LED Reading Light Current Regulation via Coding Resistor
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Solution Overview
Problem
Modern LED production techniques result in LEDs with decreasing forward voltages, making it difficult for existing supply units in civil aviation to maintain consistent light intensity, and requiring significant technical effort to adapt these units, while also necessitating the ability to replace defective LED bulbs without new power packs.
Innovation Solution
Incorporating a separate current controller within the LED reading light that uses a coding resistor to signal the maximum supply current, allowing for regulation of the operating current to achieve desired light intensity, with the current magnitude stored in an electrical component or microprocessor, enabling operation with existing supply units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If modern LED production techniques are used to reduce power loss and decrease forward voltage, then energy efficiency is improved, but compatibility with existing supply units and coding resistor systems deteriorates
Solution Approach 1:
A current regulator is introduced as an intermediary component between the supply unit and the LED light source. The supply unit continues to provide maximum current based on the coding resistor value, while the current regulator adjusts this current to the appropriate level for modern low forward voltage LEDs, thereby maintaining compatibility with existing supply units while enabling use of energy-efficient modern LEDs
Solution Approach 2:
The system is segmented into three functional parts: the supply unit (unchanged, provides maximum current), the current regulator (new component, adjusts current level), and the LED light source (modern LEDs with low forward voltage). This segmentation allows each component to be optimized independently while maintaining overall system compatibility
2Adaptability or versatility
If supply units are adapted to work with modern LED light sources, then compatibility is improved, but technical effort and complexity increase
Solution Approach 1:
The current regulation function is extracted from the supply unit and placed in a separate current regulator component within the reading light assembly. This allows the supply unit to remain unchanged and continue providing maximum current, while the extracted current regulation function handles the adaptation to modern LEDs, thereby avoiding the need to modify complex supply units
3Measurement precision
If the test current is increased to accurately measure voltage drop across the coding resistor, then measurement precision is improved, but the risk of exceeding forward voltage and causing unintended light emission increases
Solution Approach 1:
The system intentionally uses excessive current (maximum supply current) during the measurement phase, but this is safely managed because the current is briefly applied and the voltage drop is quickly measured. The current regulator then immediately limits the current to the appropriate operating level, allowing accurate measurement while preventing harmful effects through rapid control
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
Enables the LED reading light to maintain consistent light intensity across various modern LED types, allowing for seamless integration with existing supply units and the ability to adjust brightness without requiring new power packs, ensuring compatibility and reliability.
Implementation Method 1
an LED light source (12) which, depending on the supply current, emits light with a corresponding light intensity
Implementation Method 2
a coding resistor (14), the value of which indicates to which class of LED light sources the LED light source (12) belongs
Data Source
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AI summary
The lamp (10) has a coding element (14) i.e. coding resistor, with an electric parameter, which defines a variable of supply current for a LED light unit, where the supply current is provided by a supply unit (16). A current regulator (18) provides operating current for operating the LED light unit (12). The coding element comprises the electric parameter for providing a maximum supply current provided by the supply current. The current regulator regulates the operating current to a value with which the light unit emits light with desired light intensity. An independent claim is also included for a method for operating an LED reading light.