LED Driver Terminal Fault Detection Using Dual Evaluation Voltages
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Solution Overview
Problem
Existing light-emitting element driving devices face challenges in detecting resistance value abnormalities between adjacent connection terminals, which can lead to short-circuits or other faults, affecting the reliability and performance of LED lighting systems.
Innovation Solution
The implementation of an initial detection process and a regular detection process within the fault detection circuit of the LED driver, utilizing evaluation voltage generation and reference voltage generation circuits, along with switch control and comparison-judgment circuits, to identify and address resistance value abnormalities by comparing terminal voltages with a reference voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing detection methods are used, then the device structure remains simple, but the ability to detect resistance value abnormalities between connection terminals is insufficient
Solution Approach 1:
The detection circuit is segmented into multiple functional units: a voltage generation circuit that generates evaluation voltages, a switch control circuit that selectively connects terminals to evaluation nodes, and a comparison circuit that compares terminal voltages with reference voltages. This segmentation allows each component to perform a specific detection function, improving overall detection capability while maintaining manageable complexity through modular design.
Solution Approach 2:
Evaluation nodes are introduced as intermediary points between the connection terminals and the comparison circuit. These evaluation nodes serve as mediators that receive voltages from the terminals through controlled switching and facilitate the comparison process. The intermediary evaluation nodes enable indirect measurement of terminal resistance abnormalities without requiring direct complex measurement circuits at each terminal.
2Reliability
If detection is performed during light emission operation, then real-time monitoring is achieved, but the light-emitting units cannot emit light during detection
Solution Approach 1:
The detection circuit operates periodically by alternating between light emission mode and detection mode. During light emission, the light-emitting units operate normally. During detection periods, the switch control circuit selectively connects terminals to evaluation nodes to perform resistance measurements. This periodic switching enables real-time monitoring while maintaining light emission continuity through time-division multiplexing of operations.
Solution Approach 2:
The system dynamically switches between operational states: light emission state and detection state. The switch control circuit dynamically connects different terminals to evaluation nodes based on the current operational phase. This dynamic reconfiguration allows the system to adapt between maximizing light emission productivity and performing real-time reliability detection without fixed constraints on either function.
3Reliability
If all connection terminals are monitored simultaneously, then comprehensive detection is achieved, but the detection time increases
Solution Approach 1:
The detection of multiple connection terminals is segmented into sequential phases. The switch control circuit selectively connects different terminals to the evaluation nodes in separate time slots. This segmentation allows comprehensive monitoring of all terminals while reducing total detection time through parallel evaluation architecture and time-division multiplexing, where multiple terminals can be evaluated in overlapping time periods rather than strict sequential order.
Data Source
AI summary
For each channel, a light-emitting unit provided between a wire fed with a driving voltage and a connection terminal can be supplied with a driving current via the connection terminal. For each channel, a switch circuit is provided between the connection terminal and a voltage generation circuit. Based on the driving voltage, a first and a second voltage lower than the driving voltage are generated at a first and a second node. With each connection terminal cut off from the first and second nodes, the second voltage is lower than the first voltage. In a period in which each channel is not supplied with the driving current, the switch circuit operates to connect, of two adjacent connection terminals, one to the second node and the other to the first node. Based on the voltage at the one connection terminal, a resistance value abnormality between the two connection terminals is detected.