Row-Period Compensator for Image Sensor Voltage Stability
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Solution Overview
Problem
Modern image sensors experience voltage distortion due to variations in current drawn by their electrical circuitry, leading to imaging system power rail distortions and artifacts like horizontal-banding in pixel image data, which existing techniques attempt to mitigate through clamping circuits or reducing parasitic impedances, but these solutions increase cost and complexity.
Innovation Solution
The implementation of a row-period compensator, electrically coupled between the positive and negative power rails, which controls a compensation current to counteract changes in current drawn by the image sensor's electrical circuitry during a row-period, thereby minimizing voltage distortion without adding components or reducing parasitic impedances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clamping circuits are added to limit current changes, then voltage distortion is reduced, but device complexity and cost increase
Solution Approach 1:
A row-period compensator circuit is introduced as an intermediary component between the power source and the image sensor circuitry. This compensator actively monitors and compensates for current variations during row-period operations, stabilizing voltage without requiring complex clamping circuits throughout the entire system. The compensator acts as a mediator that isolates the sensitive image sensor from power rail disturbances.
2Reliability
If parasitic impedances are reduced by increasing cross-sectional area of power rails, then voltage distortion is reduced, but manufacturing cost and space requirements increase
Solution Approach 1:
Instead of physically modifying the power rail geometry (increasing cross-sectional area), the invention changes the electrical parameters by introducing an active compensator circuit. This circuit dynamically adjusts compensation current based on detected voltage distortion, effectively counteracting the effects of parasitic impedances without requiring changes to the physical dimensions or material properties of the power rails.
3Reliability
If current drawn by electrical circuitry is limited, then voltage distortion is reduced, but imaging resolution and data read-out capability deteriorate
Solution Approach 1:
The compensator circuit dynamically adjusts its compensation current in real-time based on the actual current draw of the image sensor during row-period operations. Rather than imposing a fixed current limit, the system continuously monitors voltage distortion and modulates the compensation current accordingly, allowing full imaging capability while actively counteracting voltage drops only when and where they occur.
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 row-period compensator effectively maintains a constant total current, significantly reducing voltage distortion across power rails, thus preventing improper operation of the image sensor and eliminating artifacts like horizontal-banding without increasing the image sensor's cost, complexity, or size.
Implementation Method 1
The row-period compensator is for compensating for a change in current drawn by the electrical circuitry during a row-period of the image sensor
Data Source
AI summary
An imaging system includes an image sensor and a row-period compensator. The image sensor includes an array of photosensitive pixels and electrical circuitry for controlling the array of photosensitive pixels and for reading accumulated electrical charge therefrom. The electrical circuitry is at least partially powered from a positive power rail and a negative power rail. The row-period compensator is for compensating for a change in current drawn by the electrical circuitry during at least part of a row-period of the image sensor, and the row-period compensator is electrically coupled between the positive and negative power rails. A method for compensating for a change in current drawn by electrical circuitry of an image sensor includes controlling a magnitude of compensation current drawn by a row-period compensator, to compensate for a change in current drawn by the electrical circuitry of the image sensor.