Re: Using HSPICE model directly in LTSPICE
Perhaps the error is in the conversion to PSpice?? How did you do
it?? To use in PSpice you would need 9 separate models to
cover the PMOS size range.
???? ...Jim Thompson
???? Web Site:
<>
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Re: Limit() function in waveforms not working
Andy, My use of the word "variable" may have been inappropriate.? What I meant was "one of the values must be a signal that is generated during a simulation run."? These expressions will work:?limit(V(x),1,-1), limit(V(x),V(y),1). Rick On Tuesday, December 31, 2013 9:12 AM, Andy wrote:
?
Richard Sawrey wrote, "One of the values must be a variable, and the other 2 may be a variable or constant."
So to use it, I need to add a .PARAM statement to convert my formula (involving one or two waveforms) into a variable, and then I can use it in a limit() function?
?
Hmm, I'll have to give that a try.
Odd that you can't use a waveform itself within the limit() function because it is not a variable ?Who would have known. ?Is that true of all the functions, that waveforms need to be converted into variables first before you can act on them in a waveform function? ?Apparently not all, because the Help page shows that the pow() and abs() functions can act on waveforms directly. ?So why is limit() different, and which other ones can't use waveforms as their operands?
Thanks,
Andy
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Re: Limit() function in waveforms not working
Richard Sawrey wrote, "One of the values must be a variable, and the other 2 may be a variable or constant."
So to use it, I need to add a .PARAM statement to convert my formula (involving one or two waveforms) into a variable, and then I can use it in a limit() function?
?
Hmm, I'll have to give that a try.
Odd that you can't use a waveform itself within the limit() function because it is not a variable ?Who would have known. ?Is that true of all the functions, that waveforms need to be converted into variables first before you can act on them in a waveform function? ?Apparently not all, because the Help page shows that the pow() and abs() functions can act on waveforms directly. ?So why is limit() different, and which other ones can't use waveforms as their operands?
Thanks,
Andy
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Questions to LTC1043 model / SPDT switches
Hello,
I'm going to design a voltage-to-frequency converter (and also f-to-V-converter, need linearity < 0,01% at (500¡À200) kHz carrier) using a switched capacitor circuit e.g. described at LTC1043 datasheet.
Problem: The LTC1043 model does not work with external clock to override the internal oscillator. May be other SPDT switches will do the job, but I found no models.
I tryed to use LT's vswitch model to design a SPDT, but this is awful when you need break-before-make characteristics at different frequencies.
Some ideas? Don't say AD650.
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Re: Limit() function in waveforms not working
Andy, One of the values must be a variable, and the other 2 may be a variable or constant. Rick On Monday, December 30, 2013 10:19 PM, Andy wrote:
?
The Help page for "Waveform Arithmetic" show a limit function, limit(x,y,z).
Every time I try to use it in a waveform, it generates an error:
? Error: undefined symbol in: "<>(1,2,3)"
It seems to be saying it doesn't understand the "limit" function. ?Is this a known problem?
Thanks, Andy
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Limit() function in waveforms not working
The Help page for "Waveform Arithmetic" show a limit function, limit(x,y,z).
Every time I try to use it in a waveform, it generates an error:
? Error: undefined symbol in: "<>(1,2,3)"
It seems to be saying it doesn't understand the "limit" function. ?Is this a known problem?
Thanks, Andy
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Re: Using HSPICE model directly in LTSPICE
Jim, Thanks for the reply. Yes,?pspice doesn't support binning.? Part of reasons we converted hspice model to pspice model was because of this. From what I learned from Mike Engelhardt, ltspice does support binning.
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Re: how can i calculate inverter power efficiency by ltspice?
Thanks for kind replies.
I used??method for solving my problems, but it doesn't work..
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Re: how can i calculate inverter power efficiency by ltspice?
Heres yet another trick I use for all my test schematics to measure input current, efficiency, and total internal power dissappation. Since I use this approach universally I automatically add the necessary components and steps as a template for all my schematics, thereby greatly reducing the task.?Time can also be saved by using a standard nomenclature for the parts such as Rin1 for the input test resister, etc. Once you have done this to a schematic the resulting label
formula's can be copied and pasted from schematic to schematic so only slight modifications will be necessary with new circuits. ? 1) Add a network in the input line between the test circuit and DC power source consisting of a 1 microohm (0.0001 ohm) resister in parrallel with a 1000000 uF capacitor. The capacitor is used to suppress excess ripple and improve integration accuracy. ? 2) Make one display panel to show input current by
clicking on the resister. Add "*-1" to the panel label for positive current flow if necessary. ? 3) Make another display window that will show overall efficiency by clicking on the resister for current and then modifying
the label to the calculation form: ? (v(out1)*I(Rload1))/(v(in)*I(Rin)*-1) ? Note: If there is more than one output voltage/current from the power supply circuit under test then add to the numerator of the formula thus: ? ((v(out1)*I(Rload1))+(v(out2)*I(Rload2)).....+(v(outn)*I(Rloadn)))/(v(in)*I(Rin)*-1) ? 4) Make a third display window that will show overall internal total power dissapation by first clicking on the resister to set the display to input current and then changing the label to the calculation form: ? (v(in)*I(Rin)*-1)-(v(out1)*I(Rload1)) ? Note: again if there is more than one output then the power dissapation of each output must be summed as follows: ? (v(in)*I(Rin)*-1)-((v(out1)*I(Rload1))+(v(out2)*I(Rload2))....+(v(outn)*I(Rloadn))) ? Additional note: It may be neccessary to add a "*-1" multiplier if a negative output voltage is to be added into the calculations. The wrong sign will result in subtracting instead of adding to the overall dissappation. If you are unsure run a window with that output seperated to show the calculated output power to make sure it is positive, adding the "*-1" if neccessary to correct that portion of the formula. ? - The "*-1" added to the input current
label and input power portion of the formulas is to correct for current flow as positive. ? - After the analysis run is complete the integrated values of each panel display measurement?can be displayed by using the mouse cursor to select a range of clock pulses from the display panels. I generally try to select at least 40 to 100?clocks for good integration accuracy. The integrated measurement is then displayed in the usual manner by holding down the
key, positioning the mouse cursor over the panel label of interest, and left mouse button clicking. I often enter the data as text in a tabular format right on the schematic so it will be automatically saved for future reference. ? - A final note. Before making the measurement steps use the "*1" trick added to any of the panel labels?to force vertical expansion. This allows input ripple currents and output ripple voltage peak to peak values
to be measured off the panel traces easily using the mouse cursor "box" feature to display the value at the bottom of the screen in the dynamic data line. Either adding or subtracting the "*1" to/from the label will result in forced vertical?expansion without effecting the calculated values. ? Cordially - RC ? ? ? On Monday, December 30, 2013 1:57 PM, "sawreyrw@..."
wrote:
?
Jungyeon, You could just measure the input and output power and compute it yourself.? The help file on steady also tells you how to do it if the steady state criteria is too tight. Rick
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Hello,
I also had a very few weeks ago this inconvenience or problem.
Be patient. Yahoo will delete it after 2 days.
Best regards,
Helmut
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Re: how can i calculate inverter power efficiency by ltspice?
Jungyeon, You could just measure the input and output power and compute it yourself.? The help file on steady also tells you how to do it if the steady state criteria is too tight. Rick
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Vlad wrote, "For the life of me I cannot do it, no matter what. It appears to be deleted, but after changing directories it's still there." This is a world-wide Yahoo?"Neo"?problem. ?They broke their "Delete" functions, apparently affecting not only Files, but Photos, Links, even Members. ?It's been happening for a couple of weeks now.
Moderators can't do it either. The problem comes and goes. Andy
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Helmut
Could you please delete the file Files/Filter/Filter/filter.sub ? For the life of me I cannot do it, no matter what. It appears to be deleted, but after changing directories it's still there. Cut seems to work, so maybe another solution would be making a folder Trash to temporarily store un-delete-able files.
Anticipated thanks, Vlad
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Re: Using HSPICE model directly in LTSPICE
PSpice does not support binning, so I had my oldest son, Aaron, write me a utility that adjusts the netlist after PSpice creates it.
As for HSpice model peculiarities, see this link for some pointers...
<>
Does LTspice support binning? I don't know, maybe it does. Perhaps that is the difference you are seeing?
Perhaps you could E-mail me privately with more details? (I have authorized libraries from virtually every foundry in the world.)
...Jim Thompson
James E. Thompson
35129 North Laredo Drive
San Tan Valley, AZ 85142
Voice: 480-460-2350 Skype: Contacts Only
Web Site:
Wearer of the Brass Rat - Class of 1962
America: Land of the Free, Because of the Brave
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Re: Using HSPICE model directly in LTSPICE
---In LTspice@..., <oldeagleusa> wrote:
I cannot post any model files here, but my simulation circuit if it helps.
What is the problem? How do you think we can help you, if you don't proviede the model? If it is property of your company, you may? send it to someone by email.(Maybe Helmut? if he accepts) Otherways we can't help you.
hws
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Re: Using HSPICE model directly in LTSPICE
We did use converted models in pspice, but not in ltspice.? In ltspice, we used the (hspice) models provided by the vendor directly. ? I cannot post any model files here, but my simulation circuit if it helps.
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Re: how can i calculate inverter power efficiency by ltspice?
Hello Jungyeon,
You can either do it manually in the plot window while plotting the formulas for input power and output power (V(..)*I(...) or you can use MEASURE commands. The ladder idea is the most convenient. The result of :MEASURE will be in the log file.
There is an example in the Files section.
http://groups.yahoo.com/neo/groups/LTspice/files/%20Examples/SMPS/
Here is another method using a dummy device for "steady".
http://groups.yahoo.com/neo/groups/LTspice/files/%20Examples/SMPS/
Best regards,
Helmut
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how can i calculate inverter power efficiency by ltspice?
Hello,
I want to find power efficiency on inverter.
the efficiency report doesn't work because of can't find steady state.
Is there any solutions for find power efficiency?
Jungyeon
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Re: Using HSPICE model directly in LTSPICE
In message <l9qq22+1rpnfbu@...>, dated Sun, 29 Dec 2013, yonggangcui@... writes: tried ltspice and pspice?for a while.? Basically I simulated Id vs Vds
for a pmos.? I noticed significant difference? between the ltspice
result and the vendor manual.? The pspice? results (we converted hspice
models to pspice models and used the pspice models in many actual
design) agree with the manual well.? My friend has access to hspice.?
He did the same simulation in hspice directly and told me the
simulation results are close to the manual.
Since you cannot provide even one example, we can only conclude that your converted models have some syntax incompatible with LTspice. Mostly, models that work on Pspice also work in LTspice, but it's not always true. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Nondum ex silvis sumus John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
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Re: Using HSPICE model directly in LTSPICE
Helmut,
I tried ltspice and pspice?for a while.? Basically I simulated Id vs Vds for a pmos.? I noticed significant difference? between the ltspice result and the vendor manual.? The pspice? results (we converted hspice models to pspice models and used the pspice models in many actual design) agree with the manual well.? My friend has access to hspice.? He did the same simulation in hspice directly and told me the simulation results are close to the manual.
We did all the simulation for tsmc 0.25 um process, but I cannot share any model information here.
Thanks.
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