Fault-Tolerant LED Driver Using Distributed Reactive Components
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Solution Overview
Problem
Conventional LED driving systems are sensitive to failures of individual LEDs, leading to complete system failure or reduced service life, and require additional active semiconductor components and complex circuitry for current and voltage regulation.
Innovation Solution
A fault-tolerant LED driving system using an excitor to generate an AC waveform that drives an under-damped resonant circuit with reactive components distributed among the LEDs, allowing self-regulation of current and voltage and enabling the addition or removal of LEDs without affecting other elements, and eliminating the need for semiconductor components other than the LEDs themselves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LED drivers use series and/or parallel combinations with current drivers, then LEDs can be driven with controlled current, but the system becomes sensitive to individual LED failures causing complete system failure
Solution Approach 1:
The LED array is divided into multiple independent strings, each string containing LEDs connected in series with reactive components. Each string can operate independently, so failure of one LED affects only that specific string rather than the entire system. This segmentation provides fault tolerance while maintaining relatively simple circuitry within each string.
Solution Approach 2:
Reactive components (capacitors and inductors) are distributed locally among individual LEDs within each string rather than using a centralized complex driver circuit. Each LED or small group of LEDs has its own reactive components for current regulation, providing localized control that isolates failures and reduces overall system complexity.
2Reliability
If AC current drivers with anti-parallel LEDs are used, then LEDs can be driven with AC current and some failure tolerance, but the system generates significant radio frequency interference and has lower energy efficiency
Solution Approach 1:
The system uses sinusoidal AC current at power line frequency (50-60 Hz) to drive the LED strings rather than high-frequency square wave inversion. This periodic sinusoidal operation reduces harmonic distortion and radio frequency interference while maintaining failure tolerance through the string configuration with reactive components that regulate current during each half-cycle.
3Reliability
If reactive components are distributed among lighting elements, then current and voltage can be self-regulated to individual elements, but the device complexity increases
Solution Approach 1:
Each LED string is equipped with reactive components (capacitors and inductors) that automatically regulate current and voltage without requiring external active control circuitry. The reactive components self-adjust to maintain proper current distribution among LEDs in the string, eliminating the need for complex semiconductor-based current drivers while providing reliable current regulation.
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
The system provides robust current and voltage regulation, is insensitive to individual LED failures, and enhances reliability and efficiency by minimizing active components and reducing radio frequency interference, while allowing for flexible configuration and dimming capabilities.
Implementation Method 1
The reactor is an under-damped resonant circuit that includes a network of lighting elements
Implementation Method 2
The reactor is an under-damped resonant circuit that includes a network of lighting elements. Reactive components are distributed among the lighting elements. These reactive components can regulate the current and voltage to individual lighting elements.
Data Source
AI summary
A lighting system is disclosed comprising an excitor which drives at least one reactor. The excitor is an electrical waveform generator that creates an AC waveform at a frequency between about 50 kHz and about 100 MHz. The reactor is an under-damped resonant circuit that includes a network of lighting elements. Reactive components are distributed among the lighting elements. These reactive components can regulate the current and voltage to individual lighting elements. The drive system is particularly useful for arrays of low-voltage lighting elements such as LEDs. It is fault tolerant in that the failure of individual elements need not affect the operation of remaining elements, and elements can be added and removed without affecting the serviceability of other elements.