From: Chuck <cmc...@gm...> - 2013-01-24 14:07:11
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HB simulation needs comtimuity in the function & 1st deritive. Models need to be well behaved outside off expected ranges. -------- Original message -------- Subject: Re: [Qucs-devel] Bug/logic oddity in Transient solver loop From: mike brinson <mbr...@ya...> To: Frans Schreuder <fra...@gm...>,Andrew Stevens <wac...@go...>,"quc...@li..." <quc...@li...> CC: Hello Frans and Andrew The basic Qucs semiconductor device models are similar to those found in SPICE. The EKV 2.6 MOS model I added around two to three years ago. The same comment applies to the MESFET models. All the existing models appear to work for DC, AC and TRAN simulation. Circuits with convergence problems will, of course, fail sometimes. However, one area where there are real problems is Harmonic Balance. If a model has discontinuities in its I/V or Q characteristics second order or higher derivatives HB simulation will fail and not complete. My plans at the moment are to add a number of new semiconductor device models, starting with the latest upgrades to the HICUM models. I have both BSIM 3 and BSIM 4 MOS models working with QucsStudio. These should port to Qucs without too many problems. However, please note the ADMS XML interface is different for QucsStudio and Qucs so this could take some time. Once BSIM 6 is released to the public domain I will also try and add this to Qucs. I am also thinking of adding some basic BJT and MOS models which work, hopefully without problems, with HB simulation. These should allow those interested in RF and microwave design the opportunity to apply HB simulation to a range of active circuits. Again, please note HB simulation will also require work as its not very stable at the moment. On the subject of models one area that needs work is the development of the microwave models for transient simulation. The existing microstrip models, for example, are AC linear models and do not operate correctly in the transient time domain. Lots to keep the new team occupied ! Best wishes. Mike Mike Brinson mbr...@ya... ________________________________ From: Frans Schreuder <fra...@gm...> To: Andrew Stevens <wac...@go...>; "quc...@li..." <quc...@li...> Sent: Wednesday, 23 January 2013, 22:03 Subject: Re: [Qucs-devel] Bug/logic oddity in Transient solver loop Hi Andrew, That sounds busy! But in order to help you can also do small portions, you don't need to commit your whole life to it. Anyway if you say you don't feel like joining that is ok. I also just joined the team. All i know about the mosfet models is that some of them work better than others. Especially in transient simulations there are often problems. The simulator was mainly developed by Stefan Jahn (ela) but he is not active anymore. I know something about simulators but not enough to create completely new models. I have joined qucs mainly to get it back to life and back into the major linux repositories, for that to happen we needed a qt4 port which i made. I want to concentrate now on bug fixes and to get it at least as stable as the qt3 version, after that i want to learn something about the simulator as well. I have hardly touched the simulator (qucs-core) except for the microstriplange coupler model which was derived from the coupled microstrip lines. For the future we are also looking for people who can help improving the simulator backend. Frans Op 23 jan. 2013 22:50 schreef "Andrew Stevens" <wac...@go...> hetvolgende: > On 20/01/13 17:10, quc...@li... wrote: > > > > Hi Andrew, > > > > We are now building a new team to get Qucs back on the road, at least > > the activity has been boosted. > > A couple new people are working on it now (I am also new). > > I have to get a little more familiar with the way the simulator works, I > > have now concentrated on the Qt4 part. > > It seems like you know what you are talking about, why don't you join us? > > > > Frans > > > > Hi Frans, > > Sorry about the delay responding. I've been laid out with an evil cold > for a few days. > Joining the team sounds fun but with two young kids, a working partner > and non-trivial day job I'm not sure I can make any commitments about > any kind of sustained contributions. > > I'm afraid I know only enough about Newton-Raphson solver based circuit > simulation and numerical analysis to know that I don't know much at all > ;-). I'm a C++ EDA verification/synthesis tooling guy who ended up > doing some time architectingSoC's more or less 'by accident'. > > However, I would like to get a cosimulation interface up and running. > > Regards, > > Andrew > > > PS > Whats the state of the MOSFET Models in Qucs? Some quick tests with a > circuit using a MOSFET to switch a diode-clamped inductive load produced > some pretty weird behaviour. I can't yet rule out a oops in my circuit > - if I get a moment I'll try to cross-check both on SIMetrix - but it > looked damn strange. > > Trying the same MOSFET in a flyback converter model that produce > beautiful "classical" wave with ideal switches also behaved very > strangely with a MOSFET replacing the switch. > > > > ------------------------------------------------------------------------------ > Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, > MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current > with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft > MVPs and experts. ON SALE this month only -- learn more at: > http://p.sf.net/sfu/learnnow-d2d > _______________________________________________ > Qucs-devel mailing list > Quc...@li... > https://lists.sourceforge.net/lists/listinfo/qucs-devel > ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnnow-d2d _______________________________________________ Qucs-devel mailing list Quc...@li... https://lists.sourceforge.net/lists/listinfo/qucs-devel ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnnow-d2d _______________________________________________ Qucs-devel mailing list Quc...@li... https://lists.sourceforge.net/lists/listinfo/qucs-devel |