Differential amplifiers
First Claim
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1. A differential amplifier, comprising:
- a differential input stage comprising a first transistor coupled between a first node and a second node, and a second transistor coupled between a third node and a fourth node, wherein control terminals of the first and second transistors receive an input signal;
first, second, third, and fourth fixed current sources coupled between the first node and a first voltage source, between the third node and the first voltage source, between the second node and a second voltage source, and between the fourth node and the second voltage source respectively;
a first resistive element coupled between the second node and the fourth node; and
a current-folding element outputting an output signal and comprising;
a third transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to the second node and a control terminal coupled to the first node;
a fourth transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to the fourth node and a control terminal coupled to the third node;
a fifth transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to a fifth node and a control terminal coupled to the first node; and
a sixth transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to a sixth node and a control terminal coupled to the third node.
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Abstract
Differential amplifiers comprise a differential input stage, first, second, third, and fourth fixed current sources, a first resistive element, and a current-folding element. Due to topology thereof, the differential amplifier converts the difference between the input voltages to the voltage difference between the source voltages of the transistors in the differential pair, and a current is induced through the first resistive element, thereby generating two currents. The current-folding element folds the two currents to generate output voltages.
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Citations
19 Claims
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1. A differential amplifier, comprising:
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a differential input stage comprising a first transistor coupled between a first node and a second node, and a second transistor coupled between a third node and a fourth node, wherein control terminals of the first and second transistors receive an input signal; first, second, third, and fourth fixed current sources coupled between the first node and a first voltage source, between the third node and the first voltage source, between the second node and a second voltage source, and between the fourth node and the second voltage source respectively; a first resistive element coupled between the second node and the fourth node; and a current-folding element outputting an output signal and comprising; a third transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to the second node and a control terminal coupled to the first node; a fourth transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to the fourth node and a control terminal coupled to the third node; a fifth transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to a fifth node and a control terminal coupled to the first node; and a sixth transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to a sixth node and a control terminal coupled to the third node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A semiconductor circuit, comprising:
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a differential input stage comprising a first transistor coupled between a first node and a second node, and a second transistor coupled between a third node and a fourth node, wherein control terminals of the first and second transistors receive an input signal; first, second, third, and fourth fixed current sources coupled between the first node and a first voltage source, between the third node and the first voltage source, between the second node and a second voltage source, and between the fourth node and the second voltage source respectively; a first resistive element coupled between the second node and the fourth node; and a current-folding element outputting an output signal and comprising; a third transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to the second node and a control terminal coupled to the first node; a fourth transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to the fourth node and a control terminal coupled to the third node; a fifth transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to a fifth node and a control terminal coupled to the first node; and a sixth transistor comprising a first terminal coupled to the first voltage source, a second terminal coupled to a sixth node and a control terminal coupled to the third node, wherein the third to sixth transistors are substantially the same size. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification