Problem with LTspice: Time stop too small

Thread Starter

Firenze02

Joined Sep 1, 2018
43
Hi,

I'm trying to create a variable resistor dependign from the value of current.

Please find attached the .asc file.

It doesn't work, when I run the simulation the following messages is presented:

Analysis: Time step too small; initial timepoint: trouble with node "n002".

Do you know how to fix this problem?

Thank you.
 

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Thread Starter

Firenze02

Joined Sep 1, 2018
43
hi F02,
Look at this link for 'extra LTS features, they may suggest alternatives.
E
http://ltwiki.org/index.php?title=Undocumented_LTspice#Behavioral_Resistors
Dear ericgibbs, thank you for sharing me this information.

Being "gshunt" the optional conductance I set that to a very lowe value G=1/R (high Resistance).

Please find attached the last version of the .asc file.

As you can see, I set an "if" statement in the R value, following the sintax:

R=if(condition,valueiftrue,valueiffalse)

How can I do if I have three interval?

I<1mA a=a1=10.2576
1mA ≤ I < 10 A a=a2=14.6851
I > 10A a=a3=0.5415

Do you know the correct sintax?

Really thank you.
 

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eetech00

Joined Jun 8, 2013
2,034
Try using “Limit”.

In the example below:
MIN=the minimum value for R
MAX=the maximum value for R
equation=your “if” statement

R=Limit(MIN,MAX,equation)

eT
 

Bordodynov

Joined May 20, 2015
2,697
I am sorry. .opt gshunt=1n.
Perhaps you specified an unreal function and therefore there is no solution. When I asked the inverse function, the solution was found.
 
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