High-speed three-level parallel analog-to-digital converter of CMOS image sensor and operation method of high-speed three-level parallel analog-to-digital converter

Abstract

The invention discloses a high-speed three-level parallel analog-to-digital converter of a CMOS image sensor and an operation method of the high-speed three-level parallel analog-to-digital converter.The circuit comprises a CADC timing change-over switch, an FIADC timing change-over switch, a common analog-to-electric module, an FIADC, a CADC, an SSADC and a counter. The analog input end, the FIADC timing change-over switch, the common analog-to-electric module and the FIADC are sequentially connected in series. The output end of the FIADC is electrically connected to the sampling end of theCADC through the common analog-to-digital module so as to output analog residual quantity; the CADC timing change-over switch and the FIADC timing change-over switch are connected to the common analog-to-electric module in parallel, wherein the CADC timing selector switch, the common analog-to-digital module and the CADC are sequentially connected in series, the output end of the CADC is electrically connected to the SSADC to output analog residual quantity, and the FIADC, the CADC and the SSADC are connected to the counter in parallel to output digital residual quantity to the counter respectively. An FIADC / CAC / SSADC three-level serial / parallel assembly line structure is adopted, wherein the first-stage FIADC and the second-stage CADC are in a serial working mode and share a main common analog-to-electric module, so that the considerable layout area is saved, and only different control switches and different digital logic output counting modules are needed.

Description

【Technical field】 [0001] The invention relates to a high-speed three-stage parallel analog-to-digital converter of a CMOS image sensor and an operation method thereof, belonging to the field of digital-to-analog circuit conversion. 【Background technique】 [0002] CMOS active pixel sensors (APS) were invented in 1995. With the rapid development of standard CMOS technology, CMOS image sensors have made great progress in technical indicators such as high pixels, large dynamic range, small size, and low noise. . Now CMOS image sensor (CMOS image sensor) has become a very mainstream and extremely promising field in the development and research of integrated circuits. [0003] CMOS image sensor is a solid-state imaging sensor that uses semiconductor photoelectric effect to realize photoelectric information conversion, in which the pixel itself for photoelectric conversion and the analog and digital circuits for signal reading, storage and transmission can be realized based on sta...

AI Technical Summary

Problems solved by technology

[0004] However, the traditional existing CMOS image sensor has a low internal operating speed, and its conversion efficiency has gradually failed to meet the actual needs of its use.

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