A cmos image sensor readout circuit compatible with two exposure modes

Abstract

The invention discloses a CMOS image sensor readout circuit compatible with two exposure modes, comprising a pixel, a gain amplifier, a correlated double sampling circuit, a switching circuit, a slope generating circuit, an analog-to-digital converter and a counter; the output terminal of the pixel is connected to The first input end of the gain amplifier; the second input end of the gain amplifier is connected to the first output end of the switching circuit, the output end of the gain amplifier is connected to the input end of the correlated double sampling circuit, and the output end of the correlated double sampling circuit is connected to the analog-to-digital converter The first input end of the analog-to-digital converter is connected to the output end of the ramp generating circuit, the input end of the ramp generating circuit is connected to the second output end of the switching circuit; the output end of the analog-to-digital converter is connected to the input end of the counter . The readout circuit structure of the present invention can satisfy the output of two exposure modes, so that the two exposure modes can be integrated into the same camera; while being compatible with the two exposure modes, it basically does not occupy additional area and power consumption of the system.

Description

technical field [0001] The invention belongs to the field of CMOS image sensors and relates to a CMOS image sensor readout circuit compatible with two exposure modes. Background technique [0002] The image sensor is the core of the modern electronic imaging system, and the image sensor is mainly implemented based on two processes, CMOS process and charge-coupled device (CCD) process. CMOS image sensor technology has achieved rapid development in recent years due to its advantages of high integration, small size, and low power consumption. CMOS image sensors are currently divided into two exposure modes, one is the early rolling shutter exposure mode, and the output signal The noise ratio is high, but the frame rate is small. It is used for high-definition shooting of static objects or slow-moving objects, especially for geosynchronous satellite ground monitoring; the other is the global exposure mode, the output signal-to-noise ratio is relatively low, but High frame rate,...

AI Technical Summary

Problems solved by technology

[0003] However, at present, these two exposure modes correspond to a set of readout circuit architecture design, which means that the same camera can only have one exposure mode. If another function needs to be implemented in special occasions, it cannot be realized.

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