Interface Circuit Open Circuit Failure Detection in Cascade Source Drivers
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Solution Overview
Problem
Existing interface circuits in liquid crystal display devices cannot detect open circuit failures when multiple source drivers are in cascade connection, leading to undetected disconnections even if one source driver is faulty.
Innovation Solution
An interface circuit with a timing signal generating circuit, data control circuit, anomaly detection circuits, detection result selection circuit, and a signal output unit using a MOS transistor to selectively output detection results, allowing for the detection of open circuit failures in cascade-connected source drivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple source drivers are connected in cascade to extend display coverage, then the display area increases, but the ability to detect open circuit failures in individual drivers is lost
Solution Approach 1:
The patent divides the detection function into separate segments for each source driver. Each driver independently performs detection and outputs results through dedicated terminals, allowing individual fault identification even in cascade connections. This segmentation enables the TCON to receive and analyze detection results from each driver separately, resolving the contradiction between extended display area and maintained fault detection capability.
2Reliability
If anomaly detection circuits are added to detect failures, then reliability improves, but device complexity increases
Solution Approach 1:
The patent merges the anomaly detection function with the existing interface circuit structure. The detection circuits are integrated into the source driver's existing architecture, sharing common signal lines and control mechanisms where possible. This merging approach enables failure detection while minimizing the increase in overall device complexity by utilizing existing circuit resources.
Solution Approach 2:
Each source driver performs self-diagnosis through built-in anomaly detection circuits that monitor its own operation. The drivers automatically detect and report their own faults without requiring external monitoring systems, reducing overall system complexity while maintaining high reliability through distributed self-monitoring capabilities.
3Device complexity
If detection results are output through existing signal lines, then device complexity is reduced, but detection accuracy decreases due to signal interference
Solution Approach 1:
The patent extracts the detection result output function from the main data signal lines by providing dedicated detection result terminals. This separation ensures that anomaly detection signals are transmitted through dedicated pathways, preventing interference with data signals while maintaining a relatively simple overall structure. The extraction of detection functions to separate terminals resolves the contradiction between simplicity and accuracy.
Data Source
AI summary
An interface circuit generates a timing signal indicating the timing at which to switch between a data input period and a non-input period, and outputs a second start pulse signal obtained by delaying a first start pulse signal. Anomaly detection circuits detect an anomaly that has occurred in source drivers, and a detection result selection circuit selects one of the anomaly detection circuits during the non-input period and outputs a detection result signal indicating detection results. A selector selectively outputs the second start pulse signal or the detection result signal on the basis of the timing signal.