Questions about inverting opamp configuration

[kkokkogom]

op-amp configuration

Hello
now I'm making an OPAMP

I have question about bias voltage

The Opamp what I made is very simple. 2stage
Vdd is 1v.
I think it works well.


but I got a ploblem with this schematic
(plz refer my attatchment)

I didn't work at all.
(V24) is signal and (V23) is biased at 0.5v



so I changed VDD voltage 1V ===> 0.5V
GND from 0V ===> -0.5v

and finally It worked.


I don't know why this happen.

could you explain to me?

actually I want to use 1V as VDD, 0V as GND. Isn't it possible?

 

[ieropsaltic]

Would you kindly upload the schematic of the op-amp itself so that we can check it.

One thing is that the signal's input is connected only to capacitors, implying that this node is floating and doesn't have a specific dc value (unless it's internally biased inside the op-amp). You shouldn't leave that node floating; connect it to a dc bias using a large resistance (such that 1/(2πRC) << frequency of the signal).

 

[LvW]

It seems that your opamp is powered only with a single supply.
In this case, of course, you need an input bias voltage other than 0 volts (read some basics of single supply operation).