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Original question:

UCC2897A: Document for Active Clamp Flyback Converter design

UCC2897A: UCC2897A vs UCC28780

Peter Stephenson
Prodigy 190 points
Part Number: UCC2897A
Other Parts Discussed in Thread: UCC28780

Do you know of any offline applications for UCC2897A in flyback? What are the comparisons in performance with UCC2870 methodology?

  • 0
    TI__Genius 13660 points
    Hi peter,

    I haven't found any TI reference design EVM for UCC2897A on Flyback Converter though it also can be used for flyback.
    www.ti.com/.../toolssoftware
    Actually, we recommend to use UCC2897A on Active-Clamp Forward Converter, and UCC28780 is designed for Active-Clamp Flyback Converter.

    Regards,
    Teng
  • 0
    TI__Mastermind 34465 points
    Hi Peter,
    I was not able to find any reference design for an offline flyback using the UCC2897A.
    There are a few reasons why the UCC2897A is not used in such an application.
    The UCC2897A was designed for DC/DC converters with a lower input voltage (for example 48V telecom supplies) and for the high power that is normally associated with forward converters. The UCC2897A has a fixed time delay between the main switch gate and the clamp gate. It does not have high voltage start up. It has a fixed frequency operating mode and it has hiccup mode only in over current.
    I am not duly familiar with the UCC28780 but if you read the overview section 7.1 of the data sheet you can see that this part has several advanced features specifically relating to a very high efficiency offline flyback. There is for example, multiple operating modes that ensure ZVS switching over the complete load range. There is adaptive peak primary current and adaptive burst mode as well as high voltage startup. All of these features make the UCC28780 particularly adapted for off line flyback applications.
    I hope this information answers your questions.

    Regards
    John