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UCC2897A: UCC2897A Vref

Siddhant Kumar
Prodigy 40 points
Part Number: UCC2897A

Hello There,

If we pull down the Vref pin to 2V or below, would the IC damage in long run?

Thank you

Regards

Siddhant

  • 0
    TI__Mastermind 27045 points

    Siddhant,

    To pull the VREF below 2V, you will need to introduce a low-impedance that will cause the VREF is enter short circuit protection. The VREF short circuit current can be as high as 20mA so we expect the controller will continue to dissipate power while in this mode but the IC should be protected. Also not sure if a normal soft start cycle will result when VREF is released? I would recommend not to pull down VREF as you've described. If you need a method for shut down due to some external fault condition, why not pull down the FB pin?

    Regards,

    Steve

  • 0
    Prodigy 40 points

    Hello Steven,

    Sorry for the late reply,

    Thank you for writing and suggesting the alternate way to achieve the IC shut down for external fault. I also thought the same but was concerned if closed loop would be disturbed in case there would be current leakage transistor during operation maybe at higher temperature (T_amt=60C) considering transistor body temperature 85~90C. Will it impact much, please share your thoughts?

    Regards

    Siddhant

  • 0 in reply to Siddhant Kumar
    TI__Mastermind 27045 points

    Siddhant,

    Pulling FB low during some monitored fault condition is a commonly used protection approach. You can also see the E2E here and here.

    Regards,

    Steve