Analog-to-digital converter with noise compensation in CMOS image sensor
AssigneeSamsung Electronics Co., Ltd.
InventorMyoung-Su Lee
Life of this patent
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Abstract
An analog-to-digital converter includes an amplifying unit and a noise compensation unit. The amplifying unit amplifies a difference between a trip point voltage and a modified signal voltage. The trip point voltage has a first power noise component, and the noise compensation unit incorporates a second power noise component into an original signal voltage to generate the modified signal voltage. Thus, the power noise components are cancelled in the difference.
Claims20
An analog-to-digital converter comprising:
- a first amplifying unit for amplifying a difference between a trip point voltage and a modified signal voltage to generate a first amplified voltage, the trip point voltage having a first power noise component;
- a noise compensation unit that incorporates a second power noise component into an original signal voltage to generate the modified signal voltage;
- and
- a conversion unit for generating a digital signal indicating the difference.
A CMOS (complementary metal oxide semiconductor) image sensor comprising:
- an array of pixel circuits, each pixel circuit generating an image signal voltage from an image;
- an analog-to-digital converter for generating a digital signal representing the image signal voltage;
- and
- a controller for generating control signals for controlling the pixel circuit and the analog-to-digital converter;
- wherein the analog-to-digital converter includes:
- a first amplifying unit for amplifying a difference between a trip point voltage and a modified signal voltage to generate a first amplified voltage, the trip point voltage having a first power noise component;
- a noise compensation unit that incorporates a second power noise component into the image signal voltage to generate the modified signal voltage;
- and
- a conversion unit for generating a digital signal indicating the difference.
A method of performing CDS (correlated double sampling) analog-to-digital conversion within a CMOS (complementary metal oxide semiconductor) image sensor, comprising:
- generating a trip point voltage from a reset signal voltage, the trip point voltage having a first power noise component;
- generating an image signal voltage from an image;
- generating a modified signal voltage by incorporating a second power noise component into the image signal voltage;
- amplifying a difference between the trip point voltage and the modified signal voltage to generate a first amplified voltage;
- and
- generating a digital signal indicating the difference.
Dependencies are inferred from the claim text.