Single-photon CMOS image sensor pixel circuit with small pixel size

Abstract

The invention provides a single-photon CMOS image sensor pixel circuit with a small pixel size. The circuit comprises a quenching circuit, an analog counting circuit, and a reading circuit, wherein one end of the quenching circuit is connected with the analog counting circuit; one end of the analog counting circuit is connected with the reading circuit; and the quenching circuit comprises a single-photon avalanche diode, and controls the single-photon avalanche diode to work, close and produce pulses. The single-photon CMOS image sensor pixel circuit provided by the invention has the advantages that only five NMOS transistors and the single-photon avalanche diode are adopted, so that the structure is simplified; and the circuit is applicable for a high-resolution single-photon CMOS image sensor.

Description

[technical field] [0001] The invention relates to a CMOS image sensor pixel circuit and a system framework of an integrated circuit, which is suitable for a single-photon CMOS image sensor with low pixel size and high resolution. [Background technique] [0002] In recent years, the properties of fluorescence have been increasingly used for research in life sciences. In addition to applications such as environmental detection, clinical medicine, and DNA sequencing, fluorescence can also be used for cell identification and flow cytometry classification to reveal the location and movement of substances inside cells. Steady-state fluorescence microscopy is often used in cell analysis, however, it is sensitive to certain light-intensity-based factors such as changes in the intensity of the excitation light source, photobleaching, and so on. And this technique makes it difficult to distinguish between fluorophores with the same excitation and emission spectra. Fluorescence lifet...

AI Technical Summary

Problems solved by technology

However, on the one hand, it is difficult for the traditional photodiode CMOS image sensor to achieve the sensitivity of single photon detection, and it has extremely high requirements on the signal-to-noise ratio of the processing circuit required at the back end.

On the other hand, the traditional photodiode CMOS image sensor has a relatively long integration time for photocurrent, which is a relatively slow processing process.

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