How to get circuit results outputted from LTsice?

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Flyback

Well-Known Member

• Jul 28, 2019

• #1

Hi,
I wish to run LTspice simulations, and then automatically get an output from them which is eg the power dissipated in the mosfet in watts.
Eg in the attached simulation, “V(N007,N009)*Id(M1)+V(N006,N009)*Ig(M1)” is the mosfet power in watts, how do I get the simulator to automatically spit this number out after the sim is run?

 

Attachments

• LED current regulator.asc

  2 KB · Views: 272

alec_t

Well-Known Member

Most Helpful Member

• Jul 28, 2019

• #2

Run the sim, plot the data of interest, left-click in the plot pane, then under the File menu select 'Export data as text'. A pop-up allows choice of data to export.
You can then enter the saved data into a spreadsheet.
Alternatively, you can use the .WAVE command to save node data as a .wav file (but data gets scaled down to a peak amplitude of 1).

 

Last edited: Jul 28, 2019

F

Flyback

Well-Known Member

• Jul 28, 2019

• #3

Thanks, sorry i didnt see it...eg in the attached, how do i get it to output the result of the exression...
V(N016)*I(R1) + V(N017)*I(R2)

 

Attachments

• LED current regulator_1.asc

  3.7 KB · Views: 274

ronsimpson

Well-Known Member

Most Helpful Member

• Jul 28, 2019

• #4

11.5 watts.
I hold down the ALT key and put the cursor on the part in question. Then click. At adds trace to the graph that shows 11.5 watts.

 

F

Flyback

Well-Known Member

• Jul 28, 2019

• #5

Thanks yes, i appreciate that, the thing is i have another simulation where i need the sum of the power in 5 different fets, and i need a quick way of getting that number out of the simulator....without ALT clicking each fet and adding them all up.

 

alec_t

Well-Known Member

Most Helpful Member

• Jul 28, 2019

• #6

Use a behavioural voltage source B with the function V=(V(N016)*I(R1) + V(N017)*I(R2) ) + ..........) and plot the output of B, then export as text if you want.

 

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eTech

Well-Known Member

• Jul 29, 2019

• #7

Flyback said:

Thanks yes, i appreciate that, the thing is i have another simulation where i need the sum of the power in 5 different fets, and i need a quick way of getting that number out of the simulator....without ALT clicking each fet and adding them all up.

Click to expand...

Use the “.meas” directive with the appropriate equation. You can then view the results in the error log. You can also use “AKA” and step to perform a simulation on multiple mosfet models. All the results will be in the error log.

Read “measure” in LTspice help to become familiar with it.

Pointing with the mouse for measurements is not only a pain but imprecise..

eT

 

E

eTech

Well-Known Member

• Jul 29, 2019

• #8

Hi

Here is an example:



Notice that I named the wires G, D, S. This is to use friendly names and to prevent the wire names from changing.

eT

 

Attachments

• LED current regulator with step and meas.asc

  2.3 KB · Views: 273