LED Lamp Driver for Fluorescent Ballast Compatibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
LED lamps struggle to achieve balanced operation when replacing fluorescent tubes in dual magnetic ballasts, leading to uneven lighting due to uncontrolled current flow and voltage buildup.
Innovation Solution
A driver system with a switch mode converter, including a transistor, inductor, rectifier, and pulse mode controller, is used to progressively increase voltage in LED strings, mimicking the electric load behavior of fluorescent tubes, ensuring balanced operation by intermittently activating the transistor until the LED string reaches its threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a typical switch mode converter driver is used to drive LED strings, then the LED lamps can be powered efficiently, but unbalanced operation occurs in dual magnetic ballasts resulting in alternating or uneven lighting
Solution Approach 1:
The driver changes its operating parameters by intermittently activating the transistor during startup to progressively ramp up voltage, mimicking the warm-up behavior of fluorescent tubes. This dynamic parameter adjustment allows balanced operation in dual magnetic ballast systems while maintaining efficient LED operation.
Solution Approach 2:
The transistor is activated intermittently in a periodic manner during the startup phase, creating a pulsing voltage buildup that simulates the progressive discharge characteristic of fluorescent tubes. This periodic activation pattern enables the magnetic ballast to balance power distribution between two LED lamps.
2Speed
If electronic ballasts are used to replace magnetic ballasts, then voltage buildup is faster and illumination is more instantaneous, but compatibility with existing LED lamp designs is reduced
Solution Approach 1:
The driver dynamically adjusts its startup behavior by controlling transistor activation timing and duration. This dynamic control allows the system to adapt to the slower voltage buildup characteristic of magnetic ballasts while still providing efficient LED operation, thereby maintaining compatibility with existing LED lamp designs.
Solution Approach 2:
The driver copies the electric load behavior characteristics of fluorescent tubes by intermittently activating the transistor to create progressive voltage buildup. This copying of fluorescent tube startup behavior enables LED lamps to work seamlessly with existing magnetic ballast infrastructure.
3Power
If the transistor in a switch mode converter is continuously activated, then voltage reaches threshold quickly, but power is drained from the magnetic ballast before balanced operation can be established
Solution Approach 1:
The driver performs preliminary intermittent activation of the transistor to gradually build up voltage before continuous operation begins. This preliminary phased activation prevents excessive power drainage from the magnetic ballast while ensuring both LED lamps receive sufficient voltage for balanced operation.
Solution Approach 2:
The intermittent transistor activation acts as a cushioning mechanism during startup, preventing sudden power demands that would drain the magnetic ballast. This gradual voltage buildup protects the ballast while ensuring balanced power distribution to both LED lamps.
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
This solution allows for balanced and continuous illumination of both LED lamps, effectively replacing fluorescent tubes in dual magnetic ballast systems by mimicking the electric load behavior of fluorescent tubes, preventing power drainage and ensuring consistent lighting.
Implementation Method 1
a driver which allows the LED lamps to mimic (somewhat) the electric load behaviour of fluorescent tubes. More specifically, by intermittently activating the transistor of a typical switch mode converter, the activation voltage ramped up progressively
Implementation Method 2
at least one LED string extending along at least a portion of the body; and a driver inside the body connecting the connectors to the LED string
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The Light Emitting Diode (LED) lamp is adapted for mounting in a fluorescent tube mount having a selectively activatable magnetic ballast powering two pairs of sockets with AC power upon activation. The LED lamp has a body having connectors at both opposite ends adapted to the corresponding pair of sockets, at least one LED string extending along at least a portion of the body, a driver inside the body connecting the connectors to the LED string, the driver including a transistor, an inductor, and a rectifier in a switch mode converter configuration, for converting the AC power of the sockets into a DC power of a voltage adapted to power the LED string; and a pulse mode controller for controlling the transistor in an intermittent manner upon activation of the multiple fluorescent tube mount, until conduction across the at least one LED string is achieved.