Can an opamp be used in a circuit without Vcc and ground supply connection?? I saw some circuit, which are actual circuits designed for PCB, in which some opamps have no Vcc and gnd connection. Does the opamp have any function in such mode??
Do you agree, that opamps have positive and negative supply terminals? If so, how these are connected in the circuit you have seen? Did you also see the layout? In schematics, separate symbols are sometimes used for power supply.
It is most likely that the power connections are 'hidden'. Schematic capture & PCB layout tools can usually automatically connect nets by name even if they aren't shown explicitly on the schematic.