Lighting Protection
1. Types of Core Protection Devices
1)ESD Protection Components
Used to prevent electrostatic discharge from damaging LED and other lighting devices, such as TVS diodes, semiconductor discharge tubes, etc.
Features: fast response speed (ns level), can accurately clamp voltage, suitable for the protection of high-speed signal lines.
2) Surge Protection Device
Gas Discharge Tube (GDT): large flow rate (peak value up to 20kA), low capacitance characteristics (as low as 1.5pF), suitable as a primary protection component.
Varistor (MOV): limits overvoltage through nonlinear characteristics, often used for surge absorption of AC power input ports.
Self-resettable Fuse: has both overcurrent and temperature protection functions, can automatically recover after fault elimination, suitable for LED drive circuits.
3) Transient Voltage Suppressor (TVS)
Protects the back-end circuit by quickly clamping transient high voltage, and is widely used in the lightning protection design of vehicle-mounted lighting and communication equipment.
2. Technical Principles and Application Scenarios
1) Protection Mechanism
Switching Devices (such as GDT): form a short-circuit path when a surge occurs to transfer energy.
Clamping Devices (such as TVS): absorb energy through avalanche effect and limit voltage peak.
2) Typical Applications
LED Lighting System: ESD protection (to protect chip structure) and surge protection (to deal with power supply fluctuations) need to be integrated at the same time, such as Nichia’s blue light LED solution to reduce the voltage sensitivity of white light LEDs through complementary mixing technology.
On-board Equipment: The instantaneous peak voltage generated at startup needs to be protected by a combination of TVS and MOV.
Communication Base Station: adopt a multi-level protection architecture (GDT+TVS) to ensure the reliability of equipment under lightning surge.
3. Selection Points for Lighting Protection
Match the device according to the operating voltage, current capacity, and response speed. For example, multi-level protection of GDT+TVS is preferred for high-power lighting scenarios.
Considering the impact of environmental factors (such as humidity and temperature) on device life, vehicle-mounted equipment needs to meet wide temperature range requirements.
4. Development Trends of Lighting Protection
With the popularization of smart lighting and IoT devices, protection devices are moving towards miniaturization and integration. For example, ESD and surge protection functions are integrated into a single package module to simplify circuit design and improve reliability.