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UCC28C56H: UCC28C56H Simulation issue

manoj kumatr
Prodigy 190 points
Part Number: UCC28C56H
Other Parts Discussed in Thread: UCC28C43,

Hi Team,

Namaste !!

I am trying to do the simulation the UCC2856H accordance with WEBENCH suggested schematic. but could not able to achieve the output. 

Observations are:

VDD is 19V

VFB observing 2.3V

rest all pind are seeing 0V

Specifications are:

VinMin = 40.0V VinMax = 200.0V Vout = 7.0V Iout = 3.0A

Here I am attaching the both schematics and simulated wavefomrs for your ref. PLease go thru and advise the issue. Many thanks in Advace.

  • 0
    TI__Mastermind 32895 points

    Manoj,

    You describe the input voltage as DC but show the Webench and PSPICE schematic with AC input? Regardless, attached is a fundamental flyback design, using UCC28C43 in PSPICE for TI. I hope you can run this sim and verify it works, then slowly begin replacing components until you evolve to achieve your requirements. You should maybe start with replacing the PWM controller only then verify it still runs before moving on to redefine the power stage.

    Your sim is running but not behaving/switching as you expect. Try temporarily removing everything that is not required to make the converter switch (soft start, slope comp). You also have a couple connections that I am questioning below.

    1. No connection dots are shown at the circled areas - make sure these are connected.

    UCC28C43_Steady.zip

    Regards,

    Steve

  • 0 in reply to Steven Mappus1
    Prodigy 190 points

    Hi Steve,C

    Thanks for UCC28C43 Simulation file will consider doing simulation in later stages.

    Reg UCC28C56H, 

    Connection are filne.

    I have tried removing SS & Slope comp earlier, issue still same. could you please help to share the Simulation for the above mentioned specifications!

    - Manoj. 

  • +1 in reply to manoj kumatr
    TI__Mastermind 32895 points

    Manoj,

    I will not be able to build a UCC28C56 sim file for you but this is why I sent you the working UCC28C43 sim file so you could use it as a starting point for building your own UCC28C56 sim file. Replace the UCC28C43 with UCC28C56, then modify the power stage according to your requirements. I hope this helps.

    Steve

  • 0 in reply to Steven Mappus1
    Prodigy 190 points

    Steve, 

    The file u sent, I am not not able to open thru PSPICE for TI, could you please recheck or help me how to dump .net file in application

    Manoj.

  • 0 in reply to manoj kumatr
    TI__Mastermind 32895 points

    Sorry about that. It looks like the .OPJ file was missing. Try this one:

    7838.UCC28C43_Steady.zip

    Regards,

    Steve