Motor Vehicle Lighting Device with Current-Limited LED Branches
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Solution Overview
Problem
Existing lighting devices for motor vehicles fail to manage LED failures effectively, particularly in cases of short circuits, leading to uncontrolled current increases and unwanted light distribution, and are unable to completely interrupt light emission in the pre-lighting state, resulting in electrical hazards and dissimilar lighting effects compared to traditional single-source lights.
Innovation Solution
Incorporating a current limiting device in parallel with the switch and using current mirrors to control the secondary currents flowing through each lighting branch, allowing the system to transition between pre-lighting and complete-lighting states based on predetermined current thresholds, thereby managing faults such as open or short circuits and maintaining minimal primary supply current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the electronic control circuit controls all LEDs simultaneously to produce a luminous effect similar to a single-source traditional light, then the lighting effect is improved, but the system cannot effectively manage LED failures particularly short circuits leading to uncontrolled current increases
Solution Approach 1:
The patent divides the array of light emitting sources into multiple independent lighting branches, each with its own control mechanism. This segmentation allows the system to isolate and manage failures in individual branches without affecting the entire array, resolving the contradiction between maintaining uniform lighting effect and managing LED failures effectively.
Solution Approach 2:
The patent implements a control circuit that continuously monitors the state of each lighting branch and provides feedback to adjust the driving signals accordingly. This feedback mechanism enables the system to detect LED failures (including short circuits) and respond by redistributing current or isolating affected branches, thereby maintaining reliability while preserving the overall lighting effect.
2Duration of action of moving object
If the system allows uncontrolled current increases upon LED failure, then the lighting device can maintain operation, but electrical hazards occur and unwanted light pulses are generated
Solution Approach 1:
The patent incorporates protection diodes and current limiting circuits in each lighting branch before failures occur. These protective elements are pre-configured to limit current increases and prevent electrical hazards when LED failures happen, allowing the system to maintain operation safely without generating unwanted light pulses.
Solution Approach 2:
The patent introduces intermediate control elements (such as series diodes and current limiting resistors) between the power source and the LED arrays. These intermediaries act as mediators that control and limit current flow, preventing uncontrolled current increases and electrical hazards while allowing continuous operation.
3Illumination intensity
If the system cannot completely interrupt light emission in the pre-lighting state, then the LEDs remain visible, but the lighting effect differs from traditional single-source lights and energy consumption increases
Solution Approach 1:
The patent implements a control mechanism that periodically switches the lighting branches between on and off states, including a pre-lighting state where light emission is completely interrupted. This periodic action allows the system to consume minimal energy during the pre-lighting state while still maintaining the capability to illuminate when needed, mimicking the behavior of traditional single-source lights.
4Illumination intensity
If the system uses multiple LEDs arranged in series to increase brightness, then the illumination intensity is improved, but the complexity of the electronic control circuit increases making fault detection and management difficult
Solution Approach 1:
The patent segments the complex array of multiple LEDs into smaller, manageable lighting branches with standardized configurations. Each branch can be independently controlled and monitored, reducing the overall circuit complexity while maintaining high illumination intensity through the combined effect of multiple branches.
Solution Approach 2:
The patent designs universal control circuits that can manage multiple lighting branches with different numbers of LEDs using the same control logic and components. This multi-functional approach simplifies the overall control system by eliminating the need for separate complex control circuits for each branch, making fault detection and management easier.
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 solution enables the lighting device to automatically switch to a safe pre-lighting state upon LED failures, reduces unwanted light pulses, and maintains a nominal supply current, achieving a lighting effect similar to a traditional single-source light, while ensuring electrical safety and fault diagnosis capabilities.
Implementation Method 1
an array of light emitting sources, corresponding to LEDs (standing for Light Emitting Diodes)
Data Source
AI summary
Light for motor vehicles and the like provided with a lighting device comprising a pair of power supply lines flowed through by a primary supplying current, two or more lighting branches each comprising one or more light sources adapted for being flowed through by a secondary supplying current; and an electronic control circuit configured to determine the secondary current flowing through each lighting branch; limit the primary supplying current to a predetermined minimum value when the secondary current flowing through at least one of said lighting branches is lesser than a predetermined threshold current; control the simultaneous transition of the light sources from a pre-lighting state to a complete-lighting state, when each of the secondary currents flowing through the lighting branches is greater than or equal to the predetermined current threshold.