Apparently your schematic is not OK, or else it would not give you problems.
I’ve always found simulations troublesome, don’t have much experience with them and can’t say much. But a simple suggestion is to start with something small. Maybe just a simple RC combination, and get that simulation going. Then extend in small steps into more complex simulations. I am guessing that these varistors are used somewhere inside the models (subcircuits?) for some kind of compensation.
a4 n010 0 n007 n007 n007 n007 4 n007 varistor is a clear indication that you are using a device with a proprietary LTSPICE model (see Undocumented LTspice - LTwiki-Wiki for LTspice). Unfortunately these devices cannot be simulated with any other simulator than LTSPICE.
Thank you Piotr, I didn’t know this was possible.
I’ll double check all my models. Hope I’m able to find them.
BR
René
Hello paulvdh,
You’re certainly right.
I run the ERC and get no error.
How can I find my errors.
I’ll double check my models to find those varistors.
Thank you.
BR
René
Thank you Holger,
I think you are right because I migrate my schematic from LTspice to Kicad 8.0 (manually).
I find all the models I use with Librairy Loader and must have made a mistake.
BR
René
For all : Sorry for the three responses I’ll reply at once next time.
Hi @beginner
Use the @ key then select the name of the member to alert and inform that member. Note I used @beginner .
Much information about the forum workings can be found in the links in this FAQ.
OK, understand.
Thanks
BR
1 Like
I use a LT3032 in my schemaric and the model is a LTspice one (…) that contain varistors.
Do you think I can find LT3032 Pspice model for Kicad, and where ?
Thank you
To be honest, I do not know. You may ask Analog Devices directly, if they can provide you with a PSPICE compatible model.
Thank you,
I’ll do that.
You should know that KiCad is not Spice simulator but PCB design software. Because of this many KiCad symbols need not even to have spice models.
ERC probably (I have never run ERC) checks only whether the connections raise any doubts. It can’t rise alarm when something is wrong with spice model as 99% of users (I think) don’t use Spice in KiCad.
@Piotr,
Thank you Piotr, but I’m not sure to understand what do Kicad Users use for their simulations ?
Why you assume KiCad users need simulate anything. Electronic circuits works as you design them and in most cases you need not to check anything.
I was using Protel since 1997 and KiCad since 2017 and didn’t simulated any of the designed circuits.
In 90s I have got PSpice simulator (demo, limited to 30 nets) and in 2002…2008 used it only to simulate supply filters (defining capacitors and chokes with their parasitic components) mainly to see how they behave at 10MHz…1GHz. In 2017 I moved from 32 bit WinXP to 64 bit Win7 PC and my PSpice stop working what I even didn’t noticed. At the end of last year I have done some spice experiments with KiCad, but just to see. A few months ago I had first need. I wanted to see how burst disturbance influence my inputs. So I made separate KiCad configuration where I have no libraries I typically use and made there some libraries with elements with their parazitics. Two library sets have nothing in common. Libraries for PCB have no spice models at all. Libraries for spice have no footprints at all. To use Spice I rename kicad directories at Users\AppData\Roaming to work in different environment. That way I’m sure that at spice schematic I will not use symbol having no spice model and at PCB schematic I will not use symbol having no footprint (all my symbols have footprint assigned and I never change it).
Hello Piotr,
Many thank’s for informations.
My circuit is an audio amp powered by +/- 2 300Vdc that’s 4 600 Vdc rail to rail.
It’s very easy to kill a diyer with this mass destruction weapon. So I don’t want to test it on the bench without first doing some simulations to validate the conception.
I also need to :
- Control the rise time of the power supply to avoid killing the power mosfets at start on and shut down => calibrate the softstart/softstop.
- Implement and simulate the security against shorts circuits at the outputs.
- Control the slew rate of the optocouplers.
That sort of things.
When I have 24V at PCB I assume I have high voltage 
Your post is tldr, so I’ll just say whether KiCAD users need to or not, it would be nice to have a way that is as at least as reliable and full-featured as the rest of KiCAD, no? For what it’s worth, I find mostly that the difficult part is finding open source component models that work in ngspice. I’ve been tinkering on a multi-amp 10s of kilohertz linear current source and found the availability of mosfet and mosfet gate driver models very lacking.
PSPICE compatible models should do (unfortunately not always for gate drivers which may need some editing). LTSPICE VDMOS models for power MOSFETs will do. You might have a look at Spice models and model parameters for ngspice circuit simulator or scan my examples at Simulation examples for KiCad/Eeschema/ngspice and More simulation examples for KiCad/Eeschema/ngspice for models I have been using.
Unfortunately i don’t think you will see a day when simulation models are easy to come by anytime soon. Because the KiCAD library needs to have a specific license for all its components. Simulation models also need to be tested and verified, so the logical source should be the component vendor.
But the vendor may have license agreements that stops them from being distributed. Also i dont think vendors are specifically interested in all aspects of simulation so even if you get the model form the vendor does not mean it simulates the behavior you want it to simulate.
So how would we even begin to distribute models and who would do and verify them? What would be the testing criteria?
I didn’t said that Spice in KiCad need not be as good as possible (as everything). I just said that not all KiCad users need spice. If it is less or more than 50% of users - I don’t know.
I don’t think more than 1% of KiCad users are doing something like you.
This is an often repeated argument and too often abused as a stop gap answer.
Holger already posted a link to Spice models and model parameters for ngspice circuit simulator and in for example MicroCap-LIBRARY.7z/m_opamp.lib there is a license statement with:
- Motorola Operational Amplifier Macromodel Library
- Rev 1.1
- Macromodels, simulation models, or other models provided by
- Motorola, directly or indirectly, are not warranted by
- Motorola as fully representing all of the specifications and
- operating characteristics of the semiconductor product to
- which the model relates. Moreover, these models are
- furnished on an “as is” basis without support or warranty of
- any kind, either expressed or implied, regarding the use
- thereof and Motorola specifically disclaims all implied
- warranties of merchantability and fitness of the models for
- any purpose. Motorola does not assume any liability arising
- out of the application or use of the models including
- infringement of patents and copyrights nor does Motorola
- convey any license under its patents and copyrights or the
- rights of others. Motorola reserves the right to make
- changes without notice to any model.
Looks like they are mostly concerned with waving away any sort of liability then protecting copyright claims. I also interpret the “as is” part as “free to use” / “public domain”. But my head always starts spinning from legalese. It’s an interesting library for beginners because it has a lot of “old fashioned” opamps such as TL081 and LM358.
The license above is still a bit vague, but I have also seen spice libraries that have an explicit public domain license. I think the main obstacle is that there is simply no attention at all to an implementation for KiCad in this direction.
Some Ideas towards an implementation:
- A change on the licensing page of KiCad itself, with a statement that spice models are released with whatever license they already have in their files.
- For a few models (NE555, opamps and such) they could be added to Simulation_SPICE library, but that would only work for a handful of (common) models.
- For a more universal implementation, I think a flag inside the library system is preferred. It could filter for symbols with available spice models. Maybe have a direct link to show the library text (inclusive it’s license).
- Several of KiCad’s standard library symbols could have very simple spice models. For example, a fuse could have a simple resistance (under assumption the current is “low”). Resistors and capacitors could have some “sensible defaults” for parasitic values. This is not with the intention to be very accurate (for seasoned spice users), but to give beginners an easier start.
- Symbols like connectors and net ties can have the Exclude from simulation attribute set. (I’m thinking about making a feature request for this).