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UCC2897A: UCC2897A Line Regulation Issue

Siddhant Kumar
Prodigy 40 points
Part Number: UCC2897A
Other Parts Discussed in Thread: TL431

Hello There,

I'm using UCC2897A for active clamp dc-dc, where facing an issue of line regulation >10% which is very high.

I would like to ask if that can be resolved with stabilizing the compensation loop only or some IC functionalities, if any, or other circuit parameters are also responsible?

Thank you in advance.

Regards

  • 0
    TI__Guru 74115 points

    Hi,

    For stability, please measure the Bode Plots to determine the design has enough gain and phase margin. 

    You also need to check your reference point if your feedback resistor divider can reach that reference point. If you use TL431, the resistor divider should be 2.5V or 1.25V depending on which TL431 you use.

    Check the duty cycle to see if max duty cycle is reached. If so, you need to adjust Ron to allow higher max duty. If you cannot further increase max duty, you need to change your transformor turns ratios so to allow adequate duty cycle in your design.

  • 0 in reply to Hong Huang
    Prodigy 40 points

    Hello Mr. Huang,

     

    Thank you for understanding the query and explaining all the possible causes.

    The issue has been resolved by tweaking the maximum allowed duty needed at lower voltages and compensation loop.

     

    Once again thanking you!

    Regards

    Siddhant