Light sensor readout system and method of converting light into electrical signals
AssigneeGoogle Inc.
InventorsMorakinyo John Aina, Lawrence Heyl
Life of this patent
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Abstract
Systems and methods of the disclosed subject matter for converting light into electrical signals are provided including receiving light input and outputting electrical signals proportional to the light input with a sensor, increasing a transimpedance gain of an amplifier to amplify the electrical signals with a T-network of resistors coupled to the amplifier and the sensor, filtering the electrical signals with a filter circuit coupled to the amplifier and the T-network of resistors to increase noise rejection in a predetermined frequency range, and outputting the filtered electrical signals.
Claims7
A system comprising:
- a sensor to receive light input and to output electrical signals proportional to the light input;
- a first amplifier having an output terminal that is coupled to a first resistor, a first input terminal that is connected to an output of the sensor and the first resistor in parallel, and a second input terminal coupled to a voltage source, wherein the first amplifier outputs a portion of a differential signal based on the electrical signals;
- a second amplifier having an output terminal that is coupled to a second resistor, a first input terminal that is connected to an input of the sensor and with the second resistor in parallel, and a second input terminal coupled to the voltage source, wherein the second amplifier outputs another portion of the differential signal based on the electrical signals;
- a third resistor coupled to the output of the first amplifier;
- and
- a third amplifier having an output terminal that is coupled to a fourth resistor, a first input terminal that is connected to the third resistor and the fourth resistor in parallel, and a second input terminal that is connected to a fifth resistor and a sixth resistor in parallel, wherein the fifth resistor is connected to the output of the second amplifier, and the sixth resistor is connected to the voltage source, wherein the third amplifier rejects at least a portion of a common mode signal to form a filtered signal, and wherein the third amplifier outputs the filtered signal.
A method comprising:
- receiving light input and outputting electrical signals proportional to the light input with a sensor;
- converting the electrical signals into a differential signal with a first amplifier and a second amplifier coupled to the sensor, and outputting the differential signal from the first and second amplifiers;
- rejecting at least a portion of a common mode signal with a third amplifier coupled to the first and second amplifiers to form a filtered signal, and
- outputting the filtered signal.
Dependencies are inferred from the claim text.