How to calculate energy/power in Spice ?

Thread Starter

bobpease4ever

Joined Jul 28, 2019
23
I am simulating a CMOS NAND gate in Spice, and I am trying to calculate the short circuit power, but all I can do is plot the current.

I'd like to integrate the current graph with time, so that I can find the short-circuit energy value.

Is there a way of doing this by some command? Please find the simulation file attached. It's a sub-threshold circuit. The include file is also attached for the model.

I am using LTSpice.

Thank you so much!
 

Attachments

ericgibbs

Joined Jan 29, 2010
12,518
Hi Bob,
Run the sim. place the cursor on the component you wish to measure the power, press down hold the ALT key, the cursor should change to a thermometer.
Left click mouse, the power will be plotted.
OK.
E
Edit ref mouse click
 
Last edited:

Thread Starter

bobpease4ever

Joined Jul 28, 2019
23
Hi Bob,
Run the sim. place the cursor on the component you wish to measure the power, press down hold the ALT key, the cursor should change to a thermometer.
Left click mouse, the power will be plotted.
OK.
E
Edit ref mouse click

THank you Eric.... Is there a way I can integrate the current to find the energy? I'd like to find the total power as in a number. That plot is great but calculating from it is too difficult...
 

ericgibbs

Joined Jan 29, 2010
12,518
hi,
Run the sim, use the Thermometer cursor as explained to get the power, place the cursor on the plot screen label at the top of the plot, press and hold down the CTRL key and left click, should see a pop up showing the Avg etc....

E
 

Attachments

Thread Starter

bobpease4ever

Joined Jul 28, 2019
23
In
hi,
Run the sim, use the Thermometer cursor as explained to get the power, place the cursor on the plot screen label at the top of the plot, press and hold down the CTRL key and left click, should see a pop up showing the Avg etc....

E
Incredible! Cannot thank you enough Eric. Really didn't think it was that easy!

Thank you !!!!!!
 

ericgibbs

Joined Jan 29, 2010
12,518
hi Bob,
Glad I could help, there are many LTS user here at AAC, as you have already done, whenever you have a LTS query always attach the asc file and any text or models, it make helping easier.
Eric
 

Thread Starter

bobpease4ever

Joined Jul 28, 2019
23
hi Bob,
Glad I could help, there are many LTS user here at AAC, as you have already done, whenever you have a LTS query always attach the asc file and any text or models, it make helping easier.
Eric
Eric. I cannot thank you enough. I am working on my masters thesis in microelec, and I know little about simulators unfortunately.

I am doing work on sub-threshold operation of simple MOS circuits, and I was instructed to use Cadence, but I find Cadence a bit too much for this.

Do you think LTSpice is enough for such work, or is Cadence so much better?

I need to simulate logic gates and a ripple carry adder, and a few simple analogue circuits. I find LTSpice much easier (and quicker) to use.

Do you have experience with Cadence ? Is it much better or is LTSpice good enough ? I have found good models and I am not using the simple model provided by LTSpice.
 
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