LED Array Short Circuit Detection via Voltage Threshold Comparison
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Solution Overview
Problem
Existing LED chain systems face challenges in detecting short circuit failures, as a defective LED in a short circuit condition stops radiating, making it difficult to identify compared to open circuit failures which interrupt the current.
Innovation Solution
A method and device that deliver test currents to LED chains during startup, determine maximum and minimum voltages across output nodes, and compare these to detect if the maximum voltage exceeds the minimum by a threshold, indicating a potential short circuit failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a short circuit detection method is needed for LED chains, then detection capability is improved, but the system complexity increases due to additional detection circuitry and procedures
Solution Approach 1:
The patent applies preliminary action by performing short circuit detection during the startup phase before the LED chain is fully operational. The detection circuitry activates test currents and measures voltages across LED chains during initialization, allowing short circuits to be identified before they can cause damage or interfere with normal operation. This approach enables detection without requiring complex continuous monitoring during normal operation.
Solution Approach 2:
The patent uses an intermediary detection circuit that introduces test currents and measures voltage drops across the LED chains. This intermediary circuit acts as a mediator between the power supply and the LED chains, temporarily inserting measurement functionality during startup without requiring permanent modification of the LED chain structure. The detection circuit serves as an intermediary that enables detection while maintaining simplicity of the main LED driving system.
2Measurement precision
If voltage comparison method is used for detection, then detection precision is improved, but the measurement process becomes more complex
Solution Approach 1:
The patent applies parameter changes by varying the test current parameters during the detection process. Different current levels are used to probe the LED chain characteristics, and the voltage measurements are taken under these controlled parameter conditions. By changing current parameters and comparing the resulting voltage drops, the system achieves precise detection of short circuits while keeping the measurement methodology systematic and manageable.
Solution Approach 2:
The patent segments the detection process into distinct phases: applying test currents to individual or groups of LED chains, measuring voltage drops across specific segments, and comparing results against threshold values. This segmentation of the measurement process into discrete, manageable steps allows for precise detection while maintaining clarity in the measurement methodology and reducing overall system complexity.
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 early detection of short circuits in LED chains, preventing damage and ensuring robust fault detection independent of ground shifts and temperature variations.
Implementation Method 1
delivering each corresponding current of a plurality of currents to a corresponding chain of loads... determining a maximum voltage from among a plurality of output voltages... comparing the maximum voltage with the minimum voltage
Data Source
AI summary
During a start-up phase, each corresponding test current is delivered to a corresponding chain of loads of a plurality of chain of loads. Each chain of loads is coupled between a common node and a corresponding output node. Each chain of loads includes N series-coupled loads, where N is an integer greater than one. A maximum voltage is determined from among the output voltages, where the output voltages are the voltages at the output nodes. Also, a minimum voltage is determined from among the output voltages. The maximum voltage from among the output voltages is compared with the minimum voltage from among the output voltages to make a determination as to whether the maximum voltage exceeds the minimum voltage by a threshold. An indication is output based on a result of the determination.