Two-Stage Operational Amplifier in Class AB

Two-stage operational amplifier in class AB for driving a load comprising:

• an input stage comprising differential input terminals and a first differential output terminal and a second differential output terminal for providing a first differential driving signal and a second differential driving signal, respectively;
• an output stage comprising a first output branch having a first differential input terminal operatively connected to the first differential output terminal of the input stage to receive the first differential driving signal and a second output branch having a second differential input terminal operatively connected to the second differential output terminal of the output stage to receive the second differential driving signal,
• a control circuit configured to control the output current on the first output branch and the second output branch of the output stage, the control circuit comprising a first PMOS transistor in a diode configuration and operatively connected in a current mirror configuration to a second PMOS transistor of the first output branch of the output stage, a first NMOS transistor connected in series with the first PMOS transistor and having a gate terminal connected to a bias voltage, a third PMOS transistor in a diode configuration and operatively connected in a current mirror configuration to a fourth PMOS transistor of the second output branch of the output stage, a second NMOS transistor connected in series with the third PMOS transistor and having a gate terminal connected to the bias voltage,
• wherein the control circuit further comprises:
• a third NMOS transistor operatively connected in parallel with the first NMOS transistor and having a gate terminal arranged to receive the second differential driving signal, and
• a fourth NMOS transistor operatively connected in parallel with the second NMOS transistor M and having a gate terminal arranged to receive the first differential driving signal.