PSE port protection circuit and PoE system

Abstract

The utility model discloses a PSE port protection circuit and a PoE system. The PSE port protection circuit comprises a PSE chip; the grid electrode of the first switch tube is connected with the switch control end, the source electrode is connected with the negative input end of the PoE power supply, and the drain electrode is connected with the positive input end of the PoE power supply through the first capacitor; a first diode; a second diode; a network transformer unit; the rectifying unit is provided with a first rectifying end, a second rectifying end and a third rectifying end, the first rectifying end is connected with the anode of the second diode, the second rectifying end is connected with the center tap of the primary coil of the third network transformer, and the third rectifying end is connected with the center tap of the primary coil of the fourth network transformer; the rectification unit is used for guiding surge energy in the circuit; a first protection unit; a network interface module; and a PHY module. The PSE port protection circuit provided by the utility model can realize the diversion and concentrated discharge of surge energy, and reduces the use number of protection devices.

Description

Technical Field

[0001] The utility model relates to the technical field of network communication, and particularly relates to a PSE port protection circuit and a PoE system. Background Art

[0002] With the development of network communication technology, there are more and more terminals that need to provide network services. It has become increasingly unsafe and inconvenient to use traditional strong electricity to supply power to a variety of intelligent terminals. While the Power over Ethernet (PoE) technology can transmit data signals and provide DC power supply to IP-based terminals, such as IP phones, wireless APs, network monitoring, etc., without any modification to the existing Ethernet wiring structure, maintaining compatibility with the existing Ethernet and users, significantly shortening the construction period, and reducing the installation and maintenance costs.

[0003] As a PSE (Power Sourcing Equipment, that is, PoE power supply equipment) switch that provides network access and PoE power supply to various terminals, it has also been widely used, and its application environment has become more and more complex and changeable. The PSE switch encounters more and more electromagnetic interferences such as lightning surges and static electricity in actual applications, which makes the industry's requirements for the surge and static electricity protection capabilities of the PSE switch communication port higher and higher. In the currently common PSE port protection circuit, each port needs to have a protection device, and there are many protection devices, which in turn brings the problem of high cost. Summary of the Utility Model

[0004] The utility model aims to at least solve one of the technical problems existing in the prior art. For this purpose, the utility model proposes a PSE port protection circuit, which can realize the diversion and centralized discharge of surge energy, and reduce the number of protection devices used.

[0005] The utility model also proposes a PoE system.

[0006] The PSE port protection circuit according to the first aspect embodiment of the utility model includes:

[0007] A PSE chip, having a switch control terminal, an input terminal, and a ground terminal; the input terminal is connected to the positive input terminal of the PoE power supply, and the ground terminal is connected to the negative input terminal of the PoE power supply;

[0008] A first switching tube, whose gate is connected to the switch control terminal, the source is connected to the negative input terminal of the PoE power supply, and the drain is connected to the positive input terminal of the PoE power supply through a first capacitor;

[0009] A first diode, whose anode is connected to the positive input terminal of the PoE power supply, and whose cathode is connected to the input terminal of the PSE chip;

[0010] A second diode, whose cathode is connected to the drain of the first switching transistor;

[0011] A network transformer unit, including a first network transformer, a second network transformer, a third network transformer, and a fourth network transformer. The center tap of the primary coil of the first network transformer is connected to the positive input terminal of the PoE power supply, and the center tap of the primary coil of the second network transformer is connected to the anode of the second diode; the center taps of the secondary coils of the first network transformer, the second network transformer, the third network transformer, and the fourth network transformer are connected to the first ground wire through a second capacitor.

[0012] A rectification unit, having a first rectification terminal, a second rectification terminal, and a third rectification terminal. The first rectification terminal is connected to the anode of the second diode, the second rectification terminal is connected to the center tap of the primary coil of the third network transformer, and the third rectification terminal is connected to the center tap of the primary coil of the fourth network transformer; the rectification unit is used to divert the surge energy in the circuit;

[0013] A first protection unit, connected between the positive input terminal and the negative input terminal of the PoE power supply, for discharging the surge energy in the circuit to the ground;

[0014] A network interface module, connected to the primary coils of the first network transformer, the second network transformer, the third network transformer, and the fourth network transformer;

[0015] A PHY module, connected to the secondary coils of the first network transformer, the second network transformer, the third network transformer, and the fourth network transformer.

[0016] The PSE port protection circuit according to the embodiment of the present invention has at least the following beneficial effects:

[0017] The PSE chip is used for power supply management of the PoE power input, and can drive the first switching tube for PoE power supply switching. The first diode and the second diode are used to prevent negative common-mode surge energy from passing through the PSE chip and the first switching tube. The rectifying unit is used for guiding the surge energy, guiding all the interference energy coming in from each port to the positive and negative input ends of the PoE power supply, and discharging the energy to the ground through the first protection unit. The network transformer unit is used to integrate the PoE power input and the communication signal of the PHY module, and transmit it to the network interface module. The network interface module can be used for external powered devices to access. The PSE port protection circuit of the embodiment of the present invention can achieve the guiding and centralized discharging of surge energy through the rectifying unit and the first protection unit, reduce the number of protection devices used, have low cost, be easy to implement, and have high practical value. In addition, due to the small number of protection devices used, it is convenient for PCB design and the design of multi-port PSE switches.

[0018] According to some embodiments of the present invention, the first protection unit includes:

[0019] The first varistor, connected between the positive input end of the PoE power supply and the second ground wire;

[0020] The second varistor, connected between the negative input end of the PoE power supply and the second ground wire.

[0021] According to some embodiments of the present invention, the rectifying unit includes:

[0022] The third diode, its anode is connected to the center tap of the primary coil of the second network transformer, and its cathode is connected to the positive input end of the PoE power supply;

[0023] The fourth diode, its anode is connected to the negative input end of the PoE power supply, and its cathode is connected to the anode of the third diode;

[0024] The fifth diode, its anode is connected to the center tap of the primary coil of the third network transformer, and its cathode is connected to the positive input end of the PoE power supply;

[0025] The sixth diode, its anode is connected to the negative input end of the PoE power supply, and its cathode is connected to the anode of the fifth diode;

[0026] The seventh diode, its anode is connected to the center tap of the primary coil of the fourth network transformer, and its cathode is connected to the positive input end of the PoE power supply;

[0027] The eighth diode, its anode is connected to the negative input end of the PoE power supply, and its cathode is connected to the anode of the seventh diode.

[0028] According to some embodiments of the present utility model, the third diode, the fourth diode, the fifth diode, the sixth diode, the seventh diode, and the eighth diode are fast recovery diodes.

[0029] According to some embodiments of the present utility model, the PSE port protection circuit further includes:

[0030] A unidirectional TVS diode connected between the positive input terminal and the negative input terminal of the PoE power supply.

[0031] According to some embodiments of the present utility model, the PSE port protection circuit further includes:

[0032] A secondary protection unit, including a first secondary protection sub-unit, a second secondary protection sub-unit, a third secondary protection sub-unit, and a fourth secondary protection sub-unit. The first secondary protection sub-unit, the second secondary protection sub-unit, the third secondary protection sub-unit, and the fourth secondary protection sub-unit each have a first input terminal, a second input terminal, a first output terminal, and a second output terminal;

[0033] The first input terminals and the second input terminals of the first secondary protection sub-unit, the second secondary protection sub-unit, the third secondary protection sub-unit, and the fourth secondary protection sub-unit are all connected to the PHY module; the first output terminal and the second output terminal of the first secondary protection sub-unit are respectively connected to the first end and the second end of the secondary coil of the first network transformer; the first output terminal and the second output terminal of the second secondary protection sub-unit are respectively connected to the first end and the second end of the secondary coil of the second network transformer; the first output terminal and the second output terminal of the third secondary protection sub-unit are respectively connected to the first end and the second end of the secondary coil of the third network transformer; the first output terminal and the second output terminal of the fourth secondary protection sub-unit are respectively connected to the first end and the second end of the secondary coil of the fourth network transformer.

[0034] According to some embodiments of the present utility model, the first secondary protection sub-unit, the second secondary protection sub-unit, the third secondary protection sub-unit, and the fourth secondary protection sub-unit each include a first resistor, a second resistor, a third capacitor, a fourth capacitor, and a bidirectional TVS diode; the first end of the bidirectional TVS diode is connected to the first ground wire through the first resistor and the third capacitor, and the second end of the bidirectional TVS diode is connected to the first ground wire through the second resistor and the fourth capacitor;

[0035] The common terminal of the first resistor and the third capacitor serves as the first input terminal, the common terminal of the second resistor and the fourth capacitor serves as the second input terminal, the first terminal of the bidirectional TVS diode serves as the first output terminal, and the second terminal of the bidirectional TVS diode serves as the second output terminal.

[0036] According to some embodiments of the present invention, the first diode and the second diode are Schottky diodes.

[0037] According to some embodiments of the present invention, the PSE port protection circuit further includes a second protection unit connected between the first ground wire and the second ground wire, and the second protection unit includes a third resistor and a fifth capacitor connected in parallel with the third resistor.

[0038] The PoE system according to the second aspect embodiment of the present invention includes the PSE port protection circuit as described in the first aspect embodiment. The PoE system in the embodiments of the present invention includes the PSE port protection circuit as described in the first aspect embodiment, and thus has all the beneficial effects of the PSE port protection circuit as described in the first aspect embodiment.

[0039] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present invention. Description of the Drawings

[0040] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0041] Figure 1 is a circuit schematic diagram of the PSE port protection circuit according to the embodiment of the present invention;

[0042] Figure 2 is a circuit schematic diagram of the second protection unit according to the embodiment of the present invention.

[0043] Reference Numerals:

[0044] PSE chip 100,

[0045] Rectifying unit 200,

[0046] First protection unit 300,

[0047] Network interface module 400,

[0048] PHY module 500,

[0049] Secondary protection unit 600. Detailed Embodiments

[0050] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present utility model and should not be construed as a limitation to the present utility model.

[0051] In the description of the present utility model, if the first, second, etc. are described, they are only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0052] In the description of the present utility model, it should be understood that for the orientation description, such as up, down, etc., the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0053] In the description of the present utility model, it should be noted that unless otherwise clearly defined, words such as setting, installation, connection, etc. should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the present utility model in combination with the specific content of the technical solution.

[0054] The technical solution of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some but not all embodiments of the present utility model.

[0055] See Figure 1 as shown Figure 1 is a circuit diagram of the PSE port protection circuit according to an embodiment of the present utility model. The PSE port protection circuit includes a PSE chip 100, a first switching tube, a first diode, a second diode, a network transformer unit, a rectification unit 200, a first protection unit 300, a network interface module 400, and a PHY module 500;

[0056] The PSE chip 100 has a switch control terminal, an input terminal, and a ground terminal; the input terminal is connected to the positive input terminal of the PoE power supply, and the ground terminal is connected to the negative input terminal of the PoE power supply;

[0057] The first switching tube has its gate connected to the switch control terminal, its source connected to the negative input terminal of the PoE power supply, and its drain connected to the positive input terminal of the PoE power supply through a first capacitor;

[0058] The first diode has its anode connected to the positive input terminal of the PoE power supply and its cathode connected to the input terminal of the PSE chip;

[0059] A second diode, whose cathode is connected to the drain of the first switching transistor;

[0060] A network transformer unit, including a first network transformer, a second network transformer, a third network transformer, and a fourth network transformer. The center tap of the primary coil of the first network transformer is connected to the positive input terminal of the PoE power supply, and the center tap of the primary coil of the second network transformer is connected to the anode of the second diode; the center taps of the secondary coils of the first network transformer, the second network transformer, the third network transformer, and the fourth network transformer are connected to the first ground wire through a second capacitor.

[0061] A rectification unit 200, having a first rectification terminal, a second rectification terminal, and a third rectification terminal. The first rectification terminal is connected to the anode of the second diode, the second rectification terminal is connected to the center tap of the primary coil of the third network transformer, and the third rectification terminal is connected to the center tap of the primary coil of the fourth network transformer; the rectification unit 200 is used to divert the surge energy in the circuit;

[0062] A first protection unit 300, connected between the positive input terminal and the negative input terminal of the PoE power supply, for discharging the surge energy in the circuit to the ground;

[0063] A network interface module 400, connected to the primary coils of the first network transformer, the second network transformer, the third network transformer, and the fourth network transformer;

[0064] A PHY module 500, connected to the secondary coils of the first network transformer, the second network transformer, the third network transformer, and the fourth network transformer.

[0065] The PSE chip 100 is used for power supply management of the PoE power input, and can drive the first switching tube for PoE power supply switching. The first diode and the second diode are used to prevent negative common-mode surge energy from passing through the PSE chip 100 and the first switching tube. The rectification unit 200 is used for guiding the surge energy, guiding all the interference energy coming in from each port to the positive and negative input ends of the PoE power supply, and discharging the energy to the ground through the first protection unit 300. The network transformer unit is used to integrate the PoE power input and the communication signal of the PHY (Physical) module 500, and transmit it to the network interface module 400. The network interface module 400 can be used for external powered devices to access. The PSE port protection circuit of the embodiment of the present invention can realize the guiding and centralized discharging of surge energy through the rectification unit 200 and the first protection unit 300, reduce the number of protection devices used, have low cost, be easy to implement, and have high practical value. In addition, due to the small number of protection devices used, it is convenient for PCB design and convenient for the design of multi-port PSE switches.

[0066] The above-mentioned PSE chip 100, the first switching tube, the first diode, the second diode, the rectification unit 200 and the first protection unit 300 constitute the power supply part circuit for accessing the PoE power supply. The PHY module 500 constitutes the network signal access part circuit. The network transformer unit can couple the above two parts of the circuit and transmit the output signal to the network interface module 400.

[0067] The above-mentioned first diode and second diode prevent negative common-mode surge energy from passing through the PSE chip 100 and the first switching tube by utilizing the one-way conduction characteristic of the diode; the above-mentioned first switching tube can adopt an N-channel field effect tube.

[0068] The above-mentioned PHY module 500 can be a PHY chip. The above-mentioned PHY chip can have four groups of MDI ports, and each group of MDI ports includes a positive and a negative port. The above-mentioned network interface module 400 can be an RJ45 network interface module. The above-mentioned RJ45 network interface module can have four groups of interfaces, and each group of interfaces includes two interfaces. Each group of MDI ports of the above-mentioned PHY chip is correspondingly connected to the secondary coil of one of the four network transformers in the network transformer unit, and the primary coil of the network transformer is correspondingly connected to a group of interfaces of the above-mentioned RJ45 network interface module.

[0069] In some embodiments, the first protection unit 300 includes:

[0070] The first varistor, connected between the positive input end of the PoE power supply and the second ground wire;

[0071] The second varistor, connected between the negative input end of the PoE power supply and the second ground wire.

[0072] In this embodiment, the first protection unit 300 uses varistors, which can achieve the discharge of common-mode surge to the ground. Among them, the first varistor can discharge the forward common-mode surge energy, and the first varistor and the second varistor can discharge the negative common-mode surge energy.

[0073] In a conventional circuit, in order to achieve a better protection effect, the protection operating voltage of the port-to-ground protection device is much lower than the mains voltage. Generally, a TSS with an operating voltage of 58V is used. This kind of protection device is extremely easy to be broken down by the abnormally introduced mains voltage during actual use. For example, in the case of live ground wire or live network cable, in severe cases, the product will be burned out due to overcurrent. This application uses varistors with a high operating voltage. The conduction voltage between the PSE port and the ground, that is, the voltage between the network interface module 400 and the second ground wire, is higher than the mains voltage, which can effectively prevent the PSE switch from being damaged by the abnormally introduced mains voltage breakdown.

[0074] The above-mentioned first varistor and second varistor can use varistors with an operating voltage higher than the mains voltage of 360V.

[0075] In some embodiments, the rectification unit 200 includes a third diode, a fourth diode, a fifth diode, a sixth diode, a seventh diode, and an eighth diode;

[0076] The third diode, its anode is connected to the center tap of the primary coil of the second network transformer, and its cathode is connected to the positive input terminal of the PoE power supply;

[0077] The fourth diode, its anode is connected to the negative input terminal of the PoE power supply, and its cathode is connected to the anode of the third diode;

[0078] The fifth diode, its anode is connected to the center tap of the primary coil of the third network transformer, and its cathode is connected to the positive input terminal of the PoE power supply;

[0079] The sixth diode, its anode is connected to the negative input terminal of the PoE power supply, and its cathode is connected to the anode of the fifth diode;

[0080] The seventh diode, its anode is connected to the center tap of the primary coil of the fourth network transformer, and its cathode is connected to the positive input terminal of the PoE power supply;

[0081] The eighth diode, its anode is connected to the negative input terminal of the PoE power supply, and its cathode is connected to the anode of the seventh diode.

[0082] In this embodiment, the rectification unit 200 includes multiple diodes. By utilizing the unidirectional conductivity of the diodes, the interference energy coming in from each port is rectified, and finally diverted to the positive and negative input terminals of the PoE power supply, which can achieve the diversion of surge energy.

[0083] In some embodiments, the third diode, the fourth diode, the fifth diode, the sixth diode, the seventh diode, and the eighth diode are fast recovery diodes.

[0084] In this embodiment, a fast recovery diode is a semiconductor diode with good switching characteristics and a fast reverse recovery time. Using fast recovery diodes can enable the rectification unit 200 to achieve a better effect of guiding surge energy.

[0085] In some embodiments, the PSE port protection circuit further includes a unidirectional TVS diode;

[0086] The unidirectional TVS diode is connected between the positive input terminal and the negative input terminal of the PoE power supply.

[0087] In this embodiment, the unidirectional TVS diode, that is, the unidirectional transient voltage suppression diode, is a protective electronic component that can protect electrical equipment from voltage spikes introduced by wires and can effectively suppress instantaneous overvoltage. The above unidirectional TVS diode, connected between the positive input terminal and the negative input terminal of the PoE power supply, can protect the circuit and the PSE chip 100 from transient voltage impacts.

[0088] In some embodiments, the PSE port protection circuit further includes a secondary protection unit 600;

[0089] The secondary protection unit 600 includes a first secondary protection subunit, a second secondary protection subunit, a third secondary protection subunit, and a fourth secondary protection subunit. The first secondary protection subunit, the second secondary protection subunit, the third secondary protection subunit, and the fourth secondary protection subunit all have a first input terminal, a second input terminal, a first output terminal, and a second output terminal;

[0090] The first input terminals and the second input terminals of the first secondary protection subunit, the second secondary protection subunit, the third secondary protection subunit, and the fourth secondary protection subunit are all connected to the PHY module 500; the first output terminal and the second output terminal of the first secondary protection subunit are respectively connected to the first end and the second end of the first secondary coil of the first network transformer; the first output terminal and the second output terminal of the second secondary protection subunit are respectively connected to the first end and the second end of the first secondary coil of the second network transformer; the first output terminal and the second output terminal of the third secondary protection subunit are respectively connected to the first end and the second end of the first secondary coil of the third network transformer; the first output terminal and the second output terminal of the fourth secondary protection subunit are respectively connected to the first end and the second end of the first secondary coil of the fourth network transformer.

[0091] In this embodiment, a secondary protection unit 600 is designed on the secondary side of the network transformer, including secondary protection subunits corresponding to the number of network transformers, which can effectively reduce the impact of port surge and static electricity on the product performance and working stability.

[0092] In some embodiments, the first secondary protection subunit, the second secondary protection subunit, the third secondary protection subunit, and the fourth secondary protection subunit all include a first resistor, a second resistor, a third capacitor, a fourth capacitor, and a bidirectional TVS diode; the first end of the bidirectional TVS diode is connected to the first ground wire through the first resistor and the third capacitor, and the second end of the bidirectional TVS diode is connected to the first ground wire through the second resistor and the fourth capacitor;

[0093] The common end of the first resistor and the third capacitor is used as the first input terminal, the common end of the second resistor and the fourth capacitor is used as the second input terminal, the first end of the bidirectional TVS diode is used as the first output terminal, and the second end of the bidirectional TVS diode is used as the second output terminal.

[0094] In this embodiment, each secondary protection subunit adopts a low-pass RC circuit composed of a bidirectional TVS diode, a resistor, and a capacitor. Among them, the bidirectional TVS diode can effectively suppress the surge and static electricity energy coupled to the MDI differential line of the PHY chip through the network transformer. The RC circuits composed of the first resistor and the third capacitor, and the second resistor and the fourth capacitor can effectively filter out the surge and static common-mode energy coupled to the MDI differential line of the PHY chip through the network transformer.

[0095] Since the differential-mode withstand voltage of the PHY chip is very low, the above bidirectional TVS diode can be selected as a bidirectional TVS diode with a protection operating voltage of about 3.3V.

[0096] In some embodiments, the PSE port protection circuit further includes a primary protection unit;

[0097] The primary protection unit includes a first primary protection subunit, a second primary protection subunit, a third primary protection subunit, and a fourth primary protection subunit. The first primary protection subunit, the second primary protection subunit, the third primary protection subunit, and the fourth primary protection subunit all have a first connection end and a first grounding end;

[0098] The first connection end of the first primary protection sub-unit is connected to the center tap of the primary coil of the first network transformer; the first connection end of the second primary protection sub-unit is connected to the center tap of the primary coil of the second network transformer; the first connection end of the third primary protection sub-unit is connected to the center tap of the primary coil of the third network transformer; the first connection end of the fourth primary protection sub-unit is connected to the center tap of the primary coil of the fourth network transformer; the first grounding ends of the first primary protection sub-unit, the second primary protection sub-unit, the third primary protection sub-unit and the fourth primary protection sub-unit are all connected to the second ground wire.

[0099] In some embodiments, the first primary protection sub-unit, the second primary protection sub-unit, the third primary protection sub-unit and the fourth primary protection sub-unit all include a fourth resistor and a sixth capacitor; one end of the sixth capacitor is connected to the second ground wire, the other end of the sixth capacitor is connected to the first end of the fourth resistor, and the second end of the fourth resistor serves as the first connection end.

[0100] In some embodiments, the first diode and the second diode are Schottky diodes.

[0101] In this embodiment, the first diode and the second diode prevent negative common-mode surge energy from passing through the PSE chip 100 and the first switching tube by utilizing the unidirectional conductivity of the diode. The above-mentioned first diode and second diode adopt Schottky diodes with a lower conduction voltage, which can reduce losses.

[0102] As Figure 2 shown, in some embodiments, the PSE port protection circuit further includes a second protection unit connected between the first ground wire and the second ground wire. The second protection unit includes a third resistor and a fifth capacitor connected in parallel with the third resistor.

[0103] In this embodiment, connecting a third resistor and a fifth capacitor in parallel between the first ground wire and the second ground wire can improve the electromagnetic compatibility of the circuit, and achieve electrostatic protection, prevent the occurrence of ground loops, and provide an additional current path. Furthermore, it can ensure the normal operation of the circuit and reduce the possibility of mutual interference.

[0104] In some embodiments, in the PSE port protection circuit of the present application, the PSE chip 100, the first switching tube, the first diode, the second diode, the rectification unit 200 and the first protection unit 300 constitute a power supply part circuit for accessing the PoE power supply, and the PHY module 500 and the secondary protection unit 600 constitute a network signal access part circuit. The network transformer unit can couple the above two parts of the circuit and transmit the output signal to the network interface module 400.

[0105] In some embodiments, the PSE port protection circuit of the present application can be applied to occasions where PoE power supply is carried out through network cables at different network rates using RJ45 interfaces, such as in cases where the network rates are 10M, 100M, 1G, 2.5G, 5G, 10G, etc. When applied to multi-port PSE switching, the power supply part circuits of multiple ports can be connected in parallel. Among them, the PSE chip 100, the first switching tube, the first diode, the second diode, the rectification unit 200, and the first protection unit 300 constitute the power supply part circuit for accessing the PoE power supply. At the same time, a varistor connected between the positive and negative input terminals of the PoE power supply and the ground needs to be appropriately added according to the circuit conditions.

[0106] In some embodiments, the above-mentioned PHY module 500 is a PHY chip and has four groups of MDI ports. Each group of MDI ports includes two ports, a positive port and a negative port. The above-mentioned network interface module 400 is an RJ45 network interface module and has four groups of interfaces. Each group of interfaces includes two interfaces, a positive interface and a negative interface. The four groups of interfaces of the RJ45 network interface module are the 1st and 2nd pins, the 3rd and 6th pins, the 4th and 5th pins, and the 7th and 8th pins in sequence. Among them, the 1st and 2nd pins of the RJ45 network interface module are the positive pole of the overall PSE power supply output, and the 3rd and 6th pins of the RJ45 network interface module are the negative pole of the overall PSE power supply output. Each group of MDI ports of the above-mentioned PHY chip is correspondingly connected to the secondary coil of one of the four network transformers in the network transformer unit, and the primary coil of the network transformer is correspondingly connected to a group of interfaces of the above-mentioned RJ45 network interface module.

[0107] Next, the surge energy discharge path after the rectification unit 200 diverts the surge energy in the circuit will be specifically described.

[0108] Positive common-mode surge energy discharge path: The positive common-mode surge energy is a path that divides into four paths from the four groups of interfaces of the RJ45 network interface module and flows towards the second ground wire. One path is from the 1st and 2nd pins of the RJ45 network interface module, passing through the first network transformer, the first varistor, and then to the second ground wire; the other three paths are respectively: from the 3rd and 6th pins of the RJ45 network interface module, passing through the second network transformer, the diversion of the third diode, the first varistor, and then to the second ground wire; from the 4th and 5th pins of the RJ45 network interface module, passing through the third network transformer, the diversion of the fifth diode, the first varistor, and then to the second ground wire; from the 7th and 8th pins of the RJ45 network interface module, passing through the fourth network transformer, the diversion of the seventh diode, the first varistor, and then to the second ground wire.

[0109] Negative common-mode surge energy discharge path: The negative common-mode surge energy is a path that divides into four routes from the second ground wire and flows to the four groups of interfaces of the RJ45 network interface module. One route passes through the first varistor and the first network transformer in sequence to pins 1 and 2 of the RJ45 network interface module. The other three routes, after passing through the second varistor, divide into three routes: passing through the diversion of the fourth diode and the second network transformer to pins 3 and 6 of the RJ45 network interface module in sequence; passing through the diversion of the sixth diode and the third network transformer to pins 4 and 5 of the RJ45 network interface module in sequence; passing through the diversion of the eighth diode and the fourth network transformer to pins 7 and 8 of the RJ45 network interface module in sequence.

[0110] Positive differential-mode surge energy discharge path of PSE power supply: The positive differential-mode surge energy is a path that starts from pins 1 and 2 of the RJ45 network interface module, which is the positive output of the PSE power supply, and returns to pins 3 and 6 of the RJ45 network interface module, which is the negative output of the PSE power supply. The energy starts from pins 1 and 2 of the RJ45 network interface module and passes through the first network transformer, the unidirectional TVS diode, the fourth diode, and the second network transformer in sequence to return to pins 3 and 6 of the RJ45 network interface module.

[0111] Negative differential-mode surge energy discharge path of PSE power supply: The negative differential-mode surge energy is a path that starts from pins 3 and 6 of the RJ45 network interface module, which is the negative output of the PSE power supply, and returns to pins 1 and 2 of the RJ45 network interface module, which is the positive output of the PSE power supply. The energy starts from pins 3 and 6 of the RJ45 network interface module and passes through the second network transformer, the third diode, and the first network transformer in sequence to return to pins 1 and 2 of the RJ45 network interface module.

[0112] Surge and electrostatic energy suppression and discharge path of the MDI interface of the PHY chip: The energy of differential-mode surges or static electricity coupled from the primaries of the first network transformer, the second network transformer, the third network transformer, and the fourth network transformer is suppressed by the bidirectional TVS diode. The common-mode surge and electrostatic energy are conducted to the first ground wire through the low-pass RC filter circuit composed of the first resistor and the third capacitor, and can also be conducted to the first ground wire through the low-pass RC filter circuit composed of the second resistor and the fourth capacitor. Subsequently, it is conducted to the second ground wire through the second protection unit, that is, the third resistor and the fifth capacitor connected in parallel.

[0113] The embodiment of the present invention also proposes a PoE system, which includes the PSE port protection circuit as described in the above embodiment. The PoE system in the embodiment of the present invention includes the PSE port protection circuit as described in the above embodiment, and thus has all the beneficial effects of the PSE port protection circuit as described in the embodiment of the first aspect.

[0114] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0115] Although the embodiments of the present utility model have been described in detail above in conjunction with the accompanying drawings, the present utility model is not limited to the above embodiments. Those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present utility model. The scope of the present utility model is defined by the claims and their equivalents.

Claims

1. A PSE port protection circuit, characterized in that: include: The PSE chip has a switch control terminal, an input terminal, and a ground terminal; the input terminal is connected to the positive input terminal of the PoE power supply, and the ground terminal is connected to the negative input terminal of the PoE power supply; A first switch tube, whose gate is connected to the switch control terminal, whose source is connected to the negative input terminal of the PoE power supply, and whose drain is connected to the positive input terminal of the PoE power supply through a first capacitor; a first diode, an anode of which is connected to the positive input terminal of the PoE power supply, and a cathode of which is connected to the input terminal of the PSE chip; a second diode, a cathode of which is connected to the drain of the first switch tube; A network transformer unit, comprising a first network transformer, a second network transformer, a third network transformer and a fourth network transformer, wherein a middle tap of a primary coil of the first network transformer is connected to a positive input terminal of the PoE power supply, and a middle tap of a primary coil of the second network transformer is connected to an anode of the second diode; middle taps of secondary coils of the first network transformer, the second network transformer, the third network transformer and the fourth network transformer are connected to a first ground wire via a second capacitor; A rectifier unit having a first rectifier end, a second rectifier end and a third rectifier end, wherein the first rectifier end is connected to the anode of the second diode, the second rectifier end is connected to the middle tap of the primary coil of the third network transformer, and the third rectifier end is connected to the middle tap of the primary coil of the fourth network transformer; the rectifier unit is used to conduct surge energy in the circuit; A first protection unit is connected between the positive input terminal of the PoE power supply and the negative input terminal of the PoE power supply, and is used for discharging surge energy in the circuit to the ground; A network interface module connected to the first network transformer primary coil, the second network transformer primary coil, the third network transformer primary coil and the fourth network transformer primary coil; The PHY module is connected to the first network transformer secondary coil, the second network transformer secondary coil, the third network transformer secondary coil and the fourth network transformer secondary coil.

2. The PSE port protection circuit according to claim 1, characterized in that: The first protection unit comprises: A first varistor is connected between the positive input terminal of the PoE power supply and the second ground line; The second varistor is connected between the negative input terminal of the PoE power supply and the second ground line.

3. The PSE port protection circuit according to claim 1, characterized in that: The rectifying unit comprises: A third diode, an anode of which is connected to the middle tap of the primary coil of the second network transformer, and a cathode of which is connected to the positive input terminal of the PoE power supply; a fourth diode, an anode of which is connected to the negative input terminal of the PoE power supply, and a cathode of which is connected to the anode of the third diode; a fifth diode, an anode of which is connected to the middle tap of the primary coil of the third network transformer, and a cathode of which is connected to the positive input terminal of the PoE power supply; a sixth diode, an anode of which is connected to the negative input terminal of the PoE power supply, and a cathode of which is connected to the anode of the fifth diode; a seventh diode, an anode of which is connected to the middle tap of the primary coil of the fourth network transformer, and a cathode of which is connected to the positive input terminal of the PoE power supply; An eighth diode has an anode connected to the negative input terminal of the PoE power supply, and a cathode connected to the anode of the seventh diode.

4. The PSE port protection circuit according to claim 3, characterized in that: The third diode, the fourth diode, the fifth diode, the sixth diode, the seventh diode and the eighth diode are fast recovery diodes.

5. The PSE port protection circuit according to claim 1, characterized in that: The PSE port protection circuit also includes: A unidirectional TVS diode is connected between the positive input terminal of the PoE power supply and the negative input terminal of the PoE power supply.

6. The PSE port protection circuit according to claim 1, characterized in that: The PSE port protection circuit also includes: The secondary protection unit comprises a first secondary protection subunit, a second secondary protection subunit, a third secondary protection subunit and a fourth secondary protection subunit, wherein the first secondary protection subunit, the second secondary protection subunit, the third secondary protection subunit and the fourth secondary protection subunit all have a first input terminal, a second input terminal, a first output terminal and a second output terminal; The first input end and the second input end of the first secondary protection subunit, the second secondary protection subunit, the third secondary protection subunit and the fourth secondary protection subunit are all connected to the PHY module; the first output end and the second output end of the first secondary protection subunit are respectively connected to the first end and the second end of the secondary coil of the first network transformer; the first output end and the second output end of the second secondary protection subunit are respectively connected to the first end and the second end of the secondary coil of the second network transformer; the first output end and the second output end of the third secondary protection subunit are respectively connected to the first end and the second end of the secondary coil of the third network transformer; the first output end and the second output end of the fourth secondary protection subunit are respectively connected to the first end and the second end of the secondary coil of the fourth network transformer.

7. The PSE port protection circuit according to claim 6, characterized in that: The first secondary protection subunit, the second secondary protection subunit, the third secondary protection subunit and the fourth secondary protection subunit all include a first resistor, a second resistor, a third capacitor, a fourth capacitor and a bidirectional TVS diode; the first end of the bidirectional TVS diode is connected to the first ground line through the first resistor and the third capacitor, and the second end of the bidirectional TVS diode is connected to the first ground line through the second resistor and the fourth capacitor; The common end of the first resistor and the third capacitor is used as the first input end, the common end of the second resistor and the fourth capacitor is used as the second input end, the first end of the bidirectional TVS diode is used as the first output end, and the second end of the bidirectional TVS diode is used as the second output end.

8. The PSE port protection circuit according to claim 1, characterized in that: The first diode and the second diode are Schottky diodes.

9. The PSE port protection circuit according to claim 2, characterized in that: The PSE port protection circuit further includes a second protection unit connected between the first ground line and the second ground line, and the second protection unit includes a third resistor and a fifth capacitor connected in parallel with the third resistor.

10. A PoE system, comprising the PSE port protection circuit according to any one of claims 1 to 9.

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