Solid discharge tube is an overvoltage protection device that uses solid materials as the discharge medium, opposite to gas discharge tube (which uses gas as the medium). When overvoltage occurs, it discharges current through the breakdown or conduction of solid materials, thereby protecting subsequent circuits from damage. Solid discharge tubes can be classified according to different standards, and the following are their main categories and characteristics:
1、 Classified by material type
Thyristor Surge Suppressors
Materials: Mainly using semiconductor materials such as silicon (Si).
Features: It has characteristics such as fast response, high precision, and low capacitance. Semiconductor discharge tubes can respond to overvoltage in nanoseconds, effectively protecting high-speed signal interfaces.
Application: Widely used in communication equipment, computers, consumer electronics and other fields to protect sensitive circuits from electrostatic discharge (ESD) and surge damage.
Other solid material discharge tubes
Materials: may include other solid materials such as ceramics, polymers, etc.
Characteristics: These materials have different electrical and physical properties, such as high breakdown field strength, good thermal stability, etc., and are suitable for different application scenarios.
Application: Depending on the specific material characteristics, it can be used in scenarios such as power lightning protection and signal lightning protection.
2、 Classified by structural type
Diode type solid discharge tube
Structure: It has two electrodes, similar to the structure of a diode.
Features: Suitable for unidirectional or bidirectional protection, depending on the design of the device.
Application: Can be used for overvoltage protection in scenarios such as power lines and signal lines.
Solid discharge tube of transistor type
Structure: With three electrodes, it may provide more complex protective features.
Characteristic: By controlling the third electrode (such as the trigger electrode), lower breakdown voltage or faster response time can be achieved.
Application: Suitable for scenarios with higher requirements for protection characteristics, such as high-frequency signal protection, precision instrument protection, etc.
3、 Classified by purpose type
Solid discharge tube for power lightning protection
Function: Mainly used to protect power lines from damage caused by lightning strikes or surges.
Features: It has high current capability, fast response, and low residual voltage.
Application: Widely used for the protection of power lines in switch mode power supplies, LED drivers, industrial equipment, and other power sources.
Solid discharge tube for signal lightning protection
Function: Used to protect high-speed signal interfaces (such as USB, HDMI, RS-485, CAN bus, etc.) from ESD or surge interference.
Features: It has low capacitance, low insertion loss, and high-frequency characteristics to ensure the integrity of signal transmission.
Application: Suitable for high-speed signal interface protection in communication equipment, computers, industrial control and other fields.
Special Application Solid Discharge Tube
Function: Solid discharge tubes designed for special application scenarios, such as automotive electronics, aerospace, and other fields.
Features: May have higher reliability, wider operating temperature range, or stronger radiation resistance.
Application: Used in scenarios with higher requirements for reliability and environmental adaptability, such as automotive electronic control systems and aerospace electronic equipment.
4、 Comparison between Solid Discharge Tubes and Other Overvoltage Protection Devices
Compared with TVS diodes: Solid state discharge tubes (especially semiconductor discharge tubes) have similarities with TVS diodes in response time, capacitance, and power processing capabilities, but solid state discharge tubes may have higher current carrying capacity and lower residual voltage.
Compared with varistors: Solid state discharge tubes and varistors have different overvoltage protection principles. Solid state discharge tubes discharge current through the breakdown of solid materials, while varistors limit voltage through nonlinear resistance characteristics. Solid discharge tubes typically have faster response times and lower capacitance.
5、 Selection suggestions
When choosing a solid discharge tube, the following factors need to be considered:
Protection voltage: Select the appropriate breakdown voltage based on the operating voltage of the protected circuit.
Current carrying capacity: Select the appropriate current carrying capacity according to the application scenario to ensure that the device can withstand the expected overvoltage current.
Response time: For scenarios such as high-speed signal interfaces, it is necessary to choose solid discharge tubes with fast response times.
Capacitance and insertion loss: For high-frequency signal interfaces and other scenarios, it is necessary to choose solid discharge tubes with low capacitance and low insertion loss.
Reliability and environmental adaptability: Select solid discharge tubes with sufficient reliability and environmental adaptability according to the application scenario.