OrCAD PSpice & convergence issues

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Discussion Overview

The discussion revolves around convergence issues encountered in OrCAD PSpice simulations, particularly in the context of Switch Mode Power Supplies (SMPS). Participants seek resources such as ebooks, application notes, and tutorials to address these challenges and improve their simulations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant inquires about relevant websites for OrCAD PSpice resources and specific convergence issues related to SMPS simulations.
  • Another participant asks for clarification on the specific convergence issues being faced and the type of simulation (state space or time domain) intended.
  • A participant mentions experiencing convergence issues related to time steps being too small in both simulation domains and expresses a need for updated documentation.
  • It is suggested that setting initial conditions in simulations can help with convergence, and that using a long simulation to establish an operating point may be beneficial for subsequent simulations.
  • One participant expresses frustration at being directed to search for information online instead of receiving direct links to relevant resources, questioning the purpose of the forum.
  • Another participant emphasizes the importance of self-directed research and learning how to effectively use search engines to find technical information, sharing a personal anecdote about the value of preparation before seeking help.

Areas of Agreement / Disagreement

There appears to be disagreement regarding the appropriateness of directing users to search engines for information versus providing direct assistance. Some participants advocate for self-research, while others feel that the forum should facilitate more direct support.

Contextual Notes

Participants reference older documentation and express a desire for more current resources, indicating potential limitations in available materials. The discussion also highlights varying expectations for community support and self-initiative in learning.

ElectroPhysics
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Hi
any idea what is the most relevant website to find out OrCAD PSpice ebooks, application notes and tutorials and how to resolve its convergence issues in Switch Mode Power Supplies simultions.

Please be precise and quick. :cool:
 
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ElectroPhysics said:
Hi
any idea what is the most relevant website to find out OrCAD PSpice ebooks, application notes and tutorials and how to resolve its convergence issues in Switch Mode Power Supplies simultions.

Please be precise and quick. :cool:


What convergence issues specifically are you referring to? What application notes have you found so far for simulating SMPS? Are you wanting to simulate in state space or the time domain?
 
convergence issues like time step too small. in both domains. its night here. hope some good reply till morning. by the way Berkeman you once solved my a thread very helpfully thanks for that. i have found documents on Cadence/OrCAD PSpice manual of very old time that of 2001 or before. need latest.
 
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You can help initial convergence a lot by setting initial conditions in your simulation (but you probably know that). Once you do a long simulation to get the circuit up to some operating point, you can use that operating point as a starting point for further simulations.

I googled Spice Simulation of Switched Mode Power Supplies, and got lots of good hits. Some are books for purchase, and some are on-line resources:

http://www.google.com/search?source...ce+simulation+of+switched+mode+power+supplies

.
 
@berkeman instead of telling me that there is lot of stuff on google if you could just provided me links for the latest relavent files then that was ok. the purpose of the forum should not be to tell that you find your own self on google.
i don't understand why people are so crazy in increasing no. of useless posts.
 
Last edited by a moderator:
ElectroPhysics said:
@berkeman instead of telling me that there is lot of stuff on google if you could just provided me links for the latest relavent files then that was ok. the purpose of the forum should not be to tell that you find your own self on google.
i don't understand why people are so crazy in increasing no. of useless posts.

I will be gentle in this reply.

You will probably find many times in your professional life that it is important to learn how to learn, and to apply that to your real-world technical challenges. Learning how to use Google (and Google Images), and how to come up with good additional search terms is fundamental to everyday technical work for engineers (it sure is for me).

I have asked a question here on the PF very similar to yours -- I was having convergence issues with a SPICE simulation, and posted asking for tips for my particular circuit. But it was apparent from my post that I had been doing a lot of research, and hadn't been able to find the keys to my convergence problems. You should try to post at that same level -- don't expect people to jump through hoops doing the work that you should do yourself. Folks are happy to help, *if* you show that you are making a strong effort yourself.

You will find this in your professional life as well. If you do your homework before going to a co-worker and asking for help, the help will be forthcoming much quicker, and will be at a higher level, which is more efficient for both of you.

I still remember an encounter I had with a very senior software/compiler engineer a number of years ago, when I was helping out our startup company in Customer Support for a bit. I had a technical software question that was over my head at the time, so I went to ask him about it. He said something like, "I'll help you this time, but in the future with questions like this, it would be better if you read the company in-house FAQ list, and checked these resources (several in-house server folders), before coming to me. That will often answer the questions outright, and if not, you will understand things much better, so that you understand my answer better."

Kind of a harsh thing to say, but he was definitely right. We worked great together on many questions after that, because he knew that I was making an effort before asking him questions, and that I was only having to bring the really hard questions to him (where he was the only person in the company who could answer them).

Learn how to learn. It's an important skill, and will help you do much better in your professional career, compared to the alternative.


EDIT/ADD -- BTW, when I post a Google hit list on the PF in response to a quesiton, I will usually have used a search phrase that is already partially tuned to the subject that you are asking about. I don't just say "try Google", I post the search phrase that I used, and a link to the hit list. Look at the search phrase, and think about why each term was used. That will help you in general in your own Internet searching, and in particular with this search, as you add your own additional search terms to the search phrase. Learn how to learn.
 
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