IMAGE SENSOR COMPRISING AN ADC TEST CIRCUIT CAPABLE OF MEASURING THE PERFORMANCE OF AN ANALOG DIGITAL CONVERTER(ADC)

摘要

PURPOSE: An image sensor comprising a test circuit of an ADC(Analog Digital Converter) is provided to remove an inconvenient process of directly radiating light on a pixel array by controlling the amount of light in various stages, thereby reducing a performance test time of an ADC. CONSTITUTION: A pixel array(201) generates an electric signal from an incident light. A CDS(Correlated Double Sampler)(202) outputs pure image information only by excluding noise components from the electric signal. A PGA(Programmable Gain Amplifier)(203) amplifies an output of the CDS(202) to output the amplified output. An ADC test signal supplier(204B) supplies an ADC test signal. The first selector(204A) transmits an output of the supplier(204B) or an output of the PGA(203). An ADC(205) inputs the output of the selector(204A), and converts into a digital signal. A test signal detector(204D) detects the output of the ADC(205). A DSP(206) finally outputs image information. The second selector(204C) transmits the output of the ADC(205) to the detector(204D) or the DSP(206).