This is the error I see:

enter image description here

This is my Simulation Command. What is the issue here? enter image description here

  • 4
    \$\begingroup\$ Please show your schematic. Usually this error depends on what circuit you are simulating. \$\endgroup\$
    – The Photon
    Nov 10 '18 at 0:46
  • 1
    \$\begingroup\$ "Time step too small" is usually the consequence of a "shock" or discontinuity on your models. It indicates that the solver could not achieve the desired voltage/current precision with a reasonable time step in the differential equation solver. \$\endgroup\$ Nov 10 '18 at 0:51

Your simulation is, for some reason, too hard for the solver. See this page for some guidance.

Simulators like this use numerical ordinary differential equation (ODE) solvers. Nearly all such solvers adjust the time step dynamically, trying for the largest possible time step while maintaining accuracy. So the time step gets small either when you're doing something that challenges the algorithm (like a stiff system), or when you're asking for too much (like the relative tolerance that @jrive) spoke of.

Things to try are to:

  • First, look at your schematic and ask yourself if you've just asked a nonsensical question
  • Second, try changing the solver. I'm not in the same room with an LTSpice application, but AFAIK it uses a Runga-Kutta solver, which doesn't do well with stiff systems (Google "stiff system simulation" for details). My favorite go-to in this case is the Gear solver. It is (I think!!!) in a menu selection marked "controls". They may also have a minimum time step that you can specify, at the expense of possibly screwing up the accuracy of your results.

The simulation cannot converge to the precision indicated in the settings of the simulator. I’m not in front of my PC right now, but if you go to settings , play with the reltol and absolute tolerances and see if it runs.

That said, most convergence issues are due to an error in the circuit. Post your circuit so we can help.


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