Shared Activation Circuit for Dual Conversion Gain and HDR Pixels
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Solution Overview
Problem
In CMOS active pixel sensor imagers, the inclusion of capacitors and transistors for dual conversion gain and high dynamic range increases space requirements, reducing the fill factor and charge storage capacity, as these components occupy space that could be used for photo-conversion devices.
Innovation Solution
The implementation of a shared activation circuit for dual conversion gain and high dynamic range transistors, which also serves as one plate of a capacitor, reduces the space needed by allowing these components to share control signals and circuitry, thereby minimizing the impact on the fill factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If capacitors and transistors are included for dual conversion gain and high dynamic range, then charge storage capacity and dynamic range are improved, but fill factor is reduced
Solution Approach 1:
The activation circuit for the dual conversion gain transistor is merged with the activation circuit for the high dynamic range transistor, allowing both functions to share common control signals and circuitry. This integration reduces the total space required for these components while maintaining both charge storage capacity and dynamic range enhancement
Solution Approach 2:
The shared activation circuit serves multiple functions: it controls both the dual conversion gain transistor and the high dynamic range transistor, and also functions as one plate of a capacitor. This multi-functionality reduces the number of separate components needed, thereby increasing the fill factor while preserving charge storage capacity and dynamic range
2Adaptability or versatility
If capacitors and transistors are included for dual conversion gain and high dynamic range, then dynamic range is improved, but fill factor is reduced
Solution Approach 1:
The activation circuits for dual conversion gain and high dynamic range transistors are merged into a single shared circuit, reducing the space required for control circuitry while maintaining both dynamic range enhancement capabilities
Solution Approach 2:
The shared activation circuit performs multiple functions including controlling both transistors and serving as a capacitor plate, thereby reducing component count and increasing fill factor without compromising dynamic range
3Quantity of substance
If capacitors and transistors are included for dual conversion gain and high dynamic range, then charge storage capacity is improved, but space consumption is increased
Solution Approach 1:
The activation circuits are merged to share common control signals and circuitry, reducing the total space required for implementing both dual conversion gain and high dynamic range functions while maintaining charge storage capacity
Solution Approach 2:
The shared activation circuit serves as both control circuitry and as one plate of a capacitor, eliminating the need for separate capacitor plates and reducing overall space consumption while maintaining charge storage capacity
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 approach allows for increased charge storage capacity and dynamic range without significantly affecting the fill factor of the pixel array, optimizing space usage and improving imaging performance.
Implementation Method 1
a photo-conversion device 23 for generating and collecting charge generated by light incident on the pixel cell 10
Implementation Method 2
a capacitor 20 may also be included to increase the charge storage capacity of floating diffusion region 5
Data Source
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AI summary
A pixel circuit having a shared control line for providing two control signals to the pixel array. One control line is used to provide a control signal to both a high dynamic range circuit and a dual conversion gain circuit to two pixel circuits. The pixel circuits each contain two pixel cells that have separate photo-conversion devices but share readout circuitry.