LED String Short Circuit Detection via Total Voltage Comparison
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Solution Overview
Problem
Conventional methods for identifying short circuits in optoelectronic assemblies, particularly in series connections of light emitting diode (LED) elements, are unreliable and require significant wiring and cost due to the need for individual voltage measurements at each element, making it challenging to detect defects like short circuits effectively.
Innovation Solution
A method that interrupts the energy supply to the component string and measures the total voltage between the input and output, comparing it to a sum of predefined threshold voltages to reliably identify short circuits, allowing for identification with a single input and output from the driver circuit and minimizing interference from aging and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual voltage measurements are performed at each LED element to identify short circuits, then measurement precision is improved, but device complexity and wiring requirements increase significantly
Solution Approach 1:
The patent merges multiple individual voltage measurements into a single total voltage measurement across the entire component string. By measuring the aggregate voltage at the input and output of the string and comparing it to the sum of threshold voltages of all LED elements, the system achieves short circuit detection without requiring individual wiring to each LED element, thus reducing wiring complexity while maintaining detection capability
Solution Approach 2:
The single voltage measurement system serves multiple functions: it detects short circuits in any LED element within the string, identifies the position of defects, and provides system-wide monitoring. This universal measurement approach replaces the need for multiple dedicated measurement circuits, simplifying the overall system architecture
2Measurement precision
If individual voltage measurements are performed at each LED element, then short circuit identification accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple measurement functions into a single measurement system. By measuring the total voltage across the entire component string and comparing it to the sum of threshold voltages of all LED elements, the system achieves accurate short circuit identification without requiring multiple measurement circuits, thereby reducing manufacturing costs for wiring, measurement devices, and assembly
3Productivity
If total voltage is measured during normal operation, then short circuit detection is enabled, but temperature and aging interference increase
Solution Approach 1:
The patent implements periodic measurement cycles where the component string is briefly interrupted from normal operation to perform total voltage measurement. This periodic interruption allows measurement under controlled conditions with minimal temperature rise and reduced aging effects, improving measurement reliability while maintaining overall system productivity through rapid cycling
Solution Approach 2:
The measurement is performed at a predetermined time point after interrupting the component string, allowing the system to capture voltage data before significant temperature changes or aging effects occur. This timing strategy ensures measurement reliability by capturing data under stable conditions
Data Source
AI summary
A method for operating an optoelectronic assembly which includes at least one component string having at least one section, wherein the section includes at least one light emitting diode element, is provided. According to the method, the component string is supplied with electrical energy, the supply of the component string with electrical energy is interrupted, a total voltage is detected, which is present between an input and an output of the section of the component string, the total voltage is compared with a sum of threshold voltages of all the light emitting diode elements. It is identified that the section has no short circuit if the total voltage is equal or at least approximately equal to the sum of the threshold voltages, and/or it is identified that the section has a short circuit if the total voltage is less than the sum of the threshold voltages.