Mobile base stations are mostly built in high places, such as mountains, suburbs, and buildings.The base station antenna is often higher than the existing lightning protection air terminal of the building, which becomes the high incidence point of lightning strikes.Therefore, the lightning protection of mobile base stations should not only consider the protection of direct lightning strikes, but also consider the protection of lightning induction.In particular, the induction caused by the intrusion of lightning waves into the equipment through the power line.

The following is the DC-48V base station power protection Solution designed by Socay.

Application Background

1. Global warming, more thunderstorms

2. The power cable of the DC48 base station is pulled from the equipment room to the RRU of the radio frequency unit. The cable is long and easily disturbed by lightning.

3. High surge protection of 20KA differential mode and 20KA common mode is required

4. High cost of traditional solutions

Socay Solution and Components

Gas Discharge Tubes(GDTs)

GDT1【SC2E8-600H5SMD】DC Spark-over Voltage：600V±20%，Nominal Impulse Discharge Current（8/20μS）：20kA，Maximum Capacitance＜1.0pF，Minimum Insulation Resistance >1GΩ; 

GDT2【SC2E8-90HSMD】DC Spark-over Voltage：90V±20%，Nominal Impulse Discharge Current（8/20μS）：20kA，Maximum Capacitance＜1.0pF，Minimum Insulation Resistance >1GΩ; 

Varistor(MOV)

MOV【14D820K】Varistor Voltage（at1mA）：74V-90V，Withstanding Surge Current（8/20μS）：4500A，Maximum Clamping Voltage（at5A）：135V

Application

Base station 48V power supply

The Solution Note

1.The back end of solution used MOV with fast response time and low residual voltage

2.The front end used smd GDT with  high current-handling capability 

3.Used inductors L1 and L2 for decoupling, and drive GDT to leak the amplified current in the middle

4.The solution meets surge test standards such as IEC61000-4-5, GBT17626.5