Once again, thanks for your support.
I was already in Transcient analysis and I still get an error of Convergence :
" WARNING: Convergence problems at node (netr7_2$ad). (Instance: advb2 Pin: out Port: 1) "
It seems that the R7 resistor, which the output is linked to the input of the trigger which is connected in the shematic, gives me some trouble.
The shematic represents a circuit that has been tested and it works, but not optimized.
If you are using PSPICE, then I could try to solve my problem with this software because I got it and I made the schematic on it too. (Currently, I prefer using Altium because its very user-friendly but I agree PSPICE got hard knowledge in simulation)