Common Gate Amplifier Circuit for Noise Suppression in Imaging Devices
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Solution Overview
Problem
Current imaging devices face challenges in noise suppression, particularly with the CDS technique increasing manufacturing costs and being difficult to apply to certain types of solid-state imaging devices like organic CMOS sensors, where reset noise cannot be effectively removed.
Innovation Solution
The proposed imaging device incorporates a common gate amplifier circuit with a second transistor connected to a charge accumulation region, allowing for noise suppression without relying on the CDS technique, and includes features like voltage gain control and current supply units to enhance noise cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the CDS technique is used for noise suppression, then reset noise can be removed, but manufacturing cost increases and it cannot be applied to certain solid-state imaging devices
Solution Approach 1:
The pixel circuit is divided into multiple functional blocks: photoelectric conversion unit, charge accumulation region (floating diffusion region), amplifier unit with common gate amplifier circuit, and signal output unit. This segmentation allows each block to perform its specific function independently, enabling noise suppression through the amplifier circuit without requiring the CDS technique's dual-readout structure.
Solution Approach 2:
The common gate amplifier circuit acts as an intermediary between the charge accumulation region and the signal output. It includes a first transistor connected to the charge accumulation region and a second transistor connected to the first transistor, forming an amplification path that suppresses noise while transmitting the signal, eliminating the need for post-processing noise removal.
2Object-affected harmful factors
If the CDS technique is used for noise suppression, then reset noise can be removed, but device complexity and applicability are reduced
Solution Approach 1:
The amplifier unit with the common gate amplifier circuit serves multiple functions: it amplifies the signal from the charge accumulation region, suppresses noise through its circuit configuration, and outputs the processed signal. This multi-functional design makes the noise suppression mechanism applicable to various solid-state imaging devices without requiring device-specific modifications.
Solution Approach 2:
The patent replaces the mechanical/optical CDS technique (which requires separate readout paths and timing mechanisms) with an electronic amplifier circuit solution. The common gate amplifier circuit electronically suppresses noise through transistor configuration and signal processing, making it applicable to all solid-state imaging devices regardless of their specific photoelectric conversion mechanism.
3Object-affected harmful factors
If a common gate amplifier circuit is used, then noise suppression is achieved without CDS, but circuit complexity increases
Solution Approach 1:
The common gate amplifier circuit merges the amplification function and noise suppression function into a single circuit block. The first transistor's gate is connected to the charge accumulation region, and the second transistor is connected to the first transistor, creating an integrated amplification path that simultaneously performs signal amplification and noise suppression without requiring separate circuits for each function.
Solution Approach 2:
The amplifier unit is designed to be self-contained, with the common gate amplifier circuit internally suppressing noise as the signal passes through it. The circuit uses its own transistor configuration and internal connections to achieve noise suppression without requiring external processing or additional components, making the noise suppression function inherent to the circuit design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses noise in imaging devices, reducing random noise and enabling high-quality image data acquisition without the complexity and cost of the CDS technique, while being adaptable to various imaging technologies.
Implementation Method 1
a photoelectric converter that converts light into signal charge
Data Source
AI summary
An imaging device includes a photoelectric converter that converts light into signal charge, a charge accumulation region that accumulates the signal charge, a first transistor having a gate connected to the charge accumulation region, and a common gate amplifier circuit that amplifies an output of the first transistor to output to the charge accumulation region. The common gate amplifier circuit includes a second transistor. One of a source and a drain of the second transistor is connected to one of a source and a drain of the first transistor, and the other of the source and the drain of the second transistor is connected to the charge accumulation region.