ADAS Image Sensor Voltage Regulator Verification Circuit for Fault Detection
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Solution Overview
Problem
Faults in image sensors or image sensing subsystems of advanced driver assistance systems (ADAS) can arise from improperly operating voltage regulators, necessitating rapid detection to ensure safe vehicle operation.
Innovation Solution
A circuit and method for verifying voltage regulators in ADAS systems by generating test voltages representing expected pixel values, using a test voltage generation circuit, analog-to-digital conversion, and comparison to expected values to detect malfunctions, with integrated switches and multiplexers for selective voltage application across pixel arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If voltage regulators are used to power image sensors in ADAS systems, then power supply efficiency is improved, but the risk of regulator malfunctions causing system failure increases
Solution Approach 1:
The patent implements preliminary action by generating test voltages and performing regulator functionality verification before the regulator is needed for normal operation. The test mode can be activated at power-up or periodically during operation to detect potential failures before they cause system malfunction, thus maintaining reliability while using efficient voltage regulators.
Solution Approach 2:
The patent introduces an intermediary test voltage generation circuit that acts as a mediator between the voltage regulator and the image sensor. This circuit generates test voltages that simulate expected pixel output voltages, allowing verification of regulator functionality without requiring actual image input, thus isolating the verification process from the main imaging function.
2Reliability
If test circuits are added to verify voltage regulator functionality, then system reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the test voltage generation circuit to use the same analog-to-digital conversion infrastructure already present in the image sensor. The test mode shares ADC resources with normal imaging operation, and the verification circuit can serve multiple regulators simultaneously, reducing per-regulator complexity while maintaining comprehensive coverage.
Solution Approach 2:
The patent merges the test voltage generation functionality with the existing pixel array structure. Test voltages are generated at the same nodes where pixel output voltages would normally appear, and the same readout and ADC circuits handle both test and imaging data. This consolidation avoids adding separate dedicated test circuitry for each regulator.
3Reliability
If rapid fault detection is implemented through continuous testing, then system safety is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by scheduling regulator verification at specific intervals rather than continuously. The test mode can be activated at power-up, periodically during operation, or triggered by specific events. This periodic verification maintains safety while allowing the system to operate in normal low-power mode between tests.
Solution Approach 2:
The patent applies partial action by verifying only the essential regulator functionality through test voltages rather than performing comprehensive testing of all regulator characteristics. The test uses simplified voltage generation and comparison that consumes minimal energy compared to full-scale testing, yet detects the most critical failures that would affect ADAS safety.
Data Source
AI summary
A regulator voltage verification circuit for an Advanced Driver Assistance System (ADAS) enables testing of voltage regulators in a pixel array. The circuit generates test voltages representing expected black and white pixel values as a function of the regulator's output voltage. The test voltages are selectively passed to an analog-to-digital conversion circuit in a test mode, while pixel outputs are processed in normal mode. A voltage divider connected to the regulator output creates upper and lower test voltages, which are selected by a multiplexer. The test voltages are routed through a digital correlated double sampling switch to a comparator and ripple counter, converting the analog test values to digital data. By comparing the digital output to expected values, the system can detect regulator malfunctions and issue appropriate warnings. The circuit can be implemented across multiple rows of a pixel array, with test results optionally averaged for accuracy.