Mailing list archives : pcb-rnd

ID:4214
From:gene glick <ge...@optonline.net>
Date:Wed, 24 Jun 2020 13:01:19 -0400
Subject:Re: [pcb-rnd] Off topic (maybe) - Spice simulator
in-reply-to:4213 from Robin Laing <Me...@TelusPlanet.net>
replies: 4215 from stefan <st...@gmail.com> , 4216 from Evan Foss <ev...@gmail.com> , 4219 from Gabriel Paubert <pa...@iram.es>
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Can't you take a zener diode model and crank up the breakdown voltage?
Alternatively, make a voltage controlled switch that turns on at the needed
voltage. I think a voltage dependent current source might also do the job.
 
I'll bet there are many other ways to do this as well.
 
On Wed, Jun 24, 2020, 12:22 PM Robin Laing <MeSat@telusplanet.net> wrote:
 
> On 23/06/2020 08:20, Anthony Tuttle wrote:
> > LTspice has a neon lamp model that can work without being too prone to
> > convergence issues. I have also used R={expression} as the resistance
> > value in resistors to simulate switches and this may be workable for an
> > improvised discharge model.
> >
> > There are spice models for GDTs, you may have to contact the
> > manufacturer directly to gain access. They are never perfect but there
> > has been some work on advanced GDT models.
> >
> > On Tue, Jun 23, 2020 at 1:41 AM stefan <stefan.schippers@gmail.com
> > <mailto:stefan.schippers@gmail.com>> wrote:
> >
> >
> >>     Hello,
> >>
> >>     I am involved with a project that will involve high voltage pulse
> >>     circuit design and I am looking for a circuit simulator that will
> >>     give
> >>     us an accurate representation of a circuit.
> >>
> >>     Needs to work with spark gap technology as that is the present
> >>     design.
> >>     Maybe gas discharge tube as well.
> >>
> >>     Presently one member of the team is trying to use Multisim from NI
> >>     but I
> >>     am wondering if there may be a better package.
> >>
> >     NGSPICE developers are doing a good job,
> >     ngspice netlists may contain capacitors, resistors, inductors with
> >     arbitrary expressions about their value.
> >     Moreover the 'B source' allows any type of voltage/current source
> >     with arbitrary expressions.
> >
> >     Combining these elements a model for a gas discharge/breakdown can
> >     be created.
> >     The big issue is not the simulator itself, but the quality of the
> model:
> >
> >     1) ability to accurately describe the device.
> >     2) simulator must converge to a solution.
> >
> >     Breakdown devices (devices with infinite resistance that start
> >     conducting with very low resistance when a voltage threshold is
> >     reached) are famous for giving convergence issues. This usually
> >     happen due to poor model description. A current limit must be
> >     included in the equations (no physical device can sustain 1e15 Amp
> >     of current :-) ).
> >
> >     Stefan
> >
>
> Thank you to all.
>
> The breakdown is where I ran into problems with a model years ago.  It
> was quicker to just setup an test bed and try it.  Don't do enough
> design work to take the time to learn the simulator.  Same reason that
> Multisim is being used.
>
> Robin
>
>
>
>
 
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<div dir=3D"auto">Can&#39;t you take a zener diode model and crank up the b=
reakdown voltage? Alternatively, make a voltage controlled switch that turn=
s on at the needed voltage. I think a voltage dependent current source migh=
t also do the job.<div dir=3D"auto"><br></div><div dir=3D"auto">I&#39;ll be=
t there are many other ways to do this as well.</div></div><br><div class=
=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Wed, Jun 24, 2020=
, 12:22 PM Robin Laing &lt;<a href=3D"mailto:MeSat@telusplanet.net">MeSat@t=
elusplanet.net</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" st=
yle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On 23=
/06/2020 08:20, Anthony Tuttle wrote:<br>
&gt; LTspice has a neon lamp model that can work without being too prone to=
 <br>
&gt; convergence issues. I have also used R=3D{expression} as the resistanc=
e <br>
&gt; value in resistors to simulate switches and this may be workable for a=
n <br>
&gt; improvised discharge model.<br>
&gt; <br>
&gt; There are spice models for GDTs, you may have to contact the <br>
&gt; manufacturer directly to gain access. They are never perfect=C2=A0but =
there <br>
&gt; has been some work on advanced GDT models.<br>
&gt; <br>
&gt; On Tue, Jun 23, 2020 at 1:41 AM stefan &lt;<a href=3D"mailto:stefan.sc=
hippers@gmail.com" target=3D"_blank" rel=3D"noreferrer">stefan.schippers@gm=
ail.com</a> <br>
&gt; &lt;mailto:<a href=3D"mailto:stefan.schippers@gmail.com" target=3D"_bl=
ank" rel=3D"noreferrer">stefan.schippers@gmail.com</a>&gt;&gt; wrote:<br>
&gt; <br>
&gt; <br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0Hello,<br>
&gt;&gt;<br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0I am involved with a project that will involve =
high voltage pulse<br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0circuit design and I am looking for a circuit s=
imulator that will<br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0give<br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0us an accurate representation of a circuit.<br>
&gt;&gt;<br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0Needs to work with spark gap technology as that=
 is the present<br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0design.<br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0Maybe gas discharge tube as well.<br>
&gt;&gt;<br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0Presently one member of the team is trying to u=
se Multisim from NI<br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0but I<br>
&gt;&gt;=C2=A0 =C2=A0 =C2=A0am wondering if there may be a better package.<=
br>
&gt;&gt;<br>
&gt;=C2=A0 =C2=A0 =C2=A0NGSPICE developers are doing a good job,<br>
&gt;=C2=A0 =C2=A0 =C2=A0ngspice netlists may contain capacitors, resistors,=
 inductors with<br>
&gt;=C2=A0 =C2=A0 =C2=A0arbitrary expressions about their value.<br>
&gt;=C2=A0 =C2=A0 =C2=A0Moreover the &#39;B source&#39; allows any type of =
voltage/current source<br>
&gt;=C2=A0 =C2=A0 =C2=A0with arbitrary expressions.<br>
&gt; <br>
&gt;=C2=A0 =C2=A0 =C2=A0Combining these elements a model for a gas discharg=
e/breakdown can<br>
&gt;=C2=A0 =C2=A0 =C2=A0be created.<br>
&gt;=C2=A0 =C2=A0 =C2=A0The big issue is not the simulator itself, but the =
quality of the model:<br>
&gt; <br>
&gt;=C2=A0 =C2=A0 =C2=A01) ability to accurately describe the device.<br>
&gt;=C2=A0 =C2=A0 =C2=A02) simulator must converge to a solution.<br>
&gt; <br>
&gt;=C2=A0 =C2=A0 =C2=A0Breakdown devices (devices with infinite resistance=
 that start<br>
&gt;=C2=A0 =C2=A0 =C2=A0conducting with very low resistance when a voltage =
threshold is<br>
&gt;=C2=A0 =C2=A0 =C2=A0reached) are famous for giving convergence issues. =
This usually<br>
&gt;=C2=A0 =C2=A0 =C2=A0happen due to poor model description. A current lim=
it must be<br>
&gt;=C2=A0 =C2=A0 =C2=A0included in the equations (no physical device can s=
ustain 1e15 Amp<br>
&gt;=C2=A0 =C2=A0 =C2=A0of current :-) ).<br>
&gt; <br>
&gt;=C2=A0 =C2=A0 =C2=A0Stefan<br>
&gt; <br>
<br>
Thank you to all.<br>
<br>
The breakdown is where I ran into problems with a model years ago.=C2=A0 It=
 <br>
was quicker to just setup an test bed and try it.=C2=A0 Don&#39;t do enough=
 <br>
design work to take the time to learn the simulator.=C2=A0 Same reason that=
 <br>
Multisim is being used.<br>
<br>
Robin<br>
<br>
<br>
<br>
</blockquote></div>
 
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Reply subtree:
4214 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from gene glick <ge...@optonline.net>
  4215 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from stefan <st...@gmail.com>
    4222 Re: [pcb-rnd] Off topic (maybe) - Spice simulator -- from N <ni...@gmail.com>
  4216 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Evan Foss <ev...@gmail.com>
    4217 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from gene glick <ge...@optonline.net>
      4218 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Evan Foss <ev...@gmail.com>
        4224 Re: [pcb-rnd] Off topic (maybe) - Spice simulator - openems from N <ni...@gmail.com>
      4228 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Robin Laing <Me...@TelusPlanet.net>
        4229 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Evan Foss <ev...@gmail.com>
          4231 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Robin Laing <Me...@TelusPlanet.net>
            4232 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Evan Foss <ev...@gmail.com>
              4248 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Robin Laing <Me...@TelusPlanet.net>
        4233 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from gene glick <ge...@optonline.net>
          4247 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Robin Laing <Me...@TelusPlanet.net>
  4219 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Gabriel Paubert <pa...@iram.es>
    4220 Re: [pcb-rnd] Off topic (maybe) - Spice simulator from Evan Foss <ev...@gmail.com>
      4223 Re: [pcb-rnd] Off topic (maybe) - Spice simulator - sparc model from N <ni...@gmail.com>