Pspice simulation applications

[jack_pcb]

Hi all ,

i have recently learned Pspice simulaton tool .Not Expert in it .i am in a Design team .
Can anyone please tell me at what stage of design we should use pspice ,and what type of Circuits , at what conditions we should do simulation using Pspice .
Pls tell how to study the output of any analysis of this simulation .
pls help .
Thanks in Advance

.

 

[LvW]

Can anyone please tell me at what stage of design we should use pspice ,and what type of Circuits , at what conditions we should do simulation using Pspice .
Pls tell how to study the output of any analysis of this simulation .
.

"How to study" simulation results?
At first you have to ask yourself what you are interested in (behaviour of different componenets, power consumption, signal gain, operating point, temperature dependence, distortions. output amplitude,...).

 

[mvaseem]

Pspice is basically an Analog simulator, so you can use it for simulation of most Analog circuits. Although it supports digital also (gates, FF etc) but main strength is Analog.


What stage of design - You can do behavioral simulation at design exploration stage and do transister level simulation at later stage.
You can definitely use it for pre-layout simulation. If you have a way to bring parasitics in a form of model, you can hook -in the model for post layout simulation also. Pspice does not support s-parameter analysis directly, so model should be spice type.

What condition - Not sure what you mean by that ? You can use it for temperature variations.

 

[jack_pcb]

HI , thanks for the reply .
As i see ,there are 4 or 5 types of Analysis in Pspice ,and i have done example circiut work on all of these .
So thats all is Pspice . So only knowing these analysis topics ,can i say that that i know all about Pspice .
please help how to study the output signals . can share some good study material , i have downloaded mosty from net .

thanks in advance

 

[LvW]

please help how to study the output signals .

For my opinion, the most important point is to learn the differences (and limitations) of the three basic analysis methods: DC, AC and TRAN.
And to know which of these analyses is appropriate for a particular purpose.

 

[jack_pcb]

Dear sir ,

Thanks for the reply .
What you replied is exactly my question about pspice .thats i want to know how to ,what to in pspice. please share some of knowledge ,or some of material to understand things .

 

[LvW]

Hi jack,

you only need to know what you are interested in.
* If you want to see the output (or any other voltage or current within the circuit) as a function of TIME - use the TRAN analysis. This analysis can be done for linear and non-linear systems.
* If you want to see the frequency dependent properties of a circuit (example: transfer function) - use the AC analysis. But you must realize that this analysis is valid for a LINEAR system only.
* If you want to see how a circuit reacts upon a DC signal (example: operating point of a transistor amplifier) or upon change of any resistor within a circuit - use the DC analysis.

In any case, don`t forget that the
*TRAN analysis requires a time dependent signal (sinus or step or....),
* AC analysis requires a AC source
* DC analysis requires at least one DC source.

 

[jack_pcb]

thank you for the kind information sir ,

 

[mvaseem]

As for Analysis, LvW has already explained nicely.
Back to your original question- "So only knowing these analysis topics ,can i say that that i know all about Pspice" ?

Just knowing analysis type from top cannot be said to understand simulator. This is about how deep you are diving into it. You should be able to derive meaningful conclusions from your analysis.
For example Just try to see step response (transient) of a simple LC oscillator in Pspice and you would see results not in agreement with theory. Then you should be able to interpret this and be able to make Pspice behave the way you desire (by changing various options).

Try creating small but meaningful circuits and try playing with different options available. like - maxtstep, RELTOL, VNTOL,ABSTOL, integration methods etc etc.

 

[jack_pcb]

mvaseem ,

thank you for the reply .
As u said , i m agree that i have to do more experiments to understand more .
Could u pls share some of docs, ( i hav downloaded many pdf in internet ,but i need some more relevent ) ,as when u started learning pspice , u used to understand .
Pls it will be gr8 help to me if possible .

thanks

 

[mvaseem]

You need two things -

- Solid understanding of circuit theory, electronic devices and circuits. This we typically start during UG classes, but tend to forget later. A good revision of concepts is necessary. There is ocean of knowledge on web and books for this. You just need to spend time.
- Nice readings for spice simulators. I started with the book - Inside Spice (by Ron M. Kielkowski).
Found it very useful to understand spice. You can also go for - "The Designer's Guide to SPICE and SPECTRE (by K S Kundert).
I don't know if they are available online. I read hard copies from library.