VerilogA code error:signal exceeds blowup limit

You might want to modify the current contribution statement to (note the '-' sign):

I(Iout) <+ -I(Iin);

If the current flowing into the model/block is assumed positive, then the current flowing out should be negative i.e.have inverse polarity. So, this could be one of the reasons why your circuit is struggling to converge.

Regards,

Saloni

Thanks Saloni for your suggestion. 

I tried that but now I have the same error with opposite polarity on output voltage blow up limit as shown below:

    ERROR (SPECTRE-16384): Signal V(Iout) = 732.434 GV exceeds the blowup limit for the quantity `V' which is (1 GV). It is likely that the circuit is unstable. If you really want signals this large, set the `blowup' parameter of this quantity to a larger value.

I tried to model output voltage but it won't let me. Any further suggestions?

What have you connected to the output of this current mirror? And what is the value of the current on Iin? As the convergence error is due to the voltage being generated at the output of your model, can you share your complete input.scs for further analysis.

Hi Saloni,

Good catch, output node was left open, once I connected it to a load, I could run the sim with no issues. Thank you very much for your help.

I wondered whether you really wanted to have a current controlled source as part of your monitor - this seems unnecessary. Perhaps you wanted just a probe - the code below creates a zero-volt source between the input and output and measures the current flowing through that source.

Note I changed the text of the output messages because there's no such thing as the current at a node (the current at a node should be 0, because of Kirchoff's current law):

module CurrentMonitor_VlogA(Iin,Iout);

inout Iin;
inout Iout;
electrical Iin,Iout;

real Ivalue;
parameter real IT2Limit=1m;

analog begin

  Ivalue=I(Iin,Iout);
  V(Iin,Iout)<+0;

  if (Ivalue>=IT2Limit)
    $strobe("WARNING:Value of current through %M has exceeded %g at %m, value=%g at simulation time t=%e",IT2Limit,Ivalue,$abstime);
  else
    $strobe("Current through %M=%g, simulation time=%e",Ivalue,$abstime);
end

endmodule

Regards,

Andrew.

Hi Andrew,

This is much better approach and exactly what I needed. Thank you!