【Networking Power Supply】Design with High Surge Test Reliability

Surge test, officially called Surge Immunity Test, corresponds to the international standard of IEC 61000-4-5. In the low voltage power distribution system for household and commercial use, surges can be divided into two types: external and internal. External surges mainly come from thunder and lightning and can be transmitted through the power cord as well as generated from the induction power cord. Another source of external surge is the overvoltage generated on the power cord through the operations of a public electricity grid switch.

On the other hand, internal surges refer to the ones generated from the utilization equipment below the home switchboard. 88% of the surges on low voltage power cord come from the equipment inside the building, such as the air conditioner, air compressor, arc welder, electric pump, elevator and switch power supply as well as the surge of certain inductive loads.

With the development of the urban economy, the danger of lightning invasion wave increases significantly. The development and application of global 5G network contribute to more and more sophisticated computer network and communication equipment with more operating environment requirements. The transient overvoltage of lightning and large electrical equipment passes the lines of power supply, antenna and transceiver of radio signals more and more frequently and invades the indoor electrical and network equipment.

This can result in the damage to equipment or component, interference or loss of transmitted or stored data, malfunction or temporary paralysis of electronic equipment, system downtime, interruption of data transmission or damage to LAN or even WAN and leads to great economic losses. The trend of market development also forces the development of the power supply to face severe challenges.

The power supply has to release the lightning-induced high pulse energy on the circuit within the shortest time to protect the back-end system from the impact of lightning energy. How to enhance the protection against lightning surge has become an important technology task and critical challenge when developing the networking power supply.


How does the APD meet the high surge test reliability (6KV) required by the power supply, with limited cost and footprint?

The design of APD product starts from the bleed-off path of lightning energy. By analyzing the circuit on PCB, APD reduces the interference to the circuit through reasonable component configuration and optimum layout. Key components including the fuse, bridge rectifier, thermistor, varistor, luminous discharge tube, high voltage electrolytic capacitor, Y capacitor and inductor are evaluated, with the emphasis on the voltage and current stresses, through theoretical calculation to achieve an optimized component selection.

APD possesses a wide range of professional EMC test equipment and is able to accelerate the development and achieve quick commissioning by monitoring the waveform of each pin of key components at the initial stage. The convenient test conditions with no time restrictions can verify the consistency of the power supply’s immunity against lightning surge to further ensure a more stable capability. Compared with the power supply products with equivalent surge immunity specs in the market, APD products offer a higher price-performance ratio and more stable protection against the lightning surge.

Cultivated in the power supply field of networking for many years, APD has accumulated abundant experiences of developing products with lightning surge protection and created corresponding internal design standards. Our professional team featuring quick analysis and commissioning capability of lightning surge tasks can provide solutions with a high price-performance ratio and stability as well as develop a power supply with high surge protection (6KV) through seamless cooperation with customers.