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ercolino

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How to set pulse voltage in Spice 3f5?
Mar 20^th, 2010, 6:00pm

Hi

I need to run several transient simulations for an analog circuit with a voltage source with the pulse function to study the behavior of a PWM circuit. In each simulation I have to modify several parameters including the pulse value voltage (V2) and the initial conditions at some nodes. These parameters' values are linked by simple math relationships. Is there a way to set only one parameter, say the pulse value, and automatically calculate and set the others during each simulation run? The "pedestrian" approach that I took so far is to calculate the dependent parameters' values by hand and changed in the source before each run. I'm using MacSpice that relies in Spice 3f5.

Thanks in advanced
ercolino

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ercolino New Member Offline Posts: 4	Re: How to set pulse voltage in Spice 3f5? Reply #1 - Mar 22^nd, 2010, 6:58am Sorry I'm new in electronic simulation. Perhaps this not the right place to pose this question or Spice 3f5 is not the right tool for this kind of job. Can someone point me in the right direction? Thanks in advanced...
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pancho_hideboo

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Re: How to set pulse voltage in Spice 3f5?
Reply #2 - Mar 22^nd, 2010, 7:03am

Why do you use old simulator such as MacSPICE ?

Even in Spice3f5, I think you can use ".alter" statement for your purpose.
Or prepare many netlists where necessary parameters are changed.

If you have to use free simulator, use "LTSpice".

Currently there are many free simulators, even if you use MacOS.
Show me your platform's information.

http://www.gpleda.org/index.html
http://qucs.sourceforge.net/
http://www.linear.com/designtools/software/index.jsp

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ercolino

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Re: How to set pulse voltage in Spice 3f5?
Reply #3 - Mar 22^nd, 2010, 9:42am

Thanks for your reply pancho_hideboo.

I'm using a MacBook Pro (Intel Core 2 Duo 2.53 GHz). I've couldn't find other circuit simulation software that runs with the Finder in the new macs. I could use also X11 (Unix) applications, but there also I found SPICE 3f5. So I preferred MacSpice which relies in the same simulation core but can be launched directly from the Finder. That's no a big issue, but I do not use many X11 applications and MacSpice save me some time to get it running and integrates better with other Finder applications, besides the easier installation procedure.

I've tried the .alter command, but it only lets you modify the main parameters of a device. In the case of a independent voltage source you can alter the DC and AC values, but there's no way (at least I couldn't find it) to alter the transient function parameters (pulse V2 voltage in my case). It could be a functionality not implemented in MacSpice.

I will give a try to gEDA and Qucs. Any advice?

By the way, LTSpice doesn't seem to have a Mac OS version.

Regards,
Ercolino

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ercolino New Member Offline Posts: 4	Re: How to set pulse voltage in Spice 3f5? Reply #4 - Mar 22^nd, 2010, 10:08am I found in the documentation of gEDA that it is based on NGSpice which in turns is based on SPICE 3f4. So its actually an older version than the one MacSpice uses. Is that right?
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Geoffrey_Coram Senior Fellow Offline Posts: 1999 Massachusetts, USA	Re: How to set pulse voltage in Spice 3f5? Reply #5 - Mar 22^nd, 2010, 10:29am I'm pretty sure that 3f4 and 3f5 are relatively very close, when you compare the difference between those two and NGSpice. 3f5 is more than 15 years old!
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Charles Williams

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Re: How to set pulse voltage in Spice 3f5?
Reply #6 - Mar 28^th, 2010, 9:59am

Geoffrey_Coram wrote on Mar 22^nd, 2010, 10:29am:

I'm pretty sure that 3f4 and 3f5 are relatively very close, when you compare the difference between those two and NGSpice. �3f5 is more than 15 years old!

The current version of "MacSpice 3f5" is 2.10.23.

http://www.macspice.com/

It has been continually updated and improved by me for about a decade. The release notes list the significant changes:

http://www.macspice.com/Release.html

and as you can see for yourself, it has come a long way from its roots.

All the best

Charles

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Charles Williams

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Re: How to set pulse voltage in Spice 3f5?
Reply #7 - Mar 28^th, 2010, 10:47am

ercolino wrote on Mar 20^th, 2010, 6:00pm:

Hi

I need to run several transient simulations for an analog circuit with a voltage source with the pulse function to study the behavior of a PWM circuit. In each simulation I have to modify several parameters including the pulse value voltage (V2) and the initial conditions at some nodes. These parameters' values are linked by simple math relationships. Is there a way to set only one parameter, say the pulse value, and automatically calculate and set the others during each simulation run? The "pedestrian" approach that I took so far is to calculate the dependent parameters' values by hand and changed in the source before each run. I'm using MacSpice that relies in Spice 3f5.

Thanks in advanced
ercolino

Yes, this is exactly the kind of task MacSpice has been developed for. Its scripting language is a superset of the original 'Spice 3f5/Nutmeg' language, but with the bugs and memory leaks fixed. The MacSpice website has a full set of documentation, links to tutorials and examples:

http://www.macspice.com/

One of the example files:

http://www.macspice.com/eg/Advanced.html#alter

does something similar to what you want. Use the support/feedback link on the MacSpice website to request further assistance if you require it.

All the best

Charles

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