Ethernet interface protection topology circuit

Abstract

The application provides an Ethernet interface protection topology circuit, a first interface of an APL power supply switch is connected with a backbone power supply end interface of a backbone communication cable through a first power supply protection circuit, a backbone power taking end interface of the backbone communication cable is connected with a second interface of an APL field switch through a first power taking protection circuit; a third interface of the APL field switch is connected with a branch power supply end interface of a branch communication cable through a second power supply protection circuit, and a branch power taking end interface of the branch communication cable is connected with a fourth interface of an instrument through a second power taking protection circuit. Through the power taking protection circuit and the power supply protection circuit, the backbone communication cable and the branch communication cable interface power supply anti-reverse connection function is realized, and the problems of the backbone communication cable and the branch communication cable power taking and power supply short circuit are solved.

Description

Technical Field

[0001] This invention relates to the field of industrial communication technology, specifically to an Ethernet interface protection topology circuit. Background Technology

[0002] Enhanced Physical Layer (APL) dual-wire Ethernet is an emerging industrial communication method in smart factories. APL dual-wire Ethernet supports up to 1km of trunk communication cable and 200m of spur communication cable. Both the trunk and spur communication cables can provide power, allowing field devices to draw power from the communication cables without the need for additional auxiliary power supplies.

[0003] Existing APL dual-wire Ethernet APL power switches and APL field switches both directly power the backbone and branch communication cables via external power supplies. Both the APL field switches and instruments draw power directly from these cables. However, under this existing power supply method, the polarity of the APL field switches and instruments depends on the power polarity of the bus and the correctness of the interface wiring. Furthermore, a short circuit in an APL field switch or instrument can cause other normally communicating instruments to malfunction. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide an Ethernet interface protection topology circuit to solve the problem that the polarity of the APL field switch and instrument is related to the power supply polarity of the bus and the correctness of the interface wiring under the existing power supply method, and to solve the problem that when the APL field switch or instrument is short-circuited, other normally communicating instruments will enter a fault state.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] This invention discloses an Ethernet interface protection topology circuit, which includes: an enhanced physical layer APL power switch, an APL field switch, an instrument, a first power supply protection circuit, a first power extraction protection circuit, a second power supply protection circuit, and a second power extraction protection circuit.

[0007] The first interface of the APL power switch is connected to the main power supply end interface of the main communication cable through the first power supply protection circuit, and the main power supply end interface of the main communication cable is connected to the second interface of the APL field switch through the first power supply protection circuit.

[0008] The third interface of the APL field switch is connected to the branch power supply end interface of the branch communication cable through the second power supply protection circuit, and the branch power take-off end interface of the branch communication cable is connected to the fourth interface of the instrument through the second power take-off protection circuit.

[0009] Preferably, the first power supply protection circuit includes at least: a first suppression circuit, a second suppression circuit, a first short-circuit protection circuit, and a first power supply reverse connection protection circuit; the first suppression circuit and the second suppression circuit are used to suppress surges and pulse bursts;

[0010] The first end and the second end of the first interface are respectively connected to the first end and the second end of the main power supply interface; the first end of the main power supply interface is connected to the first end of the first suppression circuit, and the second end of the main power supply interface is connected to the second end of the first suppression circuit.

[0011] The first end of the main power supply terminal interface is connected to the first end of the second suppression circuit through an inductor, and the second end of the main power supply terminal interface is connected to the second end of the second suppression circuit through an inductor.

[0012] The first terminal of the first power supply reverse connection protection circuit is connected to the first terminal of the second suppression circuit, and the first terminal of the first power supply reverse connection protection circuit is connected to the second terminal of the second suppression circuit and the first terminal of the first short circuit protection circuit through a capacitor.

[0013] The second terminal of the first short-circuit protection circuit is connected to the second terminal of the first power supply reverse connection protection circuit.

[0014] Preferably, the first power supply protection circuit includes at least: a third suppression circuit, a fourth suppression circuit, a second short-circuit protection circuit, and a second reverse connection protection circuit; the third suppression circuit and the fourth suppression circuit are used to suppress surges and pulse bursts;

[0015] The first end and the second end of the second interface are respectively connected to the first end and the second end of the main power supply interface; the first end of the main power supply interface is connected to the first end of the third suppression circuit, and the second end of the main power supply interface is connected to the second end of the third suppression circuit.

[0016] The first end of the main power input interface is connected to the first end of the fourth suppression circuit through an inductor, and the second end of the main power input interface is connected to the second end of the fourth suppression circuit through an inductor.

[0017] The first terminal of the second power supply reverse connection protection circuit is connected to the first terminal of the fourth suppression circuit, and the first terminal of the second power supply reverse connection protection circuit is connected to the second terminal of the fourth suppression circuit and the first terminal of the second short circuit protection circuit through capacitors respectively.

[0018] The second terminal of the second short-circuit protection circuit is connected to the second terminal of the second power supply reverse connection protection circuit.

[0019] Preferably, the second power supply protection circuit includes at least: a fifth suppression circuit, a sixth suppression circuit, a third short-circuit protection circuit, and a third power supply reverse connection protection circuit; the fifth suppression circuit and the sixth suppression circuit are used to suppress surges and pulse bursts;

[0020] The first and second ends of the third interface are respectively connected to the first and second ends of the branch power supply interface; the first end of the branch power supply interface is connected to the first end of the fifth suppression circuit, and the second end of the branch power supply interface is connected to the second end of the fifth suppression circuit.

[0021] The first end of the branch power supply terminal interface is connected to the first end of the sixth suppression circuit through an inductor, and the second end of the branch power supply terminal interface is connected to the second end of the sixth suppression circuit through an inductor.

[0022] The first terminal of the third power supply reverse connection protection circuit is connected to the first terminal of the sixth suppression circuit, and the first terminal of the third power supply reverse connection protection circuit is connected to the second terminal of the sixth suppression circuit and the first terminal of the third short circuit protection circuit through capacitors respectively.

[0023] The second terminal of the third short-circuit protection circuit is connected to the second terminal of the third power supply reverse connection protection circuit.

[0024] Preferably, the second power supply protection circuit includes at least: a seventh suppression circuit, an eighth suppression circuit, a fourth short-circuit protection circuit, and a fourth reverse connection protection circuit; the seventh suppression circuit and the eighth suppression circuit are used to suppress surges and pulse bursts;

[0025] The first and second ends of the fourth interface are respectively connected to the first and second ends of the branch power supply interface; the first end of the branch power supply interface is connected to the first end of the seventh suppression circuit, and the second end of the branch power supply interface is connected to the second end of the seventh suppression circuit.

[0026] The first end of the branch power take-off interface is connected to the first end of the eighth suppression circuit through an inductor, and the second end of the branch power take-off interface is connected to the second end of the eighth suppression circuit through an inductor.

[0027] The first terminal of the fourth power supply reverse connection protection circuit is connected to the first terminal of the eighth suppression circuit, and the first terminal of the fourth power supply reverse connection protection circuit is connected to the second terminal of the eighth suppression circuit and the first terminal of the fourth short circuit protection circuit through capacitors respectively.

[0028] The second terminal of the fourth short-circuit protection circuit is connected to the second terminal of the fourth power supply reverse connection protection circuit.

[0029] Preferably, the first suppression circuit includes a first transient diode and a second transient diode; the second suppression circuit includes a third transient diode and a third transient diode.

[0030] The first terminal of the main power supply terminal interface is connected to the first terminal of the first transient diode, and the second terminal of the first transient diode is connected to the first terminal of the second transient diode; the second terminal of the second transient diode is connected to the second terminal of the main power supply terminal interface.

[0031] The first terminal of the main power supply interface is connected to the first terminal of the third transient diode via an inductor, and the second terminal of the third transient diode is connected to the first terminal of the fourth transient diode; the second terminal of the fourth transient diode is connected to the second terminal of the main power supply interface via an inductor.

[0032] Wherein, the first terminal of the first transient diode is the first terminal of the first suppression circuit, the second terminal of the second transient diode is the second terminal of the first suppression circuit, the first terminal of the third transient diode is the first terminal of the second suppression circuit, and the second terminal of the fourth transient diode is the second terminal of the second suppression circuit.

[0033] Preferably, the third suppression circuit includes a fifth transient diode and a sixth transient diode; the fourth suppression circuit includes a seventh transient diode and an eighth transient diode;

[0034] The first end of the main power input interface is connected to the first end of the fifth transient diode, the second end of the fifth transient diode is connected to the first end of the sixth transient diode, and the second end of the sixth transient diode is connected to the second end of the main power input interface.

[0035] The first end of the main power input interface is connected to the first end of the seventh transient diode through an inductor, the second end of the seventh transient diode is connected to the first end of the eighth transient diode, and the second end of the eighth transient diode is connected to the second end of the main power input interface through an inductor.

[0036] Wherein, the first terminal of the fifth transient diode is the first terminal of the third suppression circuit, the second terminal of the sixth transient diode is the second terminal of the third suppression circuit, the first terminal of the seventh transient diode is the first terminal of the fourth suppression circuit, and the second terminal of the eighth transient diode is the second terminal of the fourth suppression circuit.

[0037] Preferably, the fifth suppression circuit includes a ninth transient diode and a tenth transient diode; the sixth suppression circuit includes an eleventh transient diode and a twelfth transient diode;

[0038] The first end of the branch power supply terminal interface is connected to the first end of the ninth transient diode, the second end of the ninth transient diode is connected to the first end of the tenth transient diode, and the second end of the tenth transient diode is connected to the second end of the branch power supply terminal interface.

[0039] The first end of the branch power supply terminal interface is connected to the first end of the eleventh transient diode through an inductor, the second end of the eleventh transient diode is connected to the first end of the twelfth transient diode, and the second end of the twelfth transient diode is connected to the second end of the branch power supply terminal interface through an inductor.

[0040] Wherein, the first terminal of the ninth transient diode is the first terminal of the fifth suppression circuit, the second terminal of the tenth transient diode is the second terminal of the fifth suppression circuit, the first terminal of the eleventh transient diode is the first terminal of the sixth suppression circuit, and the second terminal of the eleventh transient diode is the second terminal of the sixth suppression circuit.

[0041] Preferably, the seventh suppression circuit includes a thirteenth transient diode and a fourteenth transient diode; the eighth suppression circuit includes a fifteenth transient diode and a sixteenth transient diode;

[0042] The first end of the branch power supply interface is connected to the first end of the thirteenth transient diode, the second end of the thirteenth transient diode is connected to the first end of the fourteenth transient diode, and the second end of the fourteenth transient diode is connected to the second end of the branch power supply interface.

[0043] The first end of the branch power input interface is connected to the first end of the fifteenth transient diode through an inductor, the second end of the fifteenth transient diode is connected to the first end of the sixteenth transient diode, and the second end of the sixteenth transient diode is connected to the second end of the branch power input interface through an inductor.

[0044] Specifically, the first terminal of the thirteenth transient diode is the first terminal of the seventh suppression circuit, the second terminal of the fourteenth transient diode is the second terminal of the seventh suppression circuit, the first terminal of the fifteenth transient diode is the first terminal of the eighth suppression circuit, and the second terminal of the sixteenth transient diode is the second terminal of the eighth suppression circuit.

[0045] Preferably, the first short-circuit protection circuit includes a first fuse.

[0046] Based on the above embodiments of the present invention, an Ethernet interface protection topology circuit is provided. This Ethernet interface protection topology circuit includes: an APL power switch, an APL field switch, an instrument, a first power supply protection circuit, a first power extraction protection circuit, a second power supply protection circuit, and a second power extraction protection circuit. The first interface of the APL power switch is connected to the main power supply end interface of the backbone communication cable through the first power supply protection circuit. The main power extraction end interface of the backbone communication cable is connected to the second interface of the APL field switch through the first power extraction protection circuit. The third interface of the APL field switch is connected to the branch power supply end interface of the branch communication cable through the second power supply protection circuit. The branch power extraction end interface of the branch communication cable is connected to the fourth interface of the instrument through the second power extraction protection circuit. This solution, through the power extraction protection circuit and the power supply protection circuit, realizes the reverse connection protection function of the power supply interfaces of the backbone communication cable and the branch communication cable, and solves the problems of power extraction and power supply short circuits in the backbone communication cable and the branch communication cable. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0048] Figure 1 This is a device network topology diagram of APL dual-line Ethernet provided in an embodiment of the present invention;

[0049] Figure 2 A structural block diagram of an Ethernet interface protection topology circuit provided in an embodiment of the present invention;

[0050] Figure 3 This is a structural block diagram of the first power supply protection circuit provided in an embodiment of the present invention;

[0051] Figure 4 This is a structural block diagram of the first power supply protection circuit provided in an embodiment of the present invention;

[0052] Figure 5 This is a structural block diagram of the second power supply protection circuit provided in an embodiment of the present invention;

[0053] Figure 6 This is a structural block diagram of the second power supply protection circuit provided in an embodiment of the present invention;

[0054] Figure 7 A partial example diagram of the Ethernet interface protection topology circuit provided in the embodiments of the present invention;

[0055] Figure 8Another example diagram of the Ethernet interface protection topology circuit provided in the embodiments of the present invention. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] As can be seen from the background technology, Advanced Physical Layer (APL) dual-line Ethernet is an industrial communication method that is emerging in smart factories. APL dual-line Ethernet supports trunk communication cables up to 1km long and spur communication cables up to 200m long.

[0059] The main communication cable provides 50V / 57.5W of power, while branch communication cables provide 15V / 0.54W. Field devices can draw power from the communication cables without requiring additional auxiliary power supplies. A single communication cable can complete the industrial communication network. For example... Figure 1 The provided APL dual-line Ethernet device network topology diagram is available. Figure 1 It includes an APL PowerSwitch, an APL Field Switch, and an APL instrument; an APL instrument is mounted on one of the branch ports (Spur ports) of the APL Field Switch.

[0060] The inventors discovered through research that APL device connections rely on interface circuits. Existing APL dual-wire Ethernet power switches and field switches directly power the backbone and branch communication cables via external power supplies, and both the field switches and instruments draw power directly from these cables. However, under these existing power supply methods, the power polarity of the Trunk and Spur interfaces changes with the polarity of the external power supply. Furthermore, the polarity of the APL field switches and instruments depends on the bus power polarity and the correctness of the interface wiring. Moreover, when an APL field switch or instrument experiences a short circuit, the power supply to the backbone and branch communication cables may become undervoltage, causing cascaded APL field switches and other normally communicating instruments to malfunction due to power loss.

[0061] Furthermore, for two-wire Ethernet communication, the 1km-long backbone communication cable and the 200m branch communication cable may introduce surge and burst pulse problems. The interface lacks protection against the differential mode components of surge and burst pulses, which may damage the two-wire Ethernet equipment.

[0062] Therefore, to address the lack of power polarity protection, short-circuit protection, surge and differential mode suppression for current dual-wire Ethernet Trunk and Spur interface circuits, this solution proposes an Ethernet interface protection topology circuit. This topology circuit includes: an APL power switch, an APL field switch, instruments, a first power supply protection circuit, a first power extraction protection circuit, a second power supply protection circuit, and a second power extraction protection circuit. The power extraction and power supply protection circuits provide reverse connection protection for the backbone and branch communication cable interfaces, resolve power extraction and short-circuit issues for the backbone and branch communication cables, and address surge and differential mode suppression issues for dual-wire Ethernet interfaces. The following embodiments illustrate the Ethernet interface protection topology circuit provided in this solution.

[0063] See Figure 2 The diagram shows a structural block diagram of an Ethernet interface protection topology circuit provided by an embodiment of the present invention. The Ethernet interface protection topology circuit includes: an APL power switch 100, an APL field switch 200, an instrument 300 (which may be multiple), a first power supply protection circuit 400, a first power extraction protection circuit 500, a second power supply protection circuit 600, and a second power extraction protection circuit 700.

[0064] Specifically, the first interface of the APL power switch 100 (hereinafter referred to as the APL power switch) is connected to the trunk power supply end interface of the trunk communication cable through the first power supply protection circuit 400 (hereinafter referred to as the first power supply protection circuit), and the trunk power supply end interface of the trunk communication cable is connected to the second interface of the APL field switch 200 (hereinafter referred to as the APL field switch) through the first power supply protection circuit 500 (hereinafter referred to as the first power supply protection circuit).

[0065] The third interface of the APL field switch is connected to the branch power supply end interface of the branch communication cable (Spur) through the second power supply protection circuit 600 (hereinafter referred to as the second power supply protection circuit). The branch power supply end interface of the branch communication cable is connected to the fourth interface of the instrument 300 (hereinafter referred to as the instrument) through the second power supply protection circuit 700 (hereinafter referred to as the second power supply protection circuit).

[0066] It is understandable that the trunk power supply interface is equivalent to the trunk power supply interface, and the trunk power take-off interface is equivalent to the trunk power take-off interface; the branch power supply interface is equivalent to the Spur power supply interface, and the branch power take-off interface is equivalent to the Spur power take-off interface.

[0067] By using power extraction protection circuits and power supply protection circuits, the reverse connection protection function of the power supply interface of the main communication cable and branch communication cable is realized, the problem of power extraction and power supply short circuit of the main communication cable and branch communication cable is solved, and the problem of surge and differential mode component suppression of dual-line Ethernet interface is solved.

[0068] In some embodiments, such as Figure 3 The provided structural block diagram of the first power supply protection circuit 400 includes at least: a first suppression circuit 401, a second suppression circuit 402, a first short circuit protection circuit 403, and a first power supply reverse connection protection circuit 404; the first suppression circuit 401 and the second suppression circuit 402 are used to suppress surges and pulse bursts.

[0069] Specifically, the first end and the second end of the first interface of the APL power switch 100 are respectively connected to the first end and the second end of the main power supply interface; the first end of the main power supply interface is connected to the first end of the first suppression circuit 401, and the second end of the main power supply interface is connected to the second end of the first suppression circuit 401.

[0070] The first end of the main power supply interface is connected to the first end of the second suppression circuit 402 through inductor L, and the second end of the main power supply interface is connected to the second end of the second suppression circuit 402 through inductor L.

[0071] The first terminal of the first power supply reverse connection protection circuit 404 is connected to the first terminal of the second suppression circuit 402. The first terminal of the first power supply reverse connection protection circuit 404 is connected to the second terminal of the second suppression circuit 402 and the first terminal of the first short circuit protection circuit 403 through capacitors (two capacitors C).

[0072] The second terminal of the first short-circuit protection circuit 403 is connected to the second terminal of the first power supply reverse connection protection circuit 404.

[0073] In one specific embodiment, the first suppression circuit 401 includes a first transient diode (transient suppression diode, also referred to as TVS) and a second transient diode; the second suppression circuit 402 includes a third transient diode and a third transient diode.

[0074] The first terminal of the main power supply terminal interface is connected to the first terminal of the first transient diode, and the second terminal of the first transient diode is connected to the first terminal of the second transient diode; the second terminal of the second transient diode is connected to the second terminal of the main power supply terminal interface.

[0075] The first terminal of the main power supply interface is connected to the first terminal of the third transient diode through an inductor, and the second terminal of the third transient diode is connected to the first terminal of the fourth transient diode; the second terminal of the fourth transient diode is connected to the second terminal of the main power supply interface through an inductor.

[0076] Wherein, the first terminal of the first transient diode is the first terminal of the first suppression circuit 401, the second terminal of the second transient diode is the second terminal of the first suppression circuit 401, the first terminal of the third transient diode is the first terminal of the second suppression circuit 402, and the second terminal of the fourth transient diode is the second terminal of the second suppression circuit.

[0077] In one specific embodiment, the first short-circuit protection circuit 403 includes a first fuse.

[0078] In one specific embodiment, the first power supply reverse connection protection circuit 404 includes: a first MOSFET (P-MOSFET), a second MOSFET (P-MOSFET), a third MOSFET (N-MOSFET), a fourth MOSFET (N-MOSFET), a first Zener diode, a fourth Zener diode, and a first resistor, an eighth resistor.

[0079] The source of the first MOSFET is connected to the first terminal of the second suppression circuit 402 and the source of the second MOSFET, respectively. The source of the first MOSFET is equivalent to the first terminal of the first power supply reverse connection protection circuit 404. The drain of the first MOSFET is connected to the drain of the third MOSFET, and the drain of the second MOSFET is connected to the drain of the fourth MOSFET.

[0080] The source of the first MOSFET is connected to the first terminal of the first Zener diode and the second resistor (source - negative terminal of the first Zener diode - positive terminal of the first Zener diode - first terminal of the second resistor). The gate of the first MOSFET is connected to the first terminal of the first resistor and the second resistor. The second terminal of the second resistor is connected to the first terminal of the third resistor. The second terminal of the third resistor is connected to the gate of the third MOSFET through the fourth resistor, and the second terminal of the third resistor is connected to the source of the third MOSFET through the third Zener diode (second terminal of the third resistor - negative terminal of the third Zener diode - positive terminal of the third Zener diode - source). The source of the third MOSFET is connected to the second terminal of the first short-circuit protection circuit 403 and the source of the fourth MOSFET, respectively. The source of the third MOSFET is equivalent to the second terminal of the first reverse power supply protection circuit 404.

[0081] The source of the second MOSFET is connected to the first terminal of the second Zener diode and the sixth resistor (source - negative terminal of the second Zener diode - positive terminal of the second Zener diode - first terminal of the sixth resistor). The gate of the second MOSFET is connected to the first terminal of the fifth resistor and the sixth resistor. The second terminal of the sixth resistor is connected to the first terminal of the seventh resistor. The second terminal of the seventh resistor is connected to the gate of the fourth MOSFET through the eighth resistor. The second terminal of the seventh resistor is connected to the source of the fourth MOSFET through the fourth Zener diode (second terminal of the seventh resistor - negative terminal of the fourth Zener diode - positive terminal of the fourth Zener diode - source).

[0082] The second terminal of the sixth resistor, the drain of the first MOSFET, and the drain of the third MOSFET are connected to the power supply VCC (external power supply, such as a 50V external power supply); the second terminal of the second resistor, the drain of the second MOSFET, and the drain of the fourth MOSFET are grounded.

[0083] In some embodiments, such as Figure 4 The provided structural block diagram of the first power supply protection circuit 500 includes at least: a third suppression circuit 501, a fourth suppression circuit 502, a second short-circuit protection circuit 503, and a second power supply reverse connection protection circuit 504; the third suppression circuit 501 and the fourth suppression circuit 502 are used to suppress surges and pulse bursts;

[0084] Specifically, the first and second ends of the second interface of the APL field switch 200 are connected to the first and second ends of the main power supply interface, respectively; the first end of the main power supply interface is connected to the first end of the third suppression circuit 501, and the second end of the main power supply interface is connected to the second end of the third suppression circuit 501.

[0085] The first end of the main power input interface is connected to the first end of the fourth suppression circuit 502 through inductor L, and the second end of the main power input interface is connected to the second end of the fourth suppression circuit 502 through inductor L.

[0086] The first terminal of the second power supply reverse connection protection circuit 504 is connected to the first terminal of the fourth suppression circuit 502. The first terminal of the second power supply reverse connection protection circuit 504 is connected to the second terminal of the fourth suppression circuit 502 and the first terminal of the second short circuit protection circuit 503 through capacitors (two capacitors C).

[0087] The second terminal of the second short-circuit protection circuit 503 is connected to the second terminal of the second power supply reverse connection protection circuit 504.

[0088] In one specific embodiment, the third suppression circuit 501 includes a fifth transient diode and a sixth transient diode; the fourth suppression circuit 502 includes a seventh transient diode and an eighth transient diode;

[0089] Specifically, the first end of the main power supply interface is connected to the first end of the fifth transient diode, the second end of the fifth transient diode is connected to the first end of the sixth transient diode, and the second end of the sixth transient diode is connected to the second end of the main power supply interface.

[0090] The first end of the main power input interface is connected to the first end of the seventh transient diode through an inductor. The second end of the seventh transient diode is connected to the first end of the eighth transient diode. The second end of the eighth transient diode is connected to the second end of the main power input interface through an inductor.

[0091] Among them, the first terminal of the fifth transient diode is the first terminal of the third suppression circuit, the second terminal of the sixth transient diode is the second terminal of the third suppression circuit, the first terminal of the seventh transient diode is the first terminal of the fourth suppression circuit, and the second terminal of the eighth transient diode is the second terminal of the fourth suppression circuit.

[0092] In one specific embodiment, the second short-circuit protection circuit 503 includes a second fuse.

[0093] In one specific embodiment, the second power supply reverse connection protection circuit 504 includes: a fifth MOSFET (P-MOS transistor), a sixth MOSFET (P-MOS transistor), a seventh MOSFET (N-MOS transistor), an eighth MOSFET (N-MOS transistor), a fifth Zener diode to an eighth Zener diode, and a ninth resistor to a sixteenth resistor;

[0094] The drain of the fifth MOSFET is connected to the first terminal of the fourth suppression circuit 502 and the drain of the seventh MOSFET, respectively. The drain of the fifth MOSFET is equivalent to the first terminal of the second power supply reverse connection protection circuit 504. The drain of the sixth MOSFET is connected to the second terminal of the second short circuit protection circuit 503 and the drain of the eighth MOSFET, respectively. The drain of the sixth MOSFET is equivalent to the second terminal of the second power supply reverse connection protection circuit 504.

[0095] The gate of the fifth MOSFET is connected to the first terminals of the ninth and tenth resistors. The source of the fifth MOSFET is connected to the first terminal of the tenth resistor through the fifth Zener diode (source - negative terminal of the fifth Zener diode - positive terminal of the fifth Zener diode - first terminal of the tenth resistor). The source of the fifth MOSFET is connected to the source of the sixth MOSFET. The sources of the fifth and sixth MOSFETs are connected to the power supply VCC (taken from the trunk, the voltage can be 50V). The second terminal of the tenth resistor is connected to the first terminal of the eleventh resistor. The second terminal of the tenth resistor is connected to the drain of the sixth MOSFET. The second terminal of the eleventh resistor is connected to the gate of the seventh MOSFET through the twelfth resistor. The second terminal of the eleventh resistor is connected to the source of the seventh MOSFET through the eighth Zener diode (second terminal of the eleventh resistor - negative terminal of the eighth Zener diode - positive terminal of the eighth Zener diode - source).

[0096] The gate of the sixth MOSFET is connected to the first terminals of the thirteenth and fourteenth resistors. The source of the sixth MOSFET is connected to the first terminal of the fourteenth resistor through the sixth Zener diode (source - negative terminal of the sixth Zener diode - positive terminal of the sixth Zener diode - first terminal of the fourteenth resistor). The second terminal of the fourteenth resistor is connected to the first terminal of the fifteenth resistor. The second terminal of the fourteenth resistor is connected to the drain of the fifth MOSFET. The second terminal of the fifteenth resistor is connected to the gate of the eighth MOSFET through the sixteenth resistor. The second terminal of the fifteenth resistor is connected to the source of the eighth MOSFET through the seventh Zener diode (second terminal of the fifteenth resistor - negative terminal of the seventh Zener diode - positive terminal of the seventh Zener diode - source).

[0097] The source of the seventh MOSFET is connected to the source of the eighth MOSFET, and the source of the seventh MOSFET is grounded.

[0098] In some embodiments, such as Figure 5 The provided structural block diagram of the second power supply protection circuit 600 includes at least: a fifth suppression circuit 601, a sixth suppression circuit 602, a third short-circuit protection circuit 603, and a third power supply reverse connection protection circuit 604; the fifth suppression circuit 601 and the sixth suppression circuit 602 are used to suppress surges and pulse bursts;

[0099] Specifically, the first and second ends of the third interface of the APL field switch 200 are connected to the first and second ends of the branch power supply interface, respectively; the first end of the branch power supply interface is connected to the first end of the fifth suppression circuit 601, and the second end of the branch power supply interface is connected to the second end of the fifth suppression circuit 601.

[0100] The first end of the branch power supply interface is connected to the first end of the sixth suppression circuit 602 through inductor L, and the second end of the branch power supply interface is connected to the second end of the sixth suppression circuit 602 through inductor L.

[0101] The first terminal of the third power supply reverse connection protection circuit 604 is connected to the first terminal of the sixth suppression circuit 602. The first terminal of the third power supply reverse connection protection circuit 604 is connected to the second terminal of the sixth suppression circuit 602 and the first terminal of the third short circuit protection circuit 603 respectively through capacitors (two capacitors C).

[0102] The second terminal of the third short-circuit protection circuit 603 is connected to the second terminal of the third power supply reverse connection protection circuit 604.

[0103] In one specific embodiment, the fifth suppression circuit 601 includes a ninth transient diode and a tenth transient diode; the sixth suppression circuit 602 includes an eleventh transient diode and a twelfth transient diode;

[0104] Specifically, the first end of the branch power supply terminal interface is connected to the first end of the ninth transient diode, the second end of the ninth transient diode is connected to the first end of the tenth transient diode, and the second end of the tenth transient diode is connected to the second end of the branch power supply terminal interface.

[0105] The first end of the branch power supply interface is connected to the first end of the eleventh transient diode through an inductor. The second end of the eleventh transient diode is connected to the first end of the twelfth transient diode. The second end of the twelfth transient diode is connected to the second end of the branch power supply interface through an inductor.

[0106] Among them, the first terminal of the ninth transient diode is the first terminal of the fifth suppression circuit, the second terminal of the tenth transient diode is the second terminal of the fifth suppression circuit, the first terminal of the eleventh transient diode is the first terminal of the sixth suppression circuit, and the second terminal of the eleventh transient diode is the second terminal of the sixth suppression circuit.

[0107] In one specific embodiment, the third short-circuit protection circuit includes a third fuse.

[0108] In one specific embodiment, the third power supply reverse connection protection circuit 604 includes: a ninth MOS transistor (P-MOS transistor), a tenth MOS transistor (P-MOS transistor), an eleventh MOS transistor (N-MOS transistor), a twelfth MOS transistor (N-MOS transistor), a ninth Zener diode, a twelfth Zener diode, a seventeenth resistor, and a twenty-fourth resistor.

[0109] The source of the ninth MOSFET is connected to the first terminal of the sixth suppression circuit 602 and the source of the tenth MOSFET, respectively. The source of the ninth MOSFET is equivalent to the first terminal of the third power supply reverse connection protection circuit 604. The drain of the ninth MOSFET is connected to the drain of the eleventh MOSFET, and the drain of the tenth MOSFET is connected to the drain of the twelfth MOSFET.

[0110] The source of the ninth MOSFET is connected to the first terminal of the ninth Zener diode and the eighteenth resistor (source - negative terminal of the ninth Zener diode - positive terminal of the ninth Zener diode - first terminal of the eighteenth resistor). The gate of the ninth MOSFET is connected to the first terminal of the seventeenth and eighteenth resistors. The second terminal of the eighteenth resistor is connected to the first terminal of the nineteenth resistor. The second terminal of the nineteenth resistor is connected to the gate of the eleventh MOSFET through the twentieth resistor. The second terminal of the nineteenth resistor is also connected to the source of the eleventh MOSFET through the eleventh Zener diode (second terminal of the nineteenth resistor - negative terminal of the eleventh Zener diode - positive terminal of the eleventh Zener diode - source). The source of the eleventh MOSFET is connected to the second terminal of the third short-circuit protection circuit 603 and the source of the twelfth MOSFET. The source of the eleventh MOSFET is equivalent to the second terminal of the third reverse connection protection circuit 604.

[0111] The source of the tenth MOSFET is connected to the first terminal of the tenth Zener diode and the twenty-second resistor (source - negative terminal of the tenth Zener diode - positive terminal of the tenth Zener diode - first terminal of the twenty-second resistor). The gate of the tenth MOSFET is connected to the first terminal of the twenty-first resistor and the twenty-second resistor. The second terminal of the twenty-second resistor is connected to the first terminal of the twenty-third resistor. The second terminal of the twenty-third resistor is connected to the gate of the twelfth MOSFET through the twenty-fourth resistor. The second terminal of the twenty-third resistor is connected to the source of the twelfth MOSFET through the twelfth Zener diode (second terminal of the twenty-third resistor - negative terminal of the twelfth Zener diode - positive terminal of the twelfth Zener diode - source).

[0112] The second terminal of the 22nd resistor, the drain of the 9th MOSFET, and the drain of the 11th MOSFET are connected to the power supply VCC; the second terminal of the 18th resistor, the drain of the 10th MOSFET, and the drain of the 12th MOSFET are grounded.

[0113] In some embodiments, such as Figure 6 The provided structural block diagram of the second power supply protection circuit 700 includes at least: a seventh suppression circuit 701, an eighth suppression circuit 702, a fourth short-circuit protection circuit 703, and a fourth power supply reverse connection protection circuit 704; the seventh suppression circuit 701 and the eighth suppression circuit 702 are used to suppress surges and pulse bursts;

[0114] Specifically, the first and second ends of the fourth interface of the instrument 300 are connected to the first and second ends of the branch power supply interface, respectively; the first end of the branch power supply interface is connected to the first end of the seventh suppression circuit 701, and the second end of the branch power supply interface is connected to the second end of the seventh suppression circuit 701.

[0115] The first end of the branch power take-off interface is connected to the first end of the eighth suppression circuit 702 through inductor L, and the second end of the branch power take-off interface is connected to the second end of the eighth suppression circuit 702 through inductor L.

[0116] The first terminal of the fourth power supply reverse connection protection circuit 704 is connected to the first terminal of the eighth suppression circuit 702. The first terminal of the fourth power supply reverse connection protection circuit 704 is connected to the second terminal of the eighth suppression circuit 702 and the first terminal of the fourth short circuit protection circuit 703 through capacitors (two capacitors C).

[0117] The second terminal of the fourth short-circuit protection circuit 703 is connected to the second terminal of the fourth power supply reverse connection protection circuit 704.

[0118] In one specific embodiment, the seventh suppression circuit 701 includes a thirteenth transient diode and a fourteenth transient diode; the eighth suppression circuit 702 includes a fifteenth transient diode and a sixteenth transient diode.

[0119] Specifically, the first end of the branch power supply interface is connected to the first end of the thirteenth transient diode, the second end of the thirteenth transient diode is connected to the first end of the fourteenth transient diode, and the second end of the fourteenth transient diode is connected to the second end of the branch power supply interface.

[0120] The first end of the branch power take-off interface is connected to the first end of the fifteenth transient diode through an inductor. The second end of the fifteenth transient diode is connected to the first end of the sixteenth transient diode. The second end of the sixteenth transient diode is connected to the second end of the branch power take-off interface through an inductor.

[0121] Among them, the first terminal of the thirteenth transient diode is the first terminal of the seventh suppression circuit, the second terminal of the fourteenth transient diode is the second terminal of the seventh suppression circuit, the first terminal of the fifteenth transient diode is the first terminal of the eighth suppression circuit, and the second terminal of the sixteenth transient diode is the second terminal of the eighth suppression circuit.

[0122] In one specific embodiment, the fourth short-circuit protection circuit 703 includes a fourth fuse.

[0123] In one specific embodiment, the fourth power supply reverse connection protection circuit 704 includes: a thirteenth MOSFET (P-MOS transistor), a fourteenth MOSFET (P-MOS transistor), a fifteenth MOSFET (N-MOS transistor), a sixteenth MOSFET (N-MOS transistor), a thirteenth Zener diode, a sixteenth Zener diode, a twenty-fifth resistor, and a thirty-second resistor.

[0124] The drain of the thirteenth MOSFET is connected to the first terminal of the eighth suppression circuit 702 and the drain of the fifteenth MOSFET, respectively. The drain of the thirteenth MOSFET is equivalent to the first terminal of the fourth power supply reverse connection protection circuit 704. The drain of the fourteenth MOSFET is connected to the second terminal of the fourth short circuit protection circuit 703 and the drain of the sixteenth MOSFET, respectively. The drain of the fourteenth MOSFET is equivalent to the second terminal of the fourth power supply reverse connection protection circuit 704.

[0125] The gate of the thirteenth MOSFET is connected to the first terminals of the twenty-fifth and twenty-sixth resistors. The source of the thirteenth MOSFET is connected to the first terminal of the thirteenth Zener diode and the twenty-sixth resistor (source - negative terminal of the thirteenth Zener diode - positive terminal of the thirteenth Zener diode - first terminal of the twenty-sixth resistor). The source of the thirteenth MOSFET is connected to the source of the fourteenth MOSFET. The sources of the thirteenth MOSFET and the fourteenth MOSFET are connected to the power supply VCC (taken from the Spur, the voltage can be 9-15V). The second terminal of the twenty-sixth resistor is connected to the first terminal of the twenty-seventh resistor. The second terminal of the twenty-sixth resistor is connected to the drain of the fourteenth MOSFET. The second terminal of the twenty-seventh resistor is connected to the gate of the fifteenth MOSFET through the twenty-eighth resistor. The second terminal of the twenty-seventh resistor is connected to the source of the fifteenth MOSFET through the sixteenth Zener diode (second terminal of the twenty-seventh resistor - negative terminal of the sixteenth Zener diode - positive terminal of the sixteenth Zener diode - source).

[0126] The gate of the fourteenth MOSFET is connected to the first terminals of the twenty-ninth and thirtieth resistors. The source of the fourteenth MOSFET is connected to the first terminal of the thirtieth resistor through the fourteenth Zener diode (source - negative terminal of the fourteenth Zener diode - positive terminal of the fourteenth Zener diode - first terminal of the thirtieth resistor). The second terminal of the thirtieth resistor is connected to the first terminal of the thirty-first resistor. The second terminal of the thirtieth resistor is connected to the drain of the thirteenth MOSFET. The second terminal of the thirty-first resistor is connected to the gate of the sixteenth MOSFET through the thirty-second resistor. The second terminal of the thirty-first resistor is connected to the source of the sixteenth MOSFET through the fifteenth Zener diode (second terminal of the thirty-first resistor - negative terminal of the fifteenth Zener diode - positive terminal of the fifteenth Zener diode - source).

[0127] The source of the fifteenth MOSFET is connected to the source of the sixteenth MOSFET, and the source of the fifteenth MOSFET and the source of the sixteenth MOSFET are grounded.

[0128] The above content describes the structure of an Ethernet interface protection topology circuit provided in this solution. For a better understanding of this solution, please refer to the following... Figure 7 and Figure 8 The example diagram of the Ethernet interface protection topology circuit is shown for illustration.

[0129] See Figure 7 , Figure 7 This diagram shows a partial example of the Ethernet interface protection topology provided by this solution. Figure 7 The specific structures of the first power supply protection circuit 400 and the second power supply protection circuit 600 are given; that is, the connection relationships of the internal components of the first power supply protection circuit 400 and the second power supply protection circuit 600 can be found in [reference needed]. Figure 7 .

[0130] exist Figure 7 When describing the specific structure of the first power supply protection circuit 400, the dual-line Ethernet power supply side interface represents the backbone power supply end interface, and the "interface internal structure" part refers to the internal structure of the first interface of the APL power switch 100.

[0131] The two "surge and burst suppression" sections are the first suppression circuit 401 and the second suppression circuit 402, respectively. D28 is the first transient diode, D27 is the second transient diode, D26 is the third transient diode, and D29 is the fourth transient diode. U5 is the first fuse. L37 and L36 are inductors, and C54 and C55 are capacitors.

[0132] The "Reverse Power Connection Protection" section is the first reverse power connection protection circuit 404; in this circuit, M21 is the first MOSFET (P-MOS transistor), M19 is the second MOSFET (P-MOS transistor), M20 is the third MOSFET (N-MOS transistor), and M18 is the fourth MOSFET (N-MOS transistor). R48 is the first resistor, R50 is the second resistor, R52 is the third resistor, R54 is the fourth resistor, R47 is the fifth resistor, R49 is the sixth resistor, R51 is the seventh resistor, and R53 is the eighth resistor. D23 is the first Zener diode, D22 is the second Zener diode, D19 is the third Zener diode, and D18 is the fourth Zener diode.

[0133] exist Figure 7 When describing the specific structure of the second power supply protection circuit 400, the dual-line Ethernet power supply side interface represents the branch power supply end interface, and the "interface internal structure" part refers to the internal structure of the third interface of the APL field switch 200.

[0134] The two "surge and burst suppression" sections are the fifth suppression circuit 601 and the sixth suppression circuit 602, respectively. D28 is the ninth transient diode, D27 is the tenth transient diode, D26 is the eleventh transient diode, and D29 is the twelfth transient diode. U5 is the third fuse. L37 and L36 are inductors, and C54 and C55 are capacitors.

[0135] The "Reverse Connection Protection" section is the third reverse connection protection circuit 604; M21 is the ninth MOSFET (P-MOS), M19 is the tenth MOSFET (P-MOS), M20 is the eleventh MOSFET (N-MOS), and M18 is the twelfth MOSFET (N-MOS). R48 is the seventeenth resistor, R50 is the eighteenth resistor, R52 is the nineteenth resistor, R54 is the twentieth resistor, R47 is the twenty-first resistor, R49 is the twenty-second resistor, R51 is the twenty-third resistor, and R53 is the twenty-fourth resistor. D23 is the ninth Zener diode, D22 is the tenth Zener diode, D19 is the eleventh Zener diode, and D18 is the twelfth Zener diode.

[0136] See Figure 8 , Figure 8 This diagram shows another part of the Ethernet interface protection topology circuit provided by this solution; Figure 8 The specific structures of the first power extraction protection circuit 500 and the second power extraction protection circuit 700 are given; that is, the connection relationships of the internal components of the first power extraction protection circuit 500 and the second power extraction protection circuit 700 can be found in [reference]. Figure 8 .

[0137] exist Figure 8 When describing the specific structure of the first power supply protection circuit 500, the dual-wire Ethernet power supply side interface represents the backbone power supply end interface, and the "interface internal structure" part refers to the internal structure of the second interface of the APL field switch 200.

[0138] The two "surge and burst suppression" sections are the third suppression circuit 501 and the fourth suppression circuit 502, respectively. D24 is the fifth transient diode, D15 is the sixth transient diode, D14 is the seventh transient diode, and D25 is the eighth transient diode. U4 is the second fuse. L30 and L31 are inductors, and C53 and C45 are capacitors.

[0139] The "Reverse Connection Protection" section is the second reverse connection protection circuit 504. M15 is the fifth MOSFET (P-MOS), M17 is the sixth MOSFET (P-MOS), M14 is the seventh MOSFET (N-MOS), and M16 is the eighth MOSFET (N-MOS). R35 is the ninth resistor, R39 is the tenth resistor, R41 is the eleventh resistor, R43 is the twelfth resistor, R36 is the thirteenth resistor, R40 is the fourteenth resistor, R42 is the fifteenth resistor, and R44 is the sixteenth resistor. D16 is the fifth Zener diode, D17 is the sixth Zener diode, D13 is the seventh Zener diode, and D12 is the eighth Zener diode.

[0140] exist Figure 8 When describing the specific structure of the second power supply protection circuit 700, the dual-wire Ethernet power supply side interface represents the branch power supply end interface, and the "interface internal structure" part refers to the internal structure of the fourth interface of the instrument 300.

[0141] The two "surge and burst suppression" sections are the seventh suppression circuit 701 and the eighth suppression circuit 702, respectively. D24 is the thirteenth transient diode, D15 is the fourteenth transient diode, D14 is the fifteenth transient diode, and D25 is the sixteenth transient diode. U4 is the fourth fuse. L30 and L31 are inductors, and C53 and C45 are capacitors.

[0142] The "Reverse Connection Protection" section uses the fourth reverse connection protection circuit 704. M15 is the thirteenth MOSFET (P-MOS), M17 is the fourteenth MOSFET (P-MOS), M14 is the fifteenth MOSFET (N-MOS), and M16 is the sixteenth MOSFET (N-MOS). R35 is the twenty-fifth resistor, R39 is the twenty-sixth resistor, R41 is the twenty-seventh resistor, R43 is the twenty-eighth resistor, R36 is the twenty-ninth resistor, R40 is the thirtieth resistor, R42 is the thirty-first resistor, and R44 is the thirty-second resistor. D16 is the thirteenth Zener diode, D17 is the fourteenth Zener diode, D13 is the fifteenth Zener diode, and D12 is the sixteenth Zener diode.

[0143] Through the above Figure 7 and Figure 8 As shown in the example diagram of the Ethernet interface protection topology, this solution adds reverse polarity protection, short-circuit protection, surge and differential mode component suppression measures to both the dual-wire Ethernet power supply side interface and the dual-wire Ethernet power take-off side interface. Combined with... Figure 7 and Figure 8 The content explains and describes the reverse polarity protection (the aforementioned reverse polarity protection circuit), short circuit protection (the aforementioned short circuit protection circuit), and surge and burst pulse differential mode component suppression measures (the aforementioned suppression circuit).

[0144] 1. Power supply polarity protection against reverse connection

[0145] To implement reverse polarity protection, this solution uses a rectifier bridge; diodes and MOSFETs can be selected to implement the rectifier bridge. Compared to diodes, MOSFETs have lower on-resistance. A reverse polarity protection circuit built using MOSFETs can achieve a larger current carrying capacity while maintaining lower losses. For diodes, the larger the current flowing through them, the larger the on-state voltage drop, resulting in greater losses and temperature rise, which negatively impacts the power supply and drawdown of the trunk port. To avoid these issues, this solution can also use multiple larger-package diodes connected in parallel to achieve current sharing, thereby reducing diode losses and temperature rise. However, this approach increases cost and requires more layout space.

[0146] When selecting the MOSFET for the reverse polarity protection circuit in this solution, the MOSFET's current carrying capacity, voltage rating, operating temperature, package, and driver circuit must be considered. The selection process for the MOSFET used for reverse polarity protection is as follows:

[0147] (1) Current carrying capacity of MOSFET

[0148] For MOSFETs used in circuits providing reverse polarity protection, the first consideration must be their current-carrying capacity. Therefore, the selected MOSFET's current-carrying capacity should not be less than the rated current on the two-wire Ethernet bus. To allow for a margin, the selected MOSFET's current-carrying capacity should be approximately twice its rated current. For example, the rated current for the Trunk port is 1.15A, and the rated current for the Spur port is 36mA. Therefore, the N-MOSFETs and P-MOSFETs used for reverse polarity protection on the Trunk port need to withstand a current of approximately 2A, and the N-MOSFETs and P-MOSFETs used for reverse polarity protection on the Spur port need to withstand a current of approximately 100mA.

[0149] (2) Voltage withstand capability of MOSFET

[0150] When selecting MOSFETs, in addition to current carrying capacity, their voltage rating must also be considered. When the reverse connection protection circuit operates, an N-MOSFET and a P-MOSFET participate in forming the loop, and their combined voltage rating needs to be greater than the operating voltage on the two-wire Ethernet bus. On one hand, considering the reliability of the voltage rating, the MOSFET's voltage rating needs to have sufficient margin; therefore, the higher the voltage rating of the selected MOSFET, the better. On the other hand, selecting a high-voltage MOSFET results in higher on-resistance and higher cost; the higher the on-resistance, the greater the MOSFET's losses. To ensure reverse connection protection with lower losses, the voltage rating of the MOSFETs selected in this solution can be approximately twice the operating voltage on the bus. For example, the rated voltage of the Trunk port is 50V; therefore, the N-MOSFET and P-MOSFET used for the Trunk interface should both have a voltage rating of approximately 50V. The rated voltage of the Spur port is 15V, and considering that a Trunk port mistakenly plugging into a Spur port will not damage onboard components, the N-MOSFET and P-MOSFET used for the Spur interface should also have a voltage rating of approximately 50V.

[0151] (3) Operating temperature of MOSFET

[0152] In addition to the current carrying capacity and voltage withstand capability of the MOSFET, this solution also needs to consider the operating temperature of the MOSFET. For industrial two-wire Ethernet, the operating temperature range of the selected MOSFET should be at least -40℃ to 85℃; currently, the operating temperature range of existing MOSFETs is generally -55℃ to 150℃, so existing MOSFETs can be used in the reverse polarity protection circuit of industrial two-wire Ethernet.

[0153] (4) Packaging of MOSFETs

[0154] Commonly used MOSFET packages are mainly divided into through-hole and surface-mount (SMD) types. Through-hole MOSFETs can be cooled by external heatsinks, which is beneficial for cooling, but they occupy more PCB (Printed Circuit Board) space, which is not conducive to saving PCB space. Surface-mount MOSFETs, on the other hand, have the opposite characteristics of through-hole MOSFETs, saving space, but their heat dissipation area is smaller and they cannot be cooled by external heatsinks. This solution considers that the actual dual-wire Ethernet input and output power will not exceed half of the maximum output power of the selected MOSFET, and the selected MOSFET has already been dated for output power. Furthermore, the on-resistance of existing MOSFETs with a withstand voltage of around 50V and a current of around 2A is around 100 milliohms. These two factors determine that the temperature rise of the MOSFET in actual use will not be too high, and the heat dissipation requirement is not very high. Therefore, this solution can choose surface-mount MOSFETs for practical applications.

[0155] (5) MOSFET driving circuit

[0156] A 50V MOSFET typically has a saturation drive voltage of around 10V. A trunk voltage of 50V cannot be directly used to drive a MOSFET; it needs to be stepped down before being supplied to the MOSFET. To stabilize the drive voltage of P-MOSFETs and N-MOSFETs, a Zener diode of around 10V can be used to step down the voltage and supply it to the gate of the MOSFET. This Zener diode also provides overvoltage protection for the MOSFET gate.

[0157] II. Short Circuit Protection

[0158] The purpose of short-circuit protection is to isolate short-circuited faulty devices in a network, thereby preventing these devices from pulling down the voltage on the trunk and spur of a two-wire Ethernet network. This solution uses fuses to isolate the faulty devices. Fuse selection mainly considers the fuse type, rated voltage, rated current, and package. The fuse selection process for short-circuit protection in two-wire Ethernet is as follows:

[0159] (1) Types of fuses

[0160] Fuses are classified into two main types based on their fusing speed: fast-blow and slow-blow. When fuses have the same rated current, fast-blow fuses have a lower fusing current and a shorter fusing time than slow-blow fuses, which is advantageous for quickly clearing short circuits and restoring the operation of other network devices. Therefore, the fuse used for clearing short-circuit faults in this solution is a fast-blow type (for illustrative purposes only).

[0161] (2) Rated voltage of the fuse

[0162] The rated voltage of the fuse must be greater than the maximum operating voltage in the circuit. If the rated voltage of the fuse is lower than the operating voltage of the circuit, the fuse will blow, generating a large arc and hot gas splash, which is unsuitable for interface circuits of intrinsically safe APL instruments in Zone 0 and Zone 1. To reduce the arc and hot gas generation when the fuse blows, the rated voltage of the fuse selected in this solution is several times the maximum normal operating voltage in the circuit. Therefore, for Trunk and Spur interfaces, this solution can select fuses with a rated voltage of around 125V (example only).

[0163] (3) Rated current of the fuse

[0164] When selecting the rated current of a fuse, two considerations must be taken into account: firstly, the rated current of the selected fuse needs to avoid the maximum current that occurs in the circuit; secondly, the impact of the surge current during hot-plugging on the fuse's lifespan, and the effect of temperature changes on the rated current. Therefore, the rated current of the selected fuse can be slightly larger, approximately 1.5 times the maximum operating current in the circuit. For example, the maximum current of a Trunk fuse is 1.15A, and the maximum current of a Spur fuse is 36mA. Therefore, a fuse with a rated current of around 2A can be selected for a Trunk fuse, and a fuse with a rated current of around 100mA can be selected for a Spur fuse.

[0165] (4) Fuse packaging

[0166] Fuse packaging is mainly divided into two categories: through-hole and surface-mount. Compared to surface-mount packages, through-hole packages have a larger size. The smaller the fuse size, the less PCB space it occupies. Therefore, this solution can choose surface-mount fuses.

[0167] III. Suppression Measures for Surge and Differential Mode Components of Pulse Bursts

[0168] For surge protection, available devices include TVS, gas discharge tubes, and NTCs. Compared to other suppression methods, TVS offers advantages such as fast response, low leakage current, and stable clamping voltage, and is commonly used for surge protection of signal lines and interface circuits. To quickly suppress surges on the bus and differential-mode components of surge pulses caused by impedance mismatches between power supply and tap ports, and to quickly suppress voltage spikes generated by inductors during hot-swapping of Trunk and Spur interfaces, this solution prioritizes TVS for surge and differential-mode component suppression.

[0169] It should be noted that TVS and Zener diodes operate on similar mechanisms: under higher voltages, their impedance decreases, clamping the voltage to a fixed value through discharge current. The difference lies in that TVS utilizes avalanche breakdown for clamping, while Zener diodes use Zener breakdown for voltage clamping. Zener diodes are primarily used for power supply voltage regulation and also offer surge protection, but their discharge current is smaller than that of TVS, making them unsuitable for large surges. When selecting a TVS in this solution, considerations include its operating voltage, clamping voltage, junction capacitance, and cost. The TVS selection process for two-wire Ethernet surge and differential mode component suppression is as follows:

[0170] (1) Operating voltage of TVS

[0171] To prevent the TVS from interfering with the normal operation of the circuit, the selected TVS operating voltage should be kept away from the circuit's maximum operating voltage. Considering that the temperature of the actual operating environment will affect the leakage current of the TVS, the operating voltage of the TVS can be taken as about 1.2 times the normal operating voltage of the circuit. For example, the operating voltage of the TVS in the Trunk port can be selected to be around 60V, while the operating voltage of the TVS in the Spur port theoretically only needs to be around 20V. However, considering that mistakenly inserting a Spur into a Trunk port will not damage the onboard components, the operating voltage of the TVS in the Spur port is also the same as that in the Trunk port.

[0172] (2) Clamping voltage of TVS

[0173] The clamping voltage of the TVS must not exceed the maximum withstand voltage of the subsequent circuit components. The components used for reverse connection protection in a dual-wire Ethernet power supply include MOSFETs and power chips. The total withstand voltage of the MOSFETs is 100V, while the withstand voltage of the power chip needs to be determined based on the actual application. Considering that misinsertion will not damage the power chip, the selected power chip's withstand voltage must also be greater than 50V. Therefore, in this solution, a clamping voltage of approximately 1.3 times the TVS operating voltage can generally be used, that is, a TVS clamping voltage of around 80V (example only).

[0174] (3) Junction capacitance of TVS

[0175] For surge protection on communication lines, to prevent the junction capacitance of the TVS used from affecting communication, this solution can select a commonly used TVS array with low junction capacitance. The junction capacitance of a single integrated TVS is often around 20pF, and the series topology of multiple TVS can further reduce the junction capacitance of the TVS. For surge protection and differential component protection of power supply and extraction branches of Trunk and Spur, the influence of junction capacitance can be disregarded.

[0176] (4) Cost of TVS

[0177] Compared to other surge protection measures, the higher the protection level, the higher the cost of a single TVS used for power supply and power extraction branches. To reduce costs, this solution uses several low-power TVS units connected in series for the protection of power supply and power extraction branches.

[0178] As can be seen from the above, this solution uses a MOSFET to implement reverse polarity protection for the power supply of the dual-wire Ethernet interface. Compared to diodes, this circuit maintains lower losses even under high current. This solution uses a fuse to provide short-circuit protection for the dual-wire Ethernet, ensuring that short-circuited devices in the network can be promptly disconnected without affecting the safety of other network devices. This solution uses a TVS to address surge and differential mode component suppression issues in the dual-wire Ethernet interface, but it differentiates the TVS used at the bus and power branch points. Furthermore, to reduce engineering costs, this solution can utilize multiple low-level TVS connected in series, depending on the application environment.

[0179] In summary, the embodiments of the present invention provide an Ethernet interface protection topology circuit, which, through a power supply protection circuit and a power extraction protection circuit, realizes the reverse connection protection function of the power supply interface of the backbone communication cable and the branch communication cable, solves the problem of short circuit in the power extraction and power supply of the backbone communication cable and the branch communication cable, and solves the problem of surge and differential mode component suppression of the dual-line Ethernet interface.

[0180] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0181] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0182] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An Ethernet interface protection topology circuit, characterized in that, The Ethernet interface protection topology circuit includes: an enhanced physical layer APL power switch, an APL field switch, instruments, a first power supply protection circuit, a first power extraction protection circuit, a second power supply protection circuit, and a second power extraction protection circuit. The first interface of the APL power switch is connected to the main power supply end interface of the main communication cable through the first power supply protection circuit, and the main power supply end interface of the main communication cable is connected to the second interface of the APL field switch through the first power supply protection circuit. The third interface of the APL field switch is connected to the branch power supply end interface of the branch communication cable through the second power supply protection circuit, and the branch power take-off end interface of the branch communication cable is connected to the fourth interface of the instrument through the second power take-off protection circuit. The first power supply protection circuit includes at least: a first suppression circuit, a second suppression circuit, a first short-circuit protection circuit, and a first power supply reverse connection protection circuit; the first suppression circuit and the second suppression circuit are used to suppress surges and pulse bursts; The first end and the second end of the first interface are respectively connected to the first end and the second end of the main power supply interface; the first end of the main power supply interface is connected to the first end of the first suppression circuit, and the second end of the main power supply interface is connected to the second end of the first suppression circuit. The first end of the main power supply terminal interface is connected to the first end of the second suppression circuit through an inductor, and the second end of the main power supply terminal interface is connected to the second end of the second suppression circuit through an inductor. The first terminal of the first power supply reverse connection protection circuit is connected to the first terminal of the second suppression circuit, and the first terminal of the first power supply reverse connection protection circuit is connected to the second terminal of the second suppression circuit and the first terminal of the first short circuit protection circuit through a capacitor. The second terminal of the first short-circuit protection circuit is connected to the second terminal of the first power supply reverse connection protection circuit.

2. The Ethernet interface protection topology circuit according to claim 1, characterized in that, The first power supply protection circuit includes at least: a third suppression circuit, a fourth suppression circuit, a second short-circuit protection circuit, and a second reverse connection protection circuit; the third suppression circuit and the fourth suppression circuit are used to suppress surges and pulse bursts; The first end and the second end of the second interface are respectively connected to the first end and the second end of the main power supply interface; the first end of the main power supply interface is connected to the first end of the third suppression circuit, and the second end of the main power supply interface is connected to the second end of the third suppression circuit. The first end of the main power input interface is connected to the first end of the fourth suppression circuit through an inductor, and the second end of the main power input interface is connected to the second end of the fourth suppression circuit through an inductor. The first terminal of the second power supply reverse connection protection circuit is connected to the first terminal of the fourth suppression circuit, and the first terminal of the second power supply reverse connection protection circuit is connected to the second terminal of the fourth suppression circuit and the first terminal of the second short circuit protection circuit through capacitors respectively. The second terminal of the second short-circuit protection circuit is connected to the second terminal of the second power supply reverse connection protection circuit.

3. The Ethernet interface protection topology circuit according to claim 1, characterized in that, The second power supply protection circuit includes at least: a fifth suppression circuit, a sixth suppression circuit, a third short-circuit protection circuit, and a third reverse connection protection circuit; the fifth suppression circuit and the sixth suppression circuit are used to suppress surges and pulse bursts; The first and second ends of the third interface are respectively connected to the first and second ends of the branch power supply interface; the first end of the branch power supply interface is connected to the first end of the fifth suppression circuit, and the second end of the branch power supply interface is connected to the second end of the fifth suppression circuit. The first end of the branch power supply terminal interface is connected to the first end of the sixth suppression circuit through an inductor, and the second end of the branch power supply terminal interface is connected to the second end of the sixth suppression circuit through an inductor. The first terminal of the third power supply reverse connection protection circuit is connected to the first terminal of the sixth suppression circuit, and the first terminal of the third power supply reverse connection protection circuit is connected to the second terminal of the sixth suppression circuit and the first terminal of the third short circuit protection circuit through capacitors respectively. The second terminal of the third short-circuit protection circuit is connected to the second terminal of the third power supply reverse connection protection circuit.

4. The Ethernet interface protection topology circuit according to claim 1, characterized in that, The second power supply protection circuit includes at least: a seventh suppression circuit, an eighth suppression circuit, a fourth short-circuit protection circuit, and a fourth reverse connection protection circuit; the seventh suppression circuit and the eighth suppression circuit are used to suppress surges and pulse bursts; The first and second ends of the fourth interface are respectively connected to the first and second ends of the branch power supply interface; the first end of the branch power supply interface is connected to the first end of the seventh suppression circuit, and the second end of the branch power supply interface is connected to the second end of the seventh suppression circuit. The first end of the branch power take-off interface is connected to the first end of the eighth suppression circuit through an inductor, and the second end of the branch power take-off interface is connected to the second end of the eighth suppression circuit through an inductor. The first terminal of the fourth power supply reverse connection protection circuit is connected to the first terminal of the eighth suppression circuit, and the first terminal of the fourth power supply reverse connection protection circuit is connected to the second terminal of the eighth suppression circuit and the first terminal of the fourth short circuit protection circuit through capacitors respectively. The second terminal of the fourth short-circuit protection circuit is connected to the second terminal of the fourth power supply reverse connection protection circuit.

5. The Ethernet interface protection topology circuit according to claim 1, characterized in that, The first suppression circuit includes a first transient diode and a second transient diode; the second suppression circuit includes a third transient diode and a fourth transient diode; The first terminal of the main power supply terminal interface is connected to the first terminal of the first transient diode, and the second terminal of the first transient diode is connected to the first terminal of the second transient diode; the second terminal of the second transient diode is connected to the second terminal of the main power supply terminal interface. The first terminal of the main power supply interface is connected to the first terminal of the third transient diode via an inductor, and the second terminal of the third transient diode is connected to the first terminal of the fourth transient diode; the second terminal of the fourth transient diode is connected to the second terminal of the main power supply interface via an inductor. Wherein, the first terminal of the first transient diode is the first terminal of the first suppression circuit, the second terminal of the second transient diode is the second terminal of the first suppression circuit, the first terminal of the third transient diode is the first terminal of the second suppression circuit, and the second terminal of the fourth transient diode is the second terminal of the second suppression circuit.

6. The Ethernet interface protection topology circuit according to claim 2, characterized in that, The third suppression circuit includes a fifth transient diode and a sixth transient diode; the fourth suppression circuit includes a seventh transient diode and an eighth transient diode; The first end of the main power input interface is connected to the first end of the fifth transient diode, the second end of the fifth transient diode is connected to the first end of the sixth transient diode, and the second end of the sixth transient diode is connected to the second end of the main power input interface. The first end of the main power input interface is connected to the first end of the seventh transient diode through an inductor, the second end of the seventh transient diode is connected to the first end of the eighth transient diode, and the second end of the eighth transient diode is connected to the second end of the main power input interface through an inductor. Wherein, the first terminal of the fifth transient diode is the first terminal of the third suppression circuit, the second terminal of the sixth transient diode is the second terminal of the third suppression circuit, the first terminal of the seventh transient diode is the first terminal of the fourth suppression circuit, and the second terminal of the eighth transient diode is the second terminal of the fourth suppression circuit.

7. The Ethernet interface protection topology circuit according to claim 3, characterized in that, The fifth suppression circuit includes a ninth transient diode and a tenth transient diode; the sixth suppression circuit includes an eleventh transient diode and a twelfth transient diode; The first end of the branch power supply terminal interface is connected to the first end of the ninth transient diode, the second end of the ninth transient diode is connected to the first end of the tenth transient diode, and the second end of the tenth transient diode is connected to the second end of the branch power supply terminal interface. The first end of the branch power supply terminal interface is connected to the first end of the eleventh transient diode through an inductor, the second end of the eleventh transient diode is connected to the first end of the twelfth transient diode, and the second end of the twelfth transient diode is connected to the second end of the branch power supply terminal interface through an inductor. Wherein, the first terminal of the ninth transient diode is the first terminal of the fifth suppression circuit, the second terminal of the tenth transient diode is the second terminal of the fifth suppression circuit, the first terminal of the eleventh transient diode is the first terminal of the sixth suppression circuit, and the second terminal of the eleventh transient diode is the second terminal of the sixth suppression circuit.

8. The Ethernet interface protection topology circuit according to claim 4, characterized in that, The seventh suppression circuit includes a thirteenth transient diode and a fourteenth transient diode; the eighth suppression circuit includes a fifteenth transient diode and a sixteenth transient diode; The first end of the branch power supply interface is connected to the first end of the thirteenth transient diode, the second end of the thirteenth transient diode is connected to the first end of the fourteenth transient diode, and the second end of the fourteenth transient diode is connected to the second end of the branch power supply interface. The first end of the branch power input interface is connected to the first end of the fifteenth transient diode through an inductor, the second end of the fifteenth transient diode is connected to the first end of the sixteenth transient diode, and the second end of the sixteenth transient diode is connected to the second end of the branch power input interface through an inductor. Specifically, the first terminal of the thirteenth transient diode is the first terminal of the seventh suppression circuit, the second terminal of the fourteenth transient diode is the second terminal of the seventh suppression circuit, the first terminal of the fifteenth transient diode is the first terminal of the eighth suppression circuit, and the second terminal of the sixteenth transient diode is the second terminal of the eighth suppression circuit.

9. The Ethernet interface protection topology circuit according to claim 1, characterized in that, The first short-circuit protection circuit includes a first fuse.

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