Gray Counter Architecture for Faster, More Linear Image Sensors
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Solution Overview
Problem
Existing image sensors face challenges in converting analog light signals into digital signals efficiently due to delays and differential non-linearity caused by logic gates and replica circuits in their counter systems, which affect the speed and accuracy of image data conversion.
Innovation Solution
The implementation of a gray counter system using flip-flops to generate gray code signals in synchronization with a clock signal, avoiding delays and differential non-linearity by eliminating the need for logic gates and replica circuits, thereby enhancing the speed and accuracy of image data conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional counter systems using logic gates and replica circuits are used to convert analog light signals into digital signals, then the conversion can be performed, but delays and differential non-linearity occur which reduce the speed and accuracy of image data conversion
Solution Approach 1:
The patent extracts and removes the problematic logic gates and replica circuits from the counter system. By eliminating these components that cause delays and differential non-linearity, the system achieves both faster conversion speed and higher accuracy without the traditional trade-off
Solution Approach 2:
The patent changes the fundamental operating parameters of the counter system by using a gray code-based flip-flop architecture instead of traditional binary counting with logic gates. This parameter change in the counting method eliminates the sources of delay and non-linearity, simultaneously improving both speed and accuracy
2Ease of operation
If logic gates and replica circuits are used in the counter system, then the system can function as a traditional counter, but the complexity of the system increases due to the need for these additional components
Solution Approach 1:
The patent removes logic gates and replica circuits from the system, simplifying the counter architecture while maintaining full functionality through the gray code flip-flop mechanism alone
Solution Approach 2:
The gray code flip-flop system performs multiple functions that traditionally required separate components: it provides counting functionality, eliminates the need for replica circuits, and reduces differential non-linearity all within a unified simplified architecture
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 allows for a high-speed image sensor operation with reduced delays and differential non-linearity, improving the frequency of the clock signal and enhancing the overall performance of the image sensor by directly converting analog signals into digital signals without the limitations of traditional counter systems.
Implementation Method 1
a pixel sensor configured to sense an incident light and to output an analog sampling signal
Data Source
AI summary
An image sensor includes a pixel sensor that senses an incident light and outputs a sampling signal of an analog shape, a sampler that compares the sampling signal and a ramp signal and outputs a comparison signal being time-axis length information, and a gray counter that counts a length of the comparison signal in synchronization with a clock signal and outputs a digital value. The gray counter includes a first flip-flop that divides the clock signal by 2 and generates a first gray code signal, a second flip-flop that delays a first data signal being a four-divided signal of the clock signal and outputs a second gray code signal, and a third flip-flop that delays the second gray code signal being two-divided and outputs a third gray code signal.