Image Sensor Counter Circuit for Stable Noise-Resistant Sampling
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Solution Overview
Problem
Existing image sensors face challenges in accurately converting analog signals to digital signals due to coupling issues between signal lines, which can lead to noise and unreliable data, especially in high-definition imaging.
Innovation Solution
A counter circuit is introduced that performs complement and division operations using a D-latch and D-flip-flop configuration to stabilize count values, reducing the influence of coupling and enabling a reset multiple sampling technique for noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a counter circuit is used to convert analog signals to digital signals in high-definition image sensors, then the imaging resolution and detail are improved, but coupling issues between signal lines cause noise and reduce data reliability
Solution Approach 1:
The patent introduces a sampling unit as an intermediary component between the counter circuit and the output. This sampling unit captures and holds the count values at specific moments, preventing direct coupling between signal lines while maintaining accurate signal conversion. The sampling unit acts as a buffer that isolates the counter circuit from downstream noise and interference.
Solution Approach 2:
The patent performs complement operations on count values before they are fully processed or transmitted. By preliminarily adjusting the count values through complement operations, the system prepares the data in advance to be more resistant to noise and coupling issues, improving reliability before the signals undergo further processing.
2Measurement precision
If signal lines are densely packed to achieve high-definition imaging, then the image quality and resolution are improved, but coupling between signal lines increases causing noise
Solution Approach 1:
The sampling unit serves as a spatial and temporal intermediary that separates densely packed signal lines. By capturing signals at discrete moments and holding them in storage elements, the sampling unit prevents direct electromagnetic coupling between adjacent signal lines while maintaining high-resolution imaging capability.
Solution Approach 2:
The patent divides the continuous signal processing into discrete sampling intervals. By segmenting the signal flow into separate capture, hold, and process stages, the system reduces coupling noise between signal lines while preserving the high-definition image quality through precise temporal separation of signals.
Data Source
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AI summary
An image sensor includes a pixel sensor configured to sense an incident light and to output an analog sampling signal; a sampling unit comparing the sampling signal and a ramp signal, and outputting a comparison signal having a duration that is indicative of the amplitude of the sampling signal; and a counter counting a length of the comparison signal based on a clock signal and first and second complement control signals. The counter includes an AND gate ANDing the comparison signal and the clock signal; and a counting unit triggered at a falling edge of the AND gate output to output a count value. The counting unit includes a complement operation controller storing an inverted count value that is an inversion of the count value in response to the first complement control signal, and outputting the inverted count value in response to the second complement control signal; and a D-flip-flop that is set or reset depending on the inverted count value, and outputs the count value.