LED Lamp Circuit Emulating Fluorescent Ballast Operation
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Solution Overview
Problem
Existing LED replacement lamps require modification of fluorescent lamp fixtures, including rewiring and removal of the ballast, which is hazardous and inhibits wide market acceptance due to the need for qualified electrician intervention, as they do not emulate the behavior of fluorescent bulbs adequately for standard hot cathode fluorescent lamp ballasts.
Innovation Solution
A LED lamp circuit with two independent power rails and diode or MOSFET bridge rectifier configurations that mimic the operation of fluorescent lamps, allowing direct replacement without modifying the fixture wiring, by emulating the preheat and running states of fluorescent lamps and supporting all ballast configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If LED replacement lamps are installed in existing fluorescent fixtures without modifying the fixture wiring, then ease of installation is improved, but compatibility with standard hot cathode fluorescent lamp ballasts deteriorates
Solution Approach 1:
The LED lamp circuit emulates the electrical behavior of fluorescent lamps by copying their operational characteristics. The circuit includes a ballast emulator that replicates the preheat and running states of fluorescent lamps, allowing standard ballasts to drive LED lamps without modification. This copying approach enables the LED lamp to be recognized by the ballast as a compatible load.
Solution Approach 2:
The invention changes the electrical parameters of the LED lamp circuit to match fluorescent lamp characteristics. By controlling the timing and magnitude of current flow through the ballast emulator, the circuit mimics the preheat phase and striking phase of fluorescent operation, thereby maintaining compatibility with existing ballast designs while using LED technology.
2Reliability
If the ballast is removed and fixture wiring is rewired to support LED lamps, then LED lamp compatibility and performance are improved, but installation safety and complexity worsen
Solution Approach 1:
The ballast emulator acts as an intermediary component between the LED lamp and the existing ballast. It interfaces with the ballast's electrical characteristics while providing the appropriate current control for LED operation. This intermediary approach eliminates the need for ballast removal and rewiring while ensuring reliable LED lamp performance.
3Adaptability or versatility
If LED lamps are designed to work with all ballast configurations without modification, then market penetration is improved, but device complexity worsens
Solution Approach 1:
The LED lamp circuit is designed with universal functionality to work with multiple ballast configurations. The ballast emulator can operate in different modes depending on the input ballast type, providing adaptability across various fluorescent fixture designs. This multi-functionality enables the same LED lamp to be installed in different fixtures without requiring configuration changes.
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 safe and cost-effective replacement of fluorescent lamps with LEDs in existing fixtures without rewiring, ensuring compatibility with all ballast types and reducing the need for qualified electrician intervention, thereby increasing market penetration.
Implementation Method 1
a first plurality of diodes arranged in a bridge rectifier configuration
Implementation Method 2
a first LED light string and first power supply located in the LED lamp structure
Implementation Method 3
light emitting diode (LED) apparatus
Data Source
Figure 1~2
Figure 3(a)~3(b)
Figure 4(a)~4(b)
AI summary
A light emitting diode (LED) lamp circuit is adapted to replace a fluorescent lamp in a fluorescent light fixture without having to modify the fluorescent light fixture in any way. The LED light string and its associated drive circuitry may be divided into two symmetric light strings. Furthermore, the two strings (power rails more precisely) may be tied together with a diode voltage/current steering system. The fluorescent replacement LED lamp design 'spoofs' all fluorescent lamp drive modes that a ballast could be configured for.