ESD Protection Circuit for Solid State Lighting
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Solution Overview
Problem
Solid state lighting systems are more susceptible to electrostatic discharge (ESD) in outdoor conditions compared to traditional lighting technologies, particularly when installed near high voltage power lines, due to insufficient discharge paths for electrostatic charges, which can lead to damage from capacitively coupled currents.
Innovation Solution
The lighting system incorporates a power supply with a transformer, overcurrent protection devices, and a feedback circuit to manage and discharge electrostatic charges, including a resistor network and a transient voltage suppressor to provide a safe path for induced currents, ensuring the light emitting diodes and heat sink are connected to a common ground, thus protecting against ESD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If solid state lighting systems are used in outdoor conditions near high voltage power lines, then modern lighting efficiency and longevity are achieved, but susceptibility to electrostatic discharge damage increases due to insufficient discharge paths
Solution Approach 1:
The patent introduces an intermediary discharge path consisting of a resistor (631KΩ to 3MΩ) and capacitor network that mediates between the capacitive coupling from power lines and the sensitive LED circuits. This intermediary path provides a controlled discharge route for electrostatic charges, preventing direct damage to the lighting system while maintaining modern solid state lighting benefits.
2Reliability
If traditional lighting technology is used near high voltage power lines, then resistance to electrostatic discharge is maintained, but energy efficiency and modern lighting performance are lost
Solution Approach 1:
The patent segments the lighting system into protected and unprotected zones by introducing ESD protection circuitry only where needed - specifically protecting the LED driver electronics and control circuits while leaving the LED light-emitting components and heat sink structures unprotected. This selective segmentation maintains energy efficiency while providing targeted ESD protection to sensitive components.
3Reliability
If high impedance discharge paths are used to protect LED circuits, then ESD damage is prevented, but leakage current to ground increases
Solution Approach 1:
The patent optimizes the resistor value parameters within a specific range (631KΩ to 3MΩ) to achieve the desired balance between ESD protection and leakage current minimization. By carefully selecting resistance values in this range, the system provides adequate discharge path impedance to prevent ESD damage while keeping leakage current within acceptable limits for outdoor lighting applications.
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 configuration effectively mitigates the risk of ESD damage by providing a robust discharge path for electrostatic charges, ensuring the longevity of the lighting system even in proximity to high voltage power lines.
Implementation Method 1
High voltage power lines generate large electric fields around the conductors, which can capacitively couple large electrostatic charges onto conductive surfaces located near the power lines
Implementation Method 2
The charges from the power lines can capacitively couple to the electronic circuits of the outdoor lighting sources
Implementation Method 3
a diode to handle current induced in the light emitting diode or the heat sink
Data Source
AI summary
An apparatus for protecting a solid state retrofit lighting or illumination system from electrostatic discharge damage caused by charge induced onto conductive surfaces of the lighting or illumination system.