Network power supply circuit

Abstract

The invention provides a network power supply circuit, and the circuit comprises a network transformer, and the primary side of the network transformer is connected with a network interface. The filter circuit is connected with the network interface and the primary side of the network transformer and is used for receiving a network signal and a power supply signal; the rectification power supply circuit is connected with the primary side of the network transformer and used for separating power supply signals of the power supply circuit; and the communication signal circuit is connected with the secondary side of the network transformer and is used for receiving a communication signal. By means of the mode, electromagnetic interference can be effectively reduced, network communication signal quality is guaranteed, communication equipment is prevented from being damaged, and production and maintenance cost is reduced.

Description

Technical Field

[0001] This application relates to the field of network communication technologies, and particularly to a network power supply circuit. Background Art

[0002] With the rapid development of network informatization, the application scenarios of network devices are increasing. Under the demand for high-speed data transmission between network devices, the Power over Ethernet (POE) technology has emerged.

[0003] The POE power supply technology can simultaneously transmit data signals and power through existing Ethernet cables. In application scenarios with long-distance transmission and complex wiring environments, its electromagnetic environment is extremely vulnerable to interference, which can also cause signal loss during transmission or damage to connected network devices.

[0004] The stability of the electromagnetic environment of Ethernet power supply is related to the stable operation of network devices. Therefore, the improvement of network power supply circuits cannot be ignored. Summary of the Invention

[0005] This application provides a network power supply circuit, which can effectively reduce electromagnetic interference, ensure the quality of network communication signals, prevent damage to communication devices, and reduce production and maintenance costs.

[0006] Among them, the network power supply circuit includes:

[0007] A network transformer, the primary side of the network transformer is connected to a network interface; a filtering circuit, the filtering circuit is connected to the network interface and the primary side of the network transformer to receive network signals and power supply signals; a rectifying power supply circuit, connected to the primary side of the network transformer, and the rectifying power supply circuit is used to separate the power supply signal of the power supply circuit; a communication signal circuit, connected to the secondary side of the network transformer, and used to receive communication signals.

[0008] Among them, the filtering circuit includes a first differential signal circuit, and the first differential signal circuit is connected to the network interface and the primary side of the network transformer; each pair of first differential signal circuits is connected to the primary side winding of the network transformer to form a primary tap.

[0009] Among them, the filtering circuit further includes a first filtering circuit and a second filtering circuit; the first filtering circuit is connected in parallel with the first differential signal circuit and is used to absorb high-frequency interference of the first differential signal circuit and discharge overcurrent and overvoltage of the first differential signal circuit; the second filtering circuit is connected in series with the primary tap of the network transformer and is used to filter high-frequency noise of the first differential signal circuit.

[0010] Among them, the first filtering circuit includes absorption capacitors, and each first differential signal circuit is connected with absorption capacitors, and the absorption capacitors are connected to a protection ground point;

[0011] The second filtering circuit includes: a decoupling capacitor, an absorption resistor, a bypass capacitor, and a bypass resistor; a decoupling capacitor and an absorption resistor are respectively connected to each primary tap, and the decoupling capacitor and the absorption resistor form a filtering element with a common-mode choke with the primary winding; the bypass resistor and the bypass capacitor are connected in parallel to the decoupling capacitor and the absorption resistor and connected to the protective ground point.

[0012] Among them, the rectifying power supply circuit includes a rectifier bridge circuit and a power supply control chip; the rectifier bridge circuit is respectively connected to each primary tap, and the input end and the output end of the rectifier bridge circuit are connected in parallel; the power supply control chip is used to supply power to the connected network device; the rectifier bridge circuit separates the network signal to obtain a power supply signal and sends it to the power supply control chip.

[0013] Among them, a first filtering and voltage stabilizing element is connected in parallel between the input end and the output end of the power supply control chip, and the first filtering and voltage stabilizing element includes a capacitor and / or a zener diode.

[0014] Among them, the rectifier bridge circuit includes a control switch, and the control switch is respectively connected to each primary tap; when the differential signal of the first differential signal line is positive, the corresponding control switch is turned on, and the primary tap corresponding to the first differential signal circuit connecting the input end and the output end of the power supply control chip is switched.

[0015] Among them, the first differential signal line includes four pairs of first differential signal circuits, and two pairs of first differential signal circuits are connected to a rectifier bridge circuit group; a rectifier bridge circuit group includes two correspondingly arranged control switches; when the differential signal of the first pair of first differential signal circuits is positive and the differential signal of the second pair of first differential signal circuits is negative, the control switch corresponding to the first pair of first differential signal circuits is turned on, and the control switch corresponding to the second pair of first differential signal circuits is turned off, so that the primary tap corresponding to the first pair of first differential signal circuits is connected to the input end of the power supply control chip, and the primary tap corresponding to the second pair of first differential signal circuits is connected to the output end of the power supply control chip.

[0016] Among them, the communication signal circuit includes a second differential signal circuit and a circuit signal conversion chip, and the signal conversion chip is connected to the secondary side of the network transformer through the second differential signal circuit; a second filtering and voltage stabilizing element is connected across each pair of second differential signal circuits.

[0017] Among them, each pair of second differential signal circuits is connected to the secondary winding of the network transformer to form a secondary tap; each secondary tap of the network transformer is grounded after being connected through a decoupling capacitor.

[0018] Differing from the prior art, the network power supply circuit provided by the present application meets the requirements of high-speed data transmission, and through the settings of a filtering circuit, a network transformer, and a rectifying power supply circuit, it can effectively reduce electromagnetic interference. Especially in the case of high-current lightning strikes and high-voltage surges, it can achieve stable power supply, prevent damage to communication equipment, ensure the quality of the network communication signal received by the communication signal circuit, and reduce production and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of the first embodiment of the network power supply circuit of the present application;

[0020] Figure 2 is a schematic structural diagram of the second embodiment of the network power supply circuit of the present application;

[0021] Figure 3 is a circuit logic schematic diagram of the third embodiment of the network power supply circuit of the present application;

[0022] Figure 4 is a circuit logic schematic diagram of a partial circuit of the fourth embodiment of the network power supply circuit of the present application;

[0023] Figure 5 is a circuit logic schematic diagram of the rectifying power supply circuit of the fourth embodiment of the network power supply circuit of the present application;

[0024] The structural names represented by the reference numerals in the drawings are as follows:

[0025] 11 - Network power supply circuit; 12 - Filtering circuit; 121 - First differential signal circuit; 122 - First filtering circuit; 1221 - Absorbing capacitor; 123 - Second filtering circuit; 1231 - Decoupling capacitor; 1232 - Absorbing resistor; 1233 - Bypass capacitor; 1234 - Bypass resistor; 13 - Network transformer; 14 - Rectifying power supply circuit; 141 - Rectifier bridge circuit; 142 - Power supply control chip; 142 - First filtering and voltage stabilizing element; 15 - Communication signal circuit; 151 - Second differential signal circuit; 152 - Signal conversion chip; 153 - Decoupling capacitor; 154 - Second filtering and voltage stabilizing element. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will describe in detail the solutions of the embodiments of the present application in conjunction with the accompanying drawings of the specification.

[0027] Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5The structural schematic diagram of the network power supply circuit in [ID] is a structural logic OR circuit logic schematic. The specific connection structure shall be referred to the structure in actual production. In the following description, specific details such as specific system structures, interfaces, and technologies are presented for illustration rather than limitation, so as to thoroughly understand the present application.

[0028] POE (Power Over Ethernet) is a technology that transmits power and data to devices through twisted pairs in Ethernet. It allows direct current to be transmitted to the powered device through the line transmitting data or the idle line. With the rapid development of network informatization, POE power supply has gradually become well-known. Network cameras, wireless network access points, access control and other devices using PoE power supply can be seen everywhere in public places. POE power supply has many advantages such as flexibility, cost savings, safety and reliability, and intelligent management. Therefore, it is increasingly applied in modern network devices.

[0029] The present application provides a network power supply circuit, which can effectively reduce electromagnetic interference, ensure the quality of network communication signals, prevent damage to communication devices, and reduce production and maintenance costs.

[0030] Please refer to Figure 1 , Figure 1 is the structural schematic diagram of the first embodiment of the network power supply circuit of the present application. Among them, the network power supply circuit 11 includes:

[0031] A network transformer 13, the primary side of the network transformer 13 is connected to a network interface (not shown in the figure).

[0032] Receiving a network signal with a communication signal and a power supply signal through the network interface, the signal network transformer 13 isolates the power signal and the data signal between the network interface and the powered device, and can realize functions such as signal transmission, impedance matching, waveform repair, signal clutter suppression, and high-voltage isolation, which can prevent the power signal from interfering with the data signal and also protect the device from voltage surges and electromagnetic interference damage.

[0033] A filter circuit 12, the filter circuit 12 is connected to the network interface and the primary side of the network transformer 13, and receives the network signal and the power supply signal. The filter circuit 12 can include a filter circuit 12 composed of resistors, capacitors or inductors to stabilize the network signal entering the network power supply circuit 11 from the network interface.

[0034] A rectifier power supply circuit 14, connected to the primary side of the network transformer 13, and the rectifier power supply circuit 14 is used to separate the power supply signal of the power supply circuit. The rectifier power supply circuit 14 converts the AC voltage into a stable DC voltage, ensures the stability of the power supply voltage transmitted by the filter circuit 12 to the powered device, and can also detect the power demand of the powered device to configure the power supply voltage.

[0035] The communication signal circuit 15 is connected to the secondary side of the network transformer 13 and is used to receive communication signals. The network signal after the rectification power supply circuit 14 separates the power supply signal is transmitted by the network transformer 13 to the communication signal circuit 15, and the communication signal is transmitted by the communication signal circuit 15 to the network device.

[0036] Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of the second embodiment of the network power supply circuit of the present application.

[0037] In a specific embodiment, the filtering circuit 12 includes a first differential signal circuit 121. The first differential signal circuit 121 is connected to the network interface and the primary side of the network transformer 13; each pair of the first differential signal circuits 121 is connected to the primary winding of the network transformer 13, forming a primary tap (not labeled in the figure).

[0038] A pair of first differential signal circuits 121 respectively transmit complementary network signals. When transmitting signals, the network signals are reflected by the voltage difference between the two lines between the first differential signal circuits 121. Each pair of first differential signal circuits 121 is connected to a coil winding (not labeled in the figure). In a specific embodiment, the primary tap is the center tap of the primary coil winding of the network transformer 13, which has good common-mode noise suppression and effective impedance matching effects.

[0039] In a specific embodiment, the filtering circuit 12 further includes a first filtering circuit 122 and a second filtering circuit 123; the first filtering circuit 122 is connected in parallel with the first differential signal circuit 121 and is used to absorb the high-frequency interference of the first differential signal circuit 121 and discharge the overcurrent and overvoltage of the first differential signal circuit 121; the second filtering circuit 123 is connected in series with the primary tap of the network transformer 13 and is used to filter the high-frequency noise of the first differential signal circuit 121.

[0040] One or more capacitors are connected in parallel to each first differential signal circuit 121 near the port to absorb the high-frequency interference generated by the first differential signal circuit 121, prevent the operation of the circuit from interfering with other devices, and at the same time discharge the overcurrent and overvoltage induced on the first-stage first differential information circuit transmitted from the network interface, thereby effectively protecting the components or chips on the subsequent circuit. In order not to affect the signal quality of the network power supply circuit 11, the capacitance value of the filtering capacitor should not be too large.

[0041] The second filtering circuit 123 is connected in series with the primary tap of the network transformer 13 and forms a filtering element with the winding of the primary side.

[0042] The size of the filtering element should be selected according to the threshold voltage of the power supply voltage received by the backend network device, the turns ratio of the network transformer 13 or the isolation voltage.

[0043] In a specific embodiment, the rectifier power supply circuit 14 includes a rectifier bridge circuit 141 and a power supply control chip 142; the rectifier bridge circuit 141 is respectively connected to each primary tap, and the input end and the output end of the rectifier bridge circuit 141 are connected in parallel with those of the power supply control chip 142; the power supply control chip 142 is used to supply power to the connected network device; the rectifier bridge circuit 141 separates the network signal to obtain a power supply signal and sends it to the power supply control chip 142.

[0044] After the rectifier bridge circuit 141 rectifies the network signal transmitted by the first differential signal circuit 121, separates the power supply signal, and transmits the power supply signal on the first differential signal circuit 121 to the power supply control chip 142 to provide a suitable working voltage for the backend device.

[0045] Please refer to Figure 3 , Figure 3 which is a circuit logic schematic diagram of an embodiment of the third embodiment of the network power supply circuit of the present application.

[0046] In a specific embodiment, the first filter circuit 122 includes an absorption capacitor 1221, and each first differential signal circuit 121 is connected with an absorption capacitor 1221, and the absorption capacitor 1221 is connected to the protection ground point;

[0047] The second filter circuit 123 includes: a decoupling capacitor 1231, an absorption resistor 1232, a bypass capacitor 1233, and a bypass resistor 1234; each primary tap is respectively connected with a decoupling capacitor 1231 and an absorption resistor 1232, and the decoupling capacitor 1231 and the absorption resistor 1232 form a filtering element with a common mode choke with the primary winding; the bypass resistor 1234 and the bypass capacitor 1233 are connected in parallel to the decoupling capacitor 1231 and the absorption resistor 1232 and are connected to the protection ground point.

[0048] The sizes of the resistors and capacitors selected for the first filter circuit and the second filter circuit are selected according to the threshold voltage of the received power voltage of the backend network device, the turns ratio of the network transformer 13, or the isolation voltage. Among them, increasing the capacitance value of the capacitor has a certain effect on absorbing static electricity, but being too large is likely to cause ground leakage current.

[0049] In a specific embodiment, the communication signal circuit 15 includes a second differential signal circuit 151 and a circuit signal conversion chip 152, and the signal conversion chip is connected to the secondary side of the network transformer 13 through the second differential signal circuit 151; a second filter voltage stabilizing element 154 is connected across each pair of second differential signal circuits 151.

[0050] In a specific embodiment, each pair of second differential signal circuits 151 is connected to the secondary winding of the network transformer 13 to form a secondary tap; each secondary tap of the network transformer 13 is grounded after being connected through a decoupling capacitor 153.

[0051] The decoupling capacitor 153 provides a low-impedance return path for the common-mode noise of the differential signal, effectively reducing the common-mode current and common-mode voltage on the second differential signal circuit 151.

[0052] In a specific embodiment, the network power supply circuit 11 is applied in a network communication environment of Gigabit Ethernet. Gigabit (1000M) Ethernet is a term describing the technology of transmitting Ethernet frames at a rate of gigabits per second, defined by the IEEE802.3-2005 standard. This standard allows half-duplex Gigabit connections through hubs. Gigabit Ethernet is characterized by high efficiency, high speed, and high performance, and has been widely used in industries such as finance, commerce, education, government agencies, and factories and mines.

[0053] The transmission mode of Gigabit Ethernet is to receive four groups of network transceiver differential signals through 8 network signal lines, that is, 4 pairs of first differential signal circuits. After the differential signals (M0_P / N~M3_P / N) are input from the RJ45 network interface connector of the network interface, they are transmitted to the network transformer T1 through the first differential signal circuit 121.

[0054] The first voltage stabilization and filtering circuit and the second voltage stabilization and filtering circuit are both connected to the protective grounding point PE.

[0055] The absorption capacitors C1~C8 of the first voltage stabilization and filtering circuit are distributed on the primary side of the network transformer T1, which can effectively absorb communication high-frequency interference and suppress the radio frequency interference generated by the network device itself to the outside. In order not to affect Gigabit Ethernet communication, the capacitance value of the absorption capacitor 1221 should not be too large. In a specific embodiment, the capacitance value range of the absorption capacitor 1221 is less than 10PF.

[0056] The decoupling capacitors C9~C12 and absorption resistors R1~R4 of the second voltage stabilization and filtering circuit are connected at the center tap position of the transformer to form a low-pass filter with a common-mode choke, which can reduce the noise generated by the common-mode current. The bypass resistor R5 and bypass capacitor C17 are connected between the tap terminal and the protective grounding point, playing a shielding and discharging role. In a specific embodiment, the resistance value of the bypass resistor 1234 is greater than or equal to 1MΩ, and the range of the bypass capacitor 1233 is 1000pF~4700pF.

[0057] The primary side of the network transformer T1 is powered by a rectifying power supply circuit 14 to obtain a power supply signal. The four center taps on the primary side pass through a rectifier bridge circuit 141 to separate the POE power supply voltage on the network cable and transmit it to the POE controller. Among them, M0_P / N and M1_P / N are connected to the rectifier bridge circuit BR1, and M2_P / N and M3_P / N are connected to the rectifier bridge circuit BR2. The rectifier bridge circuit 141 rectifies the network signal transmitted by the first differential signal circuit 121 to separate the power supply signal. This connection method ensures that regardless of the positive or negative voltage direction on the connected filter circuit 12, the power supply signal on the first differential signal circuit 121 is transmitted to the power supply control chip 142, and the voltage direction transmitted to the POE controller terminal, which is a current control chip, is the same, meeting the input current requirements of the POE controller, so that the POE controller can provide a suitable working voltage for the backend device.

[0058] After passing through the network transformer T1, at this time, the POE power supply voltage has been separated on the secondary side of the network transformer T1, and only communication signals (MAC_MD0_P / N~MAC_MD3_P / N) are transmitted to the PHY (Physical Layer Device) chip, which is a signal conversion chip, on the second differential signal circuit 151 of the communication signal circuit 15.

[0059] A TVS (Transient Voltage Suppressor) diode is connected in parallel between each pair of second differential signal circuits 151 as the second filter voltage regulator element 154 to prevent excessive differential-mode voltage caused by induced electromotive force between the transceiver differential pair signals.

[0060] When the two poles of the TVS diode are subjected to a reverse transient high-energy impact, it can change the high impedance between its two poles to a low impedance at a speed of the order of 10 to the power of minus 12 seconds, absorb surge energy of up to several kilowatts, clamp the voltage between the two poles to a predetermined value. At the same time, the TVS diode also has common-mode protection and has a certain absorption and discharge ability for the residual surge on the primary side of the network transformer 13, and can prevent the un-discharged excessive differential-mode residual voltage between the differential signals of the primary side winding of the transformer from coupling to the secondary side winding of the transformer, effectively protecting the precision components in the subsequent circuit from being damaged by various surge pulses.

[0061] Please refer to Figure 4 , Figure 4 which is the circuit logic schematic diagram of part of the circuit of the fourth embodiment of the network power supply circuit of the present application. Figure 4 The circuit logic diagram of includes a filter circuit, a network transformer, and part of the communication signal circuit. The overall structure of the fourth embodiment of the network power supply circuit can be referred to Figure 3 which is the circuit logic schematic diagram of the third embodiment of the network power supply circuit of the present application.

[0062] A decoupling capacitor 1231 with a capacitance of 0.01 uF and a 75 Ω absorption resistor 1232 are respectively connected in series to the center taps of the primary coil windings connected to each pair of the first differential signal circuits 121 to form a low-pass filter with a common-mode choke to reduce the noise generated by the common-mode current. The noise can be connected to the tap terminal and the protective ground through the bypass resistor R5 and the bypass capacitor C17 to play a role in shielding and discharging.

[0063] And the center taps of the primary coil windings are respectively connected to the rectifying power supply circuit 14 from PR0 to PR3.

[0064] A decoupling capacitor 153 with a capacitance of 0.1 uF is respectively connected in series to the center taps of the primary coil windings connected to each pair of the first differential signal circuits 121 and then grounded, effectively reducing the common-mode current and common-mode voltage on the input differential signal lines.

[0065] In a specific embodiment, the rectifying power supply circuit 14 includes a rectifier bridge circuit 141 and a power supply control chip 142; the rectifier bridge circuit 141 is respectively connected to each primary tap, and the input end and the output end of the rectifier bridge circuit 141 are connected in parallel to those of the power supply control chip 142; the power supply control chip 142 is used to supply power to the connected network device; the rectifier bridge circuit 141 separates the network signal to obtain a power supply signal and sends it to the power supply control chip 142.

[0066] In a specific embodiment, the rectifier bridge circuit 141 includes a control switch (not labeled in the figure), and the control switch is respectively connected to each primary tap; when the differential signal of the first differential signal line is positive, the corresponding control switch is turned on, and the primary tap corresponding to the first differential signal circuit 121 that is respectively connected to the input end and the output end of the power supply control chip 142 is switched.

[0067] The control switch can be an N-type metal oxide semiconductor field effect transistor. The primary tap is connected to the gate of the control switch. When the source and drain of the control switch receiving the positive differential signal of the first differential signal line are turned on, the corresponding primary tap is connected to the input end of the power supply chip. When the control switch receiving the reverse differential signal of the first differential signal line is turned off, the corresponding primary tap is connected to the output end of the power supply chip.

[0068] In a specific embodiment, the first differential signal line includes four pairs of first differential signal circuits 121, and two pairs of first differential signal circuits 121 are connected to a rectifier bridge circuit 141 group; a rectifier bridge circuit 141 group includes two correspondingly arranged control switches; when the differential signal of the first pair of first differential signal circuits 121 is positive and the differential signal of the second pair of first differential signal circuits 121 is negative, the control switch corresponding to the first differential signal circuit 121 is turned on, and the control switch corresponding to the second differential signal circuit 151 is turned off, so that the primary tap corresponding to the first pair of first differential signal circuits 121 is connected to the input end of the power supply control chip 142, and the primary tap corresponding to the second pair of first differential signal circuits 121 is connected to the output end of the power supply control chip 142.

[0069] Please refer to Figure 5 , Figure 5 FIG. is a circuit logic schematic diagram of the rectifier power supply circuit of the fourth embodiment of the network power supply circuit of the present application.

[0070] The ports of the rectifier bridge circuits PR0 to PR3 corresponding to the 4 pairs of first differential signal circuits M0_P / N to M3_P / N are respectively input. PR0 and PR1 are connected in the same group of rectifier bridge circuits 141. The control switch Q2 receives the network signal of PR0, and the control switch Q1 receives the network signal of PR1. When the signal of PR0 is positive, the control switch Q2 is turned on. At the same time, when the signal of PR1 is negative, the control switch Q2 is turned off, and PR0 is connected to the input end of the power supply control chip POE. Otherwise, when the signal of PR1 is positive, the control switch Q1 is turned on. At the same time, when the signal of PR0 is negative, the control switch Q1 is turned off, and PR1 is connected to the input end of the power supply control chip POE.

[0071] PR2 and PR3 are connected in the same group of rectifier bridge circuits 141. The control switch Q4 receives the network signal of PR2, and the control switch Q3 receives the network signal of PR3. The principle is the same as that of PR0, PR1, control switch Q1 and control switch Q2, and will not be repeated.

[0072] In a specific embodiment, a first filter and voltage stabilizing element 1421 is connected in parallel between the input end and the output end of the power supply control chip 142. The first filter and voltage stabilizing element 1421 includes a capacitor and / or a voltage stabilizing diode.

[0073] A capacitor C95 and C117 are connected in parallel between the POE end of the input end of the power supply control chip 142 and the output end GND, and a voltage stabilizing diode D71 is also connected in parallel to stabilize the communication signal, reduce ripple and noise, and improve the quality of the communication signal.

[0074] The network power supply circuit 11 of this embodiment can perform a surge test with a test voltage of 1.2 kV and a voltage waveform of 1.2 / 50 μs according to the IEC61100-4-5 standard, which is higher than the 1 kV requirement for indoor communication ports in the surge test, enabling the network device to have immunity and reliability when suffering from surge voltages caused by lightning strikes or other electrical faults;

[0075] It can perform an electrical fast transient pulse group immunity test with a voltage level of ±600 V applied to the signal port according to the IEC 61000-4-4 standard, which is higher than the ±500 V requirement for indoor signal terminals; it has the tolerance ability to fast transient pulses at the signal interface;

[0076] It can perform an electrostatic discharge immunity test with 8 kV contact discharge and 15 kV air discharge according to the IEC 61000-4-2 standard, can meet the radiation emission test of the device according to the EN 55032 standard, can meet the requirements of Class A, and has a margin of more than +6 dB, having good electromagnetic compatibility.

[0077] Different from the prior art, the network power supply circuit provided in this application meets the requirements of high-speed data transmission. And through the settings of the filter circuit, network transformer, and rectifier power supply circuit, adopting a multi-level protection structure, it can effectively suppress surge voltages, ensure the continuity and stability of network communication, effectively control the radio frequency radiation interference of communication devices to the outside, and can effectively reduce electromagnetic interference. Especially in the case of large-current lightning strikes and high-voltage surges, it can achieve stable power supply, prevent communication devices from being damaged, ensure the quality of the communication signal circuit receiving network communication signals, and reduce production and maintenance costs.

[0078] In several embodiments provided in this application, it should be understood that the disclosed systems and devices can be implemented in other ways. For the technical solutions in the embodiments of this application, obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application. For example, the device embodiments described above are only illustrative. For example, the division of the modules or units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection can be through some interfaces, and the indirect coupling or communication connection of the device or unit can be in an electrical, mechanical or other forms.

[0079] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present application, then such directional indications are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0080] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "coupled", "connected", "joined", "arranged", "installed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0081] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0082] In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0083] The above are only the embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present application by the same token.

Claims

1. A network power supply circuit, characterized in that: The network power supply circuit comprises: A network transformer, the primary side of which is connected to the network interface; A filter circuit, the filter circuit is connected to the network interface and the primary side of the network transformer, and receives a network signal and a power supply signal; A rectifier power supply circuit connected to the primary side of the network transformer, the rectifier power supply circuit is used to separate the power supply signal of the power supply circuit; The communication signal circuit is connected to the secondary side of the network transformer and is used for receiving the communication signal.

2. The network power supply circuit according to claim 1, characterized in that: The filtering circuit includes a first differential signal circuit, and the first differential signal circuit is connected to the network interface and the primary side of the network transformer; Each pair of the first differential signal circuits is connected to the primary winding of the network transformer to form a primary tap.

3. The network power supply circuit according to claim 2, characterized in that: The filter circuit also includes a first filter circuit and a second filter circuit; The first filter circuit is connected in parallel with the first differential signal circuit to absorb high-frequency interference of the first differential signal circuit and discharge overcurrent and overvoltage of the first differential signal circuit; the second filter circuit is connected in series with the primary tap of the network transformer to filter out high-frequency noise of the first differential signal circuit.

4. The network power supply circuit according to claim 3, characterized in that: The first filtering circuit includes an absorption capacitor, each of the first differential signal circuits is connected to the absorption capacitor, and the absorption capacitor is connected to a protective grounding point; The second filtering circuit includes: a decoupling capacitor, an absorption resistor, a bypass capacitor and a bypass resistor; each of the primary taps is respectively connected to the decoupling capacitor and the absorption resistor, and the decoupling capacitor and the absorption resistor form a filtering element with a common-mode choke with the primary winding; the bypass resistor and the bypass capacitor are connected in parallel to the decoupling capacitor and the absorption resistor, and are connected to the protective grounding point.

5. The network power supply circuit according to claim 2, characterized in that: The rectifier power supply circuit includes a rectifier bridge circuit and a power supply control chip; The rectifier bridge circuit is connected to each of the primary taps respectively, and the rectifier bridge circuit is connected in parallel with the input end and the output end of the power supply control chip; The power supply control chip is used to supply power to the connected network device; the rectifier bridge circuit separates the network signal to obtain the power supply signal, and sends it to the power supply control chip.

6. The network power supply circuit according to claim 5, characterized in that: A first filtering and voltage stabilizing element is connected in parallel between the input end and the output end of the power supply control chip, and the first filtering and voltage stabilizing element includes a capacitor and / or a voltage stabilizing diode.

7. The network power supply circuit according to claim 5, characterized in that: The rectifier bridge circuit includes a control switch, and the control switch is respectively connected to each of the primary taps; When the differential signal of the first differential signal line is positive, the corresponding control switch is turned on to switch the primary tap corresponding to the first differential signal circuit respectively connected to the input end and the output end of the power supply control chip.

8. The network power supply circuit according to claim 7, characterized in that: The first differential signal line includes four pairs of the first differential signal circuits, and the two pairs of the first differential signal circuits are connected to the one rectifier bridge circuit group; the one rectifier bridge circuit group includes two correspondingly arranged control switches; When the differential signal of the first pair of the first differential signal circuits is positive and the differential signal of the second pair of the first differential signal circuits is negative, the control switch corresponding to the first pair of first differential signal circuits is turned on, and the control switch corresponding to the second pair of first differential signal circuits is turned off, so that the primary side taps corresponding to the first pair of first differential signal circuits are connected to the input end of the power supply control chip, and the primary side taps corresponding to the second pair of first differential signal circuits are connected to the output end of the power supply control chip.

9. The network power supply circuit according to claim 2, characterized in that: The communication signal circuit includes a second differential signal circuit and a signal conversion chip, and the signal conversion chip is connected to the secondary side of the network transformer through the second differential signal circuit; A second filtering and voltage stabilizing element is connected across each pair of the second differential signal circuits.

10. The network power supply circuit according to claim 9, characterized in that: Each pair of the second differential signal circuits is connected to the secondary winding of the network transformer to form a secondary tap; each of the secondary taps of the network transformer is connected to the ground via a decoupling capacitor.

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