Method and system for a feedback transimpedance amplifier with sub-40khz low-frequency cutoff
AssigneeCisco Technology, Inc.
InventorBrian Welch
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Abstract
A sub-40 kilohertz low-frequency cutoff is provided for via a transimpedance amplifier comprising differential inputs and differential outputs; coupling capacitors comprising input terminals configured to receive electrical signals, and output terminals coupled to the differential inputs; and feedback paths coupled to the differential outputs and operable to level shift voltage levels at the input terminals. In some embodiments, the feedback paths comprise source follower transistors wherein the differential outputs are coupled to gate terminals of the source follower transistors or the feedback paths further comprise feedback resistors. In some embodiments, a bias resistor is coupled between the differential inputs.
Claims20
A system, comprising:
- a transimpedance amplifier comprising differential inputs and differential outputs;
- coupling capacitors comprising input terminals configured to receive electrical signals, and output terminals coupled to the differential inputs;
- and
- feedback paths coupled to the differential outputs and operable to level shift voltage levels at the input terminals.
A circuit, comprising:
- an amplifier comprising an input and an output;
- a feedback path including a source follower transistor having a gate terminal coupled to the output;
- and
- a coupling capacitor having a first terminal coupled to the feedback path and a second terminal coupled to the input.
A method comprising:
- receiving, at an amplifier, a first differential input from a first output terminal of a first coupling capacitor and a second differential input from a second output terminal of a second coupling capacitor;
- amplifying the first differential input to produce a first differential output and amplifying the second differential input to produce a second differential output;
- and
- feeding the first differential output back to a first input terminal of the first coupling capacitor as a first feedback signal and feeding the second differential output back to a second input terminal of the second coupling capacitor as a second feedback signal.
Dependencies are inferred from the claim text.