Sensor Pixel Matrix Dynamic Range Gain Amplification
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Solution Overview
Problem
Current image sensor systems using submicron technologies, such as 0.18 μm technology, face a limited operating dynamic range and gain due to the use of single-oxide transistors with lower supply voltages, restricting the maximum signal attainable by pixels.
Innovation Solution
A new reading system is introduced that includes a method for processing information from active pixel matrices, utilizing unity gain amplification and differential amplifiers with current mirrors to enhance dynamic range and gain, applicable to both double-oxide and single-oxide transistors, allowing for improved signal charging and sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If submicron technologies with single-oxide transistors are used, then device integration and manufacturing are improved, but operating dynamic range and gain are reduced
Solution Approach 1:
The read amplifier is divided into two separate amplification stages: a first unity-gain amplifier that preserves dynamic range by operating with large signal swings, and a second high-gain amplifier that provides the necessary gain. This segmentation allows each stage to be optimized for its specific function, resolving the contradiction between integration benefits and dynamic range preservation.
Solution Approach 2:
The invention dynamically switches between two amplification modes depending on the signal level. For large signals, the first unity-gain amplifier operates to maximize dynamic range. For small signals, the second high-gain amplifier takes over to provide sufficient gain. This dynamic adaptation allows the system to maintain both wide dynamic range and adequate gain using submicron transistors.
2Use of energy by moving object
If supply voltage is reduced in submicron technologies, then power consumption is reduced, but maximum signal attainable by pixel is reduced
Solution Approach 1:
The dual-amplifier system dynamically adapts to low supply voltage conditions by using the first unity-gain amplifier for large signals where full dynamic range is needed, and the second high-gain amplifier for small signals where gain is critical. This allows the system to maintain signal processing capability despite reduced supply voltage in submicron technologies.
Solution Approach 2:
The invention changes the operating parameters of the amplification system by introducing two amplifiers with different gain characteristics. The first amplifier operates with unity gain and large signal swings to utilize the full available voltage range, while the second amplifier provides high gain for small signals. This parameter differentiation allows effective signal processing within reduced supply voltage constraints.
Data Source
AI summary
An image sensor includes a matrix of active pixels (PXA). A pair of sampling capacitors (C1) and (C2) per matrix column processes the information delivered by the active pixel matrix. Each matrix column further includes a differential amplifier configured in follower mode connected between the pixels of the column and the pair of sampling capacitors via a pair of switches (I1) and (I2).