• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 41 subscribers
  • Views 688 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

WEBENCH® Tools/TPS53219A: Changing output capacitor in design does not change load transient simulation

Robbie Tomaszewski
Prodigy 80 points
Part Number: TPS53219A

Tool/software: WEBENCH® Design Tools

Starting with the default TPS53219A design with Vin=4.75 to 5.25, Iout=25A, 650kHz, 0.7ms SS time, High ESR + No Ripple Circuit design, I changed the output capacitors from 2 220uF 6SVPE220MW Panasonic capacitors  to 1 330uF EEFSX0D331R Panasonic capacitor and the load transient simulation did not change.  Once the simulation is completed it displays the circuit with the 2 capacitors rather than the 1 capacitor.  

This make evaluating different components impossible but that is a necessary function to determine the best solution.  

  • 0
    TI__Guru**** 191445 points
    I'll move this to the Webench forum. In your case there is a pspice transient model available for TPS53219A. It is completely flexible about types and quantity of output filter capacitors (and most other external components as well). I personally use and recommend pspice simultations to evaluate transient performance.
  • 0 in reply to JohnTucker
    Prodigy 80 points
    WEBENCH was a second attempt at simulation. I had already tried the TI-TINA model test bench but in that case changing the feedback resistor did not change the output voltage. The output voltage was 1.1V not matter what value the feedback resistors were set. This caused me to immediately distrust the TINA simulation. I will try the Pspice model.
  • 0 in reply to Robbie Tomaszewski
    Prodigy 80 points
    The Pspice model is only rated to a minimum 8V input voltage but the part is rated to 4.5V. I tried the model anyway at 5V and 12V. The output experience a very large voltage drop during the load transient that lasted until the load was removed with the 5V supply. The voltage was basically a ramp from 1.2V to 0.898V during the load application. With the 12V supply the minimum during load was 1.13V and 1.34V when the load released. The model also does not like the 650KHz switching frequency as it did not converge when Rrf=866k. Note the Webench application does not exhibit the same issues with the 5V supply.
  • 0 in reply to Robbie Tomaszewski
    TI__Guru**** 191445 points

    I don't directly support TPS53219A, soi have actually used that specific model.  I am surprised it is not rated for the full input range.  Ltssee what the Webench support team says about the Webench simulation issue.

  • 0 in reply to JohnTucker
    Genius 4910 points
    Hi John and Robbie,

    We are looking into this issue .
    We will get back to you soon.

    Thanks and Regards,
    Atul