CN211670776U - Surge protection circuit, power supply equipment and power supply system - Google Patents

Abstract

The utility model discloses a surge protection circuit, power supply unit and power supply system, wherein, surge protection circuit includes: the diode comprises a first protection device, a first diode, a second diode and a third diode; the first end of the first protection device is connected with a first center tap of a primary coil of the network port transformer, and the second end of the first protection device is connected with the ground end; the cathode of the first diode is connected with the first end of the first protection device, and the anode of the first diode is connected with the second center tap of the primary coil of the net port transformer; the cathode of the second diode is connected with the anode of the first diode, and the anode of the second diode is connected with the ground end; the cathode of the third diode is connected with the first end of the first protection device, and the anode of the third diode is connected with the first input end of the functional circuit. The utility model provides a surge protection circuit, power supply unit and power supply system for power supply unit provides the surge protection of higher grade.

Description

Surge protection circuit, power supply equipment and power supply system

Technical Field

The utility model relates to a power over ethernet technical field especially relates to a surge protection circuit, power supply unit and power supply system.

Background

The active Ethernet (POE) technology refers to a technology that, without any change in the existing Ethernet cat.5 wiring infrastructure, can provide dc Power for IP-enabled terminals (devices with network functions) while transmitting data signals to such devices. Popular is that a network cable can not only transmit data, but also provide power.

In the POE Power supply system, one end supplying Power is called a Power Sourcing Equipment (PSE) end, and one end receiving Power is called a Power Device (PD) end. Because of the convenience of the POE technology power supply, the POE-PSE power supply is widely used in the industries of security protection, communication and the like, and the outdoor application is better than the public. Lightning surge events often occur on overhead outdoor wires, and the events that lightning surges damage net mouths are more endless for net wires which move many tens of meters, hundreds of meters and even hundreds of meters.

The POE-PD equipment is relatively clear whether the POE-PD equipment is outdoors or not, so that the surge protection capability is more emphasized in the design process, and the POE-PD equipment is generally positioned in a working room or an engineering box and is relatively safe, and the grade is relatively lower in the design process of surge protection. In fact, the surge current can propagate from the sensing point to both sides, and the POE-PSE terminal can also pass through the large surge current. Therefore, a protection circuit of high-grade POE-PSE is imminent.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides a surge protection circuit, power supply unit and power supply system for power supply unit provides the surge protection of higher grade.

In a first aspect, an embodiment of the present invention provides a surge protection circuit, including: the diode comprises a first protection device, a first diode, a second diode and a third diode;

the first end of the first protection device is connected with a first center tap of a primary coil of the network port transformer, and the second end of the first protection device is connected with the ground end;

the cathode of the first diode is connected with the first end of the first protection device, and the anode of the first diode is connected with the second center tap of the primary coil of the net mouth transformer; the cathode of the second diode is connected with the anode of the first diode, and the anode of the second diode is connected with the ground end; the cathode of the third diode is connected with the first end of the first protection device, and the anode of the third diode is connected with the first input end of the functional circuit.

In a second aspect, the embodiment of the present invention provides a power supply device, include the utility model discloses the surge protection circuit that arbitrary embodiment provided still includes:

a network port transformer, the transformer including at least a first center tap and a second center tap;

a functional circuit comprising at least a first input.

In a third aspect, the embodiment of the present invention further provides a power supply system, including the present invention provides a power supply device, and a powered device connected to the power supply device.

In the utility model, the surge protection circuit based on Ethernet power supply comprises a first protection device, a first diode, a second diode and a third diode, wherein, the first end of the first protection device is connected with the first center tap of the primary coil of the net mouth transformer, the first end is grounded, the cathode of the first diode is connected with the first end of the first protection device, the anode is respectively connected with the second center tap of the primary coil of the net mouth transformer and the cathode of the second electrode, the cathode of the second electrode is grounded, the cooperation of the first protection device, the first diode and the second diode can effectively bleed off surge voltages between the first center tap and the ground, the second center tap and the ground and the first center tap and the second center tap, then, the embodiment performs surge protection through the first protection device with high reverse withstand voltage on the premise of not needing a large number of protection devices. In addition, the first end of first protector is connected to the negative pole of third diode, and functional circuit is connected to the positive pole, then first protector sets up at functional circuit's front end, can effectively keep apart surge and functional circuit, avoids the surge residual voltage through first protector to functional circuit's damage, effectively protects the chip of back level functional circuit, improves power supply unit's functional circuit's safety protection level, guarantees power supply unit's safety.

Drawings

Fig. 1 is a schematic diagram of a surge protection circuit in the prior art;

fig. 2 is a schematic structural diagram of a surge protection circuit according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of another surge protection circuit provided in an embodiment of the present invention;

fig. 4 is a schematic diagram of a surge path from the first central tap to the ground according to an embodiment of the present invention;

fig. 5 is a schematic diagram of a surge path from the second central tap to the ground according to an embodiment of the present invention;

fig. 6 is a surge path schematic diagram of a first center tap to a second center tap provided by an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a surge protection circuit comparative example provided by an embodiment of the present invention;

FIG. 8 is a surge path schematic of a first center tap to ground of the comparative example of FIG. 7;

FIG. 9 is a surge path schematic of a second center tap to ground of the comparative example of FIG. 7;

FIG. 10 is a surge path schematic of a first center tap versus a second center tap of the comparative example of FIG. 7;

fig. 11 is a schematic structural diagram of a power supply system according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a schematic structural diagram of a surge protection circuit in the prior art, and as shown in fig. 1, the surge protection circuit in the prior art is a protection circuit based on a network interface transformer 11 ', in fig. 1, the network interface transformer 11' includes a center tap N1 'and a center tap N2', a second protection device 13 'is disposed between the center tap N1' and a ground GND ', a third protection device 14' is disposed between the center tap N2 'and the ground GND', and the second protection device 13 'and the third protection device 14' are disposed between the center tap N1 'and a center tap N2'. The second and third protection devices 13 ', 14' may be transient suppression diodes, voltage dependent resistors, transient diodes, etc. Then the surge energy between the ground ends GND 'is discharged by the center tap N1' through the second protection device 13 ', and the surge energy between the ground ends GND' is discharged by the center tap N2 'through the third protection device 14', which is PSE power common mode protection; surge energy between the center tap N1 'and the center tap N2' is discharged through the second protection device 13 'and the third protection device 14', and is protected by the PSE power differential mode. No matter above-mentioned surge protection circuit is differential mode protection or common mode protection, all adopts protective device, and protective device cost is higher, and when the product was mostly PES port design, cost defect was enlargied. In addition, the residual voltage of the protection device is directly embodied at the pin end of the PSE chip of the functional circuit 12', and when the residual voltage of the protection device is too high, the chip is damaged, so that the protection requirement of high specification cannot be met.

An embodiment of the utility model provides a surge protection circuit, include: the diode comprises a first protection device, a first diode, a second diode and a third diode;

the first end of the first protection device is connected with a first center tap of a primary coil of the network port transformer, and the second end of the first protection device is connected with the ground end;

the cathode of the first diode is connected with the first end of the first protection device, and the anode of the first diode is connected with the second center tap of the primary coil of the net port transformer; the cathode of the second diode is connected with the anode of the first diode, and the anode of the second diode is connected with the ground end; the cathode of the third diode is connected with the first end of the first protection device, and the anode of the third diode is connected with the first input end of the functional circuit.

In the embodiment of the utility model, the surge protection circuit based on the Ethernet power supply comprises a first protection device, a first diode, a second diode and a third diode, wherein, the first end of the first protection device is connected with the first center tap of the primary coil of the net mouth transformer, the anode is grounded, the cathode of the first diode is connected with the first end of the first protection device, the anode is respectively connected with the second center tap of the primary coil of the net mouth transformer and the cathode of the second electrode, the cathode of the second electrode is grounded, the cooperation of the first protection device, the first diode and the second diode can effectively bleed off surge voltages between the first center tap and the ground, the second center tap and the ground and the first center tap and the second center tap, then, the embodiment performs surge protection through the first protection device with high reverse withstand voltage on the premise of not needing a large number of protection devices. In addition, the first end of first protector is connected to the negative pole of third diode, and functional circuit is connected to the positive pole, then first protector sets up at functional circuit's front end, can effectively keep apart surge and functional circuit, avoids the surge residual voltage through first protector to functional circuit's damage, effectively protects the chip of back level functional circuit, improves power supply unit's functional circuit's safety protection level, guarantees power supply unit's safety.

Above is the core thought of the utility model, will combine the attached drawing in the embodiment of the utility model below, to the technical scheme in the embodiment of the utility model clearly, describe completely. Based on the embodiments in the present invention, under the premise that creative work is not done by ordinary skilled in the art, all other embodiments obtained all belong to the protection scope of the present invention.

Fig. 2 is a structural schematic diagram of a surge protection circuit provided by the embodiment of the utility model, mainly carry out surge protection to the PSE port, as shown in fig. 2, power supply unit's net gape transformer 11 includes that two centers take a percentage: a first centre tap N1 and a second centre tap N2, surge protection circuits being provided between the above-mentioned centre taps and the functional circuit 12 of the power supply equipment for protecting the functional circuit 12. As shown in fig. 2, the surge protection circuit includes a first protection device 13, a first diode D1, a second diode D2, and a third diode D3. A first end of the first protection device 13 is connected with a first center tap N1 of the primary coil of the network port transformer 11, and a second end is connected with a ground end GND; the cathode of the first diode D1 is connected to the first end of the first protection device 13, that is, to the first center tap N1 of the primary coil of the net gape transformer 11, and the anodes are respectively connected to the second center tap N2 of the primary coil of the net gape transformer 11 and the cathode of the second diode D2; the anode of the second diode D2 is connected to the ground GND. In addition, the third diode D3 is connected to the first end of the first protection device 13 and the cathode of the first diode D1, respectively, and the anode is connected to the input end 121 of the functional circuit 12. When the first protection device 13 discharges the surge by using the characteristic of high reverse withstand voltage, the third diode D3 separates the first protection device 13 from the functional circuit 12, so that the first protection device 13 discharges the surge at the front end of the functional circuit 12, and the formed residual voltage is separated by the third diode D3, so that the functional circuit 12 can be completely free from the influence of the surge, and the safety of the functional circuit 12 of the power supply equipment is ensured. Compared with the surge protection circuit in the prior art in fig. 1, the surge protection circuit in the embodiment is not provided with a large number of protection devices, so that the cost of batch configuration of the surge protection circuit is greatly saved.

Alternatively, with continued reference to fig. 2, the first center tap N1 may be the center tap PSE + of the high voltage coil; the second center tap N2 can be a PSE-center tap of the low-voltage coil, so that the surge protection circuit can discharge the high-voltage end-to-ground surge of the power supply equipment, the low-voltage end-to-ground surge of the power supply equipment, and the surge between the high-voltage end and the low-voltage end of the power supply equipment, thereby further protecting the power supply equipment by the surge protection circuit. Of course, the first center tap N1 and the second center tap N2 may also be center taps of primary coils at other positions, which is not limited in this embodiment.

Optionally, the rated withstand voltage of the first protection device 13 is greater than or equal to 6KV, then the first protection device 13 can withstand the surge with higher voltage, for example, the first protection device 13 can withstand the surge of 6KV, and can make the residual voltage less than 100V, and by cooperating with the third diode D3, for example, the third diode D3 can withstand about 100V, can share the residual voltage for the functional circuit 12, and prevent the residual voltage of 100V from being applied to the functional circuit 12 completely. Thereby increasing the level of protection for the PSE chip in the functional circuit 12 so that the functional circuit 12 can operate normally. And the embodiment does not have more protection devices, so that the protection cost is saved. Optionally, the rated reverse withstand voltage of the third diode D3 is greater than or equal to 200V, so as to further enhance the isolation performance of the third diode D3 between the first protection device 13 and the functional circuit 12.

Optionally, the first protection device 13 includes at least one of the following: a zener diode, a transient suppression diode, or a varistor. As shown in fig. 3, fig. 3 is a schematic structural diagram of another surge protection circuit provided in the embodiment of the present invention, fig. 3 shows a schematic structural diagram that the first protection device is a zener diode ZD, the first protection device 13 can also be a transient suppression diode or a varistor, and the above devices can clamp the voltage at a specific value after the voltage exceeds a certain value. The first protection device 13 may be another electronic device capable of voltage clamping, which is not limited in this embodiment. It should be noted that the voltage dependent resistor has no positive or negative polarity, and both ends of the voltage dependent resistor can be randomly used as the first end, and the zener diode and the transient suppression diode have both positive and negative electrodes, so that when the first protection device 13 is the zener diode and the transient suppression diode, the negative electrode is used as the first end, and the positive electrode is used as the second end.

On the basis of the above embodiment, the rated withstand voltage of the first protection device 13 is greater than or equal to 6KV, if the first protection device 13 is a transient suppressor diode or a zener diode, the reverse rated withstand voltage of the first protection device 13 is greater than or equal to 6KV, and if the first protection device 13 is a varistor, the rated withstand voltage of the first protection device 13 is greater than or equal to 6 KV.

Optionally, the rated reverse withstand voltage of the third diode D3 is greater than the residual voltage of the first protection device 13, so that the first diode D1, the second diode D2, and the third diode D3 have strong withstand voltage and current tolerance, and a diode whose rated reverse withstand voltage is greater than the residual voltage of the first protection device 13 is not easily damaged when the surge level is high, thereby ensuring that the surge protection circuit is not damaged and ensuring smooth surge discharge. Similarly, the rated reverse withstand voltage of the first diode D1 and the second diode D2 is larger than the residual voltage of the first protection device 13.

That is, the residual voltage of the first guard device 13 is less than the breakdown voltage of the first diode D1 and the second diode D2. It can be known that the residual voltage of the first protection device 13 with the rated power of 6KV is not more than 100V, and the breakdown voltage of the first diode D1 and the second diode D2 is also not more than 100V, so as to ensure that the first diode D1 and the second diode D2 are not broken by the residual voltage generated by the first protection device 13, avoid the surge protection circuit from being damaged, improve the strength of the surge protection circuit, and ensure the safety of the whole power supply device. Similarly, the residual voltage of the first protection device 13 is smaller than the breakdown voltage of the third diode D3, so as to effectively prevent the surge voltage from directly accessing the functional circuit 12, thereby isolating the first protection device 13 from the functional circuit 12.

Optionally, the surge protection circuit may further include: a package (not shown in fig. 2); the package is used to package the first guard device 13, the first diode D1, the second diode D2, and the third diode D3. The surge protection circuit formed by the first protection device 13, the first diode D1, the second diode D2 and the third diode D3 can be packaged by a package, so that the surge protection circuit can be configured for different power supply equipment of the ethernet power supply system in batch, and the cost of the devices in the packaging structure is low, and the surge protection circuit can be configured for more power supply equipment, so that the safety of the ethernet power supply is realized.

The following details the operation of the surge protection circuit shown in fig. 2, which specifically includes a surge path from the first center tap N1 to the ground terminal GND, a surge path from the second center tap N2 to the ground terminal GND, and a surge path from the first center tap N1 to the second center tap N2.

As shown in fig. 4, fig. 4 is a surge path schematic diagram of the first center tap to the ground end provided by the embodiment of the present invention, the path L1 is a forward surge path of the first center tap N1 to the ground end GND, the forward surge of the first center tap N1 to the ground end GND is released through the first protection device 13, and the residual voltage thereof is lower than the reverse withstand voltage of the third diode D3, so that the normal operation of the back-stage functional circuit 12 is not affected. The path L2 is a negative surge path from the first center tap N1 to the ground GND, and the negative surge from the first center tap N1 to the ground GND is drained through the first protection device 13, the first diode D1 and the second diode D2. Fig. 5 is the surge path sketch map of head to ground end is taken out at second center that the embodiment provides, path L3 is the positive surge path of second center tap N2 to ground end GND, path L4 is the negative surge path of second center tap N2 to ground end GND, the second center tap N2 is earlier through first diode D1 to the positive surge of ground end GND, later release through first protection device 13, the same is true, third diode D3's isolation makes back level function circuit 12 not receive surge voltage's influence, second center tap N2 directly releases through second diode D2 to the negative surge of ground end GND. Fig. 6 is a surge path diagram of first center tap to second center tap that the embodiment of the utility model provides, path L5 is first center tap N1 to the positive surge path of second center tap N2, path L6 is first center tap N1 to the negative surge path of second center tap N2, first center tap N1 is earlier through first protector 13 to the positive surge of second center tap N2, later through second diode D2 bleed, first center tap N1 is only bled through first diode D1 to the negative surge of second center tap N2.

In summary, the surge protection circuit provided in this embodiment does not use more protection devices, and through the cooperation of the first protection device 13 with a high reverse withstand voltage and the third diode D3, the first protection device 13 discharges a surge at the front stage of the functional circuit 12, thereby improving the protection level of the functional circuit 12.

On the basis of the above embodiments, this embodiment provides a comparative example, as shown in fig. 7, fig. 7 is a schematic structural diagram of a comparative example of a surge protection circuit provided in an embodiment of the present invention. The surge protection circuit includes a fourth protection device 15, a fourth diode D4, and a fifth diode D5. A first end of the fourth protection device 15 is connected with a first center tap N1 of the network port transformer 11, and a second end of the fourth protection device 15 is connected with a ground end GND; the cathode of the fourth diode D4 is connected to the first end of the fourth protection device 15, and the anode is connected to the second center tap N2 of the network port transformer 11; the cathode of the fifth diode D5 is connected to the anode of the fourth diode D4, and the anode is connected to the ground GND. Compared with the surge protection circuit of the present embodiment, although the fourth diode D4 provided in the comparative example shown in fig. 7 functions the same as the first diode D1 and the fifth diode D5 functions the same as the first diode D2, the fourth protection device 15 is not provided at the front stage of the functional circuit 12, and the isolation of the residual voltage of the functional circuit 12 from the fourth protection device 15 cannot be achieved.

Specifically, as shown in fig. 8, fig. 8 is a schematic diagram of a surge path of the first center tap to the ground terminal of the comparative example in fig. 7, a path L7 is a positive surge path of the first center tap N1 to the ground terminal GND, a path L8 is a negative surge path of the first center tap N1 to the ground terminal GND, a positive surge of the first center tap N1 to the ground terminal GND is discharged through the fourth protection device 15, and a negative surge of the first center tap N1 to the ground terminal GND is discharged through the fourth protection device 15, the fourth diode D4 and the fifth diode D5. Because the supply voltage of the functional circuit 12 is as high as 57V, and the type of the general fourth protection device 15 is over 58V, for a high-level surge, the residual voltage greater than 58V generated by the fourth protection device 15 directly acts on the functional circuit 12, and the pin of the chip related to the functional circuit 12 cannot bear the high residual voltage of the fourth protection device 15 and is easily damaged, the surge protection circuit shown in fig. 8 can only meet the protection specification of 2.5KV, which easily causes the visual effect of the surge protection circuit in the practical application process, for the comparative example shown in fig. 8, if the protection capability is increased to 6KV, the residual voltage generated by the fourth protection device 15 can only be further reduced by increasing the power of the fourth protection device 15, thereby bringing about a great increase in cost and even a change in packaging. On the premise of not using the fourth protection device 15, the functional circuit 12 is free from receiving the influence of residual voltage through the first protection device 13 and the third diode D3, and the protection specification of 6KV is met.

Fig. 9 is a schematic diagram of a surge path from the second center tap to the ground terminal of the comparative example in fig. 7, where a path L9 is a positive surge path from the second center tap N2 to the ground terminal GND, a path L10 is a negative surge path from the second center tap N2 to the ground terminal GND, a positive surge from the second center tap N2 to the ground terminal GND firstly passes through the fourth diode D4 and then is discharged through the fourth protection device 15, and a negative surge from the second center tap N2 to the ground terminal GND is discharged directly through the fifth diode D5. Similarly, the functional circuit 12 is vulnerable to the residual voltage of the fourth protective device 15. Fig. 10 is a schematic diagram of a surge path from the first center tap to the second center tap of the comparative example in fig. 7, where a path L11 is a positive surge path from the first center tap N1 to the second center tap N2, a path L12 is a negative surge path from the first center tap N1 to the second center tap N2, a positive surge from the first center tap N1 to the second center tap N2 firstly passes through the fourth protection device 15 and then passes through the fifth diode D5 for bleeding, and a surge negative surge from the first center tap N1 to the second center tap N2 only passes through the fourth diode D4 for bleeding.

In summary, compared with the comparative example shown in fig. 7, the surge protection circuit of the embodiment improves the surge protection level on the premise of not increasing the power of the protection device, so that the protection specification can resist the surge voltage of 6KV, and each device of the surge protection circuit has low cost, thereby being beneficial to realizing effective protection of each power supply device.

The embodiment of the utility model provides a still provide a power supply unit. As shown in fig. 2, the embodiment of the present invention provides a power supply device including the surge protection circuit of any embodiment of the present invention. The power supply apparatus may further comprise a network interface transformer 11, the transformer 11 comprising at least a first center tap N1 and a second center tap N2; functional circuit 12, functional circuit 12 comprising at least a first input 121.

The embodiment provides a power supply device, a surge protection circuit based on power over ethernet comprises a first protection device, a first diode, a second diode and a third diode, wherein, the first end of the first protection device is connected with the first center tap of the primary coil of the net port transformer, the second end is grounded, the cathode of the first diode is connected with the first end of the first protection device, the anode is respectively connected with the second center tap of the primary coil of the net port transformer and the cathode of the second electrode, the cathode of the second electrode is grounded, the cooperation of the first protection device, the first diode and the second diode can effectively bleed off surge voltages between the first center tap and the ground, the second center tap and the ground and the first center tap and the second center tap, then, the embodiment performs surge protection through the first protection device with high reverse withstand voltage on the premise of not needing a large number of protection devices. In addition, the first end of first protector is connected to the negative pole of third diode, and functional circuit is connected to the positive pole, then first protector sets up at functional circuit's front end, can effectively keep apart surge and functional circuit, avoids the surge residual voltage through first protector to functional circuit's damage, effectively protects the chip of back level functional circuit, improves power supply unit's functional circuit's safety protection level, guarantees power supply unit's safety.

Based on the same conception, the embodiment of the present invention further provides a power supply system, as shown in fig. 11, fig. 11 is the embodiment of the present invention provides a structural schematic diagram of a power supply system, the power supply system includes the utility model discloses arbitrary embodiment provides a power supply unit 1 to and the powered device 2 connected with this power supply unit 1.

This embodiment includes the utility model discloses arbitrary power supply unit's technical characteristic possesses the utility model discloses the beneficial effect of the power supply unit that arbitrary embodiment provided.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims (9)

1. A surge protection circuit, comprising: the diode comprises a first protection device, a first diode, a second diode and a third diode;

the first end of the first protection device is connected with a first center tap of a primary coil of the network port transformer, and the second end of the first protection device is connected with the ground end;

the cathode of the first diode is connected with the first end of the first protection device, and the anode of the first diode is connected with the second center tap of the primary coil of the net mouth transformer; the cathode of the second diode is connected with the anode of the first diode, and the anode of the second diode is connected with the ground end; the cathode of the third diode is connected with the first end of the first protection device, and the anode of the third diode is connected with the first input end of the functional circuit.

2. The surge protection circuit of claim 1, wherein the first protection device comprises: a zener diode, a transient suppression diode, or a varistor.

3. The surge protection circuit of claim 1,

the first center tap is a center tap of the high-voltage coil; the second center tap is the center tap of the low-voltage coil.

4. The surge protection circuit of claim 1, wherein the rated withstand voltage of the first protection device is greater than or equal to 6 KV.

5. The surge protection circuit of claim 1, wherein a residual voltage of the first protection device is less than a breakdown voltage of the first diode and the second diode.

6. The surge protection circuit of claim 1, wherein a residual voltage of the first protection device is less than a breakdown voltage of the third diode.

7. The surge protection circuit according to any of claims 1-6, further comprising: a package;

the package is used for packaging the first protection device, the first diode, the second diode and the third diode.

8. A power supply device comprising the surge protection circuit according to any of claims 1 to 7, further comprising:

a network port transformer, the transformer including at least a first center tap and a second center tap;

a functional circuit comprising at least a first input.

9. A power supply system, comprising: the power supply apparatus according to claim 8, and a power receiving apparatus connected to the power supply apparatus.

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