modified 10 years ago

Help hurz

00:44:56

Why i can’t put the vss of opamp @2.5v?!?
Hope it's a ec bug.. 

published 10 years ago

hurz

10 years ago

You shift ground to a virtual 2.5V ground and this is now the base were the opamp multiply all voltages by 2. So far everything is fine. Whats the problem?

lelox93

10 years ago

If i try to set "minimum input voltage" of the opamp at 2.5 V instead of 0V it says "cannot find solution"

hurz

10 years ago

And why should one need 2.5V to 7.5V output configuration? Usecase?

lelox93

10 years ago

Yes sir, i have a previous stage

lelox93

10 years ago

It sholud be the same.. The ground il a relative thing!

hurz

10 years ago

??? http://everycircuit.com/circuit/5314277006114816

lelox93

10 years ago

Nope. I mean exactly what i've done! But the opamp supply..

hurz

10 years ago

I can't imagine a real use case. And every time i open your circuit its different. So you seems to be not sure what you are looking for.

lelox93

10 years ago

I modified only the minimum supply of opamp. If you open it now, you can see 0-7.5V supply. And you can grow the lower supply of opamp till 2.49V. If you set it on 2.5V ec says "cannot find solution". Why? This is my question. This circuit is thinked to shift a 0 to 5 V signal in a 2.5 to 7.5V signal.

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