Image Sensor Row Driver Supply Switching for Read Noise Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image sensor performance is affected by the resolution of ADCs, and there is a need for compact circuit techniques to manage noise effectively.
Innovation Solution
The image sensor employs a plurality of image sensor cells with drivers and multiplexors that selectively connect negative supply terminals to power supply nodes, including a ground node, to manage noise and improve read noise isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple negative supply nodes are used for different drivers, then noise isolation is improved, but device complexity increases
Solution Approach 1:
The system divides the power supply network into multiple separate negative supply nodes (first negative supply node, second negative supply node, third negative supply node) that are selectively connected to different drivers. This segmentation isolates noise from different drivers onto different supply nodes, preventing noise propagation between drivers while maintaining functional independence of each driver cell column interface circuit.
Solution Approach 2:
The patent implements dynamic switching of negative supply node connections through multiplexors that can selectively connect each driver to different negative supply nodes based on operational requirements. This dynamic reconfiguration allows the system to adapt noise isolation strategies to different operating modes (e.g., reset mode versus read mode) and different driver states, optimizing noise performance without permanent structural complexity.
2Object-affected harmful factors
If negative supply nodes are switched during operation, then read noise is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent introduces multiplexors as intermediary switching elements between drivers and negative supply nodes. These multiplexors provide controlled, precise connection points that can be reliably manufactured and tested. The multiplexors act as mediators that manage the switching between different negative supply nodes during reset and read operations, ensuring clean transitions and reducing the direct complexity of managing multiple supply connections without significantly increasing manufacturing precision requirements.
3Measurement precision
If multiple power supply nodes are selectively connected, then image data quality is improved, but ease of operation decreases
Solution Approach 1:
The system implements self-service operation where the multiplexors automatically switch between different negative supply nodes based on control signals that correspond to different operational modes (reset versus read). The switching logic is integrated into the driver circuitry, eliminating the need for manual configuration or complex external control. The system serves itself by automatically selecting the appropriate power supply node configuration to maintain optimal image data quality without increasing operational complexity for the user.
Data Source
AI summary
An image sensor includes image sensor cells, each configured to generate an image signal in response to control signals. The image sensor also includes an ADC to receive the image signals of the image sensor cells, and a first driver to generate one or more first control signals for a first image sensor cell, where the first driver includes a first negative supply terminal. The image sensor also includes a first multiplexor to selectively connect the first negative supply terminal of the first driver to one of a plurality of power supply nodes, and a second driver to generate one or more second control signals for a second image sensor cell, where the second driver includes a second negative supply terminal. The image sensor also includes a second multiplexor to selectively connect the second negative supply terminal of the second driver to one of the power supply nodes.