Sensor Pixel Gain Adjustment via Charge Leakage Control
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Solution Overview
Problem
Existing sensor pixel circuits face challenges in dynamically adjusting their gain to prevent saturation during reading out, especially in applications with varying signal intensities, and in compensating for instability over time, which affects the accuracy and dynamic range of the imaging systems.
Innovation Solution
The integration of a gain adjustment block that allows for charge leakage from the charge storage, connected to an active component that operates similarly to the amplifier, enabling on-pixel gain adjustment and instability compensation, thereby maintaining a stable dynamic range and preventing saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If charge is stored in the charge storage component, then the signal intensity is increased, but saturation occurs during reading out when signal intensity is too high
Solution Approach 1:
The patent implements dynamic gain adjustment by making the charge storage component's capacitance variable rather than fixed. The gain control block modifies the capacitance value in real-time based on signal conditions, allowing the pixel to adapt its charge storage capacity to prevent saturation while maintaining sensitivity for weak signals.
Solution Approach 2:
The patent changes the electrical parameter of capacitance in the charge storage component dynamically. By adjusting the capacitance value through the gain control block, the system can optimize charge storage for different signal intensities, preventing both saturation and loss of sensitivity.
2Productivity
If the pixel operates continuously, then productivity is improved, but instability of active components affects accuracy over time
Solution Approach 1:
The patent implements a feedback mechanism where the pixel's output is monitored and used to adjust the gain control block's operation. This feedback loop compensates for drift and instability in active components over time, maintaining measurement accuracy during continuous operation.
Solution Approach 2:
The patent performs preliminary calibration and stabilization of the active components before full operation begins. The system establishes baseline characteristics and pre-adjusts parameters to compensate for expected drift, improving long-term accuracy.
Data Source
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AI summary
A sensor pixel 100 including a sensor 3, charge storage 5, a reset block 7 having a reset input 11, readout block 9, and a charge leakage gain adjustment block 17 having a gain adjustment control input 19. The sensor 3, charge storage 5, reset block 7, readout block 9, and charge leakage gain adjustment block 17 are each operatively connected to a node A. Adjusting the gain of a sensor pixel 100 by storing charge from a sensor 3 in a charge storage 5 connected to a node A, leaking charge from the charge storage 5 to reduce the charge at node A, and reading out a state of the pixel represented by the charge of node A.