| 摘要 |
An image sensor with a test circuit of an analog circuit is provided to stably test a PGA(Programmable Gain Amplifier) by installing a test unit between the PGA and a CDS(Correlate Double Sampling) circuit. A pixel array(110) creates a photoelectron by incident light to accumulate the photoelectron and generates an electric signal by the accumulated photoelectron. A CDS circuit(111) outputs only pure image information except for a noise component in the created electric signal. A PGA(112) amplifies output of the CDS circuit by a desired range. An ADC(Analog to Digital Converter)(113) converts an output signal of the PGA into a digital signal. The first test circuit(116) is installed between the CDS circuit and the PGA. The first test circuit applies the first and second test signals to the PGA in order to test it. The first test circuit includes the first switching unit for separating the CDS circuit from the PGA, the first and second test signal supplying unit(116a,116b) for applying the first and second test signals thereto and the second switching unit for transmitting the first and second test signals to the PGA.
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