desperado1
Full Member level 3
In a differential operational amplifier, you have two terminals, the positive one, Vp, and the negative one, Vn. Therefore, you have a differential signal Vd=Vp-Vn, and a common mode signal, Vcm=(Vp+Vn)/2.
I have read that he amplifier works properly if the common mode voltage is set accurately by a common mode feedback loop. If the common mode DC voltage is not set correctly, the amplifier saturates to its rails (either VDD, either VSS) and it not able to amplifier the differential AC signal.
My question is how do we set the common mode feeback loop in a differential amplifier ?
I have read that he amplifier works properly if the common mode voltage is set accurately by a common mode feedback loop. If the common mode DC voltage is not set correctly, the amplifier saturates to its rails (either VDD, either VSS) and it not able to amplifier the differential AC signal.
My question is how do we set the common mode feeback loop in a differential amplifier ?