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UCC2897A: Active Clamp Forward Platform

Bell Ye
Intellectual 1135 points
Part Number: UCC2897A
Other Parts Discussed in Thread: LM5026, LM5025, TIDA-00181, LM25037

Hi Team,

We got a request from customer as below, could you kindly help on it, please?

Pls see below for my design requirements: 

  • Vin: 25-50V
  • Vout: (all rails need to be independent of each other)
  1. - Vo1:  5V (tol=1%), Io=12A, Iocp=20A (hold on 50ms before hiccup launches)
  2. - Vo2(3):  +/-15V (tol=3%), Io=6.5A, Iocp=10A (hold on 350ms before hiccup launches)
  3. - Vo4(5):  +/-24V (tol=3%), Io=3A, Iocp=10A (hold on 8s before hiccup launches)
  4. -Vdd (for UCC2897A): 12~15V, Io=0.3A

OCP: shall be hiccup mode whenever fault is removed

OVP: latch mode

Transient: 5% in all conditions

Ripple: <1.25% (Vpp)

Isolation (hipot) test voltage

            - P-S 2000V 1min

            - S-CGND 700V 1min

Ta: -45~90 oC

Could you pls review my key points above and recommend some applications? Can UCC2897A fulfill this application?

thanks!

Bell

  • 0
    TI__Genius 9790 points
    Hi, Bell

    Thanks for your interest in TI here. I've contacted the appropriate product group. You should hear from them soon.
  • 0
    TI__Intellectual 2230 points
    Hi Bell,

    The UCC2897A does not support hiccup mode operation so I would recommend to consider the LM5025 or LM5026 as alternate if you perfer the Forward topology. But I think maybe push-pull would be a better choice as you can take advantage of the push-pull topology that multiple
    outputs can be controlled in parallel by a single controller (refer to TIDA-00181). And LM25037 contains all the necessary features you want to implement a push-pull control - Worth to take a look.

    Best Regards
    Oliver
  • 0 in reply to Oliver Pan91
    TI__Intellectual 1135 points
    Hi Oliver,

    Thanks a lot for your reply. It seems for UCC2897A, the chip will operate in a hiccup mode when there is a VDD Bias undervoltage which is below lockout-threshold of the controller. i'll loop you into the email.

    thanks!
    Bell