Patent ID: 8791752

Claim:
A two-stage class AB operational amplifier operative to drive a load, comprising: an input stage comprising differential input terminals and an output terminal operative to provide a driving signal; an output stage comprising first and second input terminals operatively connected to the input stage and operative to be driven on the basis of said driving signal; a driving circuit operatively interposed between the input stage and the output stage, wherein the driving circuit comprises a first portion comprising at least one resistor operatively connected between a first reference potential via a first circuitry block comprising a PMOS transistor and a second reference potential via a second circuitry block comprising a NMOS transistor, the voltage drop on said at least one resistor being fixed to a value depending on said first and second reference potentials and the gate-source voltages of said PMOS and NMOS transistors, respectively, a second portion comprising a first resistor and a second resistor having first terminals connected with one another in a common terminal which is connected to the output terminal of the input stage, said first resistor having a second terminal connected to the first input terminal of the output stage, said second resistor having a second terminal connected to the second input terminal of the output stage, said second terminals of the first and second resistors being connected to the first reference potential via a third circuitry block and to the second reference potential via a fourth circuitry block, respectively, said third and fourth circuitry blocks being arranged to be operatively connected to said first and second circuitry blocks, respectively, so that the voltage drop between the second terminals is substantially equal to the value of the voltage drop across said at least one resistor.