTE will have 12VDC range, this will create electrical issue in design. 
    Because of these UCC21521 was the prefered choice, Do you have any newer generation device where its primary voltage can go upto 12VDC. 
    If you have any other solutions in mind, Please do share. 

    Best regards, 
    Umang 

  • 0 in reply to Umang Butani
    TI__Expert 8686 points

    Hi Umang,

    We have UCC21530: https://www.ti.com/product/UCC21530 

    This part will continue to be manufactured with the wider VCCI range.

    Hope this helps.

    Regards,

    Hiroki

  • 0 in reply to Hiroki Honda
    Prodigy 160 points

    Thanks Hiroki, 
    Yes, This Its seem to be an ideal choice, though we have one doubt, 

    Our secondary side voltage is approx 12VDC, for FET driver, will this IC work fine with it? 
    As I Was going through datasheets, It looks like it require voltage more than 14.7V as per below table! 

     

    JFY, We will use bootstrape power supply mode. 



    Can you please help us to understand it better?  Do we have to increase our VDDA and VDDB above 14.7?  

    Thanks and Regards, 
    Umang

  • 0 in reply to Umang Butani
    TI__Expert 7473 points

    Hi Umang,

    Thanks for reaching out.

    We're currently closed today in observance of Labor Day. We'll get back to you once we're back in office.

    Best,

    Pratik

  • 0 in reply to Umang Butani
    TI__Expert 8686 points

    No problem Umang,

    12V on the secondary side voltage supply will work with the 8V UVLO version (UCC21530B).

    Hope this answers your question. Let me know if you have anymore questions!

    Regards,

    Hiroki