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UCC28180 Input VAC Brown-Out Protection NEEDED

Eric Lai
Expert 4940 points
Other Parts Discussed in Thread: UCC28180, LM8364, UCC24630

Hi Expert,

The RD would like to evaluate the UCC28180.

And they ask a Input VAC Brown-Out Protection.

Can you provide the external reference circuit to meet this.

TKS.

Best regards,

Eric Lai

 

Field Application Engineer

Texas Instruments Taiwan Limited

O: +886-2-2175-2582

M: +886-909-262-582

E-Mail:Eric.Lai @ti.com

  • 0
    TI__Guru 71526 points

    Eric,

    Did you ever get a Ref Design for this UCC28180?

    ~Leonard 

  • 0 in reply to LeonardEllis
    TI__Mastermind 31580 points

    Hi Eric,


    Apologies, I dont know how we missed your post.

    There is an LM8364 comparator which is biased through the input resistive divider chain that is useful in this application. The part is used on the UCC24630 EVM board where it is used as the AC UVLO for the main QR flyback controller, the output is an open collector/drain which can be used to clamp the VSENSE pin below 0.82V to hold the UCC28180 off until the AC line exceeds the desired value.

    Regards

    Peter

  • 0 in reply to Peter Meaney
    TI__Guru 71526 points

    Thanks very much Peter.  One thing I am not clear on is exactly what "brown-out protection" actually does.  The UCC24640EVM User Guide references this feature, but there is no explanation of what actually happens when VIN drops below 80VAC.

    Seems the choices would be:

    -turn OFF the controller, VOUT = 0

    -operate at a reduced or MIN VOUT

    -switch to battery back-up

    Please advise.

  • 0 in reply to LeonardEllis
    TI__Mastermind 31580 points

    Hi Leonard,


    Again I apologies for the very late response but I am not getting notifications when people reply to posts for some reason.

    But when the AC drops below the target minimum input the norm is to turn the controller off.

    Regards

    Peter