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TPS54335A/about Phase Marg simulation result

Tsukui Yusuke
Guru 21930 points
Other Parts Discussed in Thread: TPS54335A

Hi,

Could you tell me about TPS54335A webench simulation?
This device is the result changes in ways of the parts change.

1) Comp pin parts direct change
2) Use Recomp →Comp pin parts change

I will attach the two types of simulation results.
Which is correct?

Recomp ver WebenchReportsServlet.pdf

Comp direct change ver WebenchReportsServlet.pdf

Could you give me your advice?

Best regards,
Yusuke/Japan Disty

  • 0
    Guru 21930 points

    Hi,

    Can I get the information?
    If you need more information or if  I should  clarify my comment ,
    please let me know.
     
    Best Regards,
    Yusuke/Japan Disty

  • 0 in reply to Tsukui Yusuke
    TI__Genius 17905 points

    Yusuke-san,

    I believe changing the components directly (1) gives the real result, but I want to duplicate what you are seeing when you use the Recomp tool. Can you please list the steps you are taking for using the recompensation tool? Do you change Rt resistor first then change the Inductor, and then use the Recompensation tool? What are the Recomp target values you set for phase margin, gain margin, crossover, and low frequency gain?

    Kris

  • 0 in reply to Kris F
    TI__Genius 17905 points
    I was able to confirm that directly changing the components (1) is giving the correct results. There is a Recomp tool issue for this device and I will post an update here when it is fixed.
  • 0 in reply to Kris F
    TI__Genius 17905 points

    Yusuke-san,

    We've identified the issue causing the inconsistency and the fix will be going out at the end of the week.

    In the meantime, I've recreated your design and used the recomp tool to stabilize the design. Please open this shared design to see the selected compensation components:
    webench.ti.com/.../SDP.cgi

    If you take your design 1) with direct component change and change the compensation to match the components in the shared design (Rcomp = 2.21kohm, Ccomp = 15nF, Ccomp2 = 1.2nF), you will see the same consistent results as the above shared design.

    I will send another e-mail here once the fix is out on the web.

    Regards,
    Kris

  • 0 in reply to Kris F
    Guru 21930 points

    Kris-san,

    Thank you for your response and support.
    I will describe the steps of the simulation.

    1.Vin=16.7 to 16.9V , Vout=12.5V, Iout=2.56V → simulation start
    2.Rt and L1 direct change(custom parts)
    3.Recomp click
    4.Manual→Edit components→Caluculate→Apply changes to design
    tps54335a webenc.pdf
    5.End
    TPS54335a WebenchReportsServlet.pdf

    Could you give me your advice?

    Best Regards,
    Yusuke/Japan Disty

  • 0 in reply to Tsukui Yusuke
    TI__Genius 17905 points

    Yusuke-san,

    I recommend you use the compensation components in my shared design linked in my previous reply.

    For that design, I used the same design Vin/Vout/Iout as you mentioned and the same custom Rt and L1 components. Then I used the Recomp tool to recompensate the design. I did this on our testing server where we have already fixed the inconsistency issue you were seeing. The fix will be released to the web tomorrow but I wanted to send you a properly recompensated design right away.

    Regards,
    Kris

  • 0 in reply to Kris F
    Guru 21930 points

    Kris-san,

    Thank you for your kind support.
    I understood the status of webench.
    I will report the your information to the customer.

    Best Regards,
    Yusuke/Japan Disty

  • 0 in reply to Tsukui Yusuke
    TI__Genius 17905 points
    Yusuke-san,

    The fix is now out on the web, so you should no longer see discrepancies between using the recomp tool versus manually changing the compensation components.

    Thank you for reporting this issue! Your feedback is very helpful in making our tools better.

    Regards,
    Kris