Rail to rail buffer amplifier
First Claim
1. An amplifier circuit, comprising:
- first and second source follower circuits supplied with an input voltage;
a first output transistor including a control terminal that receives an output of the first source follower circuit, and a first terminal, which is supplied with a power supply voltage;
a second output transistor including a control terminal that receives an output of the second source follower circuit, and a first terminal, which is supplied with a base voltage;
a first auxiliary transistor including a second terminal, which is connected to an output terminal of the first source follower circuit, and a control terminal, which receives a first bias voltage;
a second auxiliary transistor including a second terminal, which is connected to an output terminal of the second source follower circuit, and a control terminal, which receives a second bias voltage; and
an output means for outputting a voltage at a connection node of second terminals of the first and second output transistors and first terminals of the first and second auxiliary transistors.
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Accused Products
Abstract
A buffer amplifier having a wide output voltage range includes a first source follower circuit having a first current source and a first transistor, and a second source follower circuit having a second current source and a second transistor. The first source follower circuit has an output terminal connected to a gate of a third transistor and a source of a fourth transistor. The second source follower circuit has an output terminal connected to a gate of a fifth transistor and a source of a sixth transistor. First and second voltages are respectively supplied to the gates of the fourth and sixth transistors. The sixth transistor is operated in place of the fifth transistor in a low voltage range, and the fourth transistor is operated in place of the third transistor in a high voltage range.
12 Citations
8 Claims
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1. An amplifier circuit, comprising:
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first and second source follower circuits supplied with an input voltage; a first output transistor including a control terminal that receives an output of the first source follower circuit, and a first terminal, which is supplied with a power supply voltage; a second output transistor including a control terminal that receives an output of the second source follower circuit, and a first terminal, which is supplied with a base voltage; a first auxiliary transistor including a second terminal, which is connected to an output terminal of the first source follower circuit, and a control terminal, which receives a first bias voltage; a second auxiliary transistor including a second terminal, which is connected to an output terminal of the second source follower circuit, and a control terminal, which receives a second bias voltage; and an output means for outputting a voltage at a connection node of second terminals of the first and second output transistors and first terminals of the first and second auxiliary transistors. - View Dependent Claims (2, 3, 4, 5)
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6. An amplifier circuit for generating an output voltage, comprising:
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a first source follower circuit, connected between a power supply line and a ground line, having an input terminal that receives an input voltage; a second source follower circuit, connected between the power supply line and the ground line, having an input terminal that receives the input voltage; a first output transistor having a drain connected to the power supply line and a gate connected to an output terminal of the first source follower circuit; a second output transistor having a drain connected to the ground line and a gate connected to an output terminal of the second source follower circuit; a first auxiliary transistor having a source connected to the output terminal of the first source follower circuit, and a gate that receives a first bias voltage; and a second auxiliary transistor having a source connected to the output terminal of the second source follower circuit, and a gate that receives a second bias voltage, and wherein the output voltage is generated at a node connecting the sources of the first and second output transistors and the drains of the first and second auxiliary transistors. - View Dependent Claims (7, 8)
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Specification