6 Replies Latest reply on Aug 24, 2011 12:16 PM by Steve_McKinney

    Creating rules for high current nets


      I have a design that requires High current rules.  in this design I have applied the typical rules for currents such as 2, 4, and 6 amps.  Setting the trace/plane widths is no issue.  However, in this design I need to carry this current to internal layers using vias.  currently I am unable to define a rule that can assign a minimum number of vias to any given net.  Is there a way to do this?

      Is there also a way to define a rule that could calculate how many vias needed per net on any given layer change?



      Aaron Palomar

        • 1. Re: Creating rules for high current nets



          I don't have this idea of providing different rule set except in design rule for trace width for particular trace current.


          But for via current carrying capacity i have attached a .xls file is attached. It may be help full for you. This Type of calculators are provided on net.




          Virender Jaiswal

          • 2. Re: Creating rules for high current nets

            These rules are specific to each layout package; as you are not describing the layout system it is difficult to give a precise answer.


            This question might be better answered for Expedition in:


            or for PADS



            Gary Lameris

            Technical Marketing Engineer

            • 3. Re: Creating rules for high current nets

              If the layout system is Expeditionpcb 7.9.2, you can use MVO rules file where you can define mutiple vias pattern for high current nets. After you define MVO rules, you can send it to layout and let him to put this file under job's pcb/config directory, Expeditionpcb 7.2 will respects this MVO rules.


              Additionally, Hyperlynx PI DC is an excellent tool to analysis this, I strongly suggest you consider to use this tool.


              • 4. Re: Creating rules for high current nets

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                • Learn how DC Drop and current density impact design reliability
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                • 5. Re: Creating rules for high current nets


                  Thank you for the great input. 

                  I have emplemented the MVO rule set for this application.  (I had completely forgotten about this capability)


                  In response to PI:

                  We actually do have a seat of Hyperlynx that includes PI. However, I am not very experienced with it as of yet.  I am curious to know if after simulation is there a way I can apply the results to CES as a rule?


                  One last thought on this matter.  Does anyone know if there is a plan to integrate the MVO rule set into Expedition as some kind of menu item?

                  I know that once the file is created either manually or by AATK that there is a bit menu control that can be used but it would be nice to have an interface that can completely control patterns, classes, via types, etc..  What would be really nice is having an MVO rule in CES.

                  Currently we are on 7.9.1.




                  • 6. Re: Creating rules for high current nets

                    Hi Aaron,


                    Right now, HyperLynx PI will just help you identify that there is a problem.  You can see voltage drop as well as current 'hot spots'.  Also, in the coming release (HyperLynx 8.2, currently in beta) you'll be able to tie in thermal simulation to understand the temperature increase due to areas of the board with high current density such as a via.  You can also use LineSim PDN Editor to determine a possible solution to the issue (such as adding more vias or copper) before having to go back into the layout and make the changes and doing a final verification.


                    Setup is very easy and straightforward to run the analysis - we've got a tutorial video on SupportNet that shows you how to do it if you want a guide (15 minutes long).




                    I know that doesn't answer you question regarding CES, but passing this data from HyperLynx PI back to CES isn't currently supported.