A network device

Abstract

This application relates to the field of network-enabled devices, instruments, or electronic products, and particularly to a network device. In this network device, a metal casing is electrically connected to a first connector. The shortest energizing path connecting the first connector to the negative terminal of an external power connector or power cable is a first path. The shortest energizing path connecting the first connector to a sensitive device and / or a sensitive circuit is a second path. The length of the first path is less than the length of the second path. The network device provided in this application allows for the discharge of most of the electrostatic energy to the ground instead of being transferred to the sensitive device during operation, thus reducing the probability of the sensitive device crashing or experiencing packet loss.

Description

Technical Field

[0001] This application relates to the field of network-enabled devices, apparatuses, or electronic products, and particularly to a network device. Background Technology

[0002] Currently, in order to ensure that network devices have good heat dissipation performance, the casings of network devices are mostly made of metals with good thermal conductivity.

[0003] However, in related technologies, when the casing of network equipment is made of a metal with good thermal conductivity, and during the operation of the network equipment, if the metal casing of the network equipment generates static electricity, there is a possibility that the metal casing will transfer most of the static energy generated to sensitive devices, thereby increasing the probability of sensitive devices crashing or losing packets. Summary of the Invention

[0004] The purpose of this application is to provide a network device that, during the operation of the network device, when the metal casing generates static electricity, can prevent the metal casing from transferring most of the static energy it generates to sensitive devices, thereby reducing the probability of sensitive devices crashing, packet loss, or other problems.

[0005] To address the aforementioned issues, this application provides another network device, comprising: a metal housing, a first connector connected to the metal housing, a power cable or external power connector, a circuit board, a sensitive device, and a sensitive line; the sensitive line extends from the sensitive device; the shortest power-carrying path between the first connector and the negative terminal of the external power connector or the power cable is a first path, which is a path in which the first connector is connected to the negative terminal of the external power connector or the power cable via the circuit board; the shortest power-carrying path between the first connector and the sensitive device and / or the sensitive line is a second path, which is a path in which the first connector is connected to the sensitive device and / or the sensitive line via the circuit board; the length of the first path is less than the length of the second path.

[0006] The network device provided in this application embodiment has a metal casing electrically connected to a first connector. The shortest energizing path connecting the first connector to the negative terminal of an external power connector or a power cable is a first path, and the shortest energizing path connecting the first connector to a sensitive device and / or a sensitive circuit is a second path. The length of the first path is less than the length of the second path. Thus, during network device operation, when static electricity is generated in the metal casing, most of the static energy is discharged to ground instead of being transferred to the sensitive device and / or sensitive circuit, thereby reducing the probability of the sensitive device experiencing crashes, packet loss, or other problems. Attached Figure Description

[0007] Figure 1The electrostatic discharge current waveform diagram is in accordance with the relevant requirements of the international standard IEC61000-4-2.

[0008] Figure 2 This is a schematic diagram of the circuit structure of an electrostatic discharge device.

[0009] Figure 3 This is a stacked exploded view of the network devices provided in Embodiment 1 of this application;

[0010] Figure 4 This is a partial stack-up exploded view of the network devices provided in Embodiment 1 of this application;

[0011] Figure 5 This is a partial stack-out diagram of another network device provided in Embodiment 1 of this application;

[0012] Figure 6 This is a partially exploded top view of the network device provided in Embodiment 1 of this application;

[0013] Figure 7 An electrical model of some copper foil traces in the circuit board of the network device provided in Embodiment 1 of this application;

[0014] Figure 8 An electrical model of some copper foil traces in the circuit board of the network device provided in Embodiment 1 of this application;

[0015] Figure 9 An electrical model of a portion of the circuitry of the network device provided in Embodiment 1 of this application;

[0016] Figure 10 An electrical model of a portion of the circuitry of the power adapter provided in Embodiment 1 of this application;

[0017] Figure 11 An electrical model of a portion of the circuitry of another network device provided in Embodiment 1 of this application;

[0018] Figure 12 This is a partial stacked exploded view of another network device provided in Embodiment 1 of this application;

[0019] Figure 13 This is a stacking diagram of another network device provided in Embodiment 1 of this application;

[0020] Figure 14 This is an exploded view of the network devices provided in Embodiment 2 of this application;

[0021] Figure 15 An electrical model of a portion of the circuitry of the network device provided in Embodiment 2 of this application;

[0022] Figure 16This is a top view showing a partial structural decomposition of the network device provided in Embodiment 2 of this application. Detailed Implementation

[0023] As can be seen from the background technology, when the casing of a network device is made of a metal with good thermal conductivity, and if the metal casing of the network device generates static electricity during operation, there is a possibility that the metal casing will transfer most of the static energy generated to sensitive devices, thereby increasing the probability of sensitive devices crashing or losing packets.

[0024] To reduce the probability of network devices crashing or experiencing packet loss during operation, the inventors of this application have designed a network device after in-depth research. During operation, when static electricity is generated in the metal casing of the network device, most of the electrostatic energy is discharged to the ground instead of being transferred to the sensitive devices, thereby reducing the probability of these devices crashing or experiencing packet loss.

[0025] The aforementioned network devices are applicable to various medical devices, industrial equipment, and mining equipment, and are particularly suitable for mobile phones and in-vehicle devices (such as dashcams). This application example illustrates the application of the network device in an industrial router employing a Wi-Fi 6+ 5G mobile solution (i.e., a router using 6th generation wireless technology and supporting the frequency bands of 5th generation mobile communication technology).

[0026] With the development of science and technology, regulations concerning various products are becoming increasingly comprehensive. Network equipment must meet electrostatic discharge (ESD) testing requirements and regulations after manufacturing to prevent harm to users during use. Specifically, because industrial routers and other network equipment have metal casings, they are subject to ESD contact discharge testing according to the international standard IEC61000-4-2. Specifically, the metal casings of industrial routers require 8kV (kV: kilovolt) contact discharge testing.

[0027] For information on the electrostatic discharge (ESD) testing requirements and regulations that network equipment must meet after manufacturing, please refer to [link / reference needed]. Figure 1Please refer to Table 1 below, which shows the discharge current values ​​at different time periods for contact discharge tests at 2kV, 4kV, 6kV, and 8kV levels. It can be seen that under the 2kV level contact discharge test conditions: the discharge current reaches 7.5A (A: ampere) within a 0.6ns-1ns (ns: nanosecond) rise time; 4A at 30ns; and 2A at 60ns. Under the 4kV level contact discharge test conditions: the discharge current reaches 15A within a 0.6ns-1ns rise time; 8A at 30ns; and 4A at 60ns. Under the 6kV level contact discharge test conditions: the discharge current reaches 22.5A within a 0.6ns-1ns rise time; 12A at 30ns; and 6A at 60ns. Under 8kV contact discharge test conditions: the discharge current reaches 30A within a 0.6ns-1ns rise time; 16A within a 30ns discharge current; and 8A within a 60ns discharge current. This demonstrates that the higher the contact discharge test level, the greater the generated discharge current, and the contact discharge test level is almost directly proportional to the generated discharge current. This poses a significant challenge to the electrostatic discharge protection design of products or equipment. This is especially true for automotive equipment, which requires 8kV contact discharge testing at its I / O ports (input / output ports). The stringent testing requirements greatly increase the difficulty of research and development, thus significantly extending the time to market.

[0028]

[0029] Table 1

[0030] Furthermore, to facilitate testing whether network devices can meet the relevant requirements of the international standard IEC61000-4-2, some embodiments of this application provide an electrostatic discharge device. A circuit diagram of the electrostatic discharge device can be found [link to diagram]. Figure 2 The specifications of each component in the electrostatic discharge device are as follows: Uo is the DC high-voltage power supply of the electrostatic discharge device; Rc is the internal resistance of the DC high-voltage power supply (the resistance value of Rc is approximately 50 megohms to 100 megohms); the discharge capacitor Cs is 150 pF (pF: picofarad); the internal resistance Rd is 330 ohms (330 ohms can represent the human body resistance when holding a key or other metal tools); K1 is the switch of the electrostatic discharge device; M1 is the discharge head of the electrostatic discharge device; and M2 is the discharge circuit connection point. It should be noted that some embodiments of this application only show a schematic diagram of the circuit structure of one electrostatic discharge device, while other electrostatic discharge devices may be used in other embodiments, and this application does not limit this.

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the structure of the network devices provided in the various embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0032] See Figures 3 to 5 The network device provided in Embodiment 1 of this application includes: a metal housing 110, a first connector 120 connected to the metal housing 110, an external power connector 140 or a power cable 300, a circuit board 130, a first isolation capacitor 164, a sensitive device 150, and a sensitive line 51; the sensitive line 51 is led out from the sensitive device 150; the shortest power path between the first connector 120 and the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 is the first path, and the first path is the... A connector 120 is connected to the negative terminal 141 of an external power connector 140 or the negative terminal 301 of a power cable 300 via a circuit board 130 and a first isolation capacitor 164; the shortest power-conducting path between the first connector 120 and the sensitive device 150 and / or the sensitive line 51 is a second path, which is a path in which the first connector 120 is connected to the sensitive device 150 and / or the sensitive line 51 via a circuit board 130 and a first isolation capacitor 164; the length of the first path is less than the length of the second path.

[0033] Specifically, the shortest power-carrying path between the first connector 120 and the sensitive device 150 and / or the sensitive line 51 is the second path. This can be: the shortest power-carrying path between the first connector 120 and the sensitive device 150 is the second path; the shortest power-carrying path between the first connector 120 and the sensitive line 51 is the same path, and this path is the second path; or the shortest power-carrying path between the first connector 120 and the sensitive device 150 and the shortest power-carrying path between the first connector 120 and the sensitive line 51 are two different paths, but the two paths have the same length, and both paths are the second path.

[0034] The second path is a path in which the first connector 120 is connected to the sensitive device 150 and / or the sensitive line 51 via the circuit board 130 and the first isolation capacitor 164. Specifically: when the second path is connected to the sensitive device 150, the second path is a path in which the first connector 120 is connected to the sensitive device 150 via the circuit board 130 and the first isolation capacitor 164; when the second path is connected to the sensitive line 51, the second path is a path in which the first connector 120 is connected to the sensitive line 51 via the circuit board 130 and the first isolation capacitor 164; when the second path is connected to both the sensitive device 150 and the sensitive line 51, the second path is a path in which the first connector 120 is connected to both the sensitive device 150 and the sensitive line 51 via the circuit board 130 and the first isolation capacitor 164.

[0035] In some embodiments, a portion of the power cable 300 or the external power connector 140, as well as the first connector 120, the circuit board 130, the first isolation capacitor 164, the sensitive device 150, and the sensitive line 51 are all located within the metal housing 110; a portion of the power cable 300 or the external power connector 140, as well as the first isolation capacitor 164, the sensitive device 150, and the sensitive line 51 are all located on the circuit board 130.

[0036] In some embodiments of this application, when the network device includes an external power connector 140, the external power connector 140 can be either a male or a female connector; in one embodiment, such as Figure 4 As shown, the external power connector 140 is a female connector, also known as a DC socket (DC socket: a type of power outlet). The external power connector 140 can be freely plugged into and unplugged from the external power connector male connector 306, thereby enabling the product's power-on and power-off functions. The external power connector male connector 306 can be connected to the power adapter 80 via a power cable 300 to form a single unit. In one embodiment, the external power connector 140 can be soldered onto the circuit board 130.

[0037] When the network device provided in some embodiments of this application includes a power cable 300, such as Figure 5 As shown, the power cable 300 can be directly inserted into the circuit board 130 and connected to the circuit board 130.

[0038] The sensitive line 51 can be one or more of the following: sensitive signal trace, sensitive power trace, sensitive signal via, and sensitive power via. This application does not limit this.

[0039] Sensitive line 51 is led out from sensitive device 150, meaning sensitive line 51 is connected to sensitive device 150. For details, please refer to [link to relevant documentation]. Figure 4 and Figure 5In some embodiments, the sensitive device 150 may include a baseband chip 155 and a DDR chip 156 (DDR chip: dynamic memory chip), with a sensitive line 51 leading out from the baseband chip 155 to the DDR chip 156, so that the baseband chip 155 is electrically connected to the DDR chip 156 through the sensitive line 51.

[0040] See also Figure 3 See also Figure 6 In some embodiments, the metal housing 110 is electrically connected to the circuit board 130 via the first connector 120 as follows: the network device further includes a screw post 171 located inside the metal housing 110 and fixed to the metal housing 110; the circuit board 130 is provided with a through hole 131 that penetrates the circuit board 130 and is coaxially arranged with the screw post 171; the first connector 120 is a screw that penetrates the through hole 131 and is screwed to the screw post 171; the circuit board 130 has exposed copper 132 at the end of the through hole 131, and the first connector 120 is electrically connected to the exposed copper 132 at the end of the through hole 131, and is electrically connected to the circuit board 130 through the exposed copper 132.

[0041] In this way, the metal housing 110 can be electrically connected to the circuit board 130 through the first connector 120, and the circuit board 130 can also be fixed inside the metal housing 110 by the screw (i.e. the first connector 120) to prevent the circuit board 130 and even the components fixed on the circuit board 130 from shaking inside the metal housing 110.

[0042] It should be noted that this application does not limit the specific implementation of the electrical connection between the metal housing 110 and the circuit board 130 via the first connector 120. For example, in another embodiment, the network device may also include: a screw located inside and fixed to the metal housing 110; a through hole 131 on the circuit board 130 that penetrates the circuit board 130 and is coaxially arranged with the screw; the first connector 120 being a screw post; and the screw located inside the metal housing 110 passing through the through hole and screwed to the screw post.

[0043] Specifically, in some embodiments, the through hole 131 provided in the circuit board 130 is a screw hole. Copper foil is provided on both the front and back sides of the circuit board 130 around the screw hole (i.e., through hole 131). The copper foil on the front and back sides of the circuit board 130 is larger than the diameter of the screw hole. At the same time, the ink covering the copper foil on the front and back sides of the circuit board 130 around the screw hole is removed, so that the copper foil on the front and back sides of the circuit board 130 around the screw hole forms exposed copper 132. This application does not limit the shape of the exposed copper 132, but it is preferred that the exposed copper 132 is annular. When the screw (i.e., the first connector 120) is installed in the screw hole of the circuit board 130, the screw head is located on the copper foil on the front side of the circuit board 130 where the ink has been removed. That is, the area of ​​the screw head projected on the front side of the circuit board 130 is located within the exposed copper 132 on the front side, so that the screw has a good electrical connection with the exposed copper 132 on the front side, and the screw is also electrically connected to the metal housing 110 through the screw post 171.

[0044] In some embodiments, the circuit board 130 is rectangular in shape, with a through hole 131 at the upper left corner and exposed copper 132 around the through hole 131. The exposed copper 132 is coaxially arranged with the through hole 131, and both the top and bottom layers of the circuit board 130 have exposed copper 132. A first connector 120 is provided on the through hole 131. At this time, a screw post 171 is also provided opposite to the through hole 131 and connected to the metal housing 110. The first connector 120 is a screw, which passes through the through hole 131 and is screwed to the screw post 171, thereby electrically connecting the circuit board 130 to the metal housing 110.

[0045] More specifically, in some embodiments, the first connector 120 is electrically connected to exposed copper 132 on the circuit board 130, the exposed copper 132 being connected via copper foil or traces on the circuit board 130 (e.g., Figure 3 or Figure 6 The copper foil 133 shown is electrically connected to a pad 134 for soldering to the first isolation capacitor 164. Another pad 135 for soldering to the first isolation capacitor 164 is connected via the copper foil (or trace) of the circuit board 130 to the negative terminal 141 of the external power connector 140 or the negative terminal of the power cable 300 (e.g., ...). Figure 5 As shown, the first connector 120 is electrically connected to the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 via the circuit board 130 and the first isolation capacitor 164.

[0046] The following example illustrates the connection of the first connector 120 to the negative terminal 141 of the external power connector 140 via the circuit board 130 and the first isolation capacitor 164. However, when the first connector 120 needs to be electrically connected to the negative terminal 301 of the power cable 300 via the circuit board 130 and the first isolation capacitor 164, simply replace the external power connector 140 with the power cable 300; this will not be elaborated further here. Figure 4 Compare, Figure 5 The difference is that the external power connector 140 is replaced with a power cable 300; otherwise, they are the same.

[0047] See also Figure 3 and Figure 6 Specifically, in these embodiments, a first isolation capacitor 164 is disposed at a position adjacent to the exposed copper 132 on the circuit board 130. The pad 134 of the first isolation capacitor 164 is electrically connected to the exposed copper 132 via copper foil 133. The pad 135 of the first isolation capacitor 164 is electrically connected to point A1 of the external power input filtering and protection circuit 139 via the top ground copper foil 138 of the circuit board 130. Point A1 is connected to the negative terminal of the capacitor inside the external power input filtering and protection circuit 139. In the through-hole... An external power connector 140 is located on the right side of circuit board 131. Below the external power connector 140, an external power input filtering and protection circuit 139 is located. Point A1 of the external power input filtering and protection circuit 139 is electrically connected to the negative terminal 141 of the external power connector 140 via a ground copper foil G1. Point B1 of the external power input filtering and protection circuit 139 is electrically connected to the positive terminal 142 of the external power connector 140, allowing the external power connector 140 to provide power to the entire network device through point B1. The ground copper foil 138 is part of the grounding line in circuit board 130.

[0048] See also Figure 6The shortest power path between the first connector 120 and the negative terminal 141 of the external power connector 140 is the first path. At this time, the first path is formed by: the path of the pad 134 of the first isolation capacitor 164 electrically connected to the exposed copper 132 through the copper foil 133, the path of the first isolation capacitor 164 and the pad 135 of the first isolation capacitor 164 electrically connected to the A1 point of the external power input filter and protection circuit 139 through the top ground copper foil 138, and the ground copper foil G1 from the negative terminal 141 of the external power connector 140 to the A1 point of the external power input filter and protection circuit 139. The length of the ground copper foil G1 is formed by the segment lengths L12 and L13 of the ground copper foil G1. The length of the top-layer ground copper foil 138 from the pad 135 of the first isolation capacitor 164 to point A1 of the external power input filtering and protection circuit 139 is L11. The length of the first isolation capacitor 164 is L20. The length of the copper foil 133 used to connect the pad 134 of the first isolation capacitor 164 and the exposed copper 132 is L21. That is, the length of the shortest power-carrying path (i.e., the first path) between the first connector 120 and the negative terminal 141 of the external power connector 140 is L12+L13+L11+L20+L21.

[0049] See also Figure 6 See also Figure 4 and Figure 5 The length of the conductive path from the pad 135 used for soldering the first isolation capacitor 164 to the negative terminal 141 of the external power connector 140 is L10, that is, L10 = L12 + L13 + L11. Furthermore, in these embodiments, this path from the pad 135 to the negative terminal 141 of the external power connector 140 can be referred to as region K1. High-voltage static electricity from the metal housing 110 can be discharged to the neutral wire and ground through region K1, the external power connector 140, the cable 300, and the power adapter 80.

[0050] Preferably, a via AA is provided between the top exposed copper 132 and the bottom exposed copper 132 of the circuit board 130 to reduce the impedance between the top exposed copper 132 and the bottom exposed copper 132. That is, the top exposed copper 132 and the bottom exposed copper 132 are connected into a metal whole with low impedance through the via AA.

[0051] More preferably, N ground vias 136 (where N is greater than or equal to 1) are provided at point A1, near the external power input filtering and protection circuit 139, on the top layer ground copper foil 138. The ground vias 136 interconnect the various layers of ground copper foil on the circuit board 130 in region K1 to form a low-impedance metallic whole. Specifically, taking a four-layer circuit board 130 as an example, the ground vias 136 electrically connect the top layer ground copper foil 138, the second layer ground copper foil G2, the third layer ground copper foil G3, and the bottom layer ground copper foil G4, thereby forming an electrically connected whole and reducing the impedance of the electrical connection between the four layers of ground copper foil on the circuit board 130. Each layer of ground copper foil on the circuit board 130 is a grounding line of the circuit board 130.

[0052] In this way, when a contact-type electrostatic discharge of 4kV to 10kV is injected into the metal casing 110, the high-voltage electrostatic charge on the metal casing 110 is released to the ground along the screw post 171, the first connector 120, the exposed copper 132, the copper foil 133, the first isolation capacitor 164, the top ground copper foil 138, the ground copper foil G1 located at point A1 of the external power input filtering and protection circuit 139, the negative terminal 141 of the external power connector 140, the external power connector 306, the power cable 300, and the power adapter 80.

[0053] In some embodiments, the pads 134 and 135 used for soldering to the first isolation capacitor 164 and the through holes 131 of the circuit board 130 are all provided with a spacing of 0.5 mm or more. This avoids the first isolation capacitor 164 from breaking due to stress generated on the circuit board 130 by the first connector 120 when the circuit board 130 is fixed by the first connector 120. The first isolation capacitor 164 may be a ceramic isolation capacitor, which is relatively brittle in its manufacturing process.

[0054] Preferably, the pads 134 and 135 used for soldering to the first isolation capacitor 164 are spaced at least 1.0 mm apart from the through holes 131 of the circuit board 130. This further avoids the first connector 120 generating stress on the circuit board 130, which could cause the first isolation capacitor 164 to break due to stress.

[0055] See also Figures 3 to 6The following explanation uses the sensitive device 150, which includes the baseband chip 155 and the DDR chip 156, as an example. It should be understood that the sensitive device 150 is not limited to the baseband chip 155 and the DDR chip 156. In this case, the sensitive line 51 is the DDR trace between the baseband chip 155 and the DDR chip 156 (such as DDR data lines, control lines, address lines, clock lines, etc.). It should be understood that the sensitive line 51 is a DDR trace based on the case where the sensitive device 150 includes the baseband chip 155 and the DDR chip 156. When the sensitive device 150 includes other devices, the sensitive line 51 can also be other signal traces, signal vias, power vias, power copper foil or power traces, device pads, etc.

[0056] In some embodiments, the baseband chip 155, DDR chip 156, and sensitive circuit 51 are all located in region K2, i.e., region K2 is the area where sensitive devices and sensitive signals are located. Multiple ground vias 50 are provided at the locations of the baseband chip 155 and DDR chip 156, and these ground vias 50 in region K2 are connected to the ground pins of the baseband chip 155 and DDR chip 156, respectively. The multiple ground vias 50 located in region K2 and connected to the baseband chip 155 and DDR chip 156 are electrically connected to the ground copper foil layers of region K2 of the circuit board 130. In these embodiments, illustratively, the circuit board 130 is a four-layer board. In this case, the multiple ground vias 50 located in region K2 and connected to the baseband chip 155 and DDR chip 156 are electrically connected to the ground copper foil 168 of the top layer, the ground copper foil G12 of the second layer, the ground copper foil G13 of the third layer, and the ground copper foil G14 of the bottom layer of the circuit board.

[0057] Preferably, the top ground copper foil 138 of region K1 is directly or indirectly connected to the top ground copper foil 168 of region K2; the second ground copper foil G2 of region K1 is directly or indirectly connected to the second ground copper foil G12 of region K2; the third ground copper foil G3 of region K1 is directly or indirectly connected to the third ground copper foil G13 of region K2; and the bottom ground copper foil G4 of region K1 is directly or indirectly connected to the bottom ground copper foil G14 of region K2. In other words, all the ground copper foil layers of region K1 are directly or indirectly connected to the corresponding ground copper foil layers of region K2. This provides a return path for the power supply (i.e., the power supply connected to the network device, such as the 12V power supply external to an industrial router) and signal traces from the external power connector 140 that powers the entire circuit board 130.

[0058] In some implementations, such as Figure 4 and Figure 6As shown, taking the sensitive device 150 including the baseband chip 155 as an example, the shortest power path between the first connector 120 and the sensitive device 150 and / or the sensitive line 51 is the second path. The second path is formed by the power path from the baseband chip 155 to the first isolation capacitor 164, the first isolation capacitor 164, and the pad 134 through the copper foil 133 and the exposed copper 132. The length of the power path from the baseband chip 155 to the first isolation capacitor 164 is L14, the length of the first isolation capacitor 164 is L20, and the length of the copper foil 133 from the pad 134 to the exposed copper 132 is L21. That is, the shortest power path between the first connector 120 and the sensitive device 150 is L14+L20+L21.

[0059] Sensitive circuit 51 between baseband chip 155 and DDR chip 156 (e.g.) Figure 6 The path length from the sensitive line 51 (which is a DDR trace) to the first isolation capacitor 164 is L15, and the shortest power-on path between the first connector 120 and the sensitive line 51 is L15+L20+L21.

[0060] At this point, the length of the first path is less than the length of the second path. This is to ensure that the relationship between the first path in region K1 and the second path in region K2 satisfies the following relationship: L12+L13+L11+L20+L21<L14+L20+L21 and / or L12+L13+L11+L20+L21<L15+L20+L21.

[0061] Where L12+L13+L11+L20+L21<L14+L20+L21 and / or L12+L13+L11+L20+L21<L15+L20+L21, it can be L12+L13+L11+L20+L21<L14+L20+L21<L15+L20+L21; or it can be L12+L13+L11+L20+ L21 < L12 + L13 + L11 + L20 + L21 < L15 + L20 + L21; it can also be L12 + L13 + L11 + L20 + L21 < L14 + L20 + L21 < L15 + L20 + L21, and L12 + L13 + L11 + L20 + L21 < L12 + L13 + L11 + L20 + L21 < L15 + L20 + L21.

[0062] See Figure 7In circuit board 130, some copper foils and traces containing copper are formed by multiple distributed inductors L connected in series, multiple DC resistors connected in series, and multiple distributed capacitors C connected in parallel. When a 4kV to 10kV contact discharge is injected into the metal casing 110, the static electricity is rapidly discharged into circuit board 130 through the first isolation capacitor 164 at nanosecond speeds. According to Lenz's law: inductance always opposes a sudden change in current, the shorter the first path, the smaller its impedance, that is, the less resistance to the generation of distributed inductance L, the smaller the DC resistance R, and the faster the discharge speed to power adapter 80 through power cable 300. The longer the second path, the greater its impedance, that is, the greater resistance to the generation of distributed inductance L.

[0063] Furthermore, the faster the electrostatic discharge rate, the greater the resistance to the generation of distributed inductance L in the copper foil and traces of circuit board 130. This can be understood as follows: for copper foil of the same linewidth, its length is directly proportional to the distributed inductance L, and its length is directly proportional to the DC resistance. That is, when the copper foil linewidth on the first path and the copper foil linewidth on the second path are the same, the shorter the length of the first path, the smaller the distributed inductance and DC resistance of the first path, and the smoother the electrostatic discharge of the first path; while the longer the length of the second path, the larger the distributed inductance and DC resistance of the second path, and the greater the resistance to electrostatic discharge of the second path.

[0064] Based on this, it can be concluded that the greater the difference between the lengths of the first path and the second path, the smaller the impact of electrostatic discharge (ESD) on the sensitive devices and / or sensitive signals in region K2, which can further reduce the probability of sensitive device 150 experiencing problems such as system crashes and packet loss. Specifically, the smaller the impact of ESD on the sensitive devices and / or sensitive signals in region K2, the smaller the impact of ESD on the sensitive devices in region K2; the smaller the impact of ESD on the sensitive signals in region K2, when region K2 contains both sensitive devices and sensitive signals; and the smaller the impact of ESD on both the sensitive devices and sensitive signals in region K2.

[0065] See also Figures 3 to 6 In some implementations, the length of the second path is greater than or equal to 0.5 mm.

[0066] Specifically, the shortest energizing path between the first connector 120 and the sensitive device 150 and / or the sensitive line 51 is the second path, which is L14+L20+L21 and / or L15+L20+L21. At this time, the length of the second path is greater than or equal to 0.5mm, that is, L15+L20+L21 is greater than or equal to 0.5mm and / or L14+L20+L21 is greater than or equal to 0.5mm.

[0067] Specifically, when the shortest energizing path between the first connector 120 and the sensitive device 150 is the second path, the second path is L14+L20+L21; when the shortest energizing path between the first connector 120 and the sensitive line 51 is the second path, the second path is L15+L20+L21; when the shortest energizing paths between the first connector 120 and both the sensitive device 150 and the sensitive line 51 are the second paths, both L14+L20+L21 and L15+L20+L21 are the second paths. Since the second path is the path for the electrical connection between the first connector 120 and the sensitive device 150 and / or the sensitive line 51, the second path needs to be as long as possible. The purpose is to increase the impedance of electrostatic discharge, that is, to increase the DC resistance and distributed inductance of the second path, especially the distributed inductance of the second path. By ensuring that the length of the second path is greater than or equal to 0.5 mm, the DC resistance and distributed inductance of the second path can be increased. The impedance of the sensitive device 150 and / or sensitive line 51 discharged through the second path is also increased, thus making the sensitive device 150 and / or sensitive line 51 less susceptible to interference.

[0068] Specifically, when the second path is connected to the sensitive device 150, the impedance of the sensitive device 150 discharged through the second path is relatively high, thus making the sensitive device 150 less susceptible to interference; when the second path is connected to the sensitive line 51, the impedance of the sensitive line 51 discharged through the second path is relatively high, thus making the sensitive line 51 less susceptible to interference; when the second path is connected to both the sensitive device 150 and the sensitive line 51, the impedance of both the sensitive device 150 and the sensitive line 51 discharged through the second path is relatively high, thus making both the sensitive device 150 and the sensitive line 51 less susceptible to interference.

[0069] Furthermore, since some sensitive devices 150 in circuit board 130 are themselves high-speed devices (e.g., baseband chip 155, DDR chip 156), these devices are equivalent to another source of strong interference. By ensuring the second path length is greater than or equal to 0.5 mm, it is also possible to prevent these sensitive devices 150 (e.g., baseband chip 155, DDR chip 156) from leading out sensitive lines 51 and conducting strong interference from the top ground copper foil 138 and ground copper foil G1 in the K1 area to the external power connector 140, power cable 300, and power adapter 80, thereby preventing excessive radiation or conduction of EMI in the entire device. Preferably, the length of the second path is greater than or equal to 1.0 mm. More preferably, the length of the second path is greater than or equal to 3 mm.

[0070] See also Figures 3 to 6In some embodiments, the length of the first path 100 is less than or equal to 100 mm. Thus, because the first path is shorter, it is easier to make the length of the second path greater than the length of the first path. Furthermore, it allows for a smaller distributed inductance on the first path 100, thereby reducing the impedance on the first path 100 when discharging static electricity and electromagnetic interference generated by the metal casing 110.

[0071] Since the first path is the electrical connection path between the first connector 120 and the external power connector 140, which is also the electrostatic discharge path, the first path needs to be as short as possible. This is to reduce the impedance of the electrostatic discharge, i.e., to reduce the DC resistance and distributed inductance of the first path, especially the distributed inductance. If the length of the first path is less than or equal to 100mm, the DC resistance and distributed inductance of the first path will be relatively small. The impedance of the electrostatic discharge to the external power connector 140 through the first path will be relatively small, and the high electrostatic charge injected by the first connector 120 can be promptly discharged to the external power connector 140, power cable 300, power adapter 80, mains neutral wire, and ground. This prevents high-voltage electrostatic charge from discharging to the sensitive device 150 and / or sensitive line 51 within the circuit board 130, and avoids interference from high-voltage electrostatic charge to the sensitive device 150 and / or sensitive line 51.

[0072] Specifically, the shortest power path between the first connector 120 and the negative terminal of the external power connector 140 is the first path, and the first path 100 is L12+L13+L11+L20+L21; at this time, the length of the first path 100 is less than or equal to 100mm, that is, L12+L13+L11+L20+L21 is less than or equal to 100mm.

[0073] Preferably, the length of the first path 100 is less than or equal to 20 mm. This further reduces the distributed inductance on the first path 100, thereby further reducing the impedance on the first path 100 when discharging static electricity and electromagnetic interference generated by the metal casing 110.

[0074] See also Figure 7 A single copper foil strip on a circuit board consists of a single series distributed inductor, a series DC resistor, and a parallel capacitor. (See also...) Figure 8 A copper foil of a certain width on a circuit board is formed by multiple copper foils connected in parallel and superimposed with series distributed inductance, series DC resistance and parallel capacitor. It can be seen that the wider the copper foil, the smaller the distributed inductance and the larger the DC resistance.

[0075] See also Figures 3 to 6In some embodiments, the line width of the conductive lines on the circuit board 130 located on the first path 100 is greater than or equal to 0.5 mm. This reduces the distributed inductance on the first path 100, thereby reducing the impedance of the first path 100 when dissipating static electricity and electromagnetic interference generated by the metal casing 110.

[0076] Preferably, the line width of the conductive lines on the circuit board 130 located on the first path 100 is greater than or equal to 2 mm. This further reduces the distributed inductance on the first path 100, thereby further reducing the impedance of the first path 100 when dissipating static electricity and electromagnetic interference generated by the metal casing 110.

[0077] See also Figures 3 to 6 See also Figure 9 ,exist Figure 9 In the diagram, R represents the DC resistance of the copper foil in the K1 area circuit board 130, L represents the distributed inductance of the copper foil in the K1 area circuit board 130, and C represents the distributed capacitance of the copper foil in the K1 area circuit board 130. In some embodiments, the network device further includes a first capacitor 161; the positive terminal of the first capacitor 161 is electrically connected to the positive terminal of the external power connector 140 via a first conductive line, and the negative terminal of the first capacitor 161 is electrically connected to the negative terminal of the external power connector 140 via a second conductive line. That is, the positive terminal of the external power connector 140 is electrically connected to the positive terminal of the first capacitor 161, and the negative terminal of the external power connector 140 is electrically connected to the negative terminal of the sensitive device 150 and the first connector 120 via the negative terminal of the first capacitor 161. The first capacitor 161 belongs to the capacitor in the aforementioned external power input filtering and protection circuit 139.

[0078] Specifically, in some embodiments, the positive terminal 142 of the external power connector 140 leads out a power copper foil 180. The power copper foil 180 has a DC resistance R and a distributed inductance L. The power copper foil 180 is electrically connected to the positive terminal of the first capacitor 161, that is, the power copper foil 180 is the first conductive line mentioned above. The negative terminal of the external power connector 140 is electrically connected to the negative terminal of the first capacitor 161 through a ground copper foil G1, that is, the ground copper foil G1 is the second conductive line mentioned above. A distributed capacitance C is formed between the power copper foil 180 and the ground copper foil G1. When a 4kV to 10kV contact discharge is injected into the metal housing 110, the high voltage static electricity is sent to the top ground copper foil 138 through the first connector 120, exposed copper 130, copper foil 133, and the first isolation capacitor 164. The top ground copper foil 138 also has a DC resistance R and a distributed inductance L. The top ground copper foil 138 generates a discharge current i11 to the negative terminal of the first capacitor 161. At this time, the discharge current i11 is split into two paths at the negative terminal of the first capacitor 161: one path is sent through the ground copper foil G1 to the negative terminal 141 of the external power connector 140 to generate a discharge current i13. The discharge current i13 is discharged to the neutral line and ground through the external power connector male socket 306, cable 300, and power adapter 80. The ground copper foil G1 also has DC resistance R and distributed inductance L. When the discharge current i11 is discharged to the negative terminal of the first capacitor 161, the negative terminal of the first capacitor 161... The potential is rapidly increased until the potential of the negative terminal of the first capacitor 161 exceeds that of the positive terminal. At this point, the high-voltage static electricity generates another discharge path, producing a discharge current i12 from the negative terminal to the positive terminal of the first capacitor 161. This discharge current i12 is sent through the power copper foil 180 to the positive terminal 142 of the external power connector 140, and then through the male connector 306 of the external power connector, via the ground wire in the cable 300 and the power adapter 80, to the neutral wire and ground. Since the negative terminal of the first capacitor 161 is electrically connected to the negative terminal of the external power connector 140, the negative terminal of the first capacitor 161 is point A1 of the aforementioned external power input filtering and protection circuit 139.

[0079] See Figure 10 When electrostatic energy is discharged into the power adapter 80, the electrostatic energy in the low-to-medium frequency range is coupled by the transformer winding 74, and the electrostatic energy in the low-to-medium frequency range is coupled by the primary Y capacitor C73.

[0080] exist Figure 10In the electrical model of a portion of the circuit of the power adapter 80 shown, when 90V to 264V AC power is input to the bridge rectifier 113 from the live wire L and neutral wire N respectively, after rectification by the bridge rectifier 113, the power is stored and filtered by the primary input capacitor C99, and then provides power to the switching transistor VT1. The PWM chip (PWM: Pulse Width Modulation) is used to provide PWM modulation signals to drive the switching transistor VT1 to turn on or off. The electromagnetic energy coupled by the transformer 74 is transformed to generate a pulse voltage, which is rectified by the rectifier diode VD3 and filtered by the LC filter composed of capacitor C98, inductor L30, and capacitor C97, thereby providing a stable 12V power supply to network devices (such as industrial routers).

[0081] Additionally, when a 4kV to 10kV contact discharge is injected into the metal casing 110, the high-voltage static electricity from the ground wire in the power cable 300 will be discharged to the secondary ground GND of the power board 78. The high-voltage static charge generates an instantaneous current i55 at the negative terminal of capacitor C97, which is divided into two parts. One part goes through the Y capacitor C73 to the negative terminal of the primary input capacitor C99, generating a static discharge current i51 in the Y capacitor C73. The discharge current i51 is mainly a mid-to-high frequency static discharge current. The other part is formed by the electromagnetic coupling of the secondary winding L32, magnetic core 805, and primary winding L31 of transformer 74, becoming a mid-to-low frequency static discharge current. When the switching transistor VT1 is turned on, it is injected into the negative terminal of the primary input capacitor C99 through the switching transistor VT1, injected into the neutral line N by the bridge rectifier 113, connected to the ground through the neutral line N, and discharged to the ground. When the switching transistor VT1 is turned on, the electrostatic discharge current i53 generated by it converges with the electrostatic discharge current i51 flowing through the Y capacitor C73 to form an electrostatic discharge current i59. The electrostatic discharge current i59 is injected into the bridge rectifier 113, and finally injected into the neutral line N by the bridge rectifier 113. The neutral line N is connected to the ground and discharged to the ground.

[0082] Furthermore, if the high voltage static electricity does not reach the first capacitor 161 (e.g.) Figure 9Before the negative terminal (as shown), the positive terminal potential of the first capacitor 161 is higher than the negative terminal potential. For example, when the voltage of the router's external power supply is 12V, the positive terminal potential of the first capacitor 161 is higher than the negative terminal potential, and the positive terminal potential of the first capacitor 161 is 12V. When high-voltage static electricity reaches the negative terminal of the first capacitor 161, it can make the potential of the negative terminal of the first capacitor 161 greater than the potential of the positive terminal. Specifically, the charge generated by the high-voltage static electricity will first neutralize the charge stored in the two plates of the first capacitor 161. After neutralization, the charge generated by the high-voltage static electricity will make the potential of the negative terminal of the first capacitor 161 greater than the potential of the positive terminal of the first capacitor 161. This step is equivalent to reversing the charging of the first capacitor 161; that is, the charge generated by the high-voltage static electricity will reverse charge the first capacitor 161, thereby first neutralizing the voltage difference between the positive and negative terminals of the first capacitor 161, and making the first capacitor 161 generate a reverse voltage difference. At this time, a large amount of high-voltage static charge will be consumed inside the plates of the first capacitor 161.

[0083] Therefore, in the first path from the first connector 120, the first isolation capacitor 164 to the external power connector 140, the first capacitor 161 (such as...) can be... Figure 9 As shown, the capacitor 161 is positioned in the main circuit of the first path. Specifically, the positive terminal of the first capacitor 161 is connected to the positive terminal 142 of the external power connector 140 via the power copper foil 180, and the negative terminal of the first capacitor 161 is connected to the negative terminal 141 of the external power connector 140 via the ground copper foil G1. This allows the first capacitor 161 to not only reverse charge and dissipate static electricity, but also adds another path for discharging static electricity. Specifically, the static electricity is discharged via the power copper foil 180 to the positive terminal 142 of the external power connector 140, then through the ground wire of the cable 300 to the power adapter 80, and finally to the neutral wire and ground, thereby further reducing the impedance of the discharge path.

[0084] In some implementations, see Figure 11 These implementations, compared to the aforementioned implementations (i.e. Figure 11 The implementation shown is compared to Figure 8 In the embodiments shown, a clamping diode VD2 is added between the first conductive line connecting the positive terminal of the external power connector 140 to the positive terminal of the first capacitor 161 and the second conductive line connecting the negative terminal of the external power connector 140 to the negative terminal of the first capacitor 161. The positive terminal of the clamping diode VD2 is electrically connected to the positive terminal of the first capacitor 161, and the negative terminal of the clamping diode VD2 is electrically connected to the negative terminal of the first capacitor 161.

[0085] Specifically, the anode of clamping diode VD2 is electrically connected to the first conductive line, and the cathode of clamping diode VD2 is electrically connected to the second conductive line. That is, the power supply copper foil 180 is connected to the anode of clamping diode VD2, and the ground copper foil G1 is connected to the cathode of clamping diode VD2.

[0086] Thus, when a 4kV to 10kV contact discharge is injected into the metal casing 110, the high-voltage static electricity is transmitted through the first connector 120, exposed copper 130, copper foil 133, and the first isolation capacitor 164 to the top ground copper foil 138, generating a discharge current i11 to the negative terminal of the first capacitor 161. The negative terminal of the first capacitor 161 splits into two paths: one path is sent through the ground copper foil G1 to the negative terminal 141 of the external power connector 140, generating a discharge current i13. This discharge current i13 is discharged through the male socket 306 of the external power connector, via the ground wire in the cable 300 and the power adapter 80 to the neutral wire and ground; the other path is reverse-charged through the first capacitor 161 to the power copper foil 180, then to the positive terminal 142 of the external power connector 140, and discharged through the ground wire in the cable 300 and the power adapter 80 to the neutral wire. A clamping diode VD2 is added between the first capacitor 161 and the external power connector 140, and the clamping diode VD2 is connected in parallel between the power copper foil 180 and the ground copper foil G1. When static electricity is injected into the negative terminal of the clamping diode VD2, and the static electricity on the ground copper foil G1 is not smoothly discharged to the power adapter 80 through the ground wire in the cable 300, the potential of the negative terminal of the clamping diode VD2 exceeds that of the positive terminal of the clamping diode VD2, and the clamping diode VD2 will conduct, assisting in generating a discharge current i14 to be discharged to the power copper foil 180. The discharge current i14 and the discharge current i12 of the first capacitor 161 being reverse charged are superimposed to form a discharge current i16. The discharge current i16 is discharged to the neutral wire and the ground through the ground wire and the power line 300 in the cable 300.

[0087] In some implementations, see Figure 12 These implementations, compared to the aforementioned implementations (i.e. Figure 12 The implementation shown is compared to Figure 5 In the embodiments shown, the network device further includes a crimp terminal 307 through which the power cable 300 is electrically connected to the circuit board 130. Specifically, the copper wire inside the end of the power cable 300 is connected to the circuit board 130 through the crimp terminal 307. More specifically, the crimp terminal 307 includes a copper plate 308, a copper plate 305, and a plastic shell 400. The copper plate 308 is electrically connected to the copper wire inside the end of the power cable 300, the copper plate 305 is inserted into the circuit board 130, and the copper plate 305 is electrically connected to the ground copper foil G1. The connection between the copper plate 308 and the copper plate 305 allows the power cable 300 to be electrically connected to the ground copper foil G1 of the circuit board 130 through the crimp terminal 307. In fact, Figure 12and Figure 5 It is the same type of connection method, that is, the power adapter is electrically connected to the circuit board 130 through the power cable 300, and the power cable 300 cannot be separated from the circuit board 130.

[0088] In these embodiments, copper sheet 308 and copper sheet 305 can be a single copper sheet. Furthermore, the copper wires inside the power cable 300 can be electrically connected to copper sheet 308 via a crimping connection.

[0089] In some implementations, when performing electrostatic discharge (ESD) related tests on network devices, it is possible to use a device with... Figure 3 The electrostatic discharge device 200 (e.g., an electrostatic gun) with the circuit structure shown is in contact with the metal housing 110, so that the electrostatic discharge device 200 can apply electrostatic energy to the metal housing 110 in order to simulate the situation when the metal housing 110 generates static electricity.

[0090] See also Figures 3 to 6 In some embodiments, the circuit board 130 is provided with a first conductive path (such as L20+L21 as described above), a second conductive path (such as L12+L13+L11 as described above), and a third conductive path (such as L14 as described above). One end of the first conductive path is electrically connected to the first connector 120, and the other end is electrically connected to the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 through the second conductive path. The third conductive path connects the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 to the sensitive device 150 and / or the sensitive line 51. The first path 100 is the path through which the first connector 120 is electrically connected to the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 through the first conductive path and the second conductive path. The second path is the path through which the first connector 120 is electrically connected to the sensitive device 150 and / or the sensitive line 51 through the first conductive path, the second conductive path, and at least part of the third conductive path.

[0091] Specifically, the third conductive path electrically connects the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 to the sensitive device 150 and / or the sensitive line 51. This can be achieved by connecting the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 to the sensitive device 150; or by connecting the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 to the sensitive line 51; or by connecting the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 to both the sensitive device 150 and the sensitive line 51.

[0092] The second path is the path in which the first connector 120 is electrically connected to the sensitive device 150 and / or the sensitive line 51 through the first conductive path, the second conductive path, and at least a portion of the third conductive path. Specifically: when the third path is connected to the sensitive device 150, the second path is the path in which the first connector 120 is electrically connected to the sensitive device 150 through the first conductive path, the second conductive path, and at least a portion of the third conductive path; when the third path is connected to the sensitive line 51, the second path is the path in which the first connector 120 is electrically connected to the sensitive line 51 through the first conductive path, the second conductive path, and at least a portion of the third conductive path; when the third path is connected to both the sensitive device 150 and the sensitive line 51, the second path is the path in which the first connector 120 is electrically connected to both the sensitive device 150 and the sensitive line 51 through the first conductive path, the second conductive path, and at least a portion of the third conductive path.

[0093] In some embodiments, one end of the first conductive path is electrically connected to the first connector 120 and the other end is connected to the first isolation capacitor 164, and the second conductive path has the first isolation capacitor 164 and is connected to the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300.

[0094] The first path 100 is the path through which the first connector 120 is electrically connected to the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 via the first conductive path and the second conductive path. The second path is the path through which the first connector 120 is electrically connected to the sensitive device 150 and / or the sensitive line 51 via the first conductive path, the second conductive path and at least part of the third conductive path, thus ensuring that the length of the first path 100 is less than the length of the second path.

[0095] See also Figure 3 In some embodiments, the metal housing 110 includes a metal top housing 111 and a metal bottom housing 112, the metal top housing 111 and the metal bottom housing 112 forming an integral whole, and the metal top housing 111 and the metal bottom housing 112 may or may not be electrically connected.

[0096] Specifically, in one embodiment, the metal housing 110 includes a metal top shell 111 and a metal bottom shell 112 fixed to the metal top shell 111. The first connector 120, circuit board 130, external power connector 140 or part of the power cable 300, and sensitive device 150 are all located between the metal top shell 111 and the metal bottom shell 112. Specifically, after the metal top shell 111 and the metal bottom shell 112 are fixed, an accommodating space is formed between the metal top shell 111 and the metal bottom shell 112, and the first connector 120, circuit board 130, external power connector 140 or part of the power cable 300, and sensitive device 150 are all located within this accommodating space.

[0097] See also Figures 3 to 6 In some embodiments, the network device may further include a second connector 172, which is fixed to the circuit board 130 and the metal housing 110, and a first connector 120 is fixed to the circuit board 130 and the metal housing 110. Thus, the circuit board 130 can be fixed within the metal housing 110 by the first connector 120 and the second connector 172, thereby increasing the stability of fixing the circuit board 130 within the metal housing 110.

[0098] Specifically, in some embodiments, the circuit board 130 has the same number of through holes 173 as the second connectors 172, and the metal housing 110 has the same number of screw posts as the second connectors 172, each corresponding to one of the through holes 173. Each second connector 172 passes through a through hole 173 and is screwed to a screw post to more stably fix the circuit board 130 within the metal housing 110. The second connectors 172 are screws. The through holes 173 can also be screw holes.

[0099] In one embodiment, the network device further includes: a second isolation capacitor 174; a circuit board 130 having a grounding line electrically connected to the negative terminal of an external power connector 140 or a power cable 300; a second connector 172 electrically connected to the grounding line via the second isolation capacitor 174, and the second connector 172 electrically connected to the metal housing 110. This allows noise on the metal housing 110 to be conducted to the grounding line via the second connector 172 and the second isolation capacitor 174.

[0100] In another embodiment, the second connector 172 may not be electrically connected to the ground line in the circuit board 130. In this case, the second isolation capacitor 174, which is electrically connected to the second connector 172, is also not provided. This provides a designated low-impedance discharge path for noise. The designated low-impedance discharge path is the first path described above.

[0101] It should be noted that whether the second connector 172 is electrically connected to the grounding line of the circuit board 130 through the second isolation capacitor 174 can be determined based on the radiation generated by the metal housing 110 or external interference (e.g., RS electromagnetic radiation interference test, RS stands for "radio frequency electromagnetic field radiation immunity") or in the case of power equipment in a very harsh electromagnetic environment.

[0102] In some embodiments, the example is that there are three second connectors 172, and the second connectors 172 are electrically connected to the ground line of the circuit board 130 through the second isolation capacitor 174. That is, the total number of the second connectors 172 and the first connectors 120 is 4. The four screw holes (i.e., one through hole 131 and three through holes 173) used to mate with the first connectors 120 and the three second connectors 172 are provided with exposed copper on both sides. The three second connectors 172 are all electrically connected to the ground line through a second isolation capacitor 174.

[0103] In this embodiment, the circuit board 130 is rectangular in shape. At this time, four screw holes are respectively set at the four corners of the circuit board 130, and the first isolation capacitor 164 and three second isolation capacitors 174 are also respectively set at the four corners of the circuit board 130, so as to facilitate the layout of the circuit board 130 traces and the layout of other components on the circuit board 130.

[0104] In this embodiment, each second connector 172 is electrically connected to the grounding line via a second isolation capacitor 174 in the same way. The following description illustrates how a second connector 172 is electrically connected to the grounding line via a second isolation capacitor 174. The exposed copper 175, used for electrical connection with the second connector 172, is electrically connected via copper foil 176 to a pad 177 for soldering to the second isolation capacitor 174. Another pad 178, used for soldering to the second isolation capacitor 174, is electrically connected via copper foil 179 to a ground via 101. The second isolation capacitor 174 is soldered onto pads 177 and 178. The top layer ground copper foil, the inner layer ground copper foil, the back layer copper foil, and the grounding line are connected as a whole via the ground via 101. Noise generated by the exposed copper 175, the second connector 172, the screw post, and the metal top shell 111 or metal bottom shell 112 in the screw hole projection area is guided to the grounding line via the second isolation capacitor 174.

[0105] See also Figure 3 and Figure 5 In one embodiment, the network device further includes: a network port connector 880 and a third isolation capacitor 63; the circuit board 130 is provided with a grounding line, which is electrically connected to the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300; the network port connector 880 has a metal shell 181, which is electrically connected to the grounding line through the third isolation capacitor 63, and the metal shell 181 is provided with a plug-in interface, which is exposed outside the metal shell 110.

[0106] Specifically, in some embodiments, the metal shell 181 has six sides, five of which are inside the metal shell 110, and the other side of the metal shell 181 with the plug interface protrudes outside the metal shell 110 to facilitate the plugging of network cables.

[0107] In other embodiments, the metal shell 181 has six faces, five-sixths of which are inside the metal shell 110 and one-sixth of which are outside the metal shell 110. The metal shell 181 also has a face with an insertion interface located outside the metal shell 110.

[0108] When the network connector 880 is struck by lightning, the metal shell 181 of the network connector 880 is electrically connected to the grounding line through the third isolation capacitor 63. Therefore, the third isolation capacitor 63 can buffer the lightning energy injected into the grounding line of the entire circuit board 130, thereby avoiding interference from the lightning energy to sensitive devices 150 (such as baseband chip 155, DDR chip 156, etc.) and sensitive lines 51, and reducing the probability of the sensitive devices 150 crashing or losing packets due to the lightning energy.

[0109] In some embodiments, the metal shell 181 is electrically connected to the metal outer shell 110. Specifically, the metal shell 181 may be electrically connected to the metal outer shell 110 through direct contact, or the metal shell 181 may be electrically connected to the metal outer shell 110 through indirect contact via other components.

[0110] In one embodiment, the metal shell 181 is electrically connected to the metal outer shell 110 (e.g., metal top shell 111 or metal bottom shell 112) via a spring contact 182 through a lap joint. In this case, when 4kV to 12kV of static electricity is injected into the metal shell 110, the static energy is divided into three parts: 1. Since the metal shell 110 is a large metal block, it acts as a capacitor, absorbing 5% of the static energy; 2. The remaining small portion of static energy is injected into the network port transformer 183 of the network port connector 880 through the metal shell 181. However, because the network port transformer 183 has an isolation transformer and a common-mode inductor, and there is a gap between the input signal traces and the output signal traces of the network port transformer 183, and the input and output impedances of the network port transformer 183 are very high, only a weak amount of static energy is injected into the traces of the circuit board 130 through the network port transformer 183. Furthermore, the energy injected into the traces of the circuit board 130 is very weak and will not cause damage to the sensitive device 15. 0. No system crashes or packet loss will occur, and there will be no static electricity damage to the sensitive device 150; 3. After the metal casing 110 absorbs 5% of the static energy for buffering, the remaining static energy enters the first isolation capacitor 164 through the metal casing 110, the first connector 120, and the through hole 131 of the circuit board 130. The static energy entering the first isolation capacitor 164 is then divided into three parts: a. 85% is directly discharged to the mains power and ground through the external power adapter 140; b. 5% is absorbed by the first capacitor 161 and stored in the first capacitor 161; c. 5% is injected into the grounding line 132 of the circuit board 130. Because the negative terminal 166 of the first capacitor 161 is far away from the sensitive device 150, and part of it is injected into the grounding line of the circuit board 130, it will not cause interference to the signal traces and signal pins of the sensitive device 150. In addition, almost all the energy exceeding the positive terminal 165 level of the first capacitor 161 will be absorbed by the first capacitor 161. Therefore, the level of the grounding line can be prevented from far exceeding the level of the positive terminal 165 of the first capacitor 161. This prevents the grounding line from discharging into the signal traces and signal pins of the sensitive device 150, thus preventing the sensitive device 150 from crashing, losing packets, and being damaged.

[0111] Furthermore, in this embodiment, the metal casing 110 can be directly connected to the ground. For example, the metal casing 110 can be connected to the ground via a chassis with screws, or the metal casing 110 can be connected to a cable with screws and then connected to the ground via a cable. In this way, the high-voltage lightning strike energy applied to the metal casing 110 by the metal casing 181 of the network port connector 800 can be directly discharged to the ground.

[0112] In other embodiments, when the first isolation capacitor 164 is provided on the circuit board 130, and provided that the metal housing 110 and the low-voltage portion within the circuit board 130 meet the safety requirements (i.e., meet the GB4943 standard in 3C and the North American UL62368-1 standard), the metal housing 181 of the network connector 880 may not be electrically connected to the metal housing 110. This application does not impose any limitations on this.

[0113] In addition, N ground vias 66 (N≧1) can be provided at the ground copper foil 65. The top ground copper foil 65 is electrically connected to the top ground copper foil 168, the second ground copper foil G12, the third ground copper foil G13, and the bottom ground copper foil G14 through the ground vias 66. This reduces the impedance between the top ground copper foil 65, the top ground copper foil 168, the second ground copper foil G12, the third ground copper foil G13, and the bottom ground copper foil G14.

[0114] Additionally, it should be noted that electrostatic discharge includes air discharge testing and RS testing. RS testing generates very strong electromagnetic radiation near the metal casing 110. During RS testing of the network device in Embodiment 1 of this application, electromagnetic radiation is induced on the metal casing 110, causing noise to be generated. The noise is transmitted from the metal casing 110 to the first isolation capacitor 164 via the first connector 120 and the circuit board 130, and then to the external power adapter 140 or power cable 300, thereby discharging the noise to the mains power and ground. This prevents the noise induced on the metal casing 110 from secondary radiation that could irradiate and disturb the sensitive device 150, causing it to crash or experience packet loss.

[0115] Furthermore, it should be noted that since both the capacitive reactance of a capacitor and the frequency of the circuit signal are inversely proportional to the capacitor's capacitance, when the capacitances of the first isolation capacitor 164 and the second isolation capacitor 174 mentioned above reach a certain level, their capacitive reactance to high-frequency components is low, requiring grounding of the low-frequency components in the circuit signal. To ground the low-frequency components of the circuit signal, a large-capacity isolation capacitor is required. In some embodiments of this application, the network device is powered by DC. Since the frequency of DC is zero, the capacitive reactance of the first isolation capacitor 164 and the second isolation capacitor 174 is theoretically infinite. Therefore, the frequency of the circuit signal is not affected by the first isolation capacitor 164 and the second isolation capacitor 174, and there is no need to ground the low-frequency components of the circuit signal.

[0116] Furthermore, it should be noted that when the network device is equipped with a second isolation capacitor 174, if the second isolation capacitor 174 is not placed properly, noise from the metal casing will leak to nearby audio and radio frequency circuits, interfering with them. Moreover, during electrostatic discharge, if the network device has a second isolation capacitor 174 and its placement is improper, it can easily cause system crashes or network packet loss. In other words, if the network device has a second isolation capacitor 174 and its placement is improper, it will alter the electrostatic discharge path, causing sensitive devices and circuits to be subject to electrostatic interference.

[0117] Specifically, in one embodiment, see [link to implementation details]. Figures 3 to 6 The K2 area of ​​circuit board 130 contains baseband chip 155, DDR chip 156, and DDR traces. Differential traces 512 are led out from differential pins 52 and 53 of baseband chip 155 and sent to network chip 151. The ground pin of network chip 151 is electrically connected to the top layer ground copper foil 168, the second layer ground copper foil G12, the third layer ground copper foil G13, and the bottom layer ground copper foil G14 of the K2 area of ​​circuit board 130 through ground via 501. IQ signal traces 511 (IQ signal: in-phase quadrature signal) are led out from baseband chip 155 and sent to RF chip 157; RF traces 513 are led out from RF chip 157 and sent to IPEX socket (an RF socket). The ground pin of the RF chip 157 is electrically connected to the top layer ground copper foil 168, the second layer ground copper foil G12, the third layer ground copper foil G13, and the bottom layer ground copper foil G14 of the K2 region of the circuit board 130 through a ground hole 501. The baseband chip 155 leads out an SPI trace 513 (a high-speed signal transmission line) to connect to the flash memory chip 154. The flash memory chip 154 ​​is electrically connected to the top layer ground copper foil 168, the second layer ground copper foil G12, the third layer ground copper foil G13, and the bottom layer ground copper foil G14 of the K2 region of the circuit board 130 through a ground hole 505. Among them, the baseband chip 155, DDR chip 156, Ethernet chip 151, flash memory chip 154, and RF chip 157 are all sensitive devices 150, and the DDR trace, differential trace 512, IQ signal trace 511, RF trace 513, and SPI trace 513 are all sensitive lines 51.

[0118] When the network device includes a second isolation capacitor 174, and the second isolation capacitor 174 is connected to the grounding line and the second connector 172, during the 4kV to 10kV contact discharge process injected into the metal casing 112, static electricity is discharged through the second connector 172 and screw holes (i.e., through holes 173), exposed copper 175, and the second isolation capacitor 174 to point A1 of the external power input filtering and protection circuit 139 in the circuit board 130. The static discharge path M1 passes through the RF trace 513, IQ signal trace, differential trace 512, baseband chip 155, RF chip 157, etc. These sensitive devices 150 and sensitive lines 51 are susceptible to static interference, which can easily lead to signal and data packet loss, or even system crashes, or even damage to the sensitive devices 150.

[0119] When the network device is not equipped with the second isolation capacitor 174, the electrostatic discharge path can also be controlled. For example, the electrostatic discharge can be directly discharged to the power adapter 140, the mains power, or the ground, without affecting the normal operation of other components on the circuit board 130.

[0120] In related technologies, network devices typically employ external antennas to improve the antenna gain and radiation angle of routers. When the metal casing of the network device is not connected to ground, the components inside the device radiate and couple to the metal casing. This causes interference between the external antenna and the displacement current (radiation) generated on the metal casing, resulting in a degraded performance of the external antenna. Furthermore, when the metal casing is suspended, i.e., not connected to the ground copper foil on the circuit board via a capacitor (e.g.), it can also cause interference to the external antenna.

[0121] See Figure 13 In some embodiments, the network device further includes an antenna; the sensitive device 150 includes a radio frequency chip, and the antenna is connected to the radio frequency chip.

[0122] Specifically, the antenna is an external antenna 190, and the network device also includes an antenna bracket 192. The external antenna 190 is installed inside the antenna bracket 192, which is mounted on the side of the metal housing 110. The metal housing 110 is placed horizontally on the workbench, and the external antenna 190 is perpendicular to the workbench, i.e., the external antenna 190 is vertically polarized. The circuit board 130 is located inside the metal housing 110. Various components (such as: RF chip, baseband chip 151, high-speed trace 152, BUCK power supply 153, external power connector, various capacitors, etc.) are housed inside the metal housing 110 of the network device. One end of the antenna cable 193 is connected to the RF chip, and the other end of the antenna cable 193 is connected to the external antenna 190, thereby connecting the antenna to the RF chip.

[0123] The external antenna 190 is a dipole antenna, consisting of a positive element 194 and a negative element 195. The positive element 194 is located at the top, and the negative element 195 is located at the bottom, meaning that the positive element 194 and the negative element 195 are sequentially arranged outside the metal casing 110 along the direction of gravity. When a radio frequency signal is injected into the dipole antenna, a displacement current i1 is generated between the positive element 194 and the negative element 195 from top to bottom. The displacement current i1 accounts for approximately 85% to 95% of the total radiated energy of the positive element 194. Due to the large area of ​​the metal casing 110, a displacement current i2 is also generated between the positive element 194 and the metal casing 110 from top to bottom. The displacement current i2 accounts for approximately 5% to 15% of the total radiated energy of the positive element 194. The larger the displacement current i1 between the positive element 194 and the negative element 195 accounts for of the total radiated energy of the positive element 194, the better the performance of the external antenna 190. Ideally, the displacement current i1 generated between the positive oscillator 194 and the negative oscillator 195 from top to bottom accounts for 100% of the total radiated energy of the positive oscillator 194.

[0124] In related technologies, if the baseband chip 151 generates radiation ① inside the metal housing 110, this radiation ① will couple to the metal housing 110; the high-speed trace 152 generates radiation ② inside the metal housing 110, this radiation ② will couple to the metal housing 110; the BUCK power supply 153 generates radiation ③ inside the metal housing 110, this radiation ③ will couple to the metal housing 110; the oscillator 194 and the metal housing 110 will also generate a displacement current i2 from top to bottom, which can be superimposed with radiation ①, radiation ②, and radiation ③. This will degrade the performance of the dipole antenna, such as the EVM (Error Vector Magnitude) of the transmit power and the receiver sensitivity.

[0125] However, in Embodiment 1 of this application, the noise coupled to the metal casing 110 by radiation ①, radiation ②, and radiation ③ can be transmitted to the external power adapter 140 or power cable 300 through the first connector 120 and the circuit board 130, thereby discharging the noise to the mains power or the ground. This attenuation of the noise in the metal casing 110 greatly reduces the interference of the noise in the metal casing 110 with the displacement current I2 of the external antenna 190.

[0126] See Figure 14 and Figure 15Embodiment 2 of this application provides a network device, including: a metal housing 110, a first connector 120 connected to the metal housing 110, an external power connector 140 or a power cable 300, a circuit board 130, a sensitive device 150, and a sensitive line 51; the sensitive line 51 is led out from the sensitive device 150; the shortest power-conducting path between the first connector 120 and the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 is a first path, which is a path in which the first connector 120 is connected to the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300 via the circuit board 130; the shortest power-conducting path between the first connector 120 and the sensitive device 150 and / or the sensitive line 51 is a second path, which is a path in which the first connector 120 is connected to the sensitive device 150 and / or the sensitive line 51 via the circuit board 130; the length of the first path is less than the length of the second path.

[0127] In the second embodiment of this application, when the metal casing 110 is injected with a 4kV to 10kV contact discharge, since the length of the first path is less than the length of the second path, most of the electrostatic energy on the metal casing 110 is discharged through the first connector 120 and the circuit board 130 to the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300, thereby discharging to the neutral line and ground, thereby reducing the probability of sensitive devices crashing or losing packets.

[0128] In some embodiments, a portion of the power cable 300 or the external power connector 140, as well as the first connector 120, the circuit board 130, the sensitive device 150, and the sensitive line 51 are all located within the metal housing 110; a portion of the power cable 300 or the external power connector 140, as well as the sensitive device 150 and the sensitive line 51, are all located on the circuit board 130.

[0129] Furthermore, in Embodiment 2 of this application, the metal casing 110 can be directly connected to the negative terminal of the power adapter secondary via an external power connector 140 or a power cable 300, resulting in a lower grounding impedance of the metal casing 110 and improved shielding effect.

[0130] In fact, the network device provided in Embodiment 2 of this application is largely the same as the network device provided in Embodiment 1 above. The main difference is that the network device in Embodiment 2 of this application removes the first isolation capacitor 164 in Embodiment 1 of this application, and the first connector 120 in Embodiment 2 of this application is connected to the negative terminal 141 of the external power connector 140 or the negative terminal of the power cable 300 through the circuit board 130.

[0131] The connection method between the external power connector 140 or power cable 300 and the circuit board 130, as well as the connection method between the connector 130 and the metal housing 110 and the circuit board 130, can refer to the above embodiment one, and will not be repeated here.

[0132] In some embodiments, the first connector 120 is directly electrically connected to the external power input filtering and protection circuit 139 via the ground copper foil 138 of the circuit board 130, and the negative terminal 141 of the external power connector 140 or the negative terminal of the power cable 300 is electrically connected to the external power input filtering and protection circuit 139 via the ground copper foil G1.

[0133] The following example illustrates the connection of the first connector 120 to the negative terminal 141 of the external power connector 140 via the circuit board 130. When it is necessary to connect the first connector 120 to the negative terminal of the power cable 300 via the circuit board 130, it is only necessary to replace the external power connector 140 with the power cable 300, which will not be elaborated here.

[0134] In some embodiments, ground copper foil G1 and ground copper foil 138 together form a first path. The length of ground copper foil G1 is L12, the length of ground copper foil 138 is L11, and the length of the first path is equal to the sum of the length of ground copper foil G1 (L12) and the length of ground copper foil 138 (L11), that is, the length of the first path is equal to L12 + L11.

[0135] In some implementations, the sensitive device 150 includes a baseband chip 155, a DDR chip 156, a network port chip 151, an RF chip 157, and a flash memory chip 154. It is understood that the sensitive device 150 is not limited to the baseband chip 155, DDR chip 156, network port chip 151, RF chip 157, and flash memory chip 154. In this case, the sensitive line 51 is a DDR trace, a differential line 512, an IQ signal line 511, and an SPI trace 513. It is understood that the sensitive line 51 being a DDR trace, a differential line 512, an IQ signal line 511, and an SPI trace 513 is based on the case where the sensitive device 150 includes the baseband chip 155, DDR chip 156, network port chip 151, RF chip 157, and flash memory chip 154. When the sensitive device 150 includes other devices, the sensitive line 51 can naturally be other traces or vias.

[0136] The length of the shortest circuit between the first connector 120 and any of the sensitive devices 150 is L14; the length of the shortest circuit between the first connector 120 and any of the sensitive lines 51 is L15.

[0137] At this point, the length of the first path is less than the length of the second path, i.e., L14 > L12 + L11 and / or L15 > L12 + L11.

[0138] See also Figures 14 to 16 In some embodiments, the length of the second path is greater than or equal to 0.5 cm. That is, L15 is greater than or equal to 0.5 mm and / or L14 is greater than or equal to 0.5 mm. Thus, because the second path is longer, it is convenient to make the length of the first path less than the length of the second path.

[0139] Preferably, the length of the second path is greater than or equal to 1.0 mm. More preferably, the length of the second path is greater than or equal to 3 mm.

[0140] See also Figures 14 to 16 In some embodiments, the length of the first path 100 is less than or equal to 100 mm. That is, L12 + L11 is less than or equal to 100 mm. This ensures that the length of the first path 100 is less than the length of the second path. In addition, it also makes the distributed inductance on the first path 100 smaller, so as to reduce the impedance on the first path 100 when discharging static electricity and electromagnetic interference generated by the metal casing 110.

[0141] In some implementations, the first path 100 is part of the second path. This ensures that the length of the first path 100 is less than the length of the second path.

[0142] See also Figures 14 to 16 In some embodiments, the linewidth of the conductive lines on the circuit board 130 located on the first path 100 is greater than or equal to 0.5 mm. This reduces the distributed inductance on the first path 100, thereby decreasing the impedance of the first path 100 when dissipating static electricity and electromagnetic interference generated by the metal casing 110. Preferably, the linewidth of the conductive lines on the circuit board 130 located on the first path 100 is greater than or equal to 2 mm. This further reduces the distributed inductance on the first path 100, thereby further reducing the impedance of the first path 100 when dissipating static electricity and electromagnetic interference generated by the metal casing 110.

[0143] Furthermore, the network device provided in Embodiment 2 of this application may have vias BB, N ground vias 136, ground vias 50 and each layer of ground copper foil with the same functions as the network device provided in Embodiment 1 above, which will not be described in detail here.

[0144] In some embodiments, the network device further includes: a first capacitor 161; the positive terminal of the first capacitor 161 is electrically connected to the positive terminal of the external power connector 140 or the positive terminal of the power cable 300 via a first conductive line, and the negative terminal of the first capacitor 161 is electrically connected to the negative terminal of the external power connector 140 or the negative terminal of the power cable 300 via a second conductive line; the positive terminal of the external power connector 140 or the positive terminal of the power cable 300 is electrically connected to the positive terminal of the first capacitor 161, and the negative terminal of the external power connector 140 or the negative terminal of the power cable 300 is electrically connected to the negative terminal of the sensitive device 150 and the first connector 120 via the negative terminal of the first capacitor 161.

[0145] The first capacitor 161 belongs to the capacitor in the external power input filtering and protection circuit 139 mentioned above. In the network device provided in Embodiment 2 of this application, the pad soldered to the negative terminal 166 of the first capacitor 161 is point A1, the negative terminal of the external power input filtering and protection circuit 139. The negative terminal 166 of the first capacitor 161 is electrically connected to the grounding line of the circuit board 130, and serves as the reference ground for the entire network device. The function of the first capacitor 161 can be referred to in Embodiment 1 above, such as the first capacitor 161 providing two discharge paths, etc., which will not be elaborated further here.

[0146] Specifically, during 4KV to 8KV contact discharge in the metal casing 110, 15% to 20% of the energy of the 4KV to 8KV high-voltage static electricity is absorbed by the first capacitor 161, and 60% to 70% of the energy of the high-voltage static electricity is directly discharged to the power adapter, neutral wire, and ground through the external power connector 140 or external power cable 300. 5% to 10% of the energy of the high-voltage static electricity is discharged to the ground of the entire circuit board 130, and the 5% to 10% energy of the high-voltage static electricity has almost negligible impact on the signals and pins of various components on the circuit board 130.

[0147] Furthermore, Embodiment 2 of this application may also have a clamping diode VD2 with the same structure and function as Embodiment 1 described above.

[0148] Specifically, in Embodiment 2 of this application, a clamping diode (not shown in the figure) is added between the first conductive line connecting the positive terminal of the external power connector 140 to the positive terminal of the first capacitor 161 and the second conductive line connecting the negative terminal of the external power connector 140 to the negative terminal of the first capacitor 161. That is, the positive terminal of the clamping diode is electrically connected to the first conductive line, and the negative terminal of the clamping diode is electrically connected to the second conductive line. The function of the clamping diode can be referred to Embodiment 1 above, and will not be repeated here.

[0149] See also Figures 14 to 16 The network device provided in Embodiment 2 of this application may have a second connector 172 with the same structure and function as the network device provided in Embodiment 1 above.

[0150] Specifically, the network device may further include a second connector 172, which is fixed to the circuit board 130 and the metal housing 110, and a first connector 120 is fixed to the circuit board 130 and the metal housing 110. In this way, the circuit board 130 can be fixed inside the metal housing 110 by the first connector 120 and the second connector 172, thereby increasing the stability of fixing the circuit board 130 inside the metal housing 110.

[0151] More specifically, in some embodiments, the circuit board 130 has the same number of through holes 173 as the second connectors 172, and the metal housing 110 has the same number of screw posts as the second connectors 172, each corresponding to one of the through holes 173. Each second connector 172 passes through a through hole 173 and is screwed to a screw post, thereby more stably fixing the circuit board 130 within the metal housing 110. The second connectors 172 are screws. The through holes 173 may also be screw holes.

[0152] The network device provided in Embodiment 2 of this application may have a second isolation capacitor 174 with the same function as the network device provided in Embodiment 1 above. The configuration of the second isolation capacitor 174 in the network device can also refer to Embodiment 1 above.

[0153] For example, in one embodiment, the network device further includes: a second isolation capacitor 174; a circuit board 130 having a grounding line, the grounding line being electrically connected to the negative terminal of the external power connector 140 or the negative terminal of the power cable 300; and a second connector 172 being electrically connected to the grounding line via the second isolation capacitor 174. The manner in which the second connector 172 is electrically connected to the grounding line via the second isolation capacitor 174 can be referred to in the first embodiment described above, and will not be repeated here.

[0154] The network device provided in Embodiment 2 of this application may further include: a network port connector 880 and a third isolation capacitor 63; the circuit board 130 is provided with a grounding line, which is electrically connected to the negative terminal 141 of the external power connector 140 or the negative terminal 301 of the power cable 300; the network port connector 880 has a metal shell 181, which is electrically connected to the grounding line through the third isolation capacitor 63, and the metal shell 181 is provided with a plug-in interface, which is exposed outside the metal shell 110.

[0155] Specifically, in some embodiments, the metal shell 181 has six sides, five of which are inside the metal shell 110, and the other side of the metal shell 181 with the plug interface protrudes outside the metal shell 110 to facilitate the plugging of network cables.

[0156] In other embodiments, the metal shell 181 has six faces, five-sixths of which are inside the metal shell 110 and one-sixth of which are outside the metal shell 110. The metal shell 181 also has a face with an insertion interface located outside the metal shell 110.

[0157] When the network connector 880 is struck by lightning, the metal shell 181 of the network connector 880 is electrically connected to the grounding line through the third isolation capacitor 63. Therefore, the third isolation capacitor 63 can absorb the lightning energy, thereby avoiding interference from the lightning energy to the sensitive device 150 and reducing the probability of the sensitive device 150 crashing or losing packets due to the lightning energy.

[0158] In some implementations, the metal housing 181 of the network connector 880 is not directly electrically connected to the metal housing 110.

[0159] Routers and switches, among other communication devices, have built-in TNV (Telecommunication Network Voltage) circuits. These circuits are connected to external network cables, which can be subject to high-voltage lightning strikes. China's 3C standard GB4943 explicitly requires safety certification for TNV circuits, as does North American UL62368-1. Taking North American UL62368-1 as an example, it requires a 1kV AC isolation test between the metal housing 181 of the network connector 880 and the low-voltage section within the circuit board 130, or a 1.5kV DC isolation test, to meet the relevant requirements of North American UL62368-1.

[0160] See also Figures 14 to 16 In Embodiment 2 of this application, except for the screw post 171, the first connector 120, the through hole 131, and the exposed copper 132, which can be directly electrically connected to the ground copper foil (such as ground copper foil 138) of the circuit board 130, the screw posts, connectors (such as the second connector 172, etc.), screw holes (such as screw holes 173, etc.), and exposed copper (such as exposed copper 175, etc.) at other locations must maintain a creepage distance of more than 1.2 mm from the components, traces, and copper foil (such as ground copper foil 138) in the circuit board 130. The pads at both ends of all isolation capacitors (such as the second isolation capacitor 174, etc.) must maintain a creepage distance of more than 1.2 mm. This avoids the electrostatic discharge of the metal shell 110 into the circuit board 130 when the metal top shell 111 or the metal bottom shell 112 is injected with 4kV to 10kV contact discharge, causing the low-voltage part in the circuit board 130 to be interfered with by the electrostatic discharge current, resulting in abnormal network equipment function or damage to the network equipment. The creepage distance is preferably 1.8 mm or more.

[0161] For example, pin 60 of the network connector 880 is soldered onto the circuit board 130, and the metal shell 181 is connected to pin 60. Pin 60 of the network connector 880 is electrically connected to the pad 62 of the third isolation capacitor 63 via copper foil 61. The pad 62 of the third isolation capacitor 63 is soldered to the pad 64 of the third isolation capacitor 63. The pad 64 of the third isolation capacitor 63 is electrically connected to the ground copper foil 65. The ground copper foil 65 is electrically connected to the top ground copper foil 168. The top ground copper foil 168 is electrically connected to the top ground copper foil 168. For the 38 electrical connection, to ensure a creepage distance of at least 1.2mm between pin 60 of the network connector 880 and the low-voltage portion of the circuit board 130, a creepage distance of at least 1.2mm must also be maintained between pads 62 and 64 of the third isolation capacitor 63. This ensures that the metal shell 181 of the network connector 880 and the low-voltage portion of the circuit board 130 meet the 2kV isolation requirement, thus satisfying the stringent safety testing requirements of North American UL62368-1 and Chinese 3C GB4943. A creepage distance of at least 1.8mm is preferred.

[0162] This prevents the network connector 880 from being damaged by high-voltage lightning strikes, which could damage the internal components of the circuit board 130 or cause malfunctions in the internal components of the circuit board 130.

[0163] The network device provided in Embodiment 2 of this application may have an antenna with the same structure and function as the network device provided in Embodiment 1 of this application. For example, the sensitive device 150 includes a radio frequency chip, and the antenna is connected to the radio frequency chip. The antenna includes a positive element and a negative element, which are sequentially arranged outside the metal housing 110 along the direction of gravity.

[0164] In Embodiment 2 of this application, noise radiated from other devices within the metal casing 110 and coupled to the metal casing 110 can be transmitted to the external power adapter 140 or power cable 300 via the first connector 120 and circuit board 130, thereby discharging the noise to the mains power or ground. This attenuation of the noise in the metal casing 110 significantly reduces the interference of the noise from the metal casing 110 on the antenna displacement current. When the network device in Embodiment 1 of this application is equipped with a first capacitor 161, during the noise discharge process, some of the noise transmitted to the first capacitor 161 will also be absorbed by the negative terminal 166 of the first capacitor 161.

[0165] Those skilled in the art will understand that the above embodiments are specific implementations of this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A network device, comprising: The network device comprises: a metal shell, a first connecting element connected to the metal shell, a power cable or an external power connector, a circuit board, a sensitive device and a sensitive circuit; the sensitive circuit is connected to the sensitive device; a shortest power supply path between the first connecting element and a negative pole of the external power connector or a negative pole of the power cable is a first path, and a shortest power supply path between the first connecting element and the sensitive device and / or the sensitive circuit is a second path; a length of the first path is shorter than a length of the second path; the network device further comprises a first isolation capacitor; the first path is a path in which the first connecting element is connected to the negative pole of the external power connector or the negative pole of the power cable via the circuit board and the first isolation capacitor; the second path is a path in which the first connecting element is connected to the sensitive device and / or the sensitive circuit via the circuit board and the first isolation capacitor; the network device further comprises a first capacitor; a positive pole of the first capacitor is connected to a positive pole of the external power connector or a positive pole of the power cable; a negative pole of the power cable or a negative pole of the external power connector is electrically connected to a negative pole of the sensitive device and the first connecting element through a negative pole of the first capacitor; the network device further comprises a clamping diode, a positive pole of the clamping diode is electrically connected to the positive pole of the first capacitor, and a negative pole of the clamping diode is electrically connected to the negative pole of the first capacitor; the network device further comprises a network port connector and a third isolation capacitor; the circuit board is provided with a grounding circuit, the grounding circuit is electrically connected to the negative pole of the external power connector or the negative pole of the power cable; the network port connector has a metal shell, the metal shell is electrically connected to the grounding circuit through the third isolation capacitor, and a plug-in interface of the metal shell is exposed outside the metal shell.

2. The network device of claim 1, wherein, Further comprising: a second connecting element and a second isolation capacitor; the grounding circuit is electrically connected to the negative pole of the external power connector or the negative pole of the power cable; the second connecting element is electrically connected to the grounding circuit through the second isolation capacitor, and the second connecting element is electrically connected to the metal shell.

3. The network device of claim 1, wherein, the metal shell is electrically connected to the metal shell body.

4. The network device of claim 1, wherein, The length of the second path is greater than or equal to 0.5 mm.

5. The network device of claim 1, wherein, The length of the first path is less than or equal to 100 mm.

6. The network device of claim 1, wherein, The line width of the conductive line on the circuit board in the first path is greater than or equal to 0.5 mm.

7. The network device of claim 1, wherein, The first path is part of the second path.

8. The network device of claim 1, wherein The circuit board is provided with a first conductive path, a second conductive path and a third conductive path, one end of the first conductive path is electrically connected with the first connecting piece, the other end of the first conductive path is connected with the first isolation capacitor, the second conductive path has the first isolation capacitor and is connected to the negative pole of the external power supply connector or the negative pole of the power supply cable, the third conductive path electrically connects the sensitive device and / or the sensitive circuit with the negative pole of the external power supply connector or the negative pole of the power supply cable; the first path is a path in which the first connecting piece is electrically connected with the negative pole of the external power supply connector or the negative pole of the power supply cable through the first conductive path and the second conductive path, and the second path is a path in which the first connecting piece is electrically connected with the sensitive device and / or the sensitive circuit through the first conductive path, the second conductive path and at least part of the third conductive path.

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