Built-in Test Circuitry for Display Driver Reliability
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Solution Overview
Problem
Existing display device testing methods do not effectively detect circuit failures that occur during actual operation, such as while displaying an image, which can compromise reliability, especially in safety-critical applications like automobile displays.
Innovation Solution
Incorporating test circuitry within the display driver that tests the image processing circuitry during a designated test period between display update periods, allowing for the detection of circuit failures during operation while continuing to display images, and enabling measures such as bypassing failed components to maintain normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If built-in test circuitry is added to detect circuit failures during operation, then reliability is improved, but device complexity increases
Solution Approach 1:
The test circuitry is merged with the existing display driver structure, sharing common components such as the output buffer and signal paths. The test mode is integrated into the existing driver architecture, allowing failure detection without adding completely separate testing subsystems. This merging approach enables reliability improvement while minimizing the increase in device complexity.
2Reliability
If test operations are performed during display update periods, then circuit failures can be detected, but display continuity is disrupted
Solution Approach 1:
The test circuitry performs failure detection operations periodically during designated test periods that are inserted between normal display update periods. This periodic testing approach allows the system to alternate between normal display operation and test operations, ensuring both continuous display functionality and regular failure detection without permanent disruption to the display service.
3Reliability
If test periods are inserted between display update periods, then failure detection is enabled, but display refresh rate is reduced
Solution Approach 1:
The test circuitry performs partial testing operations during the test periods, focusing on critical failure detection rather than comprehensive testing. The test mode activates only essential test functions during the inserted test periods, performing sufficient failure detection to ensure reliability while minimizing the time taken away from normal display operations, thus reducing the impact on display refresh rate.
Data Source
AI summary
A display driver includes image processing circuitry, driver circuitry, and test circuitry. The image processing circuitry is configured to generate first output data during a first display update period and generate second output data during a second display update period. The driver circuitry is configured to update a display panel based on the first output data during the first display update period and update the display panel based on the second output data during the second display update period. The test circuitry is configured to test the image processing circuitry during a test period disposed between the first display update period and the second display update period.