TOF image sensor pixel structure capable of suppressing background light

Abstract

A TOF image sensor pixel structure capable of suppressing background light is composed of a photodiode PD, a transmission switch TG, a feedback switch FBG, a reset switch rst, an MOS transistor capacitor C, a voltage-controlled current source and a charge integral amplification circuit. The negative electrode of the PD is connected with the charge integral amplification circuit through a transmission switch TG, and is connected with the MOS capacitor C and the control voltage Vctr of the voltage-controlled current source through a feedback switch FBG; the output current Ibias of the voltage-controlled current source directly flows into the negative electrode of the PD; the grid electrode of the MOS tube capacitor C is connected with the ground through a reset switch rst, and the source electrode and the drain electrode are in short circuit and are directly connected to the ground; and the structure can solve the problems that strong background light enables TOF pixels to be saturated and measurement precision to be reduced, and a traditional background light suppression scheme enables the pixel size to be significantly increased and enables the resolution of the sensor to be limited.

Description

technical field [0001] The invention relates to the field of analog integrated circuit design, in particular to a TOF image sensor pixel structure capable of suppressing background light. Background technique [0002] Three-dimensional image sensors can perceive the depth information of objects, help people obtain more complex relationships in the real world, and meet the needs of applications such as industrial automation, machine vision, and attitude detection, and have broad application prospects. [0003] Compared with other 3D imaging technologies, 3D imaging technology based on Time-of-Flight (TOF) is not restricted by geometric shape and size, and does not require complicated data processing, so it can be widely used. In the TOF image sensor, the charge generated by the background light is not helpful for measuring distance information, but it occupies a large amount of full well capacity, saturating the pixels and reducing the measurement accuracy. A traditional bac...

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Problems solved by technology

[0004] Aiming at the problems existing in the prior art, the present invention proposes a TOF image sensor pixel structure capable of suppressing background light, which solves the problem that strong background light saturates TOF pixels and reduces measurement accuracy, and the traditional background light suppression scheme makes the pixel size significantly increase, which limits the resolution of the sensor

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