Pixel Charge Control Circuit for Global Reset and Blooming Management
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Solution Overview
Problem
Existing digital image acquisition devices waste space and power due to the need for separate selection and reset decoders, which are not always independent, and previous solutions either complicate control logic or fail to allow global reset or manage blooming and pixel dynamics effectively.
Innovation Solution
A digital image acquisition device that eliminates the dedicated line reset decoder by using a single line decoder for both selection and reset, with an AND logic circuit generating a reset signal common to the array, and includes an additional transistor to control pixel sensitivity dynamically, allowing for analog signal transmission to manage blooming and pixel dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a dedicated reset decoder is used alongside a selection decoder, then independent control of selection and reset operations is achieved, but device complexity and space consumption increase
Solution Approach 1:
The patent combines the selection decoder and reset decoder into a single integrated decoder unit. The decoder receives both selection signals and reset signals, and internally routes them to appropriate pixel rows. This merging eliminates the need for two separate decoder circuits, reducing device complexity and space consumption while maintaining independent control capability through separate signal inputs.
Solution Approach 2:
The single decoder is designed to perform multiple functions: it acts as both a selection decoder and a reset decoder. By receiving different types of control signals (selection signals and reset signals) and routing them appropriately, the decoder becomes a universal control unit that handles both pixel selection and pixel reset operations, thereby eliminating the need for dedicated separate decoders.
2Area of stationary object
If transmission lines are reduced by half, then space consumption decreases, but control logic becomes more complicated
Solution Approach 1:
The patent merges the selection signal transmission and reset signal transmission into a single transmission line infrastructure. The same physical transmission lines carry both selection signals and reset signals at different time periods or through signal multiplexing. This reduces the number of transmission lines by half while the integrated decoder manages the increased control logic complexity internally through unified signal routing.
3Device complexity
If a single line decoder is used for both selection and reset, then device complexity and space are reduced, but independent control capability is lost
Solution Approach 1:
While using a single integrated decoder, the patent segments the control signals into distinct channels: selection signals and reset signals. The decoder internally separates these signal types and routes them to different output lines or time slots, maintaining independent control capability. The segmentation occurs within the decoder logic rather than requiring separate physical decoder units.
Solution Approach 2:
The patent employs periodic action by alternating between selection operations and reset operations through the same decoder. The decoder processes selection signals during one time period and reset signals during another time period, or uses time-multiplexed signal routing. This periodic separation of functions allows a single decoder to maintain independent control of both operations without requiring simultaneous independent processing paths.
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 reduces space and power usage, enables global reset of the pixel array, avoids blooming, and achieves high signal dynamics by using an AND logic circuit and an auxiliary charge control circuit to manage pixel discharge, resulting in a compact and efficient image acquisition system.
Implementation Method 1
one or more pixels, each provided with at least one photosensor
Data Source
AI summary
A digital device for image acquisition (10) comprises at least one selection decoder circuit (60) and a plurality of sub-blocks (50) each comprising one or more pixels (20) and a corresponding charge control circuit (30) which provides a circuit suitable for realizing a logic port of the AND type (31) having a selector input terminal (34) which receives the selection signal from the selection decoder circuit (60) and a suitable enabling input terminal (35) to receive an enabling signal; and interruption organs (32) connected to the reset terminal (21) of the pixel (20) to transmit a reset signal constituted alternatively by a signal output from the aforesaid circuit suitable for realizing a logic port of the AND type (31) or from a global reset signal transmitted to a corresponding global reset terminal (38). The reset signal of a sub-block can be controlled directly by the selection decoder (60), while the global signal transmitted to the global reset terminal (38) may be a digital signal suitable for performing a global reset of all the pixels of the device; it can be an analog global signal of the type suitable to limit the blooming effect or to obtain high dynamics.