Anti-surge and electrostatic protection circuit and POE device

Abstract

The utility model relates to an anti-surge and electrostatic protection circuit and a POE device. The anti-surge and electrostatic protection circuit comprises an electrostatic protection module, a voltage conversion module, a rectification module, an anti-surge module, a first input end and a second input end. The input end of the voltage conversion module is connected with the first input end, the output end of the voltage conversion module is connected with the input end of the electrostatic protection module, and the output end of the electrostatic protection module is connected with the post-stage receiving module; the input end of the rectifier module is connected with the first input end and the second input end, the output end of the rectifier module is connected with the post-stage receiving module, and the anti-surge module is arranged between the output end of the rectifier module and the post-stage receiving module. According to the utility model, electromagnetic pulse or transient voltage in a network can be effectively suppressed through the anti-surge module, equipment is prevented from being damaged, electromagnetic interference signals on a line can be suppressed through the electrostatic protection module, the data transmission quality is ensured, and the stability and transmission speed of network connection are ensured.

Description

Technical Field

[0001] The utility model relates to the field of electronic technology, and more specifically to an anti-surge and electrostatic protection circuit and a POE device. Background Art

[0002] POE (Power Over Ethernet) refers to a technology that can provide DC power to some IP-based terminals (such as IP phones, wireless LAN access points AP, network cameras, etc.) while transmitting data signals without making any changes to the existing Ethernet Cat.5 wiring infrastructure. This not only simplifies the installation and maintenance of the equipment, but also reduces system costs and power consumption.

[0003] However, in existing solutions, electromagnetic pulses or transient voltages in the network may be transmitted to the device through the POE system, causing damage or failure of the device. In addition, electromagnetic interference (such as static electricity) on the power line is transmitted to the data line, affecting the quality of data transmission, causing unstable network connection or slow speed. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a surge protection and electrostatic protection circuit and a POE device in view of the problems existing in the prior art.

[0005] The technical solution adopted by the utility model to solve the technical problem is: constructing an anti-surge and electrostatic protection circuit, including: an electrostatic protection module, a voltage conversion module, a rectification module, an anti-surge module, a first input terminal and a second input terminal;

[0006] The input end of the voltage conversion module is connected to the first input end, the output end of the voltage conversion module is connected to the input end of the electrostatic protection module, and the output end of the electrostatic protection module is connected to the subsequent receiving module;

[0007] The input end of the rectifier module is respectively connected to the first input end and the second input end, the output end of the rectifier module is connected to the subsequent receiving module, and the surge protection module is arranged between the output end of the rectifier module and the subsequent receiving module;

[0008] The electrostatic protection module is used to suppress electromagnetic interference signals during signal / data transmission;

[0009] The surge protection module is used to suppress electromagnetic pulses or transient voltages on the line.

[0010] In the surge protection and electrostatic protection circuit described in the utility model, the electrostatic protection module includes: a first electrostatic protection circuit and a second electrostatic protection circuit; the voltage conversion module includes: a first isolation transformer and a second isolation transformer; the first input end includes: a first sub-input end and a second sub-input end; the post-stage receiving module includes: a signal receiving module;

[0011] The input end of the first isolation transformer is connected to the first sub-input end, the output end of the first isolation transformer is connected to the input end of the first electrostatic protection circuit, and the output end of the first electrostatic protection circuit is connected to the signal receiving module;

[0012] The input end of the second isolation transformer is connected to the second sub-input end, the output end of the second isolation transformer is connected to the input end of the second electrostatic protection circuit, and the output end of the second electrostatic protection circuit is connected to the signal receiving module.

[0013] In the surge protection and electrostatic protection circuit described in the utility model, the first electrostatic protection circuit includes: a first electrostatic protection unit, a first voltage-limiting and current-limiting circuit, and a second voltage-limiting and current-limiting circuit;

[0014] A first end of the first electrostatic protection unit is connected to a first sub-output end of the first isolation transformer, and a second end of the first electrostatic protection unit is connected to a second sub-output end of the first isolation transformer;

[0015] An input end of the first voltage-limiting and current-limiting circuit is connected to a first end of the first electrostatic protection unit, and an output end of the first voltage-limiting and current-limiting circuit is connected to the signal receiving module;

[0016] An input end of the second voltage-limiting and current-limiting circuit is connected to the second end of the first electrostatic protection unit, and an output end of the second voltage-limiting and current-limiting circuit is connected to the signal receiving module.

[0017] In the surge protection and electrostatic protection circuit described in the utility model, the first electrostatic protection unit is an electrostatic protection diode, and the first voltage-limiting and current-limiting circuit and the second voltage-limiting and current-limiting circuit are both voltage-limiting and current-limiting resistors.

[0018] In the surge protection and electrostatic protection circuit described in the utility model, the second electrostatic protection circuit includes: a second electrostatic protection unit, a third voltage and current limiting circuit and a fourth voltage and current limiting circuit;

[0019] A first end of the second electrostatic protection unit is connected to a first sub-output end of the second isolation transformer, and a second end of the second electrostatic protection unit is connected to a second sub-output end of the second isolation transformer;

[0020] An input end of the third voltage-limiting and current-limiting circuit is connected to a first end of the second electrostatic protection unit, and an output end of the third voltage-limiting and current-limiting circuit is connected to the signal receiving module;

[0021] An input end of the fourth voltage-limiting and current-limiting circuit is connected to the second end of the second electrostatic protection unit, and an output end of the fourth voltage-limiting and current-limiting circuit is connected to the signal receiving module.

[0022] In the surge protection and electrostatic protection circuit described in the utility model, the second electrostatic protection unit is an electrostatic protection diode, and the third voltage-limiting and current-limiting circuit and the fourth voltage-limiting and current-limiting circuit are both voltage-limiting and current-limiting resistors.

[0023] In the surge protection and electrostatic protection circuit described in the utility model, the surge protection module includes: a first surge protection circuit and a second surge protection circuit; the post-stage receiving module includes: a power receiving module;

[0024] The first end of the first surge protection circuit is connected to the first sub-output end of the rectifier module, and the second end of the first surge protection circuit is connected to the second sub-output end of the rectifier module; the first sub-output end of the rectifier module is also connected to the first input end of the power receiving module, and the second sub-output end of the rectifier module is also connected to the second input end of the power receiving module;

[0025] A first end of the second surge protection circuit is connected to a second end of the first surge protection circuit, and a second end of the second surge protection circuit is grounded.

[0026] In the surge protection and electrostatic protection circuit described in the utility model, the first surge protection circuit includes: a first TVS tube; the second surge protection circuit includes: a second TVS tube;

[0027] The first end of the first TVS tube is connected to the first sub-output end of the rectifier module, and the second end of the first TVS tube is connected to the second sub-output end of the rectifier module;

[0028] The first end of the second TVS tube is connected to the second end of the second TVS tube, and the second end of the second TVS tube is grounded.

[0029] The surge protection and electrostatic protection circuit of the utility model also includes: a network port surge protection circuit;

[0030] The input end of the network port surge protection circuit is connected to the second input end and the input end of the voltage conversion module, and the output end of the network port surge protection circuit is grounded.

[0031] The utility model also provides a POE device, comprising: a rear-stage receiving module and the above-mentioned surge protection and electrostatic protection circuit.

[0032] The implementation of the anti-surge and electrostatic protection circuit and POE device of the utility model has the following beneficial effects: including: an electrostatic protection module, a voltage conversion module, a rectifier module, an anti-surge module, a first input end and a second input end; the input end of the voltage conversion module is connected to the first input end, the output end of the voltage conversion module is connected to the input end of the electrostatic protection module, and the output end of the electrostatic protection module is connected to the subsequent receiving module; the input end of the rectifier module is respectively connected to the first input end and the second input end, the output end of the rectifier module is connected to the subsequent receiving module, and the anti-surge module is arranged between the output end of the rectifier module and the subsequent receiving module. The utility model can effectively suppress electromagnetic pulses or transient voltages in the network through the anti-surge module to avoid damage to the equipment. At the same time, the electrostatic protection module can suppress electromagnetic interference signals on the line, ensure the quality of data transmission, and ensure the stability and transmission speed of the network connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0034] Figure 1 It is a structural schematic diagram of a first embodiment of a surge protection and electrostatic protection circuit provided by the utility model;

[0035] Figure 2 It is a structural schematic diagram of a second embodiment of the surge protection and electrostatic protection circuit provided by the utility model;

[0036] Figure 3 The utility model provides a circuit diagram of a specific embodiment of the surge protection and electrostatic protection circuit. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0038] In order to solve the problem that electromagnetic pulses or transient voltages in the existing network may be transmitted to the device through the POE system, causing damage or malfunction of the device, and the electromagnetic interference on the power line may be transmitted to the data line, affecting the data transmission quality and causing the network connection to be unstable or slow, the utility model provides an anti-surge and electrostatic protection circuit, which can effectively suppress the electromagnetic pulses or transient voltages generated in the network, and can also suppress the electromagnetic interference signals on the line, thereby preventing the device from being damaged or malfunctioning due to the influence of electromagnetic pulses or transient voltages, and can also ensure the data transmission quality, and improve the stability of the network connection and the transmission speed.

[0039] Specifically, Figure 1 As shown, the surge protection and electrostatic protection circuit includes: an electrostatic protection module 14 , a voltage conversion module 13 , a rectification module 16 , a surge protection module 15 , a first input terminal 11 and a second input terminal 12 .

[0040] The input end of the voltage conversion module 13 is connected to the first input end 11, the output end of the voltage conversion module 13 is connected to the input end of the electrostatic protection module 14, and the output end of the electrostatic protection module 14 is connected to the subsequent receiving module; the input end of the rectifier module 16 is respectively connected to the first input end 11 and the second input end 12, the output end of the rectifier module 16 is connected to the subsequent receiving module, and the surge protection module 15 is arranged between the output end of the rectifier module 16 and the subsequent receiving module; the electrostatic protection module 14 is used to suppress electromagnetic interference signals during signal / data transmission; the surge protection module 15 is used to suppress electromagnetic pulses or transient voltages on the line.

[0041] When an electromagnetic pulse or transient voltage is generated in the network, the electromagnetic pulse or transient voltage can be effectively suppressed by the surge protection module 15, thereby avoiding the influence of the electromagnetic pulse or transient voltage on the device, protecting the device from damage by the electromagnetic pulse or transient voltage, and extending the service life of the device. Specifically, when an electromagnetic pulse or transient voltage is generated in the network, the electromagnetic pulse or transient voltage first passes through the surge protection module 15. At this time, due to the action of the surge protection module 15, it can reduce or discharge the energy of the electromagnetic pulse or transient voltage, thereby reducing the energy transmitted to the device, and achieving effective suppression of the electromagnetic pulse or transient voltage.

[0042] When electromagnetic interference is generated on the line, the electromagnetic interference signal can be effectively suppressed by the electrostatic protection module 14, thereby reducing the impact of the electromagnetic interference signal on the line on data transmission, ensuring the stability and reliability of the network connection, and improving the quality and speed of data transmission. Specifically, when electromagnetic interference is generated on the line, at this time, due to the effect of the electrostatic protection module 14, it can reduce the electromagnetic interference on the line, thereby achieving the purpose of reducing the interference signal of data transmission.

[0043] Furthermore, if Figure 1 As shown, the surge protection and electrostatic protection circuit also includes: a network port surge protection circuit 17. Among them, the input end of the network port surge protection circuit 17 is connected to the second input end 12 and the input end of the voltage conversion module 13, and the output end of the network port surge protection circuit 17 is grounded. Specifically, by setting the network port surge protection circuit 17, it can reduce the influence of common mode noise, and can also reduce the influence of the power line on the signal through impedance matching, and shape and pre-process the signal before signal transmission to reduce clock pulling and signal distortion, thereby improving the transmission quality of the signal.

[0044] Furthermore, if Figure 2 As shown, the electrostatic protection module 14 includes: a first electrostatic protection circuit 141 and a second electrostatic protection circuit 142; the voltage conversion module 13 includes: a first isolation transformer and a second isolation transformer; the first input terminal 11 includes: a first sub-input terminal and a second sub-input terminal; the post-stage receiving module includes: a signal receiving module.

[0045] The input end of the first isolation transformer is connected to the first sub-input end, the output end of the first isolation transformer is connected to the input end of the first electrostatic protection circuit 141, and the output end of the first electrostatic protection circuit 141 is connected to the signal receiving module; the input end of the second isolation transformer is connected to the second sub-input end, the output end of the second isolation transformer is connected to the input end of the second electrostatic protection circuit 142, and the output end of the second electrostatic protection circuit 142 is connected to the signal receiving module.

[0046] Optionally, in this embodiment, the first electrostatic protection circuit 141 includes: a first electrostatic protection unit, a first voltage limiting and current limiting circuit, and a second voltage limiting and current limiting circuit; the first end of the first electrostatic protection unit is connected to the first sub-output end of the first isolation transformer, and the second end of the first electrostatic protection unit is connected to the second sub-output end of the first isolation transformer; the input end of the first voltage limiting and current limiting circuit is connected to the first end of the first electrostatic protection unit, and the output end of the first voltage limiting and current limiting circuit is connected to the signal receiving module; the input end of the second voltage limiting and current limiting circuit is connected to the second end of the first electrostatic protection unit, and the output end of the second voltage limiting and current limiting circuit is connected to the signal receiving module.

[0047] Optionally, in this embodiment, the first electrostatic protection unit is an electrostatic protection diode, and the first voltage-limiting and current-limiting circuit and the second voltage-limiting and current-limiting circuit are both voltage-limiting and current-limiting resistors.

[0048] In this embodiment, the second electrostatic protection circuit 142 includes: a second electrostatic protection unit, a third voltage and current limiting circuit, and a fourth voltage and current limiting circuit.

[0049] The first end of the second electrostatic protection unit is connected to the first sub-output end of the second isolation transformer, and the second end of the second electrostatic protection unit is connected to the second sub-output end of the second isolation transformer; the input end of the third voltage limiting and current limiting circuit is connected to the first end of the second electrostatic protection unit, and the output end of the third voltage limiting and current limiting circuit is connected to the signal receiving module; the input end of the fourth voltage limiting and current limiting circuit is connected to the second end of the second electrostatic protection unit, and the output end of the fourth voltage limiting and current limiting circuit is connected to the signal receiving module.

[0050] Optionally, in this embodiment, the second electrostatic protection unit is an electrostatic protection diode, and the third voltage-limiting and current-limiting circuit and the fourth voltage-limiting and current-limiting circuit are both voltage-limiting and current-limiting resistors.

[0051] Furthermore, if Figure 2 As shown, the surge protection module 15 includes: a first surge protection circuit 151 and a second surge protection circuit 152; the subsequent receiving module includes: a power receiving module.

[0052] The first end of the first surge protection circuit 151 is connected to the first sub-output end of the rectifier module 16, and the second end of the first surge protection circuit 151 is connected to the second sub-output end of the rectifier module 16; the first sub-output end of the rectifier module 16 is also connected to the first input end of the power receiving module, and the second sub-output end of the rectifier module 16 is also connected to the second input end of the power receiving module; the first end of the second surge protection circuit 152 is connected to the second end of the first surge protection circuit 151, and the second end of the second surge protection circuit 152 is grounded.

[0053] Optionally, in this embodiment, the first surge protection circuit 151 includes: a first TVS tube; the second surge protection circuit 152 includes: a second TVS tube; the first end of the first TVS tube is connected to the first sub-output end of the rectifier module 16, and the second end of the first TVS tube is connected to the second sub-output end of the rectifier module 16; the first end of the second TVS tube is connected to the second end of the second TVS tube, and the second end of the second TVS tube is grounded.

[0054] refer to Figure 3 , Figure 3 The present invention provides a circuit diagram of a specific embodiment of the surge protection and electrostatic protection circuit.

[0055] Specifically, Figure 3As shown, the first input terminal 11 includes: 1, 2, 3, 6 connection terminals, and the second input terminal 12 includes: 4, 5, 7, 8 connection terminals, which are usually connected with an RJ45 transceiver. Among them, the connection terminals 1 and 2 are the first sub-input terminals, and the connection terminals 3 and 6 are the second sub-input terminals. Generally, the terminals 1, 2, 3, and 6 are signal input terminals, wherein the input lines 1, 2, 3, and 6 are used as signal lines, and power is supplied through the signal lines. Since the power supply and data frequencies do not interfere with each other, power supply and data can be transmitted simultaneously on the same pair of lines, that is, relative to the cable, it can be regarded as a kind of "multiplexing". Among them, the polarity of 1, 2, 3, and 6 is arbitrary, for example, 1 and 2 are positive poles, and 3 and 6 are negative poles; or, 1 and 2 are negative poles, and 3 and 6 are positive poles. Terminals 4, 5, 7, and 8 are power supply input terminals, among which input lines 4, 5, 7, and 8 are idle lines, which can be used for power transmission, that is, transmitting power signals. Generally, the polarities of 4, 5, 7, and 8 are set as follows: 4 and 5 are positive poles, and 7 and 8 are negative poles.

[0056] like Figure 3 As shown, the network port surge protection circuit 17 includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5. The rectifier module 16 includes: a first rectifier bridge BD1 and a second rectifier bridge BD2. The first electrostatic protection unit includes: a first electrostatic diode D1, the first voltage limiting and current limiting circuit includes: a first limiting resistor RS1, and the second voltage limiting and current limiting circuit includes: a second limiting resistor RS2. The second electrostatic protection unit includes: a second electrostatic diode D2, the third voltage limiting and current limiting circuit includes: a third limiting resistor RS3, and the fourth voltage limiting and current limiting circuit includes: a fourth limiting resistor RS4. The first surge protection circuit 151 includes: a first TVS tube TVS1; the second surge protection circuit 152 includes: a second TVS tube TVS2.

[0057] Specifically, Figure 3As shown, in this embodiment, the first input end of the first isolation transformer T1 is connected to the 1 connection end, the second input end of the first isolation transformer T1 is connected to the 2 connection end, the center tap of the first isolation transformer T1 is connected to the first end of the first resistor R1, the first output end of the first isolation transformer T1 is connected to the first end of the first electrostatic diode D1 and the first end of the first limiting resistor RS1, the second end of the first limiting resistor RS1 is connected to the first input end of the signal receiving module PHY IC, the second output end of the first isolation transformer T1 is connected to the second end of the first electrostatic diode D1 and the first end of the second limiting resistor RS2, and the second end of the second limiting resistor RS2 is connected to the second input end of the signal receiving module; the first input end of the second isolation transformer T2 is connected to the 3 connection end, the second input end of the second isolation transformer T2 is connected to the 6 connection end, the first output end of the second isolation transformer T2 is connected to the first end of the second electrostatic diode D2 and the first end of the third limiting resistor RS3, the second end of the third limiting resistor RS3 is connected to the third input end of the signal receiving module PHY IC, the second output end of the second isolation transformer T2 is connected to the second end of the second electrostatic diode D2 and the first end of the fourth limiting resistor RS4, and the second end of the fourth limiting resistor RS4 is connected to the signal receiving module PHY A fourth input terminal of the IC, a center tap of the second isolation transformer T2, is connected to a first end of the second resistor R2.

[0058] like Figure 3 As shown, the first input end of the first rectifier bridge BD1 is connected to the center tap of the first isolation transformer T1, the second input end of the first rectifier bridge BD1 is connected to the center tap of the second isolation transformer T2, the first output end of the first rectifier bridge BD1 is connected to the first output end of the second rectifier bridge BD2 and is connected to the first end of the first TVS tube TVS1 and the first input end of the power receiving module NextCircuit, the first input end of the second rectifier bridge BD2 is connected to the 5th connection end, and the 4th connection end is connected to the 5th connection end, the second input end of the second rectifier bridge BD2 is connected to the 8th connection end, and the 7th connection end is connected to the 8th connection end, the second output end of the second rectifier bridge BD2 is connected to the second output end of the first rectifier bridge BD1 and is connected to the second end of the first TVS tube TVS1 and the second input end of the power receiving module NextCircuit, the first end of the second TVS tube TVS2 is connected to the second end of the first TVS tube TVS1, and the second end of the second TVS tube TVS2 is grounded.

[0059] like Figure 3As shown, the second end of the first resistor R1 is connected to the first end of the first capacitor C1, the second end of the second resistor R2 is connected to the first end of the second capacitor C2, the first end of the third resistor R3 is connected to the 5 connection end, the second end of the third resistor R3 is connected to the first end of the third capacitor C3, the first end of the fourth resistor R4 is connected to the 8 connection end, the second end of the fourth resistor R4 is connected to the first end of the fourth capacitor C4, the second end of the first capacitor C1, the second end of the second capacitor C2, the second end of the third capacitor C3 and the second end of the fourth capacitor C4 are all connected to the first end of the fifth capacitor C5, and the second end of the fifth capacitor C5 is grounded.

[0060] like Figure 3 As shown, by setting a TVS tube at the idle line end, when an electromagnetic pulse or transient voltage is generated on the line, the energy of the electromagnetic pulse or transient voltage can be reduced by the first TVS tube TVS1 and the second TVS tube TVS2, thereby effectively suppressing the impact of the electromagnetic pulse or transient voltage on the device, protecting the device from damage by the transient voltage, and extending the service life of the device. Optionally, in this embodiment, the TVS tube used can be a TVS tube with an operating voltage of 58V.

[0061] like Figure 3 As shown, by adding ESD electrostatic protection diodes (i.e., the first electrostatic protection diode D1 and the second electrostatic protection diode D2) to PHY (physical interface transceiver, a protocol for defining data transmission at the physical layer), the impact of electromagnetic interference on the power line on data transmission can be effectively reduced when electromagnetic interference is generated, ensuring the stability and reliability of network connection, and improving the quality and speed of data transmission. At the same time, by setting limiting resistors (i.e., the first limiting resistor RS1, the second limiting resistor RS2, the third limiting resistor RS3 and the fourth limiting resistor RS4, generally 2.2Ω) for use in conjunction, it can not only play the role of voltage and current limiting, but also help ESD start faster.

[0062] It should be noted that Figure 3 This is just a specific example. When there are multiple isolation transformers, the number of electrostatic protection circuits is adjusted accordingly, that is, the electrostatic protection circuits can be set according to the number of isolation transformers.

[0063] The utility model also provides a POE device, wherein the POE device includes: a post-stage receiving module and an anti-surge and electrostatic protection circuit disclosed in an embodiment of the utility model. By setting the anti-surge and electrostatic protection circuit, the POE device can not only realize device and signal transmission for the PD device, but also realize anti-surge and electrostatic protection, that is, when a surge occurs in the power supply, it is ensured that the post-stage components will not be affected, so that the service life of the device is extended; when electromagnetic interference occurs, the data transmission of the device is not affected, which greatly improves the reliability and timeliness of the network connection.

[0064] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot limit the protection scope of the utility model. All equivalent changes and modifications made to the scope of the claims of the utility model should fall within the scope of the claims of the utility model.

Claims

1. A surge protection and electrostatic protection circuit, characterized in that: include: An electrostatic protection module, a voltage conversion module, a rectification module, a surge protection module, a first input terminal and a second input terminal; The input end of the voltage conversion module is connected to the first input end, the output end of the voltage conversion module is connected to the input end of the electrostatic protection module, and the output end of the electrostatic protection module is connected to the subsequent receiving module; The input end of the rectifier module is respectively connected to the first input end and the second input end, the output end of the rectifier module is connected to the subsequent receiving module, and the surge protection module is arranged between the output end of the rectifier module and the subsequent receiving module; The electrostatic protection module is used to suppress electromagnetic interference signals during signal / data transmission; The surge protection module is used to suppress electromagnetic pulses or transient voltages on the line.

2. The surge protection and electrostatic protection circuit according to claim 1, characterized in that: The electrostatic protection module includes: a first electrostatic protection circuit and a second electrostatic protection circuit; the voltage conversion module includes: a first isolation transformer and a second isolation transformer; the first input end includes: a first sub-input end and a second sub-input end; the post-stage receiving module includes: a signal receiving module; The input end of the first isolation transformer is connected to the first sub-input end, the output end of the first isolation transformer is connected to the input end of the first electrostatic protection circuit, and the output end of the first electrostatic protection circuit is connected to the signal receiving module; The input end of the second isolation transformer is connected to the second sub-input end, the output end of the second isolation transformer is connected to the input end of the second electrostatic protection circuit, and the output end of the second electrostatic protection circuit is connected to the signal receiving module.

3. The surge protection and electrostatic protection circuit according to claim 2, characterized in that: The first electrostatic protection circuit comprises: a first electrostatic protection unit, a first voltage-limiting and current-limiting circuit, and a second voltage-limiting and current-limiting circuit; A first end of the first electrostatic protection unit is connected to a first sub-output end of the first isolation transformer, and a second end of the first electrostatic protection unit is connected to a second sub-output end of the first isolation transformer; An input end of the first voltage-limiting and current-limiting circuit is connected to a first end of the first electrostatic protection unit, and an output end of the first voltage-limiting and current-limiting circuit is connected to the signal receiving module; An input end of the second voltage-limiting and current-limiting circuit is connected to the second end of the first electrostatic protection unit, and an output end of the second voltage-limiting and current-limiting circuit is connected to the signal receiving module.

4. The surge protection and electrostatic protection circuit according to claim 3, characterized in that: The first electrostatic protection unit is an electrostatic protection diode, and the first voltage-limiting and current-limiting circuit and the second voltage-limiting and current-limiting circuit are both voltage-limiting and current-limiting resistors.

5. The surge protection and electrostatic protection circuit according to claim 2, characterized in that: The second electrostatic protection circuit comprises: a second electrostatic protection unit, a third voltage-limiting and current-limiting circuit and a fourth voltage-limiting and current-limiting circuit; A first end of the second electrostatic protection unit is connected to a first sub-output end of the second isolation transformer, and a second end of the second electrostatic protection unit is connected to a second sub-output end of the second isolation transformer; An input end of the third voltage-limiting and current-limiting circuit is connected to a first end of the second electrostatic protection unit, and an output end of the third voltage-limiting and current-limiting circuit is connected to the signal receiving module; An input end of the fourth voltage-limiting and current-limiting circuit is connected to the second end of the second electrostatic protection unit, and an output end of the fourth voltage-limiting and current-limiting circuit is connected to the signal receiving module.

6. The surge protection and electrostatic protection circuit according to claim 5, characterized in that: The second electrostatic protection unit is an electrostatic protection diode, and the third voltage-limiting and current-limiting circuit and the fourth voltage-limiting and current-limiting circuit are both voltage-limiting and current-limiting resistors.

7. The surge protection and electrostatic protection circuit according to claim 1, characterized in that: The surge protection module includes: a first surge protection circuit and a second surge protection circuit; the subsequent receiving module includes: a power receiving module; The first end of the first surge protection circuit is connected to the first sub-output end of the rectifier module, and the second end of the first surge protection circuit is connected to the second sub-output end of the rectifier module; the first sub-output end of the rectifier module is also connected to the first input end of the power receiving module, and the second sub-output end of the rectifier module is also connected to the second input end of the power receiving module; A first end of the second surge protection circuit is connected to a second end of the first surge protection circuit, and a second end of the second surge protection circuit is grounded.

8. The surge protection and electrostatic protection circuit according to claim 7, characterized in that: The first surge protection circuit includes: a first TVS tube; the second surge protection circuit includes: a second TVS tube; The first end of the first TVS tube is connected to the first sub-output end of the rectifier module, and the second end of the first TVS tube is connected to the second sub-output end of the rectifier module; The first end of the second TVS tube is connected to the second end of the second TVS tube, and the second end of the second TVS tube is grounded.

9. The surge protection and electrostatic protection circuit according to any one of claims 1 to 8, characterized in that: Also includes: Network port surge protection circuit; The input end of the network port surge protection circuit is connected to the second input end and the input end of the voltage conversion module, and the output end of the network port surge protection circuit is grounded.

10. A POE device, characterized in that: include: A post-stage receiving module and a surge protection and electrostatic protection circuit as claimed in any one of claims 1 to 9.

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