Dual-conversion gain reading circuit, reading method and image sensor

By pre-comparing the high-gain photosensitive signal and selecting an appropriate counting mode in the dual-conversion gain readout circuit, the problem of high dynamic power consumption of the readout circuit is solved, and power consumption is effectively reduced.

CN121509834APending Publication Date: 2026-02-10CHENGDU LIGHT COLLECTOR TECH
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Patent Information

Application Number
CN202511789785.X
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-12-01
Publication Date
2026-02-10

AI Technical Summary

Technical Problem

The existing dual-conversion-gain readout circuit has excessive dynamic power consumption in high conversion-gain mode, causing the internal counter of the SS ADC to continuously count, resulting in energy waste.

Method used

A dual-conversion gain readout circuit is adopted. The high-gain photosensitive signal and the ramp signal are pre-compared by the comparison module. The corresponding counting mode is selected to count the signal, including direct assignment, down-frequency counting and normal counting, thereby reducing the dynamic power consumption of the counting module.

Benefits of technology

This effectively reduces the dynamic power consumption of the counting module, thereby reducing the overall power consumption of the readout circuit and solving the problem of high dynamic power consumption in existing technologies.

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Abstract

The invention provides a dual-conversion gain reading circuit, a reading method and an image sensor, and the circuit comprises a comparison module which carries out the pre-comparison of a high-gain photosensitive signal and a ramp signal, so as to obtain a pre-comparison result, comparing the low-gain reset signal, the high-gain reset signal, the high-gain photosensitive signal and the low-gain photosensitive signal with a ramp signal to output corresponding comparison signals; and the counting module selects a counting mode according to the pre-comparison result to count the comparison signals so as to output data signals. A comparison module is used for pre-comparing a high-gain photosensitive signal with a ramp signal, and a counting module is used for selecting a corresponding counting mode for counting quantization according to a pre-comparison result, so that the corresponding counting mode can be adaptively selected according to a voltage difference value between a high-gain reset signal and the high-gain photosensitive signal; therefore, the dynamic power consumption of the counting module is effectively reduced, the overall power consumption of the reading circuit is reduced, and the problem that an existing dual-conversion gain reading circuit is large in dynamic power consumption is solved.
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