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US 7,132,882 B2Granted
Amplifier having multiple offset-compensation paths and related systems and methods
AssigneeAvago Technologies Fiber IP (Singapore) Pte. Ltd.
InventorsWei-yung Chen, Michael A. Robinson
Life of this patent
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Abstract
An amplifier includes an amplification path and multiple offset-compensation feedback paths. The amplification path has multiple amplifier stages, and the feedback paths are coupled to the amplification path. By including multiple feedback paths, such an amplifier can maintain its output DC-offset voltage at a desired level over a full range of amplitudes, i.e., power, of the input signal.
Claims26
An amplifier, comprising:
- an amplification path that includes multiple differential stages each having respective input nodes and output nodes;
- and
- multiple differential offset-compensation feedback paths having respective input nodes coupled to respective locations of the amplification path, at least two of the paths having substantially the same time constant, at least one of the paths having an input node coupled to an output node of a second one of the stages and having an output node coupled to an input node of a first one of the stages that precedes the second one of the stages.
An amplifier, comprising:
- an amplification path that includes multiple differential stages;
- multiple differential offset-compensation feedback paths having respective input nodes coupled to respective locations of the amplification path, at least two of the paths having substantially the same time constant;
- wherein a first one of the offset-compensation paths is coupled between a first stage and a second stage;
- and
- wherein a second one of the offset-compensation paths is coupled between the first stage and a third stage.
2 more elements
An amplifier, comprising:
- an amplification path that includes multiple stages each having a respective output node;
- a first offset compensation feedback path having an input node coupled to the output node of a first one of the stages and having an output node coupled to a second one of the stages;
- and
- a second offset compensation feedback path having an input node coupled to the output node of a third one of the stages and having an output node coupled to a fourth one of the stages.
1 more element
A fiber optic receiver, comprising:
- a device operable to generate an electrical signal from a received optical signal;
- and
- an amplifier operable to generate an amplified electrical signal from the electrical signal, the amplifier comprising,
- an amplification path that includes an input node operable to receive the preamplified electrical signal, an output node operable to provide the amplified
- electrical signal, and multiple stages serially coupled between the input and output nodes and each having a respective stage output node that carries a respective offset signal,
- a first offset compensation feedback path having an input node coupled to the output node of a first one of the stages and having an output node coupled to a second one of the stages,
- a second offset compensation feedback path having an input node coupled to the output node of a third one of the stages and having an output node coupled to a fourth one of the stages, and
- wherein the first and second offset compensation feedback paths operate to maintain the offset signal on at least one of the stage output nodes at or approximately at a predetermined level.
5 more elements
A method, comprising:
- detecting first and second differential offset signals at the output nodes of first and second stages of an amplifier, the first stage preceding the second stage;
- and
- maintaining at least one of the first and second differential offset signals at a predetermined level by providing to the first stages an offset-compensation signal that is related to the first and second differential offset signals.
A method, comprising:
- detecting first and second differential output signals at the output nodes of first and second stages of an amplifier, the first and second differential output signals having first and second differential offset components, respectively;
- and
- maintaining at least one of the first and second differential offset components at a predetermined level by providing to a non-input node of one of the stages an offset-compensation signal that is related to the first and second differential offset components.
A method, comprising:
- detecting first and second differential output signals at the output nodes of first and second stages of an amplifier, the first and second differential output signals having first and second differential offset components, respectively;
- maintaining at least one of the first and second differential offset components at a predetermined level by providing to one of the stages an offset-compensation signal that is related to the first and second differential offset components;
- and
- low pass filtering the first and second output signals to isolate the first and second offset components.
1 more element
An amplifier, comprising:
- an amplification path that includes first, second, and third stages each having a respective output node;
- a first bi-directional offset-compensation feedback path having an input node coupled to the output node of the second stage and having an output node coupled to a node of the first stage other than the output node of the first stage;
- and
- a second bi-directional offset-compensation feedback path having an input node coupled to the output node of the third stage and having an output node coupled to a node of the first stage other than the output node of the first stage.
1 more element
An amplifier, comprising:
- an amplification path that includes multiple differential stages each having respective input nodes and output nodes;
- and
- multiple differential offset-compensation feed back paths having respective input nodes coupled to locations of the amplification path, at least one of the paths having an input node coupled to an output node of one of the stages and having an output node coupled to a location of the amplification path other than an input node of the one stage.
Dependencies are inferred from the claim text.