Hi,
I want to simulate a DCDC controller in LTspice, which I build its subcircuit on my own.
This is my first time to create a sub-circuit in LT, so I used some guides on the net.
However, when I finished my subcircuit schematic and located all the net ports, saved as .asc, I try to save the Spice netlist.

On this netlist window though, I can't find the ".subckt ...." headline with all the pin names. Instead, it's just written "XU1 with sum non completed pin names. I see this window:



The schematic for this subcircuit is as follows:



Thanks!

 

Create a symbol for your circuit:
Hierarchy->open this sheets symbol
Click yes when prompted. A symbol will be created and saved in the current folder.

Then,
Open a new schematic sheet.
Place the new symbol on the sheet, then "view" the net list.
You will see that the netlist is now a subckt. Each "port" on the schematic is converted to a "pin" on the .subckt statement.
You can now copy and paste the subckt as you wish.

 

Your p-channel MOSFET is back to front (source and drain reversed)

 

Thanks for noticing!

 

Create a symbol for your circuit:
Hierarchy->open this sheets symbol
Click yes when prompted. A symbol will be created and saved in the current folder.

Then,
Open a new schematic sheet.
Place the new symbol on the sheet, then "view" the net list.
You will see that the netlist is now a subckt. Each "port" on the schematic is converted to a "pin" on the .subckt statement.
You can now copy and paste the subckt as you wish.

OK, will try it. Regarding a port for ground, when I open the symbol, I get only 7 pins, instead of 8 (the GND pin not included). How can I mark the gnd as a lable in order to get it on the symbol as a pin?

 

hi kobi,
Please post your LTS asc file, I will give a run.
E

 

Create a symbol for your circuit:
Hierarchy->open this sheets symbol
Click yes when prompted. A symbol will be created and saved in the current folder.

Then,
Open a new schematic sheet.
Place the new symbol on the sheet, then "view" the net list.
You will see that the netlist is now a subckt. Each "port" on the schematic is converted to a "pin" on the .subckt statement.
You can now copy and paste the subckt as you wish.

I have tried your suggestion, this is what I get (still no "subckt.."):

 

hi kobi,
Please post your LTS asc file, I will give a run.
E

Attached. Thanks.

 

hi k,
Note the F4 symbol for the 0V.
E
You may have to delete the existing asy file and start again.
E

 

hi k,
Note the F4 symbol for the 0V.
E
You may have to delete the existing asy file and start again.
E

Still no .subckt in netlist..

 

hi k,
I get it OK.
Check these images.
AS a test open a new asc file , place the model asy file on the asc file
E

 

hi k,
I get it OK.
Check these images.
AS a test open a new asc file , place the model asy file on the asc file
E

Not yet..
Did you change something in the block attribute window? is it set to "Block" or "Cell"? what about perflix, value?
I the netlist window I don't see all the connections of the controller subcircuit, such as the switches, the amplifier etc. It's all empty:

 

hi kobi,
Can you recap on how you created your Model.?
I only get a Yellow fill colour if I use the NET list to create a model, my model colour is just White.?
E

 

hi kobi,
By doing the NET list method, I get a Yellow model and the short text as you do.
E
I suspect that you using the create model from the net list.?

 

hi kobi,
I would recommend that you search the LTS master file and delete any UCC28C44.asy files, then redo using eetech00's method.

You should finish showing a White asy model.

Lets know how it goes.

E

 

OK, will try it. Regarding a port for ground, when I open the symbol, I get only 7 pins, instead of 8 (the GND pin not included). How can I mark the gnd as a lable in order to get it on the symbol as a pin?

use a different name other than GND.
GND is a reserved word that is auto associated with net 0 (ground). I usually use VGND.

 

I have tried your suggestion, this is what I get (still no "subckt.."):
View attachment 226917

that is what your supposed to get.

Finish the instructions I gave you.
Close this “symbol” and open a new schematic.

 

hi kobi,
I would recommend that you search the LTS master file and delete any UCC28C44.asy files, then redo using eetech00's method.

You should finish showing a White asy model.

Lets know how it goes.

E

Hi Eric,

Finally got something. After many attempts, I got the .subckt netlist with the controller pins, only when I delete the "Prefix" field at the symbol attribute window, and then the symbol box is no colored:

If I fill "Prefix" with "X", the symbil is yellow colored, and then the netlist not showng the ".subckt.."

 

hi kobi,
Many thanks for the feedback, pleased to hear you have found a method that works.

What is the next step in your project.
E
BTW: if you open the net list with LTS and click on the line .subckt, you will be prompted to Create a Model.
If you chose that method you get a Yellow model, thats located in the 'Auto generated' file F2 will open the folders

 

hi kobi,
Many thanks for the feedback, pleased to hear you have found a method that works.

What is the next step in your project.
E
BTW: if you open the net list with LTS and click on the line .subckt, you will be prompted to Create a Model.
If you chose that method you get a Yellow model, thats located in the 'Auto generated' file F2 will open the folders

I'm still thinking that there is a problem. I have read in some guides, that Yellow symbols represent a sub-circuit, as required here, while white blocks represent hierarchical blocks, which are not the same.. I suspect it won't work as expected.

My next goal is to simulate my DCDC flyback converter, based on this controller.