Error that Voltage Source V:U5:_DIG_SUPPLY8 and V:U7:_DIG_SUPPLY8 are paralleled in LT Spice

Thread Starter

Shankar kumar 2

Joined Jun 6, 2019
9
Hi team,

I am trying to simulate the followng circuit in LT Spice and I get the following error that Voltage Source V:U5:_DIG_SUPPLY8 and V:U7:_DIG_SUPPLY8 are paralleled making an over defined circuit matrix. How do i solve this error?
 

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ericgibbs

Joined Jan 29, 2010
11,894
hi,
OK, I would try the following, Delete V7 and C11 and connect U7 VCC_int to V3 ie: use a single supply.
The error message you are getting is indicating V3 and V7 are in parallel.
E

BTW: The reason it is not showing in mine is because I do not have that LTS model
 

ericgibbs

Joined Jan 29, 2010
11,894
hi,
Looked online for the LTSpice model for that IC.??
Could you post your model file.
The error you are showing is that two power sources have the same 'name'.
E
 

Alec_t

Joined Sep 17, 2013
11,878
The error could be due to a bug in the '5181 model. Try connecting the +ve supply pins of U5 and U7 to the 12V supply via respective low value resistors.
Unrelated to your problem, you could delete C7 and make C6 = 2000u. And a single 12V supply will suffice for the whole schematic. The fewer components you have in the schematic the quicker the sim will run.
 

Thread Starter

Shankar kumar 2

Joined Jun 6, 2019
9
hi,
Looked online for the LTSpice model for that IC.??
Could you post your model file.
The error you are showing is that two power sources have the same 'name'.
E
Hello, I have attched a zip file with all the LT Spice model files for the IC NCP5181. I have also attched the .txt for the irfh5006pbf.

Could be that my circuit connections are wrong? Please let me know if anything else is required.
 

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Thread Starter

Shankar kumar 2

Joined Jun 6, 2019
9
The error could be due to a bug in the '5181 model. Try connecting the +ve supply pins of U5 and U7 to the 12V supply via respective low value resistors.
Unrelated to your problem, you could delete C7 and make C6 = 2000u. And a single 12V supply will suffice for the whole schematic. The fewer components you have in the schematic the quicker the sim will run.
I tried the changes, and yet the same error. I will now try connecting the +ve supply to the 12V with a voltage divider.1.PNG
 

Thread Starter

Shankar kumar 2

Joined Jun 6, 2019
9
hi

I will try to fix model..Check back in a few hours.

eT
Thanks a ton!

Here is the original circuit attached that I am trying to simulate. hope these help. Thank you once again.

the second circuit is the ic that provides inputs to the first circuit.

1.PNG

2.PNG
 
Last edited:

eetech00

Joined Jun 8, 2013
2,277
Hello,

I've managed to get a working model for the NCP5181, but did so after working on an NCP5183. They are both very similar so I'll post both.
The 5181 is made from the 5183. The original 5181 was a mess..and needs to be re-written. Anyway, below is a graphic of the 5183.

upload_2019-6-9_14-25-56.png

I think most of the problem with your simulation is related to the oscillator and deadtime generator. The oscillator should operate at about 100khz so that each input to the 5181 operates at 50khz (half the operating frequency). There is a driver chip that will provide this function: NCP1392.

Below is an attempt at using your circuit. I'll leave this to you to figure out.
upload_2019-6-9_14-43-35.png


Here are the model files;
 

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Last edited:

Thread Starter

Shankar kumar 2

Joined Jun 6, 2019
9
Hello,

I've managed to get a working model for the NCP5181, but did so after working on an NCP5183. They are both very similar so I'll post both.
The 5181 is made from the 5183. The original 5181 was a mess..and needs to be re-written. Anyway, below is a graphic of the 5183.

View attachment 179387

I think most of the problem with your simulation is related to the oscillator and deadtime generator. The oscillator should operate at about 100khz so that each input to the 5181 operates at 50khz (half the operating frequency). There is a driver chip that will provide this function: NCP1392.

Below is an attempt at using your circuit. I'll leave this to you to figure out.
View attachment 179392


Here are the model files;
Thank you very much for your time and help. I will procced with the next stages.
 
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