Solid-State Imaging Column Reading Circuit for Dual Shutter Modes
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Solution Overview
Problem
Conventional CMOS image sensors require separate column reading circuits for rolling shutter and global shutter modes, as well as different signal types, leading to increased circuit complexity and power consumption.
Innovation Solution
A solid-state imaging device with a single column reading circuit configuration capable of operating in both rolling shutter and global shutter modes, and processing single-ended and differential signals, by using a shared amplifying and ADC circuit with mode-dependent feedback and search signal configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate column reading circuits are provided for rolling shutter and global shutter modes, then each mode can be processed independently, but device complexity and power consumption increase
Solution Approach 1:
The column reading circuit is designed to perform multiple functions by processing both rolling shutter and global shutter modes through the same circuit architecture. The circuit can operate in different configurations depending on the mode, eliminating the need for separate dedicated circuits for each shutter type.
Solution Approach 2:
The feedback capacitor connection configuration is made dynamic and adjustable. The capacitor can be connected to different nodes (output node or inverted input terminal) based on the operating mode, allowing the same circuit to adapt its behavior for rolling shutter versus global shutter processing without requiring separate hardware.
2Reliability
If separate column reading circuits are provided for rolling shutter and global shutter modes, then each mode can be optimized independently, but power consumption increases
Solution Approach 1:
The circuit merges the functionality of separate rolling shutter and global shutter reading circuits into a single unified circuit. By combining these functions, the total power consumption is reduced compared to operating two separate circuits, while still maintaining the ability to process both modes independently when needed.
Solution Approach 2:
A universal column reading circuit is implemented that can handle both shutter modes, reducing the overall power budget required for image processing compared to having dedicated circuits for each mode.
3Measurement precision
If different signal types require different reading circuits, then signal processing can be optimized, but device complexity increases
Solution Approach 1:
The circuit employs dynamic switching mechanisms that allow it to adapt its configuration based on the signal type being processed. Through switching elements, the same circuit can be reconfigured to optimally process different signal types without requiring separate dedicated circuits for each signal type.
4Device complexity
If a single column reading circuit is used for both rolling and global shutter modes, then device complexity and power consumption are reduced, but separate circuits were previously required for proper processing
Solution Approach 1:
The circuit uses dynamic switching mechanisms to change its configuration based on the operating mode. Switching elements enable the circuit to reconfigure itself appropriately for either rolling shutter or global shutter processing, ensuring reliable operation in both modes while using a single unified circuit structure.
Solution Approach 2:
The circuit changes its operational parameters and configuration based on the mode being used. By adjusting connection configurations and switching states, the same physical circuit can achieve the different processing requirements of rolling shutter and global shutter modes.
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 reduced circuit scale, simplified control, and lower power consumption by enabling the use of a single reading circuit for various operational modes and signal types, while maintaining image quality and aspect ratio.
Implementation Method 1
photoelectric conversion elements for detecting light and generating charges
Data Source
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AI summary
A pixel signal includes a first pixel signal and a second pixel signal. The first pixel signal includes a read-out reset signal and a read-out luminance signal that are read out in the stated order from a pixel in a first operation, and the second pixel signal includes a read-out luminance signal and a read-out reset signal that are read out in the stated order from the pixel in a second operation. A reading circuit 40 includes an amplifying part 420 for amplifying the pixel signal, and an AD converting part 430 for analog-to-digital converting, in connection with a search signal, the pixel signal amplified by the amplifying part 420. A first search signal Vramp1 for the first pixel signal and a second search signal Vramp2 for the second pixel signal are configurable such that search levels thereof are inverted.