Power over Ethernet (PoE) power supply is a power supply scheme that utilizes network cables to transmit power, consisting of power supply equipment (PSE), power receiving equipment (PD), and network cables. With the popularization of IP device applications, PoE power supply has gained widespread popularity due to its low installation cost, easy expansion, easy management, and global compatibility. The application scenarios of Ethernet POE are presented in the form of images below.
Ethernet POE switches connect indoor and outdoor equipment, so lightning surge needs to be considered when designing their use, and therefore surge and lightning safety protection need to be involved. At the same time, the POE switch is also responsible for data transmission, so the speed and authenticity of electrostatic protection and data transmission need to be considered. Therefore, the selection of ESD electrostatic protection tubes is extremely strict. Below is an explanation of the application solution of SOCAY brand in POE switches.
Background of POE switch protection scheme:
1. Climate warming, increasing thunderstorms
2. The coexistence of POE power supply and signal increases the difficulty of protection
Explanation of POE switch protection scheme and precautions:
1. This solution uses GDT for common mode (eight wire) surge protection at the front end of the transformer
2. The rear stage of the network transformer uses a small volume, low junction capacitance ESD to absorb differential mode energy, with fast ESD reaction time and protection against static electricity
3. This POE port scheme complies with the 802.11 electrical standard
4. This POE port scheme meets surge testing standards such as IEC61000-4-5 and GB/T17626.5
5. This POE port scheme meets static testing standards such as IEC61000-4-2 and GB/T17626.2
6. Can pass 10/700us-5/320uS and 1.2/50uS-8/20uS surge tests
Application of POE switch protection scheme:
1. POE power supply unit
2. POE separator
3. POE connector
4.AP
POE protection circuit diagram and recommended product models:
The recommended parameters for use during the protection period in the protection circuit scheme of POE switches are:
category | model | direct nominal voltage(V) | Impulse current(8/20uS) | Cp | resistance |
GDT | SC3E5-90LSMD | 90±20% | 5KA | <1.5pF | >1G |
2.Transient suppressor (ESD static tube)
category | model | Vrwm | Vb | Antistatic ability | Junction capacitance(F=1MHz) | package |
ESD | SC05NRE14GA | 5.0V | 6.0V | ±17KV/±25KV | 0.3pF | DFN2510-10L |
3. Transient suppressor (TVS tube)
category | model | Vbc(V) | Ir | Vrwm | p | Vc(V) | package |
TVS | SMCJ58CA | 64.4-71.2 | 5uA | 58.0V | 16.1A | 93.6 | SMC/DO-214AB |
The above is the protection scheme of SOCAY brand in POE switch provided by Hnstshop Chengcheng. For more design schemes and product recommendations, please follow the WeChat official account "hnstshop"