Solid-State Image Sensor Arbiter Failure Diagnosis
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Solution Overview
Problem
In asynchronous solid-state image sensors, it is difficult to determine whether a defective pixel or the arbiter has failed, as the detection result is outputted via the arbiter, making it impossible to identify the specific failure point.
Innovation Solution
A solid-state image sensor is designed with a test circuit that generates and outputs requests, an arbiter that arbitrates these requests, a communication circuit to transmit detection signals, and a failure determination unit to identify arbiter failures, including a transistor to supply potential to the arbiter and a logical product gate to prevent short circuits, allowing for identification of arbiter failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test method using modulation light source is used to identify defective pixels, then detection capability is improved, but it becomes impossible to distinguish whether the failure is in the pixel or the arbiter
Solution Approach 1:
The patent segments the arbiter function into multiple arbiter blocks, each handling specific pixel groups. By testing each block independently and analyzing which block fails to output requests, the system can pinpoint the failure location to a specific arbiter block rather than just identifying a defective pixel.
Solution Approach 2:
The patent introduces a test circuit as an intermediary component that generates test requests and a failure determination unit that analyzes arbitration results. This intermediary system enables the distinction between pixel failures and arbiter failures by controlling and monitoring the request generation and arbitration process separately from normal operation.
2Device complexity
If the arbiter arbitrates all pixel requests, then system integration is improved, but failure diagnosis capability deteriorates
Solution Approach 1:
The arbiter is divided into multiple arbiter blocks, each responsible for specific pixel groups. This segmentation maintains the integrated arbitration function while enabling localized failure diagnosis by testing each block independently to identify which specific block is malfunctioning.
3Speed
If asynchronous event-driven architecture is used, then processing speed is improved, but reliability of failure identification worsens
Solution Approach 1:
The patent implements preliminary testing of arbiter blocks before normal operation by forcing request output from test circuits. This preliminary action verifies the arbitration function integrity, ensuring reliable failure identification while maintaining the asynchronous event-driven architecture's real-time processing capabilities during normal operation.
Data Source
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AI summary
In a solid-state image sensor in which an arbiter arbitrates a request, a failure point is identified. A plurality of pixels generates a request for requesting transmission of a predetermined detection signal, in a case where a predetermined event is detected. A test circuit outputs the request of each of the plurality of pixels as an output request in a case where a test is not instructed, and generates a plurality of new requests and outputs each as the output request in a case where the test is instructed. The arbiter arbitrates the output request. A communication circuit transmits the detection signal on the basis of an arbitration result of the arbiter. A failure determination unit determines whether or not the arbiter has a failure on the basis of the detection signal in a case where the test is instructed.