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LM5021: COMP pin usage in a non isolated flyback

Part Number: LM5021

Hello,

We are already using LM5021 in our flyback design. In a new application the secondary( in a flyback) is not isolated from the primary.To optimize design, I want to eliminate optocoupler feedback to the comp pin and give a direct external error amplifier feedback.

Is it ok to actively drive the comp pin?

Any other design idea to drive comp pin in a non isolated setup?

regards

AAH

  • Hello,

    You would need an external amplifier and some other circuitry to get the LM5021 to operate in a non isolated flyback.

    I would recommend using one of the ucc38c4x devices instead that have an on board error amplifier for feedback.

    This will save you money and time on your design.  The following link will bring to the data sheet for the ucc38c4x devices. 

    If you do use the ucc28C4x device for your design and have questions could you re post a new thread with ucc28C4x in the title so the appropriate applications engineer can help support your issue?

    Regards,