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UCC28056: for 24V-AC input

ACGUY
Guru 11170 points
Part Number: UCC28056

Hello E2E,

Our customer is considering that to use the UCC28056 for 24V-AC input power supply. Does TI have any similar precedent for example of use? or can TI introduce us to other recommended devices?

The outline are following;
: 24V-AC input is secondary side, final output power is 35V-DC/8A_max.
: composition　 [24C-AC] -> [Ideal FET bridge(LM74670*4)] -> [PFC(UCC28xxx)] -> [DC/DC->35V]

Regards,
ACGUY

  • 0
    TI__Mastermind 47245 points

    Do you mean PFC for 24VAC input? Can you describe what is your input AC voltage and output DC voltage?

  • 0 in reply to Hong Huang
    Guru 11170 points

    The attached file is idea from customer,I think that it works fine. But, I have not conviction, so please let me know your suggestion.

    B.R

    ACGUY

  • 0 in reply to ACGUY
    TI__Mastermind 47245 points

    Its concept should be ok. But since the voltage is low the current becomes high for the same power. Even with close to 1 PF, its power losses will be high. Also for high current the size may become bigger. Not sure if this is a worth trying idea. But theoretically the idea can work. It is better to understand the benefit from this idea. 

  • 0 in reply to Hong Huang
    TI__Mastermind 47245 points

    Also, does the load require energy holdup - if so its PFC capacitance will be high. In short, you may ask your customer why doing this to move on. The IC should be ok to make control just it looks with high power losses and bigger PFC bulk capacitors which may make a bulky design. What is the frequency of AC100 to AC24,  if 50 to 60Hz, the transformer will be "huge" comparing to one with high switching frequency.  

  • 0 in reply to Hong Huang
    Guru 11170 points

    Hi,

    AC frequency is 50/60Hz, it's from general AC input voltage.

    If you designer, which will you choose DCM(QRM) or CCM for PFC? Please let me know your opinion.

    Regards,
    ACGUY

  • 0 in reply to ACGUY
    TI__Mastermind 47245 points

    You will need to try each to see which one is better and in terms of what you defined. As I am not understanding any benefit from this idea, I cannot provide my opinion as some criteria need to set up first before pick up what best to be.

    You need to tell me what benefit the design wants to achieve in order to see what to be the best or better trade-offs.

    This idea looks to me bulky and big, heavier, high cost, and more power losses. You need to ask why you need such a design and share it, before you ask opinions from others. 

  • 0 in reply to Hong Huang
    Guru 11170 points

    Hi,

    I change the words for question.
    Do you know the PFC-controller that can operation on AC-24V input by TI solution?

    Regards,
    ACGUY

  • 0 in reply to ACGUY
    TI__Mastermind 47245 points

    No we never have  such an application and cannot comment. You need make research to get your own solution.