Pixel Circuit Autonomous Reset via Feedback Control
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Solution Overview
Problem
Existing frame-free vision sensors experience delays in resetting pixel circuits due to the need for external acknowledge signals, leading to potential information loss and variability in processing time based on data traffic.
Innovation Solution
A pixel circuit with a voltage amplifier, hysteresis comparing module, and feedback control module that allows for autonomous resetting by modifying the input voltage offset based on detected light intensity changes, eliminating the need for external signals and enabling rapid detection of new events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external acknowledge signal is used to reset the pixel circuit, then the pixel circuit can be reset, but processing delays occur and information may be lost
Solution Approach 1:
The pixel circuit performs self-resetting by using its own output signal to trigger the reset operation through the feedback control module, eliminating the need for external acknowledge signals and removing processing delays associated with external communication
Solution Approach 2:
The output signal from the hysteresis comparing module is fed back to the feedback control module, which automatically generates the reset control signal for the voltage amplifier, creating a closed-loop system that eliminates waiting time for external acknowledge signals
2Reliability
If an external acknowledge signal is used for resetting, then the pixel circuit can be reset, but the processing time varies based on data traffic
Solution Approach 1:
The pixel circuit autonomously manages its own reset timing based on its detection events, making the processing speed independent of external data traffic conditions and ensuring consistent performance
3Reliability
If the pixel circuit waits for external acknowledge signal, then proper resetting can be ensured, but successive changes in light intensity may be missed
Solution Approach 1:
The feedback control module is configured to reset the voltage amplifier proactively based on the output signal from the hysteresis comparing module, ensuring the pixel circuit is prepared for the next detection event without waiting for external signals
Solution Approach 2:
The autonomous reset mechanism ensures continuous readiness of the pixel circuit for detection, eliminating gaps in the detection capability that occur when waiting for external acknowledge signals
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 enables quick and autonomous resetting of pixel circuits, reducing information loss and processing delays, allowing for continuous and efficient detection of successive changes in light intensity without external circuit dependencies.
Implementation Method 1
a photo-sensing device detecting a light intensity and generating a signal representing the detected light intensity
Implementation Method 2
a voltage amplifier configured for amplifying the signal representing the detected light intensity and generating an amplified signal
Implementation Method 3
a hysteresis comparing module configured for comparing the amplified signal to at least one threshold value and to a reference value and for generating at least one output signal based on said comparison
Data Source
Figure 1~2
Figure 3a~5b
AI summary
A pixel circuit for detecting time-dependent visual data comprises a photo sensing device detecting a light intensity and generating a signal representing the detected light intensity. The pixel circuit further comprises: - a voltage amplifier (3) configured for amplifying the signal representing the detected light intensity (VPh) and generating an amplified signal (Vo), the amplified signal being generated by taking into account a control signal (VqDc) which shifts an input voltage offset of said voltage amplifier, - a hysteresis comparing module (4) configured for comparing the amplified signal to at least one threshold value (θο+, θο- ) and to a reference value (Vref ) and for generating at least one output signal (Vο+, Vο-;Vο1+, Vο1-) based on said comparison, and - a feedback control module configured for generating said control signal of said voltage amplifier based on said at least one output signal generated by said hysteresis comparing module.