TWM621988U - Transmission circuit for ethernet - Google Patents

Abstract

A transmission circuit for Ethernet includes four transmission sub-circuits, a first capacitor and a second capacitor. Each transmission sub-circuit is coupled between an Ethernet physical layer device and an Ethernet connection device, and transmits a pair of differential-mode signals of the Ethernet network. Each transmission sub-circuit includes a diode bridge and a transformer. The first and second input terminals of the diode bridge are both coupled to the Ethernet connection device. The transformer includes a first coil and a second coil. Both ends of the first coil are coupled to the Ethernet physical layer device, and both ends of the second coil are respectively coupled to the first and the second input terminals. The first capacitor is coupled to the ground and the positive output terminal of each diode bridge. The second capacitor is coupled to the ground and the negative output terminal of each diode bridge.

Description

Transmission circuit for ethernet

The present invention relates to a transmission circuit used in an Ethernet network. More specifically, the novel Ethernet transmission circuit can replace the traditional Ethernet transformer, and provide functions of signal coupling, DC isolation and surge protection for Ethernet transmission.

Traditional network transformers for Ethernet (hereinafter referred to as "Ethernet transformers") include transformers with center taps, so they must be produced by manual winding, which results in traditional Ethernet transformers. The ability to adapt to changes in production capacity is poor, and the production cost is relatively high. In addition, the traditional Ethernet network transformer does not have the function of surge protection, which makes the Ethernet network system vulnerable to surge interference (such as lightning strikes, static electricity, or the switching action of the power supply of other loads in the same circuit). Environments often fail to function effectively, causing Ethernet service to have to be interrupted. In view of this, how to provide an Ethernet network transmission circuit that can be produced in an automated manner and has surge protection capability to replace the traditional Ethernet network transformer is a problem to be solved urgently in the technical field of the present invention. .

In order to solve at least the above-mentioned problems, the present invention discloses a transmission circuit for an Ethernet network. The transmission circuit contains four transmission subcircuits. Each of the transmission sub-circuits is coupled between an Ethernet physical layer device and an Ethernet connection device, and each of the transmission sub-circuits is used for transmitting a pair of differential mode signals of the Ethernet. Each of the transmission sub-circuits includes a diode bridge and a transformer. In each transmission sub-circuit, a first input terminal and a second input terminal of the diode bridge are both coupled to the Ethernet connection device. The transformer includes a first coil and a second coil, two ends of the first coil are coupled to the Ethernet physical layer device, and two ends of the second coil are respectively coupled to the first input end and the second input. The transmission circuit also includes a first capacitor and a second capacitor. The first capacitor is coupled to a ground terminal and a positive output terminal of each of the diode bridges. The second capacitor is coupled to the ground terminal and a negative output terminal of each of the diode bridges.

After referring to the accompanying drawings and the embodiments described later, those with ordinary knowledge in the technical field to which the present invention pertains can understand the main purpose, technical means and implementation aspects of the present invention.

The following examples are used to illustrate the technical content of the present invention, but not to limit the scope of the present invention. It should be noted that, in the following embodiments and drawings, elements irrelevant to the present invention have been omitted and not shown, and the dimensional relationships among the elements in the drawings are only for easy understanding and are not intended to limit the actual proportions. In this article, terms such as "first", "second", "third", "fourth" and so on before some elements are only used to distinguish each element, rather than to limit the order among the various elements. relation.

FIG. 1 is a schematic diagram of an implementation of the novel Ethernet transmission circuit. Referring to FIG. 1 , a transmission circuit 1 for an Ethernet network may basically include four groups of transmission sub-circuits 11 , 12 , 13 and 14 . Since the signals transmitted in the Ethernet network are generally designed to be transmitted through eight wires, the eight signals in the eight wires can be equally divided into four differential mode signal pairs, and the transmission sub-circuits 11 and 12 , 13 and 14 can respectively correspond to one of the four differential mode signal pairs. The transmission sub-circuits 11, 12, 13, and 14 have substantially the same structure, and their respective input and output types are also similar. Therefore, based on the principle of simplifying the description, the transmission sub-circuit 11 is only used as an example for description, but those with ordinary knowledge in the technical field to which the present invention belongs can understand the transmission sub-circuits 12 and 13 according to the description of the transmission sub-circuit 11. , 14, the corresponding structure, function and applicable parameters/settings of each element.

The transmission sub-circuit 11 can process a set of Ethernet signals transmitted between an Ethernet PHY layer device E1 and an Ethernet connector E2. The Ethernet connector E2 may be an Ethernet connector with an RJ-45 or 8P8C interface. Since the structures of the transmission subcircuits 12 , 13 , 14 and the transmission subcircuit 11 are substantially the same, those skilled in the art to which the present invention pertains can understand the transmission subcircuits 12 , 13 , and 14 according to the description of the transmission subcircuit 11 How to process the other three sets of Ethernet signals between the Ethernet physical layer device E1 and the Ethernet connector E2 through the same operation as the transmission sub-circuit 11, the same details will not be repeated here. .

The transmission sub-circuit 11 may include a transformer T1 and a diode bridge DB1. Transformer T1 may include a coil CL1 and a coil CL2 wound around the same magnetic core, and it may be a center-tapped design. Both ends of the coil CL1 can be coupled to the Ethernet physical layer device E1. Both ends of the coil CL2 can be coupled to the diode bridge DB1. More specifically, a connection end P1 of the coil CL2 can be coupled to an input end IP1 of the diode bridge DB1, and the other connection end The point P2 can be coupled to the other input end IP2 of the diode bridge DB1. In some embodiments, the inductance value of the transformer in each transmission sub-circuit (eg, the transformer T1 in the transmission sub-circuit 11 ) may be between 60 microhenry (uH) and 1 millihenry (mH).

Since the input end and the output end of the transformer T1 are not directly connected, it can provide the transmission circuit 1 with better DC isolation capability than capacitive components, and enable the transmission circuit 1 to meet the requirements of IEEE for network transformers. Withstand voltage specification of 1500 volts alternating current (Vac). In addition, since the transformer T1 may not have a center tap, it can have the same automated production process as the inductor.

The input end IP1 and the input end IP2 of the diode bridge DB1 can be coupled to the Ethernet connector E2. Since the diode bridge DB1 has parasitic capacitance, it can also meet the requirement of providing a specific impedance to the ground at a specific frequency, and thus can replace the inductive components in the traditional network transformer. In addition, since the diode bridge DB1 is a semiconductor component, it has the advantage of not requiring repeated fine tuning compared to the inductive components with higher tolerance in traditional network transformers.

The transmission circuit 1 may further include a capacitor C1 and a capacitor C2. Both the positive output terminal of the diode bridge DB1 (ie, the terminal that outputs a constant positive current) and the positive output terminals of the corresponding diode bridges in the transmission sub-circuits 12 , 13 and 14 can be coupled to the capacitor C1 . The negative output terminal of the diode bridge DB1 (ie, the terminal that outputs a constant negative current) and the negative output terminals of the corresponding diode bridges in the transmission sub-circuits 12 , 13 and 14 can be coupled to the capacitor C2 . In certain embodiments, the capacitance values of capacitor C1 and capacitor C2 may each be between 1 nanofarad (nF) and 1 microfarad (uF).

Both the capacitor C1 and the capacitor C2 can be coupled to a ground terminal G1. The capacitor C1 and the capacitor C2 can provide the effect of isolating the transmission circuit 1 to the ground, so as to prevent the noise from the ground terminal from being transmitted back to the signal line. In some embodiments, the ground terminal G1 may be in the form of chassis ground.

FIG. 2 is a schematic diagram of another embodiment of the transmission circuit of the present invention, which is derived from the transmission circuit 1 shown in FIG. 1 . Referring to FIG. 1 and FIG. 2 at the same time, a transmission circuit 2 for an Ethernet network may also include transmission sub-circuits 11, 12, 13, and 14, and the components of the transmission sub-circuits and the communication between the transmission sub-circuits and the Ethernet The connection relationship between the physical layer device E1 and the Ethernet connection device E2 can be the same as that of the transmission circuit 1. The difference between the two is that the transmission circuit 2 may further include a diode L1 and a diode L2.

The diode L1 can be connected in parallel with the capacitor C1, and the anode of the diode L1 can be coupled to the positive output terminal OP1 of the diode bridge DB1 and the corresponding diode bridges in the transmission sub-circuits 12, 13, and 14. Positive output terminal. The cathode of the diode L1 can be coupled to the ground terminal G1. Similarly, the diode L2 can be connected in parallel with the capacitor C2, and the cathode of the diode L2 can be coupled to the negative output terminal OP1 of the diode bridge DB1 and the corresponding diodes in the transmission sub-circuits 12, 13 and 14. The negative output terminal of the bridge, and the anode of the diode L2 can be coupled to the ground terminal G1. In certain embodiments, the capacitance values of diode L1 and diode L2 may each be between 1 picofarad (pF) and 1000 picofarads. In some embodiments, diode L1 and diode L2 may be two diodes that belong to the same package.

In some embodiments, the forward voltage values of both diode L1 and diode L2 may be higher than 1 volt. Furthermore, in some embodiments, the withstanding voltages of the capacitors C1 and C2 may not be lower than the forward voltage of the diodes L1 and L2 .

The combination of the diode bridge and the capacitors C1 and C2 and the diodes L1 and L2 in each transmission sub-circuit can provide the transmission circuit 2 with the functions of common mode filtering protection and impedance matching. Specifically, by adjusting the capacitance values of the diodes L1, L2 and the capacitors C1, C2, a suitable differential mode impedance can be obtained, and the signal crosstalk generated by other transmission channels to the transmission circuit 2 can be reduced.

FIG. 3 is a schematic diagram of another implementation of the transmission circuit of the present invention, which is derived from the transmission circuit 1 shown in FIG. 1 . 1 and 3 simultaneously, a transmission circuit 3 for Ethernet may include four transmission sub-circuits 21, 22, 23, 24 and capacitors C1, C2, and similar to the case in the transmission circuit 1, the transmission The structures of the sub-circuits 21, 22, 23, and 24 are substantially the same, and their respective input and output types are also similar, so this article only describes the structure of the transmission sub-circuit 21 in detail. The corresponding structures and connection configurations of the transmission subcircuits 22 , 23 , 24 are clear from the description of the transmission subcircuit 21 .

Like the transmission sub-circuit 11, the transmission sub-circuit 21 may also include a diode bridge DB1, a capacitor C1, and a capacitor C2. The difference between the transmission sub-circuit 21 and the transmission sub-circuit 11 is that it may further include a common mode inductor CM1. The common mode inductor CM1 may include a coil CL3 and a coil CL4, the coil CL3 may be coupled between the connection terminal P1 of the coil CL2 and the input end IP1 of the diode bridge DB1, and the coil CL4 may be coupled to the connection of the coil Between the terminal P2 and the input terminal IP2 of the diode bridge DB1. In other words, in the coil CL2 of the transmission sub-circuit 21, the connection terminal P1 may be coupled to the input terminal IP1 via the coil CL3, and the connection terminal P2 may be coupled to the input terminal IP2 via the coil CL4. The common mode inductor CM1 may further include a magnetic core, and the coil CL1 and the coil CL2 are wound around the magnetic core to form a common mode inductor.

The common mode inductors in each transmission sub-circuit (eg, the common mode inductor CM1 in the transmission sub-circuit 21 ) can provide additional common mode filtering protection for the transmission circuit 3 . In certain embodiments, the inductance values of the common mode inductors in each transmission subcircuit may each be between 10 nanohenrys (nH) and 5 microhenries.

In some embodiments, in order to enhance the isolation characteristic of the transmission circuit to ground, the transmission circuit may only include capacitors C1 and C2 without including the aforementioned diodes L1 and L2 (for example, the transmission circuits shown in FIG. 1 and FIG. 3 ) 1 and transmission circuit 3). In this case, the withstand voltage of the capacitors C1 and C2 can be designed to be no less than 500 direct current volts (Vdc), so as to maintain the differential mode impedance and reduce the function of signal crosstalk between channels.

FIG. 4 is a schematic diagram of another implementation of the transmission circuit of the present invention, which is jointly derived from the transmission circuit 2 and the transmission circuit 3 shown in FIGS. 2 and 3 . Referring to FIGS. 2 , 3 , and 4 at the same time, a transmission circuit 4 used for the Ethernet network may not only include capacitors C1 and C2 shared by the transmission circuit 2 and the transmission circuit 3 , but also include the capacitors C1 and C2 in the transmission circuit 2 . The diodes L1, L2 and the transmission sub-circuits 21, 22, 23, 24 in the transmission circuit 3, that is, the transmission circuit 4 combines the characteristics of the transmission circuit 2 and the transmission circuit 3. With this design, compared to the transmission circuit 2 and the transmission circuit 3, the transmission circuit 4 has the advantages of both to provide further common-mode filtering protection and impedance matching effects. Since those with ordinary knowledge in the technical field to which the present invention pertains can understand the specific structures of the transmission sub-circuits 21 , 22 , 23 , and 24 in the transmission circuit 4 according to the description of the transmission circuit 3 , detailed descriptions are omitted.

Similar to the transmission circuit 2 and the transmission circuit 3, in the transmission circuit 4, the diode L1 can be connected in parallel with the capacitor C1, and the anode of the diode L1 can be coupled to the anode of the diode bridge DB1 of the transmission sub-circuit 21 The output terminal OP1 and the positive output terminals of the corresponding diode bridges in the transmission sub-circuits 22 , 23 and 24 . The cathode of the diode L1 can be coupled to the ground terminal G1. Similarly, the diode L2 can be connected in parallel with the capacitor C2, and the cathode of the diode L2 can be coupled to the negative output terminal OP1 of the diode bridge DB1 of the transmission sub-circuit 21 and the transmission sub-circuits 22, 23 and 24. The negative output terminal of the corresponding diode bridge, and the anode of the diode L2 can be coupled to the ground terminal G1. In certain embodiments, the capacitance values of diode L1 and diode L2 may each be between 1 picofarad and 1000 picofarads. In some embodiments, diode L1 and diode L2 may be two diodes that belong to the same package.

In some embodiments, to meet the requirements of ground isolation and surge protection above 2000 volts at the same time, the diodes L1 and L2 in FIG. 2 and FIG. 4 can be further replaced with gas discharge tubes (GDTs) ) or varistor.

To sum up, the transmission circuits 1, 2, 3, and 4 for the Ethernet network in this new model do not need to be produced by manual winding, etc., have a structure that can be automated production, and can provide the Ethernet network Signal coupling, DC isolation, surge protection and other functions required for transmission. Therefore, the new Ethernet network transmission circuit has the ability to replace the traditional Ethernet network transformer, and provides higher environmental adaptability for the transmission of the Ethernet network.

The above-mentioned examples are only used to illustrate the embodiments of the present invention and to illustrate the technical characteristics of the present invention, and are not intended to limit the protection scope of the present invention. Any changes or equivalent arrangements that can be easily accomplished by those with ordinary knowledge in the technical field to which the present invention pertains fall within the claimed scope of the present invention.

As follows: 1, 2, 3, 4: Transmission circuit 11, 12, 13, 14, 21, 22, 23, 24: Transmission subcircuits E1: Ethernet physical layer device E2: Ethernet connection device C1, C2: capacitors CL1, CL2, CL3, CL4: Coil CM1: Common Mode Inductor DB1: Diode Bridge G1: ground terminal IP1, IP2: input terminal L1, L2: Diodes ON1: negative output terminal OP1: Positive output terminal P1, P2: connection endpoints T1: Transformer

Below in conjunction with the drawings and specific embodiments, the present invention will be described in further detail, wherein: 1 is a schematic diagram of an implementation of a transmission circuit for an Ethernet network of the present invention; 2 is a schematic diagram of another implementation of the transmission circuit of the present invention; 3 is a schematic diagram of another implementation of the novel transmission circuit; and FIG. 4 is a schematic diagram of another embodiment of the transmission circuit of the present invention.

1: Transmission circuit

11, 12, 13, 14: Transmission subcircuits

E1: Ethernet physical layer device

E2: Ethernet connection device

C1, C2: capacitors

CL1, CL2: Coil

DB1: Diode Bridge

G1: ground terminal

IP1, IP2: input terminal

ON1: negative output terminal

OP1: Positive output terminal

T1: Transformer

Claims (11)

A transmission circuit for an Ethernet network, comprising: Four transmission sub-circuits, each of which is coupled between an Ethernet physical layer device and an Ethernet connection device, and each of the transmission sub-circuits is used to transmit a pair of Ethernet differential mode signal, and each of the transmission sub-circuits includes: a diode bridge, a first input end and a second input end of the diode bridge are both coupled to the Ethernet connection device; and A transformer includes a first coil and a second coil, two ends of the first coil are coupled to the Ethernet physical layer device, and two ends of the second coil are respectively coupled to the first input end and the second input; a first capacitor coupled to a ground terminal and a positive output terminal of each of the diode bridges; and A second capacitor is coupled to the ground terminal and a negative output terminal of each of the diode bridges. The transmission circuit of claim 1, further comprising: A first diode is connected in parallel with the first capacitor, and an anode of the first diode is coupled to the positive output terminal of each of the diode bridges, and a cathode of the first diode is coupled to connected to the ground terminal; and A second diode is connected in parallel with the second capacitor, and a cathode of the second diode is coupled to the negative output terminal of each of the diode bridges, and an anode of the second diode is coupled to connected to the ground terminal. The transmission circuit of claim 2, wherein the capacitance value of the first diode and the capacitance value of the second diode are each between 1 picofarad and 1000 picofarads. The transmission circuit of claim 2, wherein the forward voltage values of the first diode and the second diode are both higher than 1 volt. The transmission circuit of claim 2, wherein the first diode and the second diode are two diodes that belong to the same package. The transmission circuit of claim 2, wherein the withstand voltage of the first capacitor and the second capacitor is not lower than the forward conduction voltage of the first diode and the second diode. The transmission circuit of claim 1, wherein the inductance value of the transformer in each of the transmission sub-circuits is between 60 microhenry and 1 millihenry. The transmission circuit of claim 1, wherein the capacitance values of the first capacitor and the second capacitor are each between 1 nanofarad and 1 microfarad. The transmission circuit of claim 1, wherein a withstand voltage of the first capacitor and the second capacitor is not lower than 500 DCV. The transmission circuit as claimed in claim 1 or 2, wherein each of the transmission sub-circuits further comprises a common mode inductor, and the common mode inductor is coupled to the two ends of the second coil and the first input end and the first input end. between the two inputs. The transmission circuit of claim 10, wherein the inductance value of the common mode inductor in each of the transmission sub-circuits is between 10 nanohenry and 5 microhenry respectively.

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