Electronics > Projects, Designs, and Technical Stuff

Just another DC Load

<< < (10/12) > >>

henmill:
(Continued due to attachment limit)

Here is the schematic showing the other mosfet in use:

RoGeorge:
You may want to read about "ako" (a kind of) feature in LTspice.
https://ltwiki.org/index.php?title=Undocumented_LTspice

"ako" is very useful when comparing the outcome of running the same schematic with different parts, so you won't have to compare them manually.  LTspice can ".step" the model of a component just the same as you ".step" the value of a parameter, and can show them all on the same plot.

Same for the phase margin.  You write a ".meas" to find the phase margin, define ako models for each op amp type (or for each MOSFET type), then .step the .ac simulation.  Then look at the log file (usually opens with CTRL+L) to see the values of the phase margins for all the op amp you stepped through.

henmill:
Thank you for the tip! That does sound much more efficient than what I've done to this point. It was a bit tedious running and re-running making sure I've got the differences right.

Jay_Diddy_B:
Hi,

Here is a much faster model. I used the SPICE model for the MOSFET from Littelfuse. I could not find the exact part, so I used another similar part:



The SPICE model is pasted on the schematic. If you do this you don't need the .lib directive and the .asc file is self contained.

This runs in the frequency domain.

After running the model plot V(a)/V(b) to get the loop gain.


I have attached the model.

I used an op-amp from the LTspice library.

Regards,

Jay_Diddy_B

 IXTH30N60L2 version.JPG (112.98 kB. 1456x730 - viewed 22 times.)

Jay_Diddy_B:
Hi,
With the faster model you try things easily. Here is an more optimized circuit, for this MOSFET:



Regards,

Jay_Diddy_B

Navigation

[0] Message Index

[#] Next page

[*] Previous page