LED Lamp Noise Suppression via Reference Potential Wire
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Solution Overview
Problem
LED drive circuits generate noise that propagates through metal components in LED lamps, leading to radio interference, necessitating noise suppression measures to comply with standards like CISPR 15.
Innovation Solution
Incorporating a module board with a light-emitting element, a circuit board with a drive circuit, an output wire, a metal component such as a heat sink, and a reference potential wire that connects the metal component to the drive circuit's reference potential, along with a capacitor in series with the reference potential wire, to effectively suppress noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a drive circuit is used to light up LEDs, then the LEDs can be illuminated efficiently, but noise is generated that propagates through metal components and wiring
Solution Approach 1:
A reference potential wire is introduced as an intermediary element to connect metal components (heat sink, pedestal) to the reference potential of the drive circuit. This mediator provides a controlled electrical path that prevents noise propagation through the metal components while maintaining their primary functions of heat dissipation and structural support.
Solution Approach 2:
The patent applies equipotentiality by connecting all metal components to the same reference potential through the reference potential wire. This creates an equipotential zone that prevents potential differences from driving noise currents through the metal components, thereby suppressing electromagnetic radiation while preserving the drive circuit's energy efficiency.
2Temperature
If metal components are used in the LED lamp, then heat dissipation and structural support are improved, but noise propagates through these metal components
Solution Approach 1:
The reference potential wire acts as an intermediary that electrically connects metal components to the drive circuit's reference potential. This connection provides a controlled path that prevents noise from using the metal components as antennas, while the metal components continue to perform their heat dissipation and structural functions effectively.
Solution Approach 2:
The patent applies local quality by providing selective electrical connection only where needed - the reference potential wire is connected to metal components at specific locations (pedestal and heat sink) to suppress noise propagation, while leaving other areas of the metal components free to perform their primary thermal and mechanical functions.
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 significantly reduces noise radiation from LED lamps, ensuring compliance with noise regulations and minimizing interference with other devices.
Implementation Method 1
a reference potential wire electrically connecting the metal component to a reference potential of the drive circuit
Implementation Method 2
a heat sink that is thermally connected to the module board via the pedestal, the heat sink being for dissipating heat generated by the light-emitting element
Data Source
AI summary
A light bulb-shaped lamp according to the present invention includes: a board on which an LED is mounted; a circuit board on which a drive circuit that turns on the LED is mounted; output wires for supplying power for turning on the LED from the drive circuit to the LED; a pedestal; and a potential-stabilizing wire electrically connecting the pedestal to a circuit ground of the drive circuit.