Image Sensor Self-Pull-Down Circuit for Noise Reduction
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Solution Overview
Problem
As the resolution of image data increases, image sensors face challenges with noise due to the decrease in data read time, which existing techniques have not adequately addressed, impacting the reliability and performance of image sensors.
Innovation Solution
The implementation of an image sensor device with a self-pull-down circuit that operates based on the output voltage of the data line, allowing for independent voltage stabilization without a separate control signal, thereby simplifying the layout and improving reliability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels is increased to improve image resolution, then the image quality is improved, but the data read time decreases and noise increases
Solution Approach 1:
The self-pull-down circuit performs preliminary action by proactively pulling down the data line voltage before noise can significantly affect the signal. The circuit operates autonomously to maintain voltage stability during the reduced read time, preventing noise accumulation that would otherwise occur with higher pixel counts and faster readout speeds.
Solution Approach 2:
The self-pull-down circuit serves itself by automatically detecting when voltage stabilization is needed and executing the pull-down operation without external control signals. This self-service mechanism ensures that each data line is independently stabilized according to its own voltage conditions, maintaining signal integrity across all pixels regardless of read time variations.
2Ease of operation
If a traditional pull-down circuit with separate control signal is used, then voltage control is possible, but the layout complexity increases
Solution Approach 1:
The invention extracts the control signal requirement from the pull-down circuit, removing the need for separate control signal lines while retaining voltage control capability. The pull-down operation is triggered automatically by voltage threshold detection, eliminating the complexity of external control wiring and simplifying the overall layout.
Solution Approach 2:
The self-pull-down circuit acts as an intermediary between the data line voltage and the pull-down operation. Instead of requiring an external control signal as a mediator, the circuit uses the data line's own voltage level as the trigger condition, eliminating the need for additional control signal pathways and reducing layout complexity.
Data Source
AI summary
An image sensor device includes a pixel that converts a light signal into an electrical signal and outputs the converted electrical signal through a data line, a current bias element that is connected between the data line and a ground voltage, and a self-pull-down circuit that is connected between the data line and the ground voltage and pulls down the data line based on an output voltage of the data line.