free energy!

Please don't toss out the word "spice" as if it were generic.

If LTspice failed you, cite LTspice.

If PSpice failed you, cite PSpice.

If Cadence failed you, cite Cadence.

See tag line for most common cause of simulation failures. ...Jim Thompson

There are simulators that are symplectic, i.e. they conserve energy exactly, but of course doing that with a circuit simulator would require a 3-D thermal model running simultaneously.

Cheers

Phil Hobbs

hat he needs. I also use LTSpice, because I'm a cheapskate. For my limited designing time it's sufficient so far. Well nearly, I wish it did some thin gs, but afaik no sim does them.

some sort of voltage multiplier powered by a thermopile. I think there were cmos inverters in there, which bootstrapped its own supply before connecti ng the load. Wanted to know at what V_in it would begin to oscillate & whet her it would keep going when it turned the load on. But afaik Spice et al d on't model what happens as Vdd goes low. Fairly likely I'm not remembering the details accurately.

I said it was LTSpice. The reason for failure is that one can not connect p arts of the circuit to an IC's power pins, and even if one could afaik ICs' real world behaviour are not modelled outside their rated Vdd.

NT

Apart from the tedious Usenet wrangling, the main difference is that foundry models are good (because they have to be) and board-level models stink (except for BJTs, which are frequently more or less OK).

A lot of the modelling I do is for customer reassurance, and because of the crappy models, most of the rest is basically sanity checking (making sure the feedback loop is the right way round, for instance).

Cheers

Phil Hobbs

Here you go....

It's a flaw in LTspice (BAD equation setup). Mr. Larkin would have no way to know, he is, after all, an amateur... though he does claim, "I've paid for three circuit simulators and wrote some of my own."

When the LTspice List first began it was devoted to "how to" topics, now it's pretty much become a bug list, and "How do I overcome this anomaly?"

The main topic currently is how LTspice has trouble dealing with centralized libraries. I harped on that from day one... schematic and symbols required to be in same folder :-( ...Jim Thompson

What does that have to do with power dissipated _in_a_component_?

Mikey did a simplistic approximation and blew it. ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

Nope. It is a failure to maintain signs. Even resistors, for simulation purposes, (should *) have positive and negative terminals.

(*) Not in LTspice. ...Jim Thompson

Poor guy, stuck on Windows. The rest of us use symlinks, so it's no problem at all.

Cheers

Phil Hobbs

A symplectic integrator would get it right, is what. They aren't necessarily more accurate in other ways, of course.

Cheers

Phil Hobbs

It's easy in Windows, also... IF you have any clue of directory calls and structures. I haven't quite figured out what all the falderal is all about. ...Jim Thompson

Sheeeesh! ...Jim Thompson

If it's so easy, why keep grousing about it? You're throwing a lot of dung, but not much is sticking. ;)

Cheers

Phil Hobbs

Look at the LTspice List, it's their complaint. Because I have literally HUNDREDS of libraries, it's easier for me to simply paste "Spice directives" on the schematic... as I do in PSpice... I RARELY EVER use LTspice schematic entry... I simply "play" a .CIR file from PSpice... avoids the accuracy-destroying short-cuts in LTspice (forces the equivalent of Solver=Alternate), yet allows me to model check for LTspice users.

I throw dung because certain village idiots post such nonsense as "free energy!"... and it's such fun to tweak them >:-}

...Jim Thompson

It doesn't come up a lot for me--in the early stages I use one big library with all my faves in it, and later on I make a separate library and separate symbols to be zipped up with the simulation files to send to the customer.

LTspice updates preserve user customizations to their parts libraries, which is a nice touch, but I like to keep my collection separate, and under version control.

Cheers

Phil Hobbs

Why I put paths to libraries ON the schematic...

Not even HALF my total. ...Jim Thompson

Sure, but that's a full set of libraries from N processes. Since that's all you do, basically, and have done it for a long time, one would expect there to be lots. (You should see my lens collection.) ;)

Cheers

Phil Hobbs

Yep. If you don't "directory-ize" it can get profoundly messy. X-Fab, not even shown in that list, has 12 separate processes, and I don't have the most recent offerings loaded yet ;-) ...Jim Thompson

Power display in PSpice...

...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

What a bizarre circuit! Don't you hate LTC parts, LT Spice, and Sallen-Key filters?

And as usual, you post screen shots with no backup.

I've designed a few hundred million dollars worth of electronics, which is hardly amateur.

They obviously do not.