Vehicle LED Lighting Device with Dynamic Threshold Adjustment
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Solution Overview
Problem
Judging disconnection or short-circuit abnormalities in vehicle LED lamps is challenging due to fluctuations in power supply voltage, which affect current values, making precise detection difficult.
Innovation Solution
A vehicle LED lighting device with a drive control system that includes an abnormality detection unit, which uses a current detection unit to compare current values with dynamically adjusted determination values based on power supply voltage, allowing for precise disconnection or short-circuit judgment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If current value detection is used to judge disconnection or short-circuit abnormalities, then the detection method is simple, but the judgment precision deteriorates due to power supply voltage fluctuations
Solution Approach 1:
The patent dynamically changes the determination value (threshold) based on the detected power supply voltage. When voltage fluctuates, the determination value is adjusted proportionally, allowing accurate abnormality judgment despite voltage changes. This resolves the contradiction by making the detection system adaptive to voltage variations while maintaining simple current-based detection.
2Device complexity
If a fixed determination value is used for abnormality detection, then the device complexity is low, but the reliability deteriorates under varying power supply conditions
Solution Approach 1:
The patent implements a dynamic determination value that automatically adjusts according to the detected power supply voltage. Instead of using a fixed threshold, the system calculates the determination value as a ratio based on real-time voltage measurements, ensuring reliable abnormality detection across varying electrical conditions without requiring complex calibration.
3Measurement precision
If voltage-based abnormality detection is used, then the judgment precision improves, but the device complexity increases
Solution Approach 1:
The patent makes the existing current detection unit perform dual functions: normal operation monitoring and abnormality detection. By using the same hardware for both purposes and simply adding voltage-based determination value adjustment, the system achieves precise detection without requiring separate voltage-based detection circuits, thus avoiding increased complexity.
Data Source
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AI summary
In a vehicle lamp, enabled to detect a disconnection or a short circuit, judgment of the disconnection abnormality or the short-circuit abnormality by detection of a current value can be performed with high precision even if variation occurs in the power supply voltage that drives an LED lamp. A vehicle LED lighting device includes a drive control means (51) performing drive control of LED lamps (20) and (30) installed in a vehicle, the drive control means (51) includes an abnormality detection means detecting a disconnection or short-circuit abnormality of the LED lamp, the abnormality detection means includes a current detection unit detecting the value of a current flowing through the LED lamps (20) and (30) when the LED lamps (20) and (30) are driven by the drive control means (51), a comparison unit comparing the current value detected by the current detection unit with a predetermined abnormality determination value, and a determination value switching unit switching the abnormality determination value in accordance with variation of a power supply voltage of the vehicle, and whether or not there is the disconnection or short-circuit abnormality is judged based on the abnormality determination value switched by the determination value switching unit (63) and the detected current value.