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Optimizing a model parameter

danncad

Hi all,

I'am new to Orcad Capture and Pspice (v16-6).

My problem is that I would like to optimize the parameters of some models (i.e. of the standard diode model or of a standard level 1 mosfet) with the Standard or Curve fit Optimizer.

I tried in different ways with no success. I have no problem in running optimizations (both with Standard or Curve fit Optimizer) where i try to optimize for instance the value of standard resistors or capacitors but when I want to optimize some models parameters I don't know how to proceed.

For instance I would like to optimize the Rs parameter of a diode D in order to fit a measured I/V characteristic but I 'm not able to import this model parameter in the "Parameters" list in the Pspice Advanced Analysis Optimizer.

It is possible to do this kind of optimization in Capture/Pspice ? I read a lot the help but with no answer.

Thank you very much!

Best regards.

 Dan

  • Yes. It is possible to optimize the model parameter using optimizer.

    First you should parametrize model parameters which you would like to optimize or vary. Then these model parameter would show up in optimizer parameter list and can be selected for optimization.

    For parameterizing the model parameter

    1. Do Edit model for device whose model parameter you would like to optimize

    2. Parametrized the model parameter. Example

    .Model DMOD D IS={IS_VAL} RS ={RS_VAL} TT=100n BV =200;

    3. Place PARAM component from SPECIAL.olb and declare these two parameters.

    Now run the simulation to confirm every thing is working fine and run the optimizer. Here IS and RS would show up in parameter list in optimizer.

     

     

  • Dear alokt,
    thank you very much for your help !

    Everything is perfectly working as you explain except your very last sentence.

    I'm not able to see in the "Parameters" list in the "Pspice Advanced Analysis Optimizer" any
    parameter (such as IS_VAL and RS_VAL) defined in a PARAM component from "SPECIAL.olb" placed in the schematic.

    I tried also to select the PARAM component and then "Pspice" -> "advanced Analysis" -> "Import Optimization Parameter.." but I get the following error:

      "ERROR (ORCAP-15072): Model parameters could not be imported for 1.
      Please check the library configuration."


    I tried also to follow the example in the "PSpice® Advanced Analysis User Guide - Product Version 16.6 -October 2012" (pspaugca.pdf) under  "Parametric Plotter Example", pg. 247.
    This is not an optimization but just a parametric sweep with PSpice Advanced Analysis. The explanation of the example says that I should be able to sweep a "tran" parameter defined in a PARAM component (as per figure on pg.252).

    This is not my case, parameters defined under PARAM (only these) doesn't shows up in the list.
    So, also this example from the guide is not working for me.

    I tried also on a different PC with same OrCAD version and license with same results.

    I am missing something?

    Any advice would be highly appreciated!

    Best regards
    Dan

  • Ha!
    I have no hotfix installed....reading now the (long) list of corrected bugs from hotfixes for 16.6
    and found:

    ....

    DATE: 03-29-2013   HOTFIX VERSION: 006
    ==========================================================================================================
    CCRID   PRODUCT        PRODUCTLEVEL2   TITLE
    ==========================================================================================================
    ....

    1105443 PSPICE         AA_OPT           Parameter selection window in optimizer  does not list param part
    ...

    So, this will likely solve my problem...I hope.
    I'm downloading.

  •  No,

    now I'am really disappointed with OrCAD.

    I installed the last hotfix and now nothing is working. All the Advanced Analysis just does not start and instead chrashes

    with an unexpected failure which says to contact Cadence...

    I don't know if it is worth loosing more time with Orcad...I'll try to import my netlist in Advanced Design System.

  • You may want to contact customer support and they shall be able to provide you a resolution for crash issue quickly.

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