Common-mode feedback amplifier
AssigneeTexas Instruments Incorporated
InventorsAjay Kumar, Krishnaswamy Nagaraj
Life of this patent
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Abstract
A circuit is provided for use with a reference voltage. The circuit includes a voltage source, a common-mode feedback amplifier and a feedback impedance portion. The common-mode feedback amplifier may be connected to the voltage source and may be arranged to receive the reference voltage. The common-mode feedback amplifier may include an input stage, an output stage, a positive input, a negative input and an output. The output may be connected to the feedback impedance portion. The feedback impedance portion may additionally be connected to one of the positive input and the negative input. A feedback factor, based on the feedback impedance portion, is less than one.
Claims20
A circuit for use with a reference voltage, said circuit comprising:
- a voltage source;
- a common-mode feedback amplifier connected to said voltage source and arranged to receive the reference voltage, said common-mode feedback amplifier having an input stage, an output stage, a positive input, a negative input and an output;
- and
- a feedback impedance portion having at least a resistor and a second resistor,
- wherein said output is connected to said feedback impedance portion,
- wherein said feedback impedance portion is additionally connected to said negative input,
- wherein said negative input is coupled to the second resistor, wherein the second resistor is coupled to the positive input of the amplifier, and
- wherein a loop gain, based on said feedback impedance portion, is less than one.
A circuit for use with a reference voltage, said circuit comprising:
- a voltage source;
- a common-mode feedback amplifier connected to said voltage source and arranged to receive the reference voltage, said common-mode feedback amplifier having an input stage, an output stage, a positive input, a negative input and an output;
- and
- a feedback impedance portion,
- wherein said output is connected to said feedback impedance portion,
- wherein said feedback impedance portion is additionally connected to one of said positive input and said negative input, and
- wherein a loop gain, based on said feedback impedance portion, is less than one,
- wherein said voltage source is electrically connected to said positive input and said feedback impedance portion, and
- wherein said feedback impedance portion is connected to said negative input.
A method of amplifying a reference voltage, said method comprising:
- generating, by way of a voltage source, an input voltage;
- receiving, by way of a common-mode feedback amplifier, the input voltage and the reference voltage, the common-mode feedback amplifier having an input stage, an output stage, a positive input, a negative input and an output;
- and
- amplifying, by way of the common-mode feedback amplifier, the reference voltage,
- wherein the output is connected to a feedback impedance portion,
- wherein the feedback impedance portion is additionally connected to one of the positive input and the negative input, and
- wherein a loop gain, based on the feedback impedance portion, is less than one
- wherein said voltage source is electrically connected to said positive input and said feedback impedance portion, and
- wherein said feedback impedance portion is connected to said negative input.
A system comprising:
- a reference voltage generator operable to generate a reference voltage;
- a voltage source operable to generate a source voltage;
- a common-mode feedback amplifier arranged to receive the source voltage and to receive the reference voltage, said common-mode feedback amplifier having an input stage, an output stage, a positive input, a negative input and an output;
- and
- a feedback impedance portion,
- wherein said output is connected to said feedback impedance portion,
- wherein said feedback impedance portion is additionally connected to one of said positive input and said negative input, and
- wherein a loop gain, based on said feedback impedance portion, is less than one,
- wherein said voltage source is electrically connected to said positive input and said feedback impedance portion, and
- wherein said feedback impedance portion is connected to said negative input.
Dependencies are inferred from the claim text.