Re: defining special kind of behavioral for current controlled oscilator in ltspice
On Mon, Mar 17, 2025 at 03:56 AM, Tony Casey wrote:
That's exactly true. YIG are tuned by varying the magnetic field the element is in, hence the coils. This also defines the dynamic behaviour.
If that is true, then john23's specifications are wrong, and the LTspice "model" I made for it is wrong.
?
The Tune input should have been driven by a current, not by a voltage.
?
Andy
?
|
Re: LF356 simulation errors
Thanks Tony and John,
LTspice v24.1.0 was installed automatically yesterday with the internal update. Today tried to update again and now installed new version 24.1.5
I've loaded the test simulation of LF356 and make sure to reset all settings, modified again the "Component attribute editor" to original setting for U2, applied the suggestions (rise/fall times and the option directive), now works perfectly... Thank you Tony!
Best regards, Stephano
|
Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?
Sorry, forgot, I have used 1e-9 today in Matlab, I didn't wait it ran all 200us, Just 23% to see the most shape of the leading, the scale is the same, peak approx 40mV.
?
Best regards.
?
On Mon, Mar 17, 2025 at 09:14 PM, <ericsson.sunshine@...> wrote:
Hi, Marcel:
?
In fact, it doesn't matter to add a '-' sign in time or s-domain.
It just changes the positive/negative, instead of the amplitude.
?
Best regards.
?
On Mon, Mar 17, 2025 at 08:43 PM, <mhx@...> wrote:
I think I found it. When the time-domain waveform is plotted from t=0 to t=50us, it
shows a *negative-going* exponential pulse reaching -5.037kV at 960ns. (The shape is
approximately waht your picture shows, the scale is not.) At 41us it is about -20V. I am
sure that when Simulink is told to use a sample-rate of 10ns and an accuracy of 10e-9
or better, it will show the same thing. As should LTspice.
-marcel
?
?
?
|
Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?
Hi, Marcel:
?
In fact, it doesn't matter to add a '-' sign in time or s-domain.
It just changes the positive/negative, instead of the amplitude.
?
Best regards.
?
On Mon, Mar 17, 2025 at 08:43 PM, <mhx@...> wrote:
I think I found it. When the time-domain waveform is plotted from t=0 to t=50us, it
shows a *negative-going* exponential pulse reaching -5.037kV at 960ns. (The shape is
approximately waht your picture shows, the scale is not.) At 41us it is about -20V. I am
sure that when Simulink is told to use a sample-rate of 10ns and an accuracy of 10e-9
or better, it will show the same thing. As should LTspice.
-marcel
?
?
?
|
Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?
I think I found it. When the time-domain waveform is plotted from t=0 to t=50us, it
shows a *negative-going* exponential pulse reaching -5.037kV at 960ns. (The shape is
approximately waht your picture shows, the scale is not.) At 41us it is about -20V. I am
sure that when Simulink is told to use a sample-rate of 10ns and an accuracy of 10e-9
or better, it will show the same thing. As should LTspice.
-marcel
|
Re: LF356 simulation errors
On 17/03/2025 12:27, Tony Casey wrote:
On 17/03/2025 11:40, Stephano via
groups.io wrote:
using the TI model of LF356 on LTspice v24.1.0 result in strange behaviour, DC output from OpAmp is over 18V when the supply voltages are ¡À 15V.
In the "Component attribute editor" I've changed parameters for this version of LTspice, the original from the file area "LF356_test.zip" result in errors at simulation start.
I want to simulate a input circuit of an test equipment (Boonton 4200) that is oscillating at 93Hz square wave with amplitude near the supply coltages. I'm curious to see the Phase Margin of this differential stage with three LF356.
Clearly this pspice model is incompatible with this LTspice version, or there is a workaround possible to apply ?
I don't have version 24.1.0 installed, but with 24.1.5, the
(Helmut's) original circuit stalled at 40% completion, but was
correct up to that point. When I changed the rise and fall times
of the source to 100n from 10n, it simulated perfectly. With
version 25.0.12, the original unedited circuit had no problems. I
also ran an input voltage sweep and saw the output clipped well
inside the supply voltages.
The version 24.1.0 was quite short-lived because there were a
number of problems with it. There have been many internal changes
in the 24.1.x release. some of these have since been fixed, but
others remain.
It may be that nobody can duplicate the problem you are having,
but if you have changed anything in the schematic, you should
upload it to Files > Temp, so more people can try. Did you
change any of the Control Panel > SPICE settings from default?
The Trtol parameter in 24.1 is different from 24.0 in the default
state.
Adding ".options gshunt=1e-12 cshunt=1e-14" fixed the stalling at
40% issue with 24.1.5.
--
Regards,
Tony
|
Re: LF356 simulation errors
On 17/03/2025 11:40, Stephano via
groups.io wrote:
using the TI model of LF356 on LTspice v24.1.0 result in strange behaviour, DC output from OpAmp is over 18V when the supply voltages are ¡À 15V.
In the "Component attribute editor" I've changed parameters for this version of LTspice, the original from the file area "LF356_test.zip" result in errors at simulation start.
I want to simulate a input circuit of an test equipment (Boonton 4200) that is oscillating at 93Hz square wave with amplitude near the supply coltages. I'm curious to see the Phase Margin of this differential stage with three LF356.
Clearly this pspice model is incompatible with this LTspice version, or there is a workaround possible to apply ?
I don't have version 24.1.0 installed, but with 24.1.5, the
(Helmut's) original circuit stalled at 40% completion, but was
correct up to that point. When I changed the rise and fall times of
the source to 100n from 10n, it simulated perfectly. With version
25.0.12, the original unedited circuit had no problems. I also ran
an input voltage sweep and saw the output clipped well inside the
supply voltages.
The version 24.1.0 was quite short-lived because there were a number
of problems with it. There have been many internal changes in the
24.1.x release. some of these have since been fixed, but others
remain.
It may be that nobody can duplicate the problem you are having, but
if you have changed anything in the schematic, you should upload it
to Files > Temp, so more people can try. Did you change any of
the Control Panel > SPICE settings from default? The Trtol
parameter in 24.1 is different from 24.0 in the default state.
--
Regards,
Tony
|
Re: LF356 simulation errors
We can't help much unless you let us see more
of what you are doing. Upload your .ASC file AND all the other
files required to run the simulation, but not .RAW? and .LOG
files or pictures,? in a ZIP archive to Files => Temp.
Go to the web page: /g/LTspice/topics. Click on
Files in the list on the left. Then click on Temp. Then click on
New Upload in the blue box at top left. Click on Upload File in
the drop-down menu. Then send a message to tell us that you did
that.
On 2025-03-17 10:40, Stephano via
groups.io wrote:
Hi,
using the TI model of LF356 on LTspice v24.1.0 result in strange behaviour, DC output from OpAmp is over 18V when the supply voltages are +/- 15V.
In the "Component attribute editor" I've changed parameters for this version of LTspice, the original from the file area "LF356_test.zip" result in errors at simulation start.
I want to simulate a input circuit of an test equipment (Boonton 4200) that is oscillating at 93Hz square wave with amplitude near the supply coltages. I'm curious to see the Phase Margin of this differential stage with three LF356.
Clearly this pspice model is incompatible with this LTspice version, or there is a workaround possible to apply ?
Thanks, Stephano
--
OOO - Own Opinions only
If something is true:
* as far as we know - it's science
*for certain - it's mathematics
*unquestionably - it's religion
|
Hi,
using the TI model of LF356 on LTspice v24.1.0 result in strange behaviour, DC output from OpAmp is over 18V when the supply voltages are +/- 15V.
In the "Component attribute editor" I've changed parameters for this version of LTspice, the original from the file area "LF356_test.zip" result in errors at simulation start.
I want to simulate a input circuit of an test equipment (Boonton 4200) that is oscillating at 93Hz square wave with amplitude near the supply coltages. I'm curious to see the Phase Margin of this differential stage with three LF356.
Clearly this pspice model is incompatible with this LTspice version, or there is a workaround possible to apply ?
Thanks, Stephano
|
Re: Parts Number Re-numbering
That's a bit too much freedom. LTspice will not warn you of
duplicate designators until you run an analysis, which will
obviously fail. If you leave it entirely to LTspice you will never
get duplicates. Caution! This does not apply to net names.
--
Regards,
Tony
On 17/03/2025 00:50, John Woodgate
wrote:
toggle quoted message
Show quoted text
Right-click
on the number, such as R1. An editing pane opens where you can
change it to anything you like, within reason.
|
Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?
I don't know, in my domain what I can do the best is to spend the tiny time step = 1ps. (already the smallest when considering the computing performance.)
But neither LTspice nor Matlab/simulink has the expected answer. (Thay have the same output ~ 40mV)
?
About the algorithm inside transfer function, I really have no idea, maybe not enough decimal digits been calculated. Can't find any where to configure that.
?
Best regards.
?
On Mon, Mar 17, 2025 at 04:02 PM, <mhx@...> wrote:
The transfer function and time domain expressions look OK to me but the scope plot is obviously "wrong".
This could be caused by the sample-based Simulink implementation. What is the sample-rate / solver
algorithm? If there is aliasing all three representations could be correct.
-marcel
?
?
|
Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?
The transfer function and time domain expressions look OK to me but the scope plot is obviously "wrong".
This could be caused by the sample-based Simulink implementation. What is the sample-rate / solver
algorithm? If there is aliasing all three representations could be correct.
-marcel
|
Re: defining special kind of behavioral for current controlled oscilator in ltspice
That's exactly true. YIG are tuned by varying the magnetic field the element is in, hence the coils. This also defines the dynamic behaviour.
-- Regards, Tony?
On 17 Mar 2025 05:06, "Andy I via groups.io" <AI.egrps+io@...> wrote: On Sun, Mar 16, 2025 at 09:13 AM, Tony Casey wrote:
Typically, the TUNE coil will be 10s of mH and FM coil will be about 10uH. ...
This implies that both inputs might respond to current, unless the TUNE coil has enough resistance which is stable and predictable.
?
Andy
?
|
Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?
In simple words, ...
The user's fault or math's fault ?
?
Beg your pardon first, so noisy, definitely my fault.
?
In fact, my default thoughts is 99% belong to user's fault, but I don't know what's wrong.
?
If any hint,?
?
Thank you very much.
|
Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?
Hi, :
?
You know what ? I'm surprised about I do have the memory about using this in Matlab.
It got the same result. I worship the math as some kind of religion, but this time, I can't get the desired answer, what's going on ?
?
Is the math wrong ?
?
Can someone tell any configuration wrong ? It almost broke my religion. Hope someone recognize it.
?
I am wondering, how many people are you here...
?
Wish you all happy & healthy.
?
Best regards.
|
Re: proper way to simulate fluctuating load for voltage regulator
aside: please note that for time-varying resistors, the theoretical circuit equations will change and new derivative terms for (otherwise fixed) component parameters will enter into your equations. this may worry if not considered.
|
Hi
I have LTspice XVII installed in the directory:
C:Program files\LTC\LTspice XVII
Is it safe to install LTspice 24? so that I keep my old Auto_Genrated models?
Can you please advise? is the new LTspice 24 any better ?
Regards,
Suded
|
Re: defining special kind of behavioral for current controlled oscilator in ltspice
On Sun, Mar 16, 2025 at 09:13 AM, Tony Casey wrote:
Typically, the TUNE coil will be 10s of mH and FM coil will be about 10uH. ...
This implies that both inputs might respond to current, unless the TUNE coil has enough resistance which is stable and predictable.
?
Andy
?
|
Re: defining special kind of behavioral for current controlled oscilator in ltspice
On Sun, Mar 16, 2025 at 05:15 AM, john23 wrote:
How sould I use MODULATE to define this unique behavior?
john23,
?
I uploaded "YIG VCO.asc" to the "Temp" directory.? It models what you apparently wanted.? It has two inputs and one output.
?
The "Coarse" input is for your "TUNE" signal that sets the center frequency.? The "Fine" input is for your "FM" signal that modulates its frequency around the center.? Both inputs have infinite bandwidth.
?
Both inputs are ideal, so you should add whatever is needed to model each of their electrical characteristics:
- The "Coarse" (or Tune) input is infinite impedance.? If you know its input impedance, connect it in parallel, between the two input pins.
- The "Fine" (or FM) input is zero impedance.? If you know its input impedance, connect it IN SERIES with that input.
- In simulations, both inputs should be given a ground reference, not left floating.
- Both inputs have infinite bandwidth.? Add your own filtering if needed.
The output is +10 dBm when terminated in an external 50 ohms load.? The schematic I uploaded has a 50 ohm load, so remove that when driving something else that provides a termination.
?
Andy
?
|
Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?
On Fri, Mar 14, 2025 at 06:35 PM, Tony Casey wrote:
On 14/03/2025 11:30, Andy I via groups.io wrote:
Tony uploaded "IEC_61000-4-2_Test.zip", but it has a symbol that LTspice might not have and can't be opened in older versions.
Oops. Zip file updated with symbol.
--
Regards,
Tony
?
?
Just to note, in the latest LTspice 24.1.5, it will have the following message... It seems 'SCOPEDATA=' is forced to replace the 'file='.
Looks like, compatible issue between newer & older...was used to the older XVII...
?
"Monotonically increasing value expected. You may want to use SCOPEDATA=<filename> instead. (See the LTspice help for more details.)
1.00E-09,0.9088###>
1.00E-09<###,0.9110"
?
And, Thanks for the inspiration of varistors.
|
Stephano
Tony Casey
John Woodgate