Patent ID: 7795975

Claim:
An amplifier, comprising: a first input transistor having a first electrode, a second electrode, and a control terminal for receiving a first input voltage; a first impedance unit coupled to the first electrode of the first input transistor; a current source coupled to the second electrode of the first input transistor; a first push-pull output circuit comprising a first PMOS transistor and a first NMOS transistor electrically connected in series to output a first output voltage, wherein the first electrode of the first input transistor is coupled to a control terminal of the first NMOS transistor; a first level shifting unit coupled between the first electrode of the first input transistor and the first push-pull output circuit, for shifting a voltage of the first electrode of the first input transistor and providing a first shifted voltage corresponding to the voltage of the first electrode of the first input transistor to a control terminal of the first PMOS transistor; a second input transistor having a first electrode, a second electrode coupled to the current source, and a control terminal for receiving a second input voltage; a second impedance unit coupled to the first electrode of the second transistor; a second push-pull output circuit comprising a second PMOS transistor and a second NMOS transistor electrically connected in series to output a second output voltage, wherein the first electrode of the second input transistor is coupled to a control terminal of the second NMOS transistor; and a second level shifting unit coupled between the first electrode of the second input transistor and the second push-pull output circuit, for shifting a voltage of the first electrode of the second input transistor and providing a second shifted voltage corresponding to the voltage of the first electrode of the second input transistor to a control terminal of the second PMOS transistor, wherein a voltage of the control terminal of the first NMOS transistor is substantially equal to the voltage of the first electrode of the first input transistor.