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REFERENCE VOLTAGE GENERATOR, COLUMN ANALOG TO DIGITAL CONVERSION DEVICE, AND IMAGE CENSOR FOR ELIMINATING POWER SUPPLY AND SWITCHING NOISE IN IMAGE SENSOR, AND METHOD THEREOF
REFERENCE VOLTAGE GENERATOR, COLUMN ANALOG TO DIGITAL CONVERSION DEVICE, AND IMAGE CENSOR FOR ELIMINATING POWER SUPPLY AND SWITCHING NOISE IN IMAGE SENSOR, AND METHOD THEREOF
A reference voltage generator of an image sensor, a column analog-to-digital converter, an image sensor, and a column analog-to-digital conversion method for eliminating power supplied to a pixel array and switching noise are provided to cancel a noise component in an active correlated double sampling operation by using a noise replica reference voltage to achieve an analog-to-digital conversion operation robust to noise. A column analog-digital converter includes a reference voltage generator(150) and an active correlated double sampling circuit(132,134,136). The reference voltage generator generates a correlated-double-sampled OB(Optical Black) sampling signal from an OB pixel output signal in response to the OB pixel output signal and a first lamp signal and generates a second reference voltage based on the OB sampling signal and a first reference voltage. The active correlated double sampling circuit generates a correlated-double-sampled active sampling signal from an active pixel output signal in response to the active pixel output signal and a second lamp signal and compares the active sampling signal with the second reference voltage to generate a signal for generating a digital code.
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