Retrofit LED Tube Step Dimming via Short Circuit Switch
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Solution Overview
Problem
Legacy ballasts in multi-lamp luminaire lighting systems are unable to dim LED tube lamps below a certain light level due to unstable power factor correction when not in use, and difficulty in entering standby mode due to open and short circuit protective circuitry, limiting step-dimming capabilities in professional applications.
Innovation Solution
A retrofit LED tube with a controllable switch circuit and control unit that allows for wireless dimming commands to short circuit the LED array, enabling step-dimming by connecting LED and fluorescent tubes in series, allowing for multiple lighting levels including full on, full off, and intermediate levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If legacy ballasts are used in multi-lamp luminaire systems, then the system can operate with traditional fluorescent lamps, but the system cannot achieve step-dimming below a certain light level due to unstable power factor correction
Solution Approach 1:
The patent changes the electrical parameters of the LED tube by incorporating a controllable switch circuit that can alter the impedance characteristics. This allows the LED tube to present different electrical states (full on, dimmed, off) to the ballast, enabling stable operation across multiple light levels without compromising power factor correction stability.
Solution Approach 2:
The invention introduces dynamic control capability to the LED tube through a controllable switch circuit that can rapidly transition between different states. This dynamic response enables the system to achieve step-dimming while maintaining stable power factor correction, as the switch circuit adapts the electrical characteristics in real-time based on dimming commands.
2Adaptability or versatility
If legacy ballasts with open and short circuit protective circuitry are used, then the system is protected against circuit failures, but the system cannot enter standby mode or achieve extended dimming levels
Solution Approach 1:
The controllable switch circuit acts as an intermediary between the ballast's protective circuitry and the LED array. It provides a controlled impedance path that satisfies the ballast's protection requirements while enabling dimming functionality. The switch circuit mediates between the conflicting requirements of protection and adaptability by presenting appropriate electrical characteristics to the ballast.
Solution Approach 2:
The LED tube with controllable switch circuit serves multiple functions: it provides light emission, enables step-dimming, maintains power factor correction stability, and interfaces with the ballast's protective circuitry. This multi-functionality resolves the contradiction by making the same device adaptable to different operating modes without requiring separate protective circuits.
3Adaptability or versatility
If LED tubes are connected in series with fluorescent tubes in multi-lamp systems, then the system can achieve step-dimming through selective short-circuiting, but the circuit configuration becomes more complex
Solution Approach 1:
The invention segments the LED tube into functionally distinct components: the LED array for light emission and the controllable switch circuit for impedance control. This segmentation allows each component to perform its specific function independently, simplifying the overall circuit configuration while enabling step-dimming capability in series-connected multi-lamp systems.
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 stable step-dimming in multi-lamp luminaire systems by short-circuiting the LED array based on dimming commands, maintaining current flow and preventing light emission, thus supporting efficient power management and extended dimming levels.
Implementation Method 1
a power rectifier having an input and an output, wherein the rectifier is arranged to receive an AC supply voltage at its input, in use, to convert said AC supply voltage to a DC voltage
Implementation Method 2
a controllable switch circuit arranged to short circuit said LED array such that the LED array does not emit light
Data Source
AI summary
A retrofit Light Emitting Diode, LED, tube to be used in a multi lamp luminaire system is presented, which LED tube comprises a controllable switch circuit arranged to short circuit the LED array of the LED tube such that the LED array does not emit light and such that the current path in the multi lamp luminaire system is not interrupted.