multisim

[cuongland]

hi, I am novince in Multisim. I am trying to add a power mosfet named stp85nf55l from ST Microelectronics to Multisim. I went throught 8 steps in Component Wizards and already fixed the line that start .end to move to the end of file. The transistor does not work in simulator. 

Here is the link of the model: 

http://www.st.com/web/catalog/sense_power/FM100/CL824/SC1165/PF64805?s_searchtype=partnumber#

Please tell me how to fix it. Thank you very much and have a nice day

[SnowMule]

MultiSIM falls under the "Circuit Design Suite" software family - you'll get more help there than in LabVIEW forums.

http://forums.ni.com/t5/Circuit-Design-Suite/bd-p/370

[cuongland]

hi SnowMule: I did find recently that my topic is staying wrongly in different forum. I already reported it to admins. Also, I did not see anywhere that i can close, delete, or move the topic because of my failure. I am trying to fix my error but it seems like i do not have any duty to do that. Thank for your replying. I am still waiting someone can help me out.

Have a nice day

[Dennis_Knutson]

You pick the forum to post to when you select new message. If you reported your mispost to the admin by clicking on Options, it will eventually get moved. If you can't wait, just repost your question to the correct board yourself.

[WenR]

Hi cuongland

As SnowMule and Dennis_Knutson mention, it might be better if you repost this question in the Circuit Design board. Regarding your question, I see you posted a webpage, but I was not able to find the source of the model attached in your post in that page. 

Also, when you mention that the component does not work, do you mean that you receive an error when trying to simulate, if so, which error do you receive? Does the component simulate but is not behaving as you expect?

Depending on the source of the model, it might not be able to work in Multisim, checking if the parameters for other N Mosfet power transistors are the same as the model that you are using would be worth trying as well.

WenR

[OStep · Accepted solution]

One thing that is not explained in the model is the meaning of the pins on the .subckt line: .SUBCKT STP85NF55L 1 2 3

Usually manufacturers either name the pins meaningfully or provide a comment, but neither is present in this case. 

I just happen to know that the common order for mosfets is Drain, Gate, Source. Your symbol to model mapping should look as it does in MOSFET_mapping.png

I created the component and indeed I ran into a convergence problem when I tried to simulate it. For power mosfets (and power circuits generally), it helps to loosen the convergence criteria (Simulate->Analysis->Transient Analysis->Analysis Options->Customize). I loosened vntol and abstol. ST talks about this in their App note UM1575 at http://www.st.com/web/catalog/sense_power/FM100/CL824/SC1165/PF64805?s_searchtype=partnumber#

A working circuit is attached. Run transient analysis.

Hope that helps.

[cuongland]

HI OStep:

I am really appreciated for what you have done. Thank you for pointing out what i missed. I got it work now. Now I can start to build my project. 

Have a nice day. The topic should be closed. And you already gave the solution really well.

Have a nice day.