High performance class ab operational amplifier
AssigneesSTMicroelectronics (Grenoble 2) SAS, STMicroelectronics S.r.l.
InventorsMarcoOrazio CAVALLARO, Serge RAMET, Tiziano CHIARILLO
Life of this patent
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Abstract
A class AB operational amplifier includes an input stage, an output stage and a level shifter stage to control the quiescent current of the output stage and to transfer the signal from the input stage to the output stage, and a control circuit of the level shifter stage. The control circuit includes a transistor differential pair having a differential input terminals and the differential voltage at the differential terminals of the differential pair controls the level shifter stage.
Claims20
A class AB operational amplifier comprising an input stage, an output stage and a level shifter stage adapted to control the quiescent current of the output stage and to transfer the signal from the input stage to the output stage, a control circuit of the level shifter stage, characterized in that the control circuit comprises at least one transistor differential pair having differential input terminals, said control circuit being configured with replica transistors and currents so that the differential voltage at the differential terminals of the transistor differential pair controls the level shifter stage.
A class AB operational amplifier comprising:
- an input stage;
- an output stage;
- a level shifter stage to control the bias current of the output stage and to transfer the signal from the input stage to the output stage;
- and
- a control circuit of the level shifter stage,
- wherein the control circuit comprises replica transistors from the level shifter stage and the output stage, as well as a replica output current from the output stage.
A class AB operational amplifier comprising:
- two symmetrical circuit portions, each circuit portion comprising:
- an input stage;
- an output stage;
- a level shifter stage to control the bias current of the output stage and to transfer the signal from the input stage to the output stage;
- and
- a control circuit of the level shifter stage,
- wherein the control circuit comprises replica transistors from the level shifter stage and the output stage, as well as a replica output current from the output stage.
Dependencies are inferred from the claim text.