TW201644131A - Network filtering circuit and apparatus of using the same - Google Patents

Abstract

A network interface circuit includes a cable side, a chip side, and a plurality of transmitting channels disposed between the cable side and the chip side. Each transmitting channel includes an isolation transformer having a primary coil connecting with the cables side and a secondary coil connecting with the physical side. The primary coil has a center tap directly connecting to ground. The secondary has a center tap directly connecting to ground, and a two outer ends electrically connecting with one side of a capacitor. The other side of the capacitor connects to the physical side.

Description

Network filter circuit and network filter device using the same

The present invention relates to a network filter circuit and a network filter device using the same, and more particularly to a center tap grounding setting of an isolation transformer in a network filter circuit.

For prior art related to this creation, please refer to the TWI405369 patent published on August 11, 2013, which discloses a network filter circuit including a cable side (CABLE SIDE), a network chip side (PHY SIDE), and a connection to A plurality of signal transmission channels between the cable side and the network chip side, each of the signal transmission channels including an isolation transformer and a common mode choke. The primary side of the isolation transformer is connected to the network side, and the secondary side of the isolation transformer is connected to the common mode choke and connected to the chip side. The center tap of the primary side of the isolation transformer is connected to the ground through a metal mask housing by connecting a resistor and capacitor (Bob-smith circuit) in series. In addition, this patent application also discloses a combination connector of RJ 45 stacked USB using this network filter circuit. Due to the setting of the resistor and the capacitor, the manufacturing cost of the connector is increased, and since the resistor and the capacitor are struck by lightning on the network cable, a high surge causes the resistor and the capacitor to burn out, resulting in the network connector not working properly. It even caused the burnout of the network chip on the external motherboard.

In addition, the network filter circuit can also be used in a network transformer, such as the network transformer of the patent document Continental Patent No. CN 203 562 517 U and U.S. Patent No. 8,861,204 B.

The technical problem to be solved by the present invention is to provide a network filter circuit and a network filter device using the same, which has a high lightning protection level.

In order to solve the above technical problem, the present invention provides a network filter circuit electrically disposed between a network chip and a network cable. The network filter circuit includes: a network cable side for electrically connecting the network cable, Electrically connecting the wafer side of the network chip and at least one signal transmission channel disposed between the network line side and the wafer side, the transmission channel is provided with an isolation transformer having a primary side and a secondary side, the primary side electrical connection On the side of the network line, the secondary side is electrically connected to the wafer side, wherein the center tap of the primary side is directly electrically connected to the ground end, and the center tap of the secondary side is also directly electrically connected to the ground end, the second The side also has two connecting ends, one of which is connected in series with a capacitor and then electrically connected to the wafer side.

A network filtering device is electrically disposed between a network chip and a network cable. The network filtering device includes: a circuit board and at least one signal transmission channel disposed on the circuit board, the transmission channel is provided with a primary side And a secondary side isolation transformer, the primary side is electrically connected to the network line, and the secondary side is electrically connected to the network chip, wherein the center tap of the primary side is directly electrically connected to the ground end, The center tap of the secondary side is also directly electrically connected to the ground end. The secondary side also has two connection ends, and a connection end is connected in series with a capacitor and then electrically connected to the wafer side.

Compared with the prior art, the present invention breaks through the conventional understanding, omitting the traditional design of the Bob Smith circuit, and directly connecting the primary side of the isolation transformer to the ground terminal, breaking through the bottleneck limitation of the resistor and the capacitor to withstand high breakthrough. Significantly improved the network filter circuit and the lightning protection level of the circuit. In addition, since the high glitch generated by the lightning strike cannot be instantaneously connected to the ground, the wafer is coupled from the primary side to the secondary side to damage the wafer. In the present invention, a capacitor is connected in series between the serial side of the transformer and the wafer side, and the filter is filtered. The glitch coupled from the primary side to the secondary side. Moreover, since the center tap of the secondary side is directly electrically connected to the ground side, the coupling from the primary side to the secondary side is prevented from being conducted to the network wafer by the center tap.

The first figure is a circuit diagram of a network filter circuit in accordance with the present invention.

Referring to the first figure, a network filter circuit 100 according to the present invention is electrically disposed between a network chip and a network cable.

The network filter circuit 100 includes: a network line side 10 for electrically connecting the network lines, a wafer side 11 for electrically connecting the network chips, and at least one signal disposed between the network line side 10 and the wafer side 11 Transmission channel 13. The signal transmission channel 13 is provided with an isolation transformer 14 having a primary side 141 and a secondary side 142. The primary side 141 is electrically connected to the network side 10, and the secondary side 142 is electrically connected to the wafer side 11, the primary side. The center tap 1411 of the 141 is directly electrically connected to the ground terminal 17. The secondary side 142 has two connecting ends 1422. A connecting end 1422 is connected in series with a capacitor 15 and then electrically connected to the wafer side 11. Preferably, each connecting end 1422 is connected in series with a capacitor 15 and then electrically connected to the wafer side 11. The center tap 1421 of the secondary side 142 is also directly electrically connected to the ground terminal 18. The ground terminal 17 and the ground terminal 18 are typically connected to the same ground on a motherboard having a network chip.

The signal transmission channel 13 is further provided with a common mode choke coil 16 . One end of the common mode choke coil 16 is electrically connected to the capacitor 15 , and the other end of the common mode choke coil 16 is electrically connected to the wafer side 11 . The common mode choke 16 is a two-wire common mode choke.

When the network filter circuit 100 is used for 10/100M Base-TX, the network filter circuit 100 only needs two signal transmission channels of the same setting; and when the network filter circuit 100 is used for 1000M Base-T and higher, the network The path filter circuit 100 requires four signal channels of the same setting. The embodiment shown in the first figure is four signal transmission channels of the same setting.

The network filter circuit 100 can be applied to an RJ45 network connector with a filter component or a network filter device of a network transformer. The network filter device is electrically disposed between the network chip and the network cable. The device includes: a circuit board and at least one signal transmission channel disposed on the circuit board, the transmission channel is provided with an isolation transformer having a primary side and a secondary side, wherein the primary side is electrically connected to the network line, the secondary side For electrically connecting to the network chip, the center tap of the primary side is directly electrically connected to the ground end, and the center tap of the secondary side is also directly electrically connected to the ground end, and the secondary side further has two connection ends. A connector is connected in series with a capacitor and electrically connected to the wafer side. A common mode choke coil is further mounted on the circuit board, and one end of the common mode choke coil is electrically connected to the capacitor through a conductive path disposed on the circuit board, and the other end of the common mode choke coil is electrically connected to the network chip. connection.

When the network filtering device is an RJ45 network connector, the network filtering device includes a metal housing (corresponding to the grounding end 17) connected to the ground, and the circuit board is disposed in the metal mask housing and electrically connected to the metal housing. The conductive path of the primary side center tap disposed on the circuit board is directly electrically connected to the metal mask housing. The conductive path of the secondary side center tap disposed on the circuit board is directly electrically connected to the ground layer on the external main board (corresponding to the ground end 18). The RJ45 network connector also includes eight mating terminals for contacting the network cable and mounting terminals for mounting to an external motherboard that is mounted to the external motherboard.

When the network filtering device is a network transformer, the network chip is also mounted on a circuit board. The circuit board is also equipped with a passive network RJ45 connector having a docking terminal for connecting to the network cable.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and those skilled in the art will be able to make equivalent modifications or changes in accordance with the spirit of the present invention. It is covered by the following patent application.

100‧‧‧Network filter circuit

10‧‧‧Network side

11‧‧‧ wafer side

13‧‧‧Signal transmission channel

14‧‧‧Isolation transformer

141‧‧‧ primary side

141‧‧‧Center tap 1

142‧‧‧ secondary side

1421‧‧‧Center tap

1422‧‧‧Connected end

15‧‧‧ capacitor

16‧‧‧Common mode choke

17, 18‧‧‧ Grounding

no

100‧‧‧Network filter circuit

10‧‧‧Network side

11‧‧‧ wafer side

13‧‧‧Signal transmission channel

14‧‧‧Isolation transformer

141‧‧‧ primary side

1411‧‧‧Center tap

142‧‧‧ secondary side

1421‧‧‧Center tap

1422‧‧‧Connected end

15‧‧‧ capacitor

16‧‧‧Common mode choke

17‧‧‧ Grounding

18‧‧‧ Grounding

Claims (9)

A network filter circuit is electrically disposed between a network chip and a network cable, and the network filter circuit includes:
Used to electrically connect the network cable side of the network cable;
a chip side for electrically connecting the network chip; and at least one signal transmission channel disposed between the network line side and the wafer side, the transmission channel is provided with an isolation transformer having a primary side and a secondary side, the primary side power The second side is electrically connected to the ground side, and the center tap of the primary side is directly electrically connected to the ground end, and the center tap of the secondary side is also directly electrically connected to the ground end. The secondary side also has two connection ends, and a connection end is connected in series with a capacitor and then electrically connected to the wafer side. The network filter circuit of claim 1, wherein each of the terminals is connected in series with a capacitor and electrically connected to the wafer side. The network filter circuit of claim 1, wherein the signal transmission channel further comprises a common mode choke, and one end of the common mode choke is electrically connected to the capacitor, and the common mode choke is The other end is electrically connected to the wafer side. The network filter circuit of claim 3, wherein the common mode choke coil is a two-wire common mode choke coil. The network filter circuit of claim 1, wherein the at least one signal transmission channel is two signal channels of the same setting or four signal channels of the same setting. A network filtering device is electrically disposed between a network chip and a network cable, and the network filtering device includes:
a circuit board; and at least one signal transmission channel disposed on the circuit board, the transmission channel is provided with an isolation transformer having a primary side and a secondary side, wherein the primary side is electrically connected to the network line, and the secondary side is used for Electrically connected to the network chip, wherein the center tap of the primary side is directly electrically connected to the ground end, and the center tap of the secondary side is also directly electrically connected to the ground end, and the secondary side further has two connection ends, one The terminal is connected in series with a capacitor and electrically connected to the wafer side. The network filtering device of claim 6, wherein the network filtering device is an RJ45 network connector, the network filtering device comprises a grounded metal case, and the circuit board is disposed on the metal mask case. The body is electrically connected to the metal casing, and the conductive path of the primary side of the center tap disposed on the circuit board is directly electrically connected to the metal mask casing. The network filtering device of claim 6, wherein the network filtering device is a network transformer, the network chip is also mounted on a circuit board, and the circuit board is further equipped with a passive RJ45 connector, the passive type The network RJ45 connector has a docking terminal for connection to the network cable. The network filter device of claim 6, wherein the circuit board further has a common mode choke coil, and one of the common mode choke coils is electrically connected to the capacitor by a conductive path disposed on the circuit board. The other end of the common mode choke is electrically connected to the network chip.