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Re: proper way to simulate fluctuating load for voltage regulator

 

I wrote:
Perhaps a Pi-source?
I meant to write Bi-source.? In other words, a B-source with I=<value>.? You can get fancy where the I depends on its voltage, thus turning it into a controllable resistance.? That's one of many ways to do it.
?
Sorry.? ?Apparently my mind was still on Pi Day.? :-)? (Or :-( since I effectively missed it.)
?
Andy
?


Re: proper way to simulate fluctuating load for voltage regulator

 
Edited

On Sat, Mar 15, 2025 at 11:26 AM, john23 wrote:
?
Hello ,I am trying to test a voltage regulator by re[lacing a steady resistor with some sort of varying resistor.
Given the circuit in the attached Zip file , what kind of "resistor" you reccomend?
Your uploaded files have very little information.
?
Is the "regulator" the 3-transistor circuit, with R4 being the load at the regulator's output?
?
Can you? describe how you want the load to vary?? Do you know what you want it to do, or do you just want it to be random?
?
Can you describe it mathematically using a B-source?? Perhaps a Pi Bi-source?? That should lead you to what you should try.
?
Andy
?


proper way to simulate fluctuating load for voltage regulator

 

?
Hello ,I am trying to test a voltage regulator by re[lacing a steady resistor with some sort of varying resistor.
Given the circuit in the attached Zip file , what kind of "resistor" you reccomend?
Thanks.


Re: DanTherm model (SOAtherm)

 

Hello to all,
I just discovered the discussion.
I would be very interested by the SOATherm simulation.
I found it crazy that this is almost unusable as there is almost no documentation on it.
Does anyone have any news ?
Thanks a lot in advance.


Re: cannot plot power dissipation from elements in ltspice 24.1.4

 

¿ªÔÆÌåÓý

On 15/03/2025 07:11, thereitis via groups.io wrote:
after simulation, i do the following:
?
e.g. on a resistor R1, holding alt button and hovering over the element R1 shows in the status bar "Left-click to plot R1 dissipation: ...".
but doing so, does not add any plot.
?
other than manually typing and adding the plot, is there a correct way for the same. or am i doing something wrong here?
You're not, by any chance using Linux+Wine, are you? If so, try ctrl-alt-leftclick. Apparently, alt-leftclick is assigned to something else on most Linuxes, even though the alt key alone produces the thermometer cursor graphic. I guess that's possible on other platforms, so might be worth trying, if you're on Windows.

Ctrl-alt-leftclick works for me on all versions of LTspice, including 24.1.4.

--
Regards,
Tony


Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?

 

On Sat, Mar 15, 2025 at 02:09 AM, <mhx@...> wrote:
I'm curious as to why you want to (inaccurately) do this in the s-domain?
Your equation is available in the time domain, and it perfectly fits
the way of working of the EXP() voltage source:
Vxxx n+ n- EXP(V1 V2 Td1 Tau1 Td2 Tau2).

-marcel
Hello, Marcel:
?
At first, it's the ideal in sketch the applied circuitry in s-domain on how to attenuate the surge amplitude. Sometimes, in math domain, possibly solutions will be clear to see, though not everytime.
?
Some reasons else maybe:
?
1. For fun to see more ways to implement on simulator.
2. Curiosity the capability of LTspice's Laplace.
3. Puzzle for group ? (puzzle or not , not sure.)
?
Thank you , wish you happy and healthy.


cannot plot power dissipation from elements in ltspice 24.1.4

 

after simulation, i do the following:
?
e.g. on a resistor R1, holding alt button and hovering over the element R1 shows in the status bar "Left-click to plot R1 dissipation: ...".
but doing so, does not add any plot.
?
other than manually typing and adding the plot, is there a correct way for the same. or am i doing something wrong here?
?
thanks.


Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?

 

I'm curious as to why you want to (inaccurately) do this in the s-domain?
Your equation is available in the time domain, and it perfectly fits
the way of working of the EXP() voltage source:
Vxxx n+ n- EXP(V1 V2 Td1 Tau1 Td2 Tau2).

-marcel


Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?

 

¿ªÔÆÌåÓý

On 14/03/2025 15:07, ericsson.sunshine via groups.io wrote:
So that, the picture is not about 'confidential material' it's public knowledge, no 'confidential issue', but *.asc, I am not so sure, any insignificant thing could damage huge, says 'A single spark can start a prairie fire'.
Just to avoid any suspect.?
.asc files are sometimes used in public key cryptography. This might be the reason they are restricted - might be on the IT department's blacklist. Just like there are many types of files you can't attach in emails any longer. (Well, you can attach them, but they get stripped out by the mail server, without notifying the sender.)

--
Regards,
Tony


Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?

 

Hi, Tony, Andy:
?
Thank you for your opinions and sharing files.
?
The file uploading issue was not about technical, it's about company policy, they will log the uploaded files, and trace the content maybe (I am not sure what detailed will be done.)
So that, the picture is not about 'confidential material' it's public knowledge, no 'confidential issue', but *.asc, I am not so sure, any insignificant thing could damage huge, says 'A single spark can start a prairie fire'.
Just to avoid any suspect.?
?
In fact, the main concern of this topic is about the s-equation, if you have ran the simulation , you will see the amplitude of time domain is about 5KV, but only? 40mV in the s-domain, though the s-equation was surely correct by matlab or ChatGPT by doing laplace tranform from its time's.
?
If you have any idea, why their output are different, please kindly share some opinions.
(Is it bug or something else .... ? After some time, I presume the initial condition of the voltage should be 0V same as time-domain....., the different is the scale mV vs. KV...)
?
Thank you very much.
Best regards.


Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?

 

¿ªÔÆÌåÓý

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


Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?

 

On Fri, Mar 14, 2025 at 02:32 AM, <ericsson.sunshine@...> wrote:
Then since I can't upload the file , (the policy of ... some confidential reason, though I don't know what needed to be confidential), I beg your pardon, please allow me to paste the .asc content in the tail if this thread.
I uploaded your file for you, in "IEC_61000-4-2_Surge_6KV_ericsson_sunshine.asc" in the Temp folder.
?
It is curious that you can upload a Photo but not a File.? Does groups.io actually allow one but block the other?? What is the message you see when attempting to upload a file?
?
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.
?
Andy
?


Re: Use a TABLE function in a BV to make a custom defined function.

 

¿ªÔÆÌåÓý

On 14/03/2025 03:38, Andy I via groups.io wrote:
I just uploaded "LTspice_TableTest_AI.zip" to the Temp folder.? It corrects your Bv source with the Table() function, and it shows that it works to refer to the voltage V(SET) instead of a fixed parameter, as the index to the table's values.
Be aware that this BV table syntax is broken in LTspice 24.1.x at the moment. We have been assured that it will be fixed in 24.1.6, but we don't know when that will happen.

--
Regards,
Tony


Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?

 

¿ªÔÆÌåÓý

On 14/03/2025 07:32, ericsson.sunshine via groups.io wrote:
Hi, :
?
May I ask a question about to generate the surge waveform using time equation & s-equation, on how to do that in LTspice ?
?
For example, I asked the ChatGPT, about the 6.0KV surge waveform of time domain, then same as the s-domain equation, but I don't quite know how to express the s-equation exactly. I presume maybe some initial condition needed to be given, but brain twisted. And not sure if that's supported in BV's laplace expression, often it's for transfer function. In the following, it shows the equation for time & s as well.
?
Then since I can't upload the file , (the policy of ... some confidential reason, though I don't know what needed to be confidential), I beg your pardon, please allow me to paste the .asc content in the tail if this thread.
?
Have a nice day. Thank you very much.
Best regards.
?
the image about equation description here. (I don't know how to insert picture correctly here, it said me don't have the privilege.)
The solution I came up with a few years ago was to use a simple look-up table. At the time, I needed IEC 61000-4-2. I don't know what the differences are compared to IEC 61000-4-5, but you could simply replace the look-up table, as necessary.

Here is a Test Schematic.

--
Regards,
Tony


How to create IEC 61000-4-5 surge waveform in time & s behavioral ?

 

Hi, :
?
May I ask a question about to generate the surge waveform using time equation & s-equation, on how to do that in LTspice ?
?
For example, I asked the ChatGPT, about the 6.0KV surge waveform of time domain, then same as the s-domain equation, but I don't quite know how to express the s-equation exactly. I presume maybe some initial condition needed to be given, but brain twisted. And not sure if that's supported in BV's laplace expression, often it's for transfer function. In the following, it shows the equation for time & s as well.
?
Then since I can't upload the file , (the policy of ... some confidential reason, though I don't know what needed to be confidential), I beg your pardon, please allow me to paste the .asc content in the tail if this thread.
?
Have a nice day. Thank you very much.
Best regards.
?
the image about equation description here. (I don't know how to insert picture correctly here, it said me don't have the privilege.)
?
Version 4
SHEET 1 1120 680
WIRE 0 112 0 96
WIRE 192 112 0 112
WIRE 672 112 672 96
WIRE 864 112 672 112
WIRE 0 208 0 192
WIRE 192 208 192 192
WIRE 672 208 672 192
WIRE 864 208 864 192
FLAG 0 208 0
FLAG 192 208 0
FLAG 0 96 V_time
FLAG 672 208 0
FLAG 864 208 0
FLAG 672 96 V_s
SYMBOL bv 0 96 R0
WINDOW 3 -274 178 Left 2
SYMATTR InstName B1
SYMATTR Value V=6000*( ?exp(-3.5e6*time) - exp(-0.14e6*time) ?)
SYMBOL res 176 96 R0
SYMATTR InstName R1
SYMATTR Value 1
SYMBOL bv 672 96 R0
WINDOW 3 -274 178 Left 2
SYMATTR InstName B2
SYMATTR Value V=1*u(time) laplace=6000*( 1/(s+3.5e6) - 1/(s+0.14e6) )
SYMBOL res 848 96 R0
SYMATTR InstName R2
SYMATTR Value 1
TEXT 148 -90 Left 2 !.tran 200u startup


Re: Chan model for saturable transformer LTSPICE simulation #Transformer

 

Hi.
The ferrite you specified is low-frequency. There is a Fe - Feddy parameter in my model. ?As the frequency increases, the magnetization reversal loop expands. See the file NonLinearTransformer_pulse_AB3.zip in the TEMP folder.


Re: Use a TABLE function in a BV to make a custom defined function.

 

jad700,
?
I just uploaded "LTspice_TableTest_AI.zip" to the Temp folder.? It corrects your Bv source with the Table() function, and it shows that it works to refer to the voltage V(SET) instead of a fixed parameter, as the index to the table's values.
?
Andy
?


Re: Use a TABLE function in a BV to make a custom defined function.

 

Oops, I had an extra "V=" in my reply.? Should be "V=Table" not "V=V=Table".


Re: Use a TABLE function in a BV to make a custom defined function.

 
Edited

On Thu, Mar 13, 2025 at 09:50 PM, <jad700@...> wrote:
Hello? ... I need a BV source to use a TABLE to look up a response.? This works if the controlling variable is a .param ( Static for the full sim)? but I need the BV to be dynamic ( Use the TABLE lookup in response to a changing voltage and respond with the voltage result )? I have tried to do this, but no success yet.? I uploaded? LTspice_TableTest.zip to the temp folder.? Thank you so very much for any help you can provide!!? JD
The example in the schematic you uploaded does not make sense.? The syntax is wrong, and that is true even with the Table() function depending on a parameter KK.
?
The answer to your question is: what you want to do works!? Yes, the Table() function can depend on a voltage too.? The reason you had no success is that you did not use the Table() function correctly.
?
Do the following:
  1. Fix the Table() function.
    1. In your example, it is short enough so you could paste all the values into the Table() function itself.
  2. Verify that it works using parameter {KK}.
  3. Change the index parameter from "{KK}" to "V(SET)".
  4. Verify that it still works.
?
If you need to have the list of Table() values in an external file, you'll have to do it differently than what you tried to do.? One way to do that (prior to? LTspice V24.1.x, that is), is to write the B1 element and the .INC command as two consecutive SPICE Directive lines.? In other words, you can't use the schematic symbol for this B-source; it must be in a SPICE Directive - immediately followed by the .INC command.? Something like this:
B1 OUT 0 V=Table(V(set),
.inc table_R1.txt
which must be both in the same SPICE Directive on the schematic.? (I did not verify that this works, but I've seen others doing that.)? Also, your file table_R1.txt needs some fixing up.? Get rid of the line with the "+ n".
?
Andy
?


Re: Looking for ideal fully differential amplifier spice model

 

The bottom ?of the E source IS the common mode input.
?
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