AD Conversion Circuit Signal Phase Adjustment
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Solution Overview
Problem
In image pickup devices, the existing analog-to-digital conversion circuits require complex phase adjustment and large circuit scales due to the need for high-speed transmission of multiple signals for binarization and subtraction processing, which hinders the increase in pixel density and speed.
Innovation Solution
An image pickup device with an AD conversion circuit that performs binarization and subtraction within the column unit, utilizing a delay circuit, latch unit, lower counting unit, and higher counting unit to generate and process difference signals, simplifying signal phase adjustment and reducing the number of output signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If binarization and subtraction processing are performed outside the column unit, then the circuit scale is reduced, but the number of signals to be transmitted increases and phase adjustment becomes complex
Solution Approach 1:
The patent merges the binarization circuit and subtraction circuit into the column unit, integrating multiple functions within a single module. This eliminates the need for separate external circuits and reduces the number of signals requiring transmission outside the column unit, thereby simplifying phase adjustment while maintaining compact circuit scale.
2Quantity of substance
If the number of pixels is increased, then the pixel density is improved, but the signal transmission speed and circuit complexity become problematic
Solution Approach 1:
The patent segments the signal processing functions by performing binarization and subtraction within each column unit before output. This segmentation reduces the number of signals that need to be transmitted at high speed, allowing the system to accommodate increased pixel density without proportionally increasing transmission complexity or reducing speed.
3Quantity of substance
If binarization and subtraction are performed within the column unit, then the number of output signals is reduced, but the column unit circuit scale increases
Solution Approach 1:
The column unit is designed to perform multiple functions: photoelectric conversion, signal amplification, binarization, and subtraction. By making the column unit multi-functional, the patent consolidates processing steps that would otherwise require separate external circuits, reducing the total number of output signals while distributing the circuit complexity across a universal processing module.
Data Source
AI summary
An image pickup device may include an image pickup unit in which a plurality of pixels are arranged, the plurality of pixels outputting a first and second pixel signals, and an analog-to-digital (AD) conversion circuit that outputs a digital difference signal. The AD conversion circuit may include a delay circuit that has a plurality of delay devices, the delay circuit outputting a first and second lower phase signals, a latch unit that latches the first and second lower phase signals, a lower counting unit that generates a first and second lower count signals, the lower counting unit generating and outputting a lower difference signal, and a higher counting unit that generates a higher difference signal, subtracts a predetermined number from the higher difference signal, or adds the predetermined number to the higher difference signal, and outputs the higher difference signal after subtraction or addition processing.