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US 7,795,975 B2Granted
Class AB amplifier
AssigneeMediatek Inc.
InventorsYu-Hsin Lin, Hsueh-Kun Liao
Life of this patent
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Abstract
An amplifier is disclosed. An input transistor receives an input voltage. An impedance unit is coupled to a first electrode of the input transistor. A current source is coupled to a second electrode of the input transistor. A push-pull output circuit comprises a PMOS transistor and a NMOS transistor electrically connected in series to output an output voltage. The first electrode of the input transistor is coupled to a control terminal of the NMOS transistor. A level shifting unit is coupled between the first electrode of the input transistor and the push-pull output circuit, for shifting a voltage of the first electrode of the input transistor and providing a shifted voltage corresponding to the voltage of the first electrode of the input transistor to the control terminal of the PMOS transistor.
Claims22
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.
7 more elements
A class AB amplifier, comprising:
- an input stage for receiving a first input voltage to generate a first intermediate voltage and receiving a second input voltage to generate a second intermediate voltage;
- a first cascade common source amplifying stage comprising a first MOS path and a second MOS path cascaded with each other for outputting a first output voltage, wherein the first cascade common source amplifying stage is arranged to shift the first intermediate voltage to provide a first shifted voltage for the first MOS path;
- and
- a second cascade common source amplifying stage comprising a third MOS path and a fourth MOS path cascaded with each other for outputting a second output voltage, wherein the second cascade common source amplifying stage is arranged to shift the second intermediate voltage to provide a second shifted voltage for the third MOS path, wherein the second MOS path continuously transmits a voltage and the voltage is substantially equal to the first intermediate voltage.
1 more element
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;
- and
- a second impedance unit coupled to the first electrode of the second transistor;
- a second push-pull output circuit coupled to the second input 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.
6 more elements
Dependencies are inferred from the claim text.