Why does the 'Convergence Assistant' fail?

[08Ultrasound]

Hi,

I'm attempting to simulate the circuit i've attached to this but i get the error message..

Error message from simulation: doAnalyses: Timestep too small

To fix this issue i've looked at this website

http://digital.ni.com/public.nsf/allkb/4B99B2CD6C0C3B6A86257205005D58E0

and this website

http://digital.ni.com/public.nsf/allkb/4B99B2CD6C0C3B6A86257205005D58E0

Altering the settings doesn't allow the circuit to simulate. So i'm curious as to what is stopping the simulation with the circuit in question.

Running the 'Convergence Assistant' doesn't successfully complete either.

Any help is much appreciated!

[08Ultrasound]

I believe that between the two posts, it should be all of the sections of the circuit.

[hicksc]

Hi 08Ultrasound

I've downloaded your files and been able to replicate the issue here using Multisim 12.0, I also allowed the convergence assistant to run and it fails as you stated.

I have encountered this error before where BAS40 diodes were used in a circuit, it turned out that the model for that item was faulty.

You need to find the simplest possible scenario in which the error occurs, can you test each circuit component individually to narrow the scope?

Kind Regards

[08Ultrasound]

I've simulated the circuit in two halves, both sections of the circuit work seperately as expected but when i combine them the issue arrises. 

So i've simulated the output of the MOSFETS with a simple resistor, capacitor load. I've also simulated the load with an ideal input source from the Multisim library.

I've once got the entire circuit to work together. I altered some of the parameters in my load and i got the convergence issue. For some reason, when i attempted to put it back to a working state, the circuit wouldn't work again.