Your opinion about Amplifier sim. - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 28th February 2005, 07:11 PM   #1
Dori is offline Dori  France
diyAudio Member
 
Join Date: Feb 2005
Location: Le Pradet
Default Your opinion about Amplifier sim.

I try to simulate an amplifier. The simulation works but I have a note that mention warning :

Note: starting Gmin stepping
Warning: Gmin step failed
Warning: Gmin stepping failed
Note: starting source stepping
Note: One successful source step
Note: Source stepping completed

I suppose this note is normal because I have made an Operating Point analysis, so for me Gmin Step can't be proceed. Because Gmin is a small signal transconductance.

Are you agree with me or you think I'm wrong ?
  Reply With Quote
Old 28th February 2005, 07:24 PM   #2
diyAudio Member
 
destroyer X's Avatar
 
Join Date: Feb 2004
Location: Recife - Brasil Northeast
Default If your simulating program is Multisim or Electronics Workbench...

You have a bad contact...can you believe those things....nodes connection opened...and line is there...everything saying it is connected.

A bad solder joint even in virtual...this is too much realism...to turn users crazy.

reconnect....will work!

Carlos
__________________
A Darlington audio amplifier, a toy for your weekend enjoyment; https://www.youtube.com/watch?v=yk0qvkwsAOY, No overshot; https://www.youtube.com/watch?v=CEgK4l0MH8k
  Reply With Quote
Old 28th February 2005, 08:33 PM   #3
jleaman is offline jleaman  Belgium
Banned
 
Join Date: Apr 2002
Send a message via AIM to jleaman
What is the program your using ? Got a link ?
  Reply With Quote
Old 1st March 2005, 10:42 AM   #4
Dori is offline Dori  France
diyAudio Member
 
Join Date: Feb 2005
Location: Le Pradet
Hi, jleaman.

The programm is protel v. 99SE
But I think a lot of CAD as Pspice, Cadence and so on use this kind of step analysis.

I find in help menu that but I am french and I am not sure about the meaning :
GMINSTEP :Sets the number of steps in the GMIN stepping algorithm. When set to 0, GMIN stepping is disabled, making source stepping the simulator’s default DC (operating point) convergence algorithm. Default=10 steps.

So I repeat my question :
Operating Point analysis => Gmin Step can't be proceed. Gmin is a small signal transconductance.

Are you agree with me or you think I'm wrong ?
  Reply With Quote
Old 1st March 2005, 11:43 AM   #5
Giaime is offline Giaime  Italy
diyAudio Member
 
Giaime's Avatar
 
Join Date: Oct 2004
Send a message via MSN to Giaime
Hi, I'm having these problems too with Multisim. I found that it should be related to two things:

1) first of all, the lack of processing power on my PC, because I've tried with others and the same circuit worked well, even with the same simulation settings.

2) it has to be something related the calculation with a node short circuited: for example if I put a potentiometer, if I set it to the full 100% position or the 0% position, the simulation stops saying those kind of messages.

I just don't know why. I'm not an expert...
  Reply With Quote
Old 1st March 2005, 12:04 PM   #6
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
I am not an expert either but it is logical that any program uses an algorithm for simulation calculations.

These algorithms are not that difficult to write, and one program or the other needs to have the same algorithm to come up with the same answer, right ?

For simulations to work the algorithm can be self-resolving.
Meaning: after one calculation the endresult is put back into the algorithm for a second calculation untill the set parameter is reached.
Another option is to set the number of calculations, the algorithm will then choose the size of the calculation step based on the number of steps.

For an operating point analysis a calculation step can not be made, so step number is 0, just the one calculation is done to get the operation point number.
If you do not set it to 0, default is 10, so it will make 1 step and then terminate.
(standard error with finite element algorithms)

I have no trouble with EW MultiSim2001
(running XP Pro)
__________________
2015 : World Cup Cat Hacky Sack
  Reply With Quote
Old 1st March 2005, 12:51 PM   #7
wimms is offline wimms  Estonia
diyAudio Member
 
Join Date: Mar 2004
Location: home
Default Re: Your opinion about Amplifier sim.

Quote:
Originally posted by Dori
I try to simulate an amplifier. The simulation works but I have a note that mention warning :

Note: starting Gmin stepping
Warning: Gmin step failed
Warning: Gmin stepping failed
Note: starting source stepping
Note: One successful source step
Note: Source stepping completed

I suppose this note is normal because I have made an Operating Point analysis, so for me Gmin Step can't be proceed. Because Gmin is a small signal transconductance.

Are you agree with me or you think I'm wrong ?
Wrong. Failures in gmin stepping hints that there is something fishy in the circuit and mathematical methods used in the spice are unable to achieve converging results (it is reaching contradictory state or insufficient precision) within constraints configured. In short: you can't trust the results. May be indirect warning that some element would fail. Most probably occurs when currents/voltages in circuit tend to reach levels outside of model meaningful behaviour (like 100Amps through BC547). That includes, but is not limited to, short circuits, unconnected nodes, nonlinear feedbacks, instabilities within selected timestep precision, etc.

Source stepping is a "backup" method, and it succeeded. Still I'd suggest looking into the circuit and try until it resolves without warnings.

http://www.elecdesign.com/Articles/I...leID=8282&pg=2
Taking A Peek Under The Hood Of Your Spice Circuit-Simulation Engine
Understanding Spice numerical methods, convergence issues, and innovative simulation techniques can rev up your circuit design expertise.

That was the very first result google offered when searching for "gmin spice"
  Reply With Quote
Old 1st March 2005, 06:48 PM   #8
Dori is offline Dori  France
diyAudio Member
 
Join Date: Feb 2005
Location: Le Pradet
Thanks for your information wimms.

I had search for Gmin step in google and read about this interesting article. But in fact, when you are working on a complex project alone (and I am also searching for a job, in France, it is very difficult !!), you don't have a lot of time to understand how a simulator works in detail, and how it creates the impedance matrix or things like that.
That's why I'd want to know other opinion to save time.

Good night folks !!
  Reply With Quote
Old 1st March 2005, 09:37 PM   #9
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
c'est difficile a ce moment en France, pour les ingenieurs ?

j.
__________________
2015 : World Cup Cat Hacky Sack
  Reply With Quote
Old 1st March 2005, 10:57 PM   #10
Dori is offline Dori  France
diyAudio Member
 
Join Date: Feb 2005
Location: Le Pradet
Ben ouai, ou alors je n'ai pas le comportement qu'il faudrait avoir en entretien pour inspirer confiance aux recruteurs. Ca fait un an et demi que je recherche (spécialité Microélectronique), j'ai eu une douzaine d'entretien, mais toujours sur le carreau.
Et je suis pas le seul dans ce cas la. C'est super chaud pour les jeunes diplômés la france dans mon domaine. D'ailleurs si vous avez des contacts ou des tuyaux pour travailler à l'étranger, je suis preneur.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Connexelectronic TA2022 amplifier with FE167E (94dB/w/m) opinion? lhgin Class D 5 3rd August 2009 05:34 AM
class a amplifier opinion tadiam Solid State 4 2nd April 2007 12:04 PM
Opinion about this hi-fi amplifier viktor1986 Solid State 31 15th November 2006 02:12 PM
Opinion about Legendino-6 amplifier viktor1986 Solid State 4 30th April 2006 05:20 PM
My N_channel Mosfet Amplifier-opinion zox2003 Solid State 9 9th April 2005 10:46 PM


New To Site? Need Help?

All times are GMT. The time now is 12:17 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2