How to simulate digital logic using CMOS technology (MOSFET) in Proteus?

Thread Starter

Luiz Fernando Vieira

Joined Aug 24, 2015
55
Hello I'm having trouble with Proteus to do this CMOS logic simulation, I used transistors, I can do the logic perfectly, but when I use CMOS for some reason the logic doesn't work. I used the methods of feeding voltage or applying a digital signal and it still doesn't work. Is there any modification that I must do on top of the component?


DD.png
 

Wolframore

Joined Jan 21, 2019
2,280
What you drew is not a logic gate, first Q1 and Q2 are duplicates since both has input of A is not needed. Same with Q3 and Q4. Not sure what you’re doing but it’s not correct.33DA6DF9-C887-4E1B-87B4-991D1E8472C5.jpeg
 

Thread Starter

Luiz Fernando Vieira

Joined Aug 24, 2015
55
What you drew is not a logic gate, first Q1 and Q2 are duplicates since both has input of A is not needed. Same with Q3 and Q4. Not sure what you’re doing but it’s not correct.View attachment 229215
see i don't know if my translation from my language to english is having communication failure. my problem is the use of CMOS (mosfet), the transistor works perfectly, but mosfet does not.

Sem título.png
 

dl324

Joined Mar 30, 2015
12,871
Sorry, I didn't see it, but still with error. Note: I was changing the entries.
Look closely at how you have the P channel MOSFETs connected.

Proteus is giving you a grid, why aren't you using it?

It's more traditional for the gate connections to be drawn. The disjointed style you're using makes it more difficult than necessary to read. Look at some RCA or Motorola NAND datasheets. You should also have been shown examples by your instructor.
 

Wolframore

Joined Jan 21, 2019
2,280
For P channel mosfets the source goes to the most positive voltage because there’s a body diode which will conduct otherwise. But there seems to be a problem Q3 & Q4 should be on also.
 

crutschow

Joined Mar 14, 2008
27,231
In a CMOS IC the body diodes are not connected to the sources.
The P-MOSFET diodes are connected to V+ and the N-MOSFET diodes are connected to V- (typically circuit common).

That may or may not affect the circuit operation depending upon the circuit configuration.
 

Thread Starter

Luiz Fernando Vieira

Joined Aug 24, 2015
55
Look at this picture and compare the mosfet symbols to your schematic. Do your mosfets looks like they are connected right?


View attachment 229310
I think I have dyslexia because it is not possible, I am seeing correct symbols and for that reason I invested symbols and it did not work. I checked the connections if there was a relative who is not connected correctly. and I found nothing wrong. If you have Proteus software and build the circuit yourself. If you can get congratulations, because that's not what is happening here. Using the software '' 'CADENCE' '' DO NOT RUN THIS.
 

eetech00

Joined Jun 8, 2013
2,366
I think I have dyslexia because it is not possible, I am seeing correct symbols and for that reason I invested symbols and it did not work. I checked the connections if there was a relative who is not connected correctly. and I found nothing wrong. If you have Proteus software and build the circuit yourself. If you can get congratulations, because that's not what is happening here. Using the software '' 'CADENCE' '' DO NOT RUN THIS.
Then you are not looking carefully. The symbols are correct. The connections on your circuit is incorrect.
 
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