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WEBENCH® Tools/UCC28C44: application about the UCC28C44 SCH suggestion.

user4786735
Intellectual 460 points
Part Number: UCC28C44

Tool/software: WEBENCH® Design Tools

 

I would like to check an application about the UCC28C44, as attached schematic, I would like to check several component whether could replace or not

 

Rstartup1 & startup2, 10.2 Kohm into 10K.

Rsnub1 & 2, 1/8W or 16W or else?

Dsec1 & sec2, minimue for those two

Rsns 25mohm for 1/8W or 1/16W or else 

ShawnWBDesign21_shawn.pdf

  • 0
    TI__Genius 13660 points
    Hello,

    Please refer below information.
    1. startup1 & startup2, 10.2 Kohm into 10K.
    Q: Yes, this will reduce start-up time but not very much, because of large charging current.
    2. Rsnub1 & 2, 1/8W or 16W or else?
    Q: Since the maximum Snubber Pd is 1.524W in the design report, So Rsnub1 and Rsnub2 must be larger than 1.525/2=0.762W. So it should be selected larger than 1W.
    3. Dsec1 & sec2, minimue for those two
    Transformer Secondary1 Peak Current is 11.529A, So the average rectified forward current should be selected larger than 11.529*2=23.058 A.
    (Vin_max*Ns1toNp+Vout)*2=(28*2.401+24)*2=182.456V, So the peak repetitive reverse voltage should be selected larger than 182.456V.
    4. Rsns 25mohm for 1/8W or 1/16W or else
    The maximum Rsns Pd is 2.876W in the design report. So it should be selected larger than 3W.

    Regards,
    Teng
  • 0 in reply to Teng Feng
    Intellectual 460 points

    Hi Teng

    Thanks

    Shawn

  • 0 in reply to Teng Feng
    Intellectual 460 points

    HI Teng

    Another Question.

    can u help me to check T1 Datasheet?

    because the T1 have no recommended materials that I should to find transformer to meet TI suggestion spec.

    Shawn

    attach file is Transformer spec PW07206ST 网络版SPEC.pdf

  • 0 in reply to user4786735
    TI__Genius 13660 points
    Hello,

    You can purchase this part directly from its manufacture.
    www.fpe.com.cn/.../index.asp
    Or you can design this transformer in any magnetic components manufacture using this transformer datasheet. The often used magnetic core material for flyback is ferrite.

    Regards,
    Teng