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Original question:

UCC28951: efficiency curve, compared with UCC28950

UCC28951: bad efficiency at secondary Di rect. at light load

Hiroshi Doi35
Expert 2845 points
Part Number: UCC28951
Other Parts Discussed in Thread: LM74700-Q1,

Hi Colin-san,

Customer complained bad efficiency at secondary Di rect. at light load.

New LLC IC UCC25630x is good light load efficiency if faster burst mode in.

I have asked  full bridge rect. using 4pcs of LM74700-Q1 and MOSFET.

It can be use maybe 48V output.

But It cannot, E2E response is GND pin of LM74700-Q1 is not good for this rect.

Can you make ideal fullbridge RECT circuit?

I think every EV,PHV isolated DCDC Unit maker want this ideal full-bridge rect. 

  • 0
    TI__Mastermind 25570 points
    Hello Doi-san

    I'm afraid I don't understand the problem and I need some clarifications

    How bad was the efficiency, what power level was it measured at and what was their target / expected efficiency?
    what is the input and output voltage of their system
    What is the full load power of their system
    Do you want to use the UCC25630x in a full bridge LLC ?
    Do you want to use a full bridge rectifier at the output of a Phase Shifted Full Bridge power stage controlled by a UCC28951?

    Can you post a schematic of the system showing which diodes you are concerned about

    I'm going to be out of the office until 13th Feb so I'm going to ask my colleague to monitor this thread until I get back.
    Regards
    Colin
  • 0 in reply to Colin Gillmor
    Expert 2845 points

    Hi Colin-san,

    When I answer the specification, products and customers will be identified.

    If customer demand is too high, I will ask you by mail with cc your manager.

    Thank you.