LED Matrix Open Short Detection via Voltage Comparison
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Solution Overview
Problem
Conventional methods, such as current injection techniques, are ineffective in detecting open/short conditions in cross-plex LED connections and fail to identify individual faulty LEDs in both conventional and cross-plex connections.
Innovation Solution
A system comprising a control algorithm circuit, level shifter circuit, connection switches circuit, comparator, reference generation circuit, signal pass block, and output pass block is introduced to detect open or short conditions in LEDs by generating and comparing reference voltages with individual LED output pins, allowing conditional outputting of status signals based on an Enable signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional current injection technique is used, then detection system is simple, but it cannot detect open/short conditions in cross-plex LED connections and cannot identify individual faulty LEDs
Solution Approach 1:
The patent divides the LED matrix into individually addressable segments by implementing separate X and Y scanning pathways with independent control. Each LED can be individually tested by activating specific row and column combinations, allowing precise identification of faulty LEDs in both conventional and cross-plex configurations without requiring a complete system redesign.
Solution Approach 2:
The detection circuit is designed to universally handle both conventional and cross-plex LED connections through a unified architecture. The same detection circuitry and control algorithm can adapt to different connection types by modifying the scanning sequence, eliminating the need for separate detection systems for each connection type and thereby improving reliability without proportionally increasing complexity.
2Measurement precision
If individual LED detection is implemented, then faulty LED identification is accurate, but detection time increases due to sequential testing
Solution Approach 1:
The patent implements periodic scanning of LED rows and columns in a systematic sequence, where each LED is tested at regular intervals through controlled activation of corresponding X and Y signals. This periodic action allows individual LED identification while maintaining efficient detection timing by reusing the same scanning infrastructure for multiple LEDs rather than requiring separate testing sequences.
Solution Approach 2:
The detection system maintains continuous operation by seamlessly transitioning between LED tests without idle periods. The control algorithm continuously scans through the LED matrix, immediately transitioning from one LED test to the next, thereby minimizing detection time while preserving the ability to accurately identify individual faulty LEDs through uninterrupted systematic testing.
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
Enables accurate detection of open or short conditions in individual LEDs for both conventional and cross-plex connections, improving the reliability of LED display panels by identifying faulty connections.
Implementation Method 1
a comparator to compare the LED output pins with a second and third reference voltages
Data Source
AI summary
An apparatus to detect faulty connection of LED (open/short conditions) which may affect the function of LED display panel is presented. The apparatus basically controls the switches through control algorithm circuit to get the information of LED driver output pins voltage and compare them with two reference voltages to determine the open/short condition of individual LED.