Image Pixel Dark Node Segmentation for Power Supply Noise
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Solution Overview
Problem
Conventional image pixels are sensitive to power supply noise due to the loss of power supply information when dark nodes are reset, leading to errors in digital output during the readout phase.
Innovation Solution
The image pixel design incorporates a dark node with two charge storage units and an information output unit, allowing the first power supply information to remain stored during the second sample stage, reducing sensitivity to power supply noise by maintaining consistent power supply information across all light nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dark node is reset during the readout phase to update power supply information, then the power supply information is kept current, but the consistency of power supply information across all light nodes is lost, causing sensitivity to power supply noise
Solution Approach 1:
The dark node is segmented into two separate charge storage units: a first charge storage unit that retains the original power supply information throughout the readout phase, and a second charge storage unit that is reset to update power supply information. This segmentation allows the system to maintain both current power supply information and consistent reference information simultaneously, resolving the contradiction between keeping power supply information current and maintaining its consistency across all light nodes.
2Reliability
If multiple dark nodes are used to maintain power supply information for all light nodes, then power supply noise sensitivity is reduced, but the device complexity and area increase
Solution Approach 1:
Instead of using multiple dark nodes, the invention segments a single dark node into two charge storage units. This approach achieves the same effect of maintaining power supply information for all light nodes without increasing the number of dark nodes, thereby reducing device complexity and area while maintaining robustness to power supply noise.
3Loss of information
If the dark node retains power supply information throughout the readout phase, then consistency across all light nodes is maintained, but the power supply information becomes outdated
Solution Approach 1:
The dark node is divided into two charge storage units with different functions: the first charge storage unit retains power supply information consistently throughout the readout phase, while the second charge storage unit is reset to update power supply information. This segmentation allows the system to maintain both consistency and accuracy simultaneously.
Solution Approach 2:
The second charge storage unit discards its previous power supply information and recovers new power supply information by being reset during the readout phase. This allows the system to maintain current power supply information while the first charge storage unit maintains consistency for comparison.
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 solution reduces the image pixel's sensitivity to power supply noise, ensuring accurate digital output by maintaining consistent power supply information across all light nodes, thereby minimizing errors and potentially reducing the number of dark nodes required.
Implementation Method 1
a first charge storage unit coupled to the power supply for storing first power supply information related to the power supply during a first time period
Implementation Method 2
a second charge storage unit coupled to the power supply for storing second power supply information related to the power supply during a second time period
Data Source
AI summary
An image pixel includes light nodes and a dark node. The dark node includes: a first charge storage unit for storing first power supply information during a first time period; a second charge storage unit for storing second power supply information related to the power supply during a second time period; and an information output unit for outputting a first sample signal related to the first power supply information or a second sample signal related to the second power supply information. The first power supply information remains in the first charge storage unit during the second time period and during when the second sample signal is outputted by the information output unit.