Apparatus and methods for a difference amplifier
AssigneeAnalog Devices Global
InventorAndreas Koch
Life of this patent
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Abstract
Apparatus and methods for a difference amplifier are provided. In certain examples, the difference amplifier can provide high common mode rejection without differential signal attenuation. In an example, a difference amplifier circuit can include first and second amplifiers, first and second buffer amplifiers, a first feedback voltage divider coupled between an output of the first buffer amplifier and an output of the second amplifier, and a second feedback voltage divider coupled between an output of the second buffer amplifier and an output of the first amplifier.
Claims20
A difference amplifier circuit comprising:
- first and second amplifiers;
- first and second buffer amplifiers;
- a first feedback voltage divider coupled between an output of the first buffer amplifier and an output of the second amplifier;
- and
- a second feedback voltage divider coupled between an output of the second buffer amplifier and an output of the first amplifier.
A method for operating a difference amplifier, the method comprising:
- receiving an input voltage at first and second inputs of a differential amplifier;
- generating a first voltage drop across a first input resistor coupled to the first input;
- generating a second voltage drop across a second input resistor coupled to the second input;
- buffering the first voltage drop using a first buffer amplifier to provide a first buffered voltage drop;
- buffering the second voltage drop using the second buffer amplifier to provide a second buffered voltage drop;
- receiving the second buffer voltage drop at the first input resistor via a first feedback voltage divider and a first current sense resistor;
- receiving the first buffered voltage drop at the second input resistor via a second feedback voltage divider and a second current sense resistor;
- and
- providing a representation of a voltage difference of the input voltage at an output of the first buffer amplifier and at an output of the second buffer amplifier.
Dependencies are inferred from the claim text.