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UCC24630: best fit for 3.3V/1A design

Ue
Genius 17165 points
Part Number: UCC24630
Other Parts Discussed in Thread: LM5180,

Hi all

My customer is using the LM5180 for an isolated PoE design, 48V => 3.3V / 1A.

As their design is space limited and fully enclosed they are looking for highest efficiency and would therefore like to use a synchronous rectifier on the output.

It the UCC24630 a good fit ?

Or would you rather suggest another device ?

Best regards

Ueli

  • +1
    TI__Expert 7080 points

    Hi Ue,

    UCC24630 can  work with LM5180 as the SR controller.  since the VDD turn on threshold of UCC24630 is ~4V which is above 3.3V output voltage, it's recommend to add a secondary side auxiliary winding to supply the VDD.  and design the LM5180 switching frequency lower than 200khz.

    Thanks. 

  • +1 in reply to Jaden Ning
    TI__Genius 17165 points

    Hi Jaden

    Thank you for the quick reply, I appreciate your support.

    Best regards

    Ueli

  • 0 in reply to Ue
    TI__Genius 17165 points

    Hi Jaden

    Here come two follow on questions from my customer:

    Does the UCC24630 work with the Frequency foldback mode (FFM) of the  LM5180?

    And could one also generate the VDD of the  UCC24630 with this  D-R-C network instead of an Aux-winding?

    Best regards

    Ueli

  • +1 in reply to Ue
    TI__Expert 7080 points

    Hi Ueli,

    Please find my reply in the E-mail I sent to you. so I'll close this post.

    Thanks.

  • +1 in reply to Jaden Ning
    TI__Genius 17165 points

    Hi Jaden

    Thank you for the quick reply, I appreciate your support and I copy your comments below.

    Best regards

    Ueli

    ----------------------------------------

    UCC24630 can work with FFM of LM5180.

    Basically, The DRC network is workable , but it will sacrifice the efficiency  since the voltage of the secondary winding is high (Vin_max/Nps) particularly at high line input voltage . In this application , the input is not universal input (90Vac264Vac). So the power loss on the  DRC network is lower, the customer can try this workaround solution if they don’t want an extra AUX winding  .