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Re: Ltc3765 & 3766 combo dc/dc simulation goes wild

 

Hello Olek,
Have you tried with more load, e.g. 100Ohm instead of 1kOhm?
Best regards,
Helmut

--- In LTspice@..., "oleka111" <oleka111@...> wrote:

Nice to see that you spotted it too......
What if real circuit would behave the same way ?
Hope Linear will fix this issue soon.
I didn't post the original file, because everyone can load it as an LT's example named 3765.asc and see the effect of diminishing of the voltage feedback resistor.

Regards,
Olek A.

--- In LTspice@..., "Tony Casey" <tony@> wrote:



--- In LTspice@..., "oleka111" <oleka111@> wrote:

Hello,

Running an dc/dc example named 3765.asc with slightly lowered feedback resistor (4.42 --> 4.2k) gives Vout appr. several times bigger than expected.
Just the opposite what we should expect while lowering the feedback resistor.
It can be even dangerous to the sensitive load.

Why it behaves this way ?
Hello,

Well spotted. I have tried this distribution example circuit on two machines, and it behaves as you describe.

I swept the feedback resistor from 4k1 to 4k3 in 10R steps and found that the LTC3766 transitions from closed loop to open loop behaviour when the value goes below 4210R. Whether this a model error or not, I don't know, but the example circuit is clearly unsatisfactory.

I have reported this as a bug to Mike.

Regards,
Tony


Re: Ltc3765 & 3766 combo dc/dc simulation goes wild

 

Nice to see that you spotted it too......
What if real circuit would behave the same way ?
Hope Linear will fix this issue soon.
I didn't post the original file, because everyone can load it as an LT's example named 3765.asc and see the effect of diminishing of the voltage feedback resistor.

Regards,
Olek A.

--- In LTspice@..., "Tony Casey" <tony@...> wrote:



--- In LTspice@..., "oleka111" <oleka111@> wrote:

Hello,

Running an dc/dc example named 3765.asc with slightly lowered feedback resistor (4.42 --> 4.2k) gives Vout appr. several times bigger than expected.
Just the opposite what we should expect while lowering the feedback resistor.
It can be even dangerous to the sensitive load.

Why it behaves this way ?
Hello,

Well spotted. I have tried this distribution example circuit on two machines, and it behaves as you describe.

I swept the feedback resistor from 4k1 to 4k3 in 10R steps and found that the LTC3766 transitions from closed loop to open loop behaviour when the value goes below 4210R. Whether this a model error or not, I don't know, but the example circuit is clearly unsatisfactory.

I have reported this as a bug to Mike.

Regards,
Tony


Re: UAF42

 

That one is easy. Its "just" a couple of op-amps. follow the block diagram in the spec sheet and you pretty much have it.

Jim Wagner
Oregon Research Electronics.

On Jul 18, 2013, at 3:18 PM, Suleiman wrote:

Hello.
Has anyone already modelled the universal filter UAF42 on LTspice?

Thanks


Re: LTspice Genealogy - The Heritage of Simulation Ubiquity

 

Hello, a.s.

I'm impressed by the work you have put in on this.

I would like to add one note, which I have peripherally mentioned in the list before. Newcomers are likely to not remember or never have known what the "state of computing" was when spice began in the early 1970s. I encountered it on machines limited to punch-card input and line printer output, only. You submitted "job decks" (and some still refer to a netlist as a "spice deck"); woe unto you who dropped one of those punch card boxes! And the reams of fanfold paper needed to print out the initial node conditions plus the response of selected nodes. The response was an "ASCII graph" with an even time step. I don't know if it was computed on an even time step or if it was interpolated after the fact.

An important part of this as that as long as the machine ran FORTRAN, accepted punch card input and did line printer output, spice would run. There were no issues of "operating system" or cross-platform behavior. I saw it run on big IBM mainframes and CDC6400s.

I think that it was the graphic user interface that really pushed various implementations into one OS or another. It was simply too hard to do a two-OS implementation (for the most part).

So, maybe one of the important anchor points in your timeline ought to be when GUIs began to be made as an integral part of the various spice versions.

Thans for all your great work.

Jim Wagner
Oregon Research Electronics

On Jul 18, 2013, at 9:08 AM, analogspiceman wrote:

Please visit this new page at the LTwiki.



It is still "under construction" and I would appreciate your
suggestions for corrections, omissions noted or improvements
needed. -- a.s.


Re: inductance with a permeability in dependency of frequency

 

--- In LTspice@..., "sawreyrw" <sawreyrw@...> wrote:


I understand that, but there is no function of frequency shown at that link. If you don't think that is the case, double check it.

Rick
My mistake. Here's the web page and correct link:





Other related stuff there.

RL


UAF42

 

Hello.
Has anyone already modelled the universal filter UAF42 on LTspice?


Thanks


Re: looking for a model for AD8363

Tony Casey
 

--- In LTspice@..., "gift4jo" <gift4jo@...> wrote:


Hi Tony,
I just need something for higher frequency, say 10MHz.


--- In LTspice@..., "Tony Casey" <tony@> wrote:



--- In LTspice@..., "gift4jo" <gift4jo@> wrote:

I have tried to search on the file content page without luck, Anyone can help me find this or any other RMS-DC converter.
What's wrong with the LTC1966 - LTC1968, which are included in the LTspice distribution? Did you think of looking there?

You can find them in:
Components=>SpecialFunctions

Regards,
Tony
Perhaps if you had included all of your requirements in your post, instead of just "...any other RMS-DC converter", you might have avoided needlessly further increasing the entropy of the universe.

If you really want an RF RMS to DC converter, you mighty want to check out ADI:


Maxim do them too:


You won't find any models there, but I have created behavioural models from the datasheets, but unfortunately I can't share them with you as someone else paid for it. But it's not that hard.

Don't expect the same accuracy as you would get from a proper LF RMS to DC converter, though.

Regards,
Tony


Re: LTspice Genealogy - The Heritage of Simulation Ubiquity

 

--- In LTspice@..., "analogspiceman" <analogspiceman@...> wrote:

Please visit this new page at the LTwiki.



It is still "under construction" and I would appreciate your
suggestions for corrections, omissions noted or improvements
needed. -- a.s.
Hello analogspiceman,

Thanks a lot for collecting all the mile stones.

I always wonder that 1999 was the "birth" of LTspice.
I personally discovered that LTspice is a SPICE program in
the summer 2001. I still believe that I was one of the early
adopters using it as a general SPICE program. Also the
discussions about LTspice started in 2001 in the usenet, sci.electronics.design and sci.electronics.cad.

Best regards,
Helmut


Re: Ltc3765 & 3766 combo dc/dc simulation goes wild

Tony Casey
 

--- In LTspice@..., "oleka111" <oleka111@...> wrote:

Hello,

Running an dc/dc example named 3765.asc with slightly lowered feedback resistor (4.42 --> 4.2k) gives Vout appr. several times bigger than expected.
Just the opposite what we should expect while lowering the feedback resistor.
It can be even dangerous to the sensitive load.

Why it behaves this way ?
Hello,

Well spotted. I have tried this distribution example circuit on two machines, and it behaves as you describe.

I swept the feedback resistor from 4k1 to 4k3 in 10R steps and found that the LTC3766 transitions from closed loop to open loop behaviour when the value goes below 4210R. Whether this a model error or not, I don't know, but the example circuit is clearly unsatisfactory.

I have reported this as a bug to Mike.

Regards,
Tony


LTspice Genealogy - The Heritage of Simulation Ubiquity

 

Please visit this new page at the LTwiki.



It is still "under construction" and I would appreciate your
suggestions for corrections, omissions noted or improvements
needed. -- a.s.


Re: Ltc3765 & 3766 combo dc/dc simulation goes wild

 

oleka111 wrote:

Running an dc/dc example named 3765.asc with slightly lowered feedback
resistor (4.42 --> 4.2k) gives Vout appr. several times bigger than
expected.
Just the opposite what we should expect while lowering the feedback
resistor.
It can be even dangerous to the sensitive load.

Why it behaves this way ?
Nobody can answer this because you gave us no information. Try uploading
your complete schematic so we can see what is going on.

Andy


Re: Changing the mutual inductance coefficient of K statements with time

 

Thank you for pointing that out.
?
I made a mistake in the syntax when I typed it in the message. Yes there is only one pair of inductors in my circuit. Otherwise I would have used Kx (K1, K2,... Kn) in my statement.?
?
cheers,


UC1834

 

Hello all,

I am in need of an LTSpice IC model of UC1834 (TI). Anyone who has ever come across one, kindly reply.


Re: MPS4250

John Woodgate
 

In message <1374140838.88699.YahooMailNeo@...>,
dated Thu, 18 Jul 2013, abeill¨¦ jean-claude
<jean_claudeabeille@...> writes:

I am a french retired computer analyst and a music and
electonicsenthusiast. Please, will you excuse my english.
It is quite good.

For the moment, I try to understand how does work my amp with LTSpice.
Actually, after an error in handling, one channel failed and activated
a protection circuit (too much quiescent on one output stage polarity).
I tried to fix this but I failed and ordered a complete replacement
PCB. But I am curious and like to understand things. So I drawn the
circuit in LTSpice from the PCB and could not understand it in some places.
Please upload the circuit (we use the US term ''schematic' on this list)
to Files => Temp on the list's web site:



I asked Bob Cordell some help but he was to busy and answer me to read
chapter 1-4 from his book. OK. In fact, in LTSpicen there is almost no
quiescent current in output stage and the VBE spreader does not work at
all. I thought that some models where not correct but I don't know. I'm
deadlocked.
I expect we can help once we see the schematic.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK


Re: MPS4250

abeill¨¦ jean-claude
 

OK, thank you John.
?Perhaps you can help me in my quest.
I am a french retired computer analyst and a music and electonicsenthusiast. Please, will you excuse my english.
For the moment, I try to understand how does work my amp with LTSpice.
Actually, after an error in handling, one channel failed and activated a protection circuit (too much quiescent on one output stage polarity). I tried to fix this but I failed and ordered a complete replacement PCB.
But I am curious and like to understand things. So I drawn the circuit in LTSpice from the PCB and could not understand it in some places. I asked Bob Cordell some help but he was to busy and answer me to read chapter 1-4 from his book. OK.
In fact, in LTSpicen there is almost no quiescent current in output stage and the VBE spreader does not work at all.
I thought that some models where not correct but I don't know.
I'm deadlocked.

Jean-Claude.





________________________________
De?: John Woodgate <jmw@...>
??: LTspice@...
Envoy¨¦ le : Mercredi 17 juillet 2013 18h55
Objet?: Re: [LTspice] MPS4250



?
In message <ks6d15+3s9u@...>, dated Wed, 17 Jul 2013,
jean_claudeabeille <jean_claudeabeille@...> writes:

Can anybody here tell me where I can find a spice model for this PNP ?
Thank you;
Apart from the packaging, it is similar to a BC556 or BC557.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK


Re: Changing the mutual inductance coefficient of K statements with time

John Woodgate
 

In message <747691374138968@...>, dated Thu, 18 Jul 2013, =?koi8-r?B?4czFy9PBzsTSIOLP0sTPxNnOz9c=?= <BordodunovAlex@...> writes:

My source files without any corrections you simulated?
Yes, I deleted the first download and downloaded the zip again, opened it and saved all five files to Desktop. I made no changes. The 'Unknown subckt...' error occurred. I opened Core.lib with UltraEdit and copied the .subckt Winding0 to the schematic as a Spice directive. The simulation then ran.

Just to see what would happen, I converted the directive to a comment and the simulation did not run, giving the 'Unknown subckt...' error.

I am using Windows XP SP3, but I don't believe this has anything to do with Windows.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK


Re: Changing the mutual inductance coefficient of K statements with time

 

John Woodgate.
My source files without any corrections you simulated?
Bordodynov.

18.07.2013, 12:40, "John Woodgate" <jmw@...>:

In message <256711374134677@...>, dated Thu, 18 Jul 2013,
=?koi8-r?B?4czFy9PBzsTSIOLP0sTPxNnOz9c=?= <BordodunovAlex@...>
writes:

John Woodgate, I had a similar problem when using the ". inc". It was a
month or two ago. I do not remember. I wanted to place the sample in
the group, but gave LTspice is the same message as you. I think it bugs
LTspice. Then I decided to put the model to the page of the electronic
circuit. Then I discovered that you can reference on library in the
symbol. Library while in the current folder.
Try to upgrade.
I have version 4.19m, the latest. I can make the simulation run by
copying the .subckt to the schematic. I can see that 'winding0' is the
VALUE in the symbol Winding0.asy', but I don't see how LTspice knows it
should look in Core.lib for the subckt.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK


Re: Changing the mutual inductance coefficient of K statements with time

John Woodgate
 

In message <256711374134677@...>, dated Thu, 18 Jul 2013, =?koi8-r?B?4czFy9PBzsTSIOLP0sTPxNnOz9c=?= <BordodunovAlex@...> writes:

John Woodgate, I had a similar problem when using the ". inc". It was a month or two ago. I do not remember. I wanted to place the sample in the group, but gave LTspice is the same message as you. I think it bugs LTspice. Then I decided to put the model to the page of the electronic circuit. Then I discovered that you can reference on library in the symbol. Library while in the current folder.
Try to upgrade.
I have version 4.19m, the latest. I can make the simulation run by copying the .subckt to the schematic. I can see that 'winding0' is the VALUE in the symbol Winding0.asy', but I don't see how LTspice knows it should look in Core.lib for the subckt.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK


Re: Changing the mutual inductance coefficient of K statements with time

 

John Woodgate, I had a similar problem when using the ". inc".
It was a month or two ago. I do not remember. I wanted to
place the sample in the group, but gave LTspice is the same message as you. I think it bugs LTspice.
Then I decided to put the model to the page of the electronic circuit. Then I discovered that you can reference on library in the symbol. Library while in the current folder.
Try to upgrade.
Bordodynov.

18.07.2013, 11:13, "John Woodgate" <jmw@...>:

In message <622831374124699@...>, dated Thu, 18 Jul 2013,
=?koi8-r?B?4czFy9PBzsTSIOLP0sTPxNnOz9c=?= <BordodunovAlex@...>
writes:

In my example, there is no need to use DOT commands ".inc" and ". Lib".
I know; I was trying to find out why I have the problem.

LTspice allows it. Link to the library name within the symbol
"Winding0.asy". Just run the simulation.
It still doesn't run. I will try downloading again.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK


Re: Changing the mutual inductance coefficient of K statements with time

John Woodgate
 

In message <622831374124699@...>, dated Thu, 18 Jul 2013, =?koi8-r?B?4czFy9PBzsTSIOLP0sTPxNnOz9c=?= <BordodunovAlex@...> writes:

In my example, there is no need to use DOT commands ".inc" and ". Lib".
I know; I was trying to find out why I have the problem.

LTspice allows it. Link to the library name within the symbol "Winding0.asy". Just run the simulation.
It still doesn't run. I will try downloading again.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK