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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,

Hello all,

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

In message <1374140838.88699.YahooMailNeo@...>,
dated Thu, 18 Jul 2013, abeillé 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

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@...
Envoyé 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

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

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

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

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 ?

Hi.
Look:
.MODEL MPS4250 PNP IS =2.01722E-14 NF=1.00872 VAF =55.5699 IKF= 0.108955 ISE = 6.37359E-16 NE =1.35818 BR =4.41291 NR= 1.02097 VAR= 6.54054 IKR = 0.0178791 ISC =2.78089E-14 NC=1.13928 RB = 85.9809 RE= 0.260437 EG=1.11 XTI = 3 CJE= 9.35999p VJE = 0.805219 MJE= 0.390963 VJC = 0.270529 MJC= 0.295929 FC= 0.5 BF =3.213490E+02 CJC = 6.39675p RC=2.2484 TF=1.0E-10 XTF =1

Bordodynov.

17.07.2013, 20:04, "jean_claudeabeille" <jean_claudeabeille@...>:

--- In LTspice@..., John Woodgate <jmw@...> wrote:

In message <93141374063607@...>, dated Wed, 17 Jul 2013,
=?koi8-r?B?4czFy9PBzsTSIOLP0sTPxNnOz9c=?= <BordodunovAlex@...>
writes:

The model is in the file CORE.LIB. The symbol contains the name of the
library.

Then it's very odd that my computer can't find it. Anyway, thanks for
the explanation.
--
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

John,

It worked fine for me. There must be an issue with your PC.

Rick

Hi John Woodgate.
In my example, there is no need to use DOT commands ".inc" and ". Lib". LTspice allows it. Link to the library name within the symbol "Winding0.asy". Just run the simulation.
Bordodynov.

17.07.2013, 20:19, "John Woodgate" <jmw@...>:

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

--- In LTspice@..., legg@... wrote:

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

--- In LTspice@..., legg@ wrote:

Here's an example of a material exhibiting reduced permeability with frequency.



RL

The link doesn't show anything about permeability vs. frequency.

Rick

Material permeability is directly related to inductance of the sample, if only the frequency changes in the test.

RL

RL,

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

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

--- In LTspice@..., legg@ wrote:

Here's an example of a material exhibiting reduced permeability with frequency.



RL

The link doesn't show anything about permeability vs. frequency.

Rick

Material permeability is directly related to inductance of the sample, if only the frequency changes in the test.

RL

--- In LTspice@..., Dhara Weerasinghe <the_sky_falcon@...> wrote:

Hi All,
?
Thanks so much for your help. I got it to work. I used :
?
K L1 L2 {X}
?
.step param {X} 0.01 0.07 0.01
?
Thanks again for your help.?
?
Falcon

[Non-text portions of this message have been removed]

Falcon,

You got lucky. Even though you were given the right syntax, you chose not to use it.

The K statement should use the Kx syntax, where x is usually numeric, but must be unique. If there is only one K statement, it will obviously be unique, but as soon as you introduce another, you must explicitly make it so.

Secondly, the curly braces are not appropriate in the .step param statement. LTspice often silently ignores syntax errors, but that shouldn't be a guiding principle.

Perhaps you should read the manual. (Usual expletive omitted.)

Regards,
Tony

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

I have a simulation of a open loop SMPS that I would like to know the transformer losses, but using the following script gives an efficiency of >100%.....which I know is not true.

After digging a bit I came across a example in the files area for AC power, complex_power1_meas-1.asc. But the notes state "Steady State Power Calculation With Pure Sine Voltages And Linear Components".

My question is will this same approach work for a rectangle waveform?


.param mes_start=6m mes_end=9.9m

.meas TRAN Vrms_pri RMS V(vpri1,vpri2) from {mes_start} to {mes_end}
.meas TRAN Irms_pri RMS I(L1) from {mes_start} to {mes_end}
.meas Ppri PARAM Vrms_pri*Irms_pri

.meas TRAN Vrms_can RMS V(vac_can1,vac_can2) from {mes_start} to {mes_end}
.meas TRAN Irms_can RMS I(L2) from {mes_start} to {mes_end}
.meas Pcan PARAM Vrms_can*Irms_can

.meas TRAN Vrms_rs RMS V(vac_rs1,vac_rs2) from {mes_start} to {mes_end}
.meas TRAN Irms_rs RMS I(L3) from {mes_start} to {mes_end}
.meas Prs PARAM Vrms_rs*Irms_rs

.meas eff_tx PARAM (Pcan+Prs)/Ppri

Hello,

Discounting errors in the scripts, "measured" efficiencies of greater than 100%, are often due to not waiting long enough before deciding "steady state" has been reached. If there is significant ringing in the SMPS transient response and the measurement interval is over a period of net downward trajectory of the output voltage, it is easily possible that more energy is being taken out of the system than is being put in. You should do some sanity checks that prove that you are not in such a region.

First step: try doubling the simulation time.

Conversely, an upward trajectory in voltage could indicate a pessimistic estimation of efficiency.

Regards,
Tony

In message <ks6pg9+ovi6@...>, dated Wed, 17 Jul 2013, sawreyrw <sawreyrw@...> writes:

A K statement is not directly applicable to a nonlinear inductor.

But that is exactly what the thread is about!
--
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

--- In LTspice@..., John Woodgate <jmw@...> wrote:

In message <ks6lf3+t8c1@...>, dated Wed, 17 Jul 2013, sawreyrw
<sawreyrw@...> writes:

There is no reason you can't use x as a parameter. The only thing
special about x is that it is used to represent the current in a
nonlinear inductor and the volt across a nonlinear capacitance, but it
is not visible outside the component model.

I just recommend not using it in order to avoid what would appear to be
inexplicable error, especially where the context is, indeed, non-linear
inductors.
--
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

John,

I know the statement flux={x}*tanh(x) looks strange, but LTspice knows that the parameter x is not the current x. Of course, I wouldn't recommend it, because of the possible confusion others might have. A K statement is not directly applicable to a nonlinear inductor.

Rick

Rick