LED Lighting Unit Parallel Current Limiting for Deep Dimming
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Solution Overview
Problem
Existing lighting devices struggle to achieve deep dimming due to voltage drops caused by phase control dimmers, making it difficult to maintain sufficient voltage for LED light-emitting elements, and switch mode power supply drivers are complex and costly.
Innovation Solution
A lighting unit with a current limiting circuit connected in parallel to some light-emitting units, using a current limiting element to ensure remaining units emit light even when the voltage is below the overall turn-on voltage, allowing for deep dimming with a simple structure and low cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a phase control dimmer is used to dim the light-emitting assembly, then the brightness can be adjusted, but the voltage output becomes too low during deep dimming, causing the voltage to be lower than the turn-on voltage of the LED light-emitting elements
Solution Approach 1:
The light-emitting assembly is divided into multiple light-emitting units connected in series. By segmenting the total voltage requirement into smaller units, the system can operate with lower overall voltage while maintaining individual unit operation, enabling deep dimming capability.
Solution Approach 2:
The patent changes the electrical parameters by using multiple light-emitting units with specific turn-on voltage characteristics. The system exploits the relationship between voltage, current, and brightness by adjusting the number of active light-emitting units rather than relying solely on voltage reduction, enabling operation at voltages below the traditional turn-on threshold.
2Illumination intensity
If a switch mode power supply driver is used to enable deep dimming, then deep dimming can be achieved, but the design becomes complex and the cost increases
Solution Approach 1:
The light-emitting units themselves provide the dimming function through their inherent electrical characteristics. When voltage drops below the turn-on threshold, fewer units conduct current, automatically reducing brightness without requiring external control circuitry. This self-regulating behavior eliminates the need for complex switch mode power supply designs.
Solution Approach 2:
The patent uses simple, inexpensive light-emitting units with straightforward electrical characteristics rather than expensive, complex driver circuits. The solution replaces costly switch mode power supply components with basic LED units that naturally exhibit the desired dimming behavior through their voltage-current characteristics.
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 deep dimming while maintaining a stable output voltage, achieving a simple and cost-effective lighting device capable of operating at reduced brightness levels without complex design or high costs.
Implementation Method 1
a current limiting circuit comprising a current limiting element, wherein the current limiting element is connected in parallel to some of the plurality of light-emitting units
Data Source
AI summary
Provided is a lighting unit, a lighting device and a lighting system. The lighting unit connects to a drive element and a dimmer and includes a light-emitting assembly having a plurality of light-emitting units connected in series, and a current limiting circuit that includes a current limiting element and is connected in parallel to some of the plurality of light-emitting units, so as to achieve the technical effects of the lighting unit, the lighting device and the lighting system capable of deep dimming and having a simple structure and low cost.