Row Selection Circuit for Blooming Suppression in CMOS Sensors
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Solution Overview
Problem
Existing CMOS image sensors face challenges in suppressing blooming while maintaining high-speed readout operations, as current methods either increase power consumption or complicate pixel access control, and there is a lack of efficient circuit configurations for vertical selection in addressing blooming across all pixel operations.
Innovation Solution
A solid-state imaging device with a row selection circuit that controls pixel states to perform electronic shutter operations and readout, utilizing a configuration that sets at least three states for charge accumulation and discharge, allowing for efficient blooming suppression without increasing circuit size, by using a combination of transfer and reset gate control signals to manage charge overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple electronic shutters are used to suppress blooming in thinning-out mode, then blooming is suppressed, but power consumption increases and decoding time increases
Solution Approach 1:
The patent combines multiple electronic shutter operations into a single unified control mechanism. By merging the discharge operations of multiple shutters into one coordinated action, the system suppresses blooming effectively while reducing the total number of decoding accesses required, thereby lowering power consumption and decoding time compared to using separate electronic shutters for each row.
Solution Approach 2:
The invention creates a multi-functional row selection circuit that can perform both reading and electronic shutter operations. The circuit is designed to handle multiple functions (readout, electronic shutter, and blooming suppression) within a single unified structure, eliminating the need for separate dedicated circuits for each function and reducing overall system complexity and power consumption.
2Object-affected harmful factors
If multiple electronic shutters are used to suppress blooming in thinning-out mode, then blooming is suppressed, but decoding time increases
Solution Approach 1:
The patent combines multiple electronic shutter operations into a single unified control mechanism. By merging the discharge operations of multiple shutters into one coordinated action, the system suppresses blooming effectively while reducing the total number of decoding accesses required, thereby lowering power consumption and decoding time compared to using separate electronic shutters for each row.
Solution Approach 2:
The invention performs preliminary coordination of shutter operations before actual decoding occurs. By pre-planning and organizing the electronic shutter sequences in advance, the system minimizes the number of decoding accesses needed during actual operation, thereby reducing decoding time while maintaining effective blooming suppression.
3Object-affected harmful factors
If pixel voltage setting method with multiple periods is used, then blooming is suppressed, but pixel access control becomes complicated
Solution Approach 1:
The patent segments the pixel array into distinct readout rows and electronic shutter rows that are controlled independently through a unified row selection circuit. This segmentation allows different operations to be performed on different rows simultaneously, simplifying the control logic compared to applying multiple voltage periods to all pixels, while still achieving effective blooming suppression.
Solution Approach 2:
The invention implements dynamic row-by-row control where the row selection circuit can flexibly switch between readout mode and electronic shutter mode for different rows. This dynamic approach allows the system to adapt control signals in real-time based on the specific row being accessed, simplifying the overall control structure compared to static multi-period voltage settings.
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
The solution effectively suppresses blooming while enabling high-speed readout operations with reduced power consumption and simplified pixel access control, supporting various pixel operations including thinning-out modes and complex address patterns.
Implementation Method 1
a pixel section in which a plurality of pixels including photoelectric conversion devices converting optical signals into electric signals and accumulating the electric signals
Data Source
AI summary
A solid-state imaging device includes: a pixel section wherein pixels including photoelectric conversion devices are arranged in a matrix; and a pixel driving section including a row selection circuit which controls the pixels to perform an electronic shutter operation and readout of the pixel section. The row selection circuit has a function of selecting a readout row from which a signal is read out and a shutter row on which reset is performed by discharging charge accumulated in the photoelectric conversion devices, in accordance with address and control signals. The row selection circuit can set, in accordance with the address and control signals, in the pixels of the selected row, at least a readout state, a discharge state where a smaller amount of the charge accumulated in the photoelectric conversion devices than the reset is discharged, an electronic shutter state, and a charge state where the charge is accumulated in the photoelectric conversion devices.