It's because of its photovoltaic junction responding to the light from your screen. Turn the brightness down to zero and try it again. ;)
I have experienced similar results in some LTSpice simulations. I think it might be from a model parameter that is expressed as a voltage without a corresponding current.
Paul
he needs. I also use LTSpice, because I'm a cheapskate. For my limited des igning time it's sufficient so far. Well nearly, I wish it did some things, but afaik no sim does them.
Really? I can't remember the full details, but one I wanted to sim used som e sort of voltage multiplier powered by a thermopile. I think there were cm os inverters in there, which bootstrapped its own supply before connecting the load. Wanted to know at what V_in it would begin to oscillate & whether it would keep going when it turned the load on. But afaik Spice et al don' t model what happens as Vdd goes low. Fairly likely I'm not remembering the details accurately.
NT
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
--
| 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 http://www.analog-innovations.com | 1962 |
Spice is like a sports car...
Performance only as good as the person behind the wheel.
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
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
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
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
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
--
| 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 http://www.analog-innovations.com | 1962 |
It's what you learn, after you know it all, that counts.
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
--
| 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 http://www.analog-innovations.com | 1962 |
It's what you learn, after you know it all, that counts.
Poor guy, stuck on Windows. The rest of us use symlinks, so it's no problem at all.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
A symplectic integrator would get it right, is what. They aren't necessarily more accurate in other ways, of course.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
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
--
| 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 http://www.analog-innovations.com | 1962 |
It's what you learn, after you know it all, that counts.
Sheeeesh! ...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 http://www.analog-innovations.com | 1962 |
It's what you learn, after you know it all, that counts.
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
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
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
--
| 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 http://www.analog-innovations.com | 1962 |
It's what you learn, after you know it all, that counts.
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
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
Why I put paths to libraries ON the schematic...
Not even HALF my total. ...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 http://www.analog-innovations.com | 1962 |
It's what you learn, after you know it all, that counts.
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
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
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
--
| 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 http://www.analog-innovations.com | 1962 |
It's what you learn, after you know it all, that counts.
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
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