Its a Bi phase DC clamp , the amp has no gain
as the inv is linked to the o/p which is ground ,
the cap's probably provide a
little transcendental compliance
Can I warn against one feature shown in the circuit diagram
The two 10uF electrolytics connected from the output of the first opamp to
the supply rails should not be there. They cause instability as opamps
are not designed to drive capacitive loads and frequently go unstable.
If an opamp is used to deliver a mid voltage rail like this, the temptation
to add extra decoupling should be avoided. The opamp output gives a very
low source impedance that will not benefit from any extra
decoupling.
If you do not get nay instability using that circuit as it stands, then you
are very lucky - or perhaps it is oscillating and not noticed
I recently fell into this trap quite accidentally. It is so
"natural" to want to decouple supply rails with capacitors placed
everywhere that I placed several 100nF caps on a PCB without
thinking. All of them had to be removed to stabilise the resulting
circuitry.
Andy G4JNT
