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US 7,411,460 B2Granted
Elimination of dummy detector on optical detectors using input common mode feedback
AssigneeExar Corporation
InventorRichard W. Randlett
Life of this patent
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Abstract
A voltage reference forces a constant voltage at the inputs to an amplifier, thereby negating a need for a dummy detector on the non-active input of the amplifier.
Claims17
A circuit to amplify an electrical signal comprising:
- a photo-detector to provide an input signal;
- a first amplifier to receive an input signal from the photo-detector and to amplify the input signal to form an output signal, the first amplifier comprising an active input to receive the input signal and a non-active input;
- and
- a second amplifier to force a constant voltage at the active and non-active input of the first amplifier, thereby negating a need for a dummy detector on the non-active input of the first amplifier;
- wherein the second amplifier maintains an input common mode voltage at an approximately constant level.
2 more elements
A circuit to amplify an electrical signal comprising:
- a photo-detector to provide an input signal;
- a first amplifier to receive an input signal from the photo-detector and to amplify the input signal to form an output signal, the first amplifier comprising an active input to receive the input signal and a non-active input;
- and
- a second amplifier to force a constant voltage at the active and non-active input of the first amplifier, thereby negating a need for a dummy detector on the non-active input of the first amplifier;
- further comprising a reference voltage, V reference, to provide a reference voltage to a non-inverting input of the second amplifier.
2 more elements
A circuit to amplify an electrical signal comprising:
- a photo-detector to provide an input signal;
- a first amplifier to receive an input signal from the photo-detector and to amplify the input signal to form an output signal, the first amplifier comprising an active input to receive the input signal and a non-active input;
- and
- a second amplifier to force a constant voltage at the active and non-active input of the first amplifier, thereby negating a need for a dummy detector on the non-active input of the first amplifier;
- wherein the first amplifier is a transimpedance amplifier.
2 more elements
a circuit comprising:
- a photo-detector;
- a transimpedance amplifier operably connected to the photo-detector;
- and
- a second amplifier having a first input being the input common mode voltage of the transimpedance amplifier and a second input being a reference voltage, the output of the second amplifier providing feedback to the transimpedance amplifier.
1 more element
Dependencies are inferred from the claim text.