[SOLVED] time step too small in ltspice, problem with diode.

[AbhimanyuSingh]

Circuit 1,2 and 3 are very similar, except that circuit 3 has 0 dc value of the source while circuit 1 and 2 have positive and negative DC values respectively. Circuits 1 and 2 get simulated as expected and give good result. But as soon as I start circuit 3, I get a message "time step too small......trouble with mbr20100ct-instance d1"
So, I grounded both the nodes across d1 with very high resistances. The simulation started running, but the speed was insanely less in the order of few femtoseconds, which was useless. The snapshots could be confusing, so I am also attaching the zipped circuit files.

 

[keith1200rs]

shorting out a capacitor with zero ohms is never a good idea in a simulation - C3. It may not be the cause of your problem but errors are often not reported in the correct place.

Keith

 

[AbhimanyuSingh]

Thanks Keith. I shorted it purposely as the capacitor was not needed anymore. Btw, due to wrong selection of the mosfet model, te circuit wasnt getting smulated.