The cause of lightning surge of switching power supply and several anti-surge components
1) Lightning strikes (mainly indirect lightning):
For example, lightning strikes an outdoor line, and a large amount of current flows into an external line or a grounding resistor, thereby generating an interference voltage;
Another example is the voltage or current induced on the line by an indirect lightning strike (such as a lightning strike between clouds or clouds);
For another example, lightning strikes a nearby object and establishes an electromagnetic field around it. When the outdoor circuit passes through the electromagnetic field, voltage and current are induced on the line;
For example, lightning strikes the surrounding ground, and the interference introduced when the ground current passes through the public grounding system.
(2) Switching transients:
For example, interference generated when the main power system is switched (for example, switching of a compensation capacitor group);
In another example, in the same power grid, there are some large types of switches around the device that are disturbed when they are beating;
For another example, switching a thyristor device having a resonant line;
For example, various systemic faults, such as short circuit or arcing faults generated between equipment grounding networks or grounded systems.
The switching power supply cannot be damaged after a lightning surge occurs. Two common types, "lightning strike" and "ringing" waves.
2, lightning surge basic protection device introduction
GDT Ceramic Gas Discharge Tube Gas Discharge Tubes
The ceramic gas discharge tube is a voltage-conducting switching device that is used in parallel between the line and the line or line of the protected device and the ground. Ceramic gas discharge tube is the most widely used switching device in lightning protection equipment. The surge current is large, the interelectrode capacitance is as low as 1p, the insulation resistance is up to 10G, and the breakdown voltage is more dispersed.
TVS transient suppression diode
The TVS diode is a voltage-limiting overvoltage protection device that limits the excessive voltage to a safe range at pS speeds, thus protecting the back circuit.
The varistor is a semiconductor voltage limiting surge device sintered by using zinc oxide as a material. It is widely used in electronic circuits for protection due to its excellent nonlinear characteristics and superior surge absorption capability.
A self-recovering fuse is an overcurrent electronic protection component. The polymer organic polymer is processed by a special process under the conditions of high pressure, high temperature and reaction, after adding conductive particle material.
ESD/TVS electrostatic protection array
The electrostatic protection array has a fast response speed, less than 0.5 nS, low on-voltage, small volume, high integration, and multiple data line protections at the same time, and the capacitance value is low. Up to 0.3pF, it is an ideal high frequency protection device.
The glass discharge tube is an overvoltage protection device that suppresses abnormal high voltage pulses and protects the low voltage circuit from instantaneous high voltage damage. It is a guiding protection component that utilizes the principle of micro-gap discharge and is developed by the activation of semiconductor chips. It has the advantages of fast response, impact resistance, stable performance, good repeatability and long life.