OrCad/ question

May 18, 2010 5 Replies

I am running a magnetic transformer simulation. However, I get an error involving convergence.



A message comes up saying that the minimum time step allowed is 35.00 E-15 seconds. Is this an absolute minimum? Or can I change it? If so, then where because I have been searching all over and cannot find where to change it.



TIA, Dave


Decreasing the time step won't help. Its better to add some parasitic resistance or capacitance. Convergence problems usually indicate the simulator can't deal with the circuit.

Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------

\ Dave, You can't really change it. (i.e. you can, but it is more complex than you want to handle!) What you want to do is figure out why your circuit isn't simulating. When in doubt, remember that in the real world there are no pure resistances, inductances or capacitances. Enter those into your simulation, and you will be amazed at what you can simulate!

Charlie

Shhhhh! Don't give away our trivial secrets :-) ...Jim Thompson

| James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | The only thing bipartisan in this country is hypocrisy

I bet he is running a square wave...

Typical problem is a hard connection somewhere which lets the voltage/ current in the circuit take off rapidly. Remedy is to change DEVTOL to a larger value or add resistances in series with circuit paths (10mohm often does the trick). Also, don't use a VSRC as your PSU, use the VPWL or VPULSE, so you can ramp up the PSU slowly like in a real circut.

Regards

Klaus

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