CN210898527U - Lightning protection circuit - Google Patents
Lightning protection circuit Download PDFInfo
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- CN210898527U CN210898527U CN201921545679.7U CN201921545679U CN210898527U CN 210898527 U CN210898527 U CN 210898527U CN 201921545679 U CN201921545679 U CN 201921545679U CN 210898527 U CN210898527 U CN 210898527U
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Abstract
The application relates to a lightning protection circuit, which comprises a first lightning protection device and a first diode; the first lightning protection device is connected between an output positive electrode and an output negative electrode of the POE network port and used for clamping voltage at two ends of the PD chip; the negative pole of first diode is connected with the output negative pole of POE net gape, and the positive pole of first diode passes through the PD chip and is connected with DC power supply's input negative pole for block surge current and flow through the PD chip. After the PD chip is connected with the first diode in series and then connected with the first lightning protection device in parallel, the conduction direction of the MOS tube in the first diode and the PD chip is the same, and the conduction direction of the first lightning protection device is opposite to that of the first diode, so that the MOS tube inside the PD chip is cut off, the dead hanging and damage of the PD chip are prevented, and the normal work of the circuit is ensured.
Description
Technical Field
The application relates to the technical field of circuits, in particular to a lightning protection circuit.
Background
A Power supply circuit with a Power Over Ethernet (POE) port, which belongs to a mature circuit technology and is currently widely used in IP cameras. The equipment can be powered by POE (Power over Ethernet) or low-voltage AC/DC power supply. For the power supply system of the POE and the low-voltage power supply sharing one power chip, when there is a thunder and lightning in the open air, the network transmission cable used by the POE often induces a higher thunder and lightning voltage, resulting in damage to the internal (PD) chip and affecting the normal operation thereof. Therefore, the POE network port needs to be protected against lightning, so that the internal PD chip is prevented from being damaged.
Conventionally, surge energy flowing from a parasitic diode inside a MOS transistor of a PD chip is shared by using one or more diodes at the PD chip, but considering the manufacturing process of the PD chip and individual differences thereof, the characteristics of the parasitic diode and the external diode are different, and it is difficult to accurately control the flow of the surge current of the parasitic diode, thereby causing PD damage. In addition, because the direction of the surge current flowing through the parasitic diode in the PD is opposite to the direction of the current flowing through the actual POE functional circuit in normal use, a latch phenomenon may occur in the logic gate in the PD chip, so that the PD chip is hung up and damaged, and the circuit function is affected.
SUMMERY OF THE UTILITY MODEL
The application provides a lightning protection circuit can prevent hanging of PD chip and dying and damage.
A lightning protection circuit is applied to a POE power supply system, wherein the POE power supply system comprises a POE network port for Ethernet power supply, a power port, a direct current power supply and a PD chip, the PD chip is respectively connected with an output positive electrode and an output negative electrode of the POE network port and an input negative electrode of the direct current power supply, the input positive electrode of the direct current power supply is connected with the output positive electrode of the POE network port and the output positive electrode of the power port, the input negative electrode of the direct current power supply is connected with the output negative electrode of the power port, and the lightning protection circuit comprises a first lightning protection device and a first diode;
the first lightning protection device is connected between an output positive electrode and an output negative electrode of the POE network port and used for clamping voltage at two ends of the PD chip;
the negative pole of first diode with the output negative pole of POE net gape is connected, the positive pole of first diode passes through the PD chip with DC power supply's input negative pole is connected for block surge current flows through the PD chip.
In an embodiment, the first lightning protection device comprises a transient suppression diode.
In an embodiment, the lightning protection circuit still includes third lightning protection device, the one end of third lightning protection device respectively with the output positive pole of POE net gape, DC power supply's input positive pole is connected, the other end ground connection of third lightning protection device is used for releasing the surge current of POE net gape.
In an embodiment, the third lightning protection device comprises any one of a transient suppressor diode or a varistor.
In an embodiment, the POE gateway includes at least one first rectifier bridge, the output positive pole of the POE gateway is the output positive pole of the at least one first rectifier bridge, and the output negative pole of the POE gateway is the output negative pole of the at least one first rectifier bridge.
In one embodiment, the power port includes a second rectifier bridge, a second diode and a fifth lightning protection device,
the anode of the second diode is connected with the second rectifier bridge, and the cathode of the second diode is connected with the input anode of the direct-current power supply;
one end of the fifth lightning protection device is connected with the input anode and the input cathode of the power supply port respectively, and the other end of the fifth lightning protection device is connected with the second rectifier bridge;
the output positive pole of the power supply port is the output positive pole of the second rectifier bridge, and the output negative pole of the power supply port is the output negative pole of the second rectifier bridge.
In an embodiment, the lightning protection circuit further includes a fourth lightning protection device and a sixth lightning protection device connected in series, and the fourth lightning protection device is connected between an input positive electrode and an input negative electrode of the power port; one end of the sixth lightning protection device is connected with the input cathode of the power port, and the other end of the sixth lightning protection device is grounded and used for discharging surge current of the power port.
In an embodiment, the fourth lightning protection device and the sixth lightning protection device are any one of a transient suppression diode or a varistor.
In one embodiment, the lightning protection circuit further comprises a seventh lightning protection unit,
the positive electrode of the seventh lightning protection unit is connected with the output negative electrode of the POE port; and the negative electrode of the seventh lightning protection unit is connected with the input negative electrode of the direct-current power supply.
In an embodiment, the seventh lightning protection unit comprises at least one diode.
The lightning protection circuit is applied to a POE power supply system, the POE power supply system comprises a POE network port, a power port, a direct current power supply and a PD chip, the PD chip is respectively connected with an output anode, an output cathode of the POE network port and an input cathode of the direct current power supply, the input anode of the direct current power supply is connected with the output anode of the POE network port and the output anode of the power port, the input cathode of the direct current power supply is connected with the output cathode of the power port, and the lightning protection circuit comprises a first lightning protection device and a first diode; the first lightning protection device is connected between an output positive electrode and an output negative electrode of the POE network port and used for clamping voltage at two ends of the PD chip; the negative pole of first diode with the output negative pole of POE net gape is connected, the positive pole of first diode passes through the PD chip with DC power supply's input negative pole is connected for block surge current flows through the PD chip. After the PD chip is connected with the first diode in series and then connected with the first lightning protection device in parallel, the conduction direction of the MOS tube in the first diode and the PD chip is the same, and the conduction direction of the first lightning protection device is opposite to that of the first diode, so that the MOS tube inside the PD chip is cut off, the dead hanging and damage of the PD chip are prevented, and the normal work of the circuit is ensured.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a POE power supply system according to an embodiment;
FIG. 2 is a circuit diagram of a lightning protection circuit according to an embodiment;
FIG. 3 is a circuit diagram of a lightning protection circuit according to another embodiment;
fig. 4 is a circuit diagram of a lightning protection circuit according to yet another embodiment.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to provide a thorough understanding of the present application, and in the accompanying drawings, preferred embodiments of the present application are set forth. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. This application is capable of embodiments in many different forms than those described herein and those skilled in the art will be able to make similar modifications without departing from the spirit of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise. In the description of the present application, "a number" means at least one, such as one, two, etc., unless specifically limited otherwise.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Fig. 1 is a schematic structural diagram of a POE power supply system according to an embodiment, and fig. 2 is a circuit diagram of a lightning protection circuit according to an embodiment. As shown in fig. 1 and fig. 2, the POE power supply system includes a POE ethernet port 110, a power port, a dc power supply 120, and a PD chip 130. The PD chip 130 is connected to the output positive electrode and the output negative electrode of the POE gateway 110 and the input negative electrode of the dc power supply 120, respectively, the input positive electrode of the dc power supply 120 is connected to the output positive electrode of the POE gateway 110 and the output positive electrode of the power port, and the input negative electrode of the dc power supply 120 is connected to the output negative electrode of the power port.
The DC power supply refers to a DC/DC converter that converts an input DC voltage into another DC voltage for output, and in this application, the DC power supply 120 converts a DC voltage input from a power port and a DC voltage output from the PD chip 130 into another DC voltage for output.
The power supply port comprises a second rectifier bridge, the output positive pole of the power supply port is the output positive pole of the second rectifier bridge, and the output negative pole of the power supply port is the output negative pole of the second rectifier bridge.
As shown in fig. 2, the lightning protection circuit includes a first lightning protection device 210 and a first diode D6. The first lightning protection device 210 is connected between the output positive electrode and the output negative electrode of the POE gateway 110, and is configured to clamp a voltage across the PD chip 130. The cathode of the first diode D6 is connected to the output cathode of the POE gateway 110, and the anode of the first diode D6 is connected to the input cathode of the dc power supply 120 through the PD chip 130, so as to block surge energy from flowing through the PD chip 130.
Specifically, as shown in fig. 2, one end of the first lightning protection device 210 is connected to the output anode and the output cathode of the POE gateway 110, respectively, and the other end of the first lightning protection device 210 is connected to the input anode of the dc power supply 120 and the first diode D6, respectively.
In an embodiment, the clamping voltage of the first lightning protection device 210 is less than the carrying voltage of the dc power supply 120 and the PD chip 130, so as to prevent the dc power supply 120 and the PD chip 130 from being damaged.
In an embodiment, the first lightning protection device 210 is a Transient Voltage Suppressor (TVS), and the TVS selects a TVS with a working voltage of 58V for absorbing differential mode energy, clamping a voltage between a positive electrode and a negative electrode of the PD chip 130, and protecting the PD chip 130. The first lightning protection device 210 may include a plurality of TVSs connected in parallel, so that the voltage across the PD chip 130 may be better clamped, preventing the PD chip 130 from being damaged.
The first diode D6 is used to block the parasitic diode inside the PD chip 130 from flowing surge current, and prevent the PD chip 130 from hanging up.
In an embodiment, the POE gateway 110 includes at least one rectifier bridge, an output positive electrode of the POE gateway 110 is an output positive electrode of the at least one rectifier bridge, and an output negative electrode of the POE gateway 110 is an output negative electrode of the at least one first rectifier bridge. As shown in fig. 2, the POE gateway 110 includes two rectifier bridges, namely a first rectifier bridge 111 and a second rectifier bridge 112, where the first rectifier bridge 111 is connected to the network transformer T, and the second rectifier bridge 112 is connected to the first lightning protection device 210. The positive output terminal of the POE gateway 110 is the positive output terminal of the second rectifier bridge 112, and the negative output terminal of the POE gateway 110 is the negative output terminal of the second rectifier bridge 112.
In one embodiment, the power port includes a third rectifier bridge 113 and a second diode D5, the anode of the second diode D5 is connected to the third rectifier bridge 113, and the cathode of the second diode D5 is connected to the input anode of the dc power supply 120. The output positive pole of the power supply port is the output positive pole of the third rectifier bridge 113, and the output negative pole of the power supply port is the output negative pole of the third rectifier bridge 113.
As shown by the dotted line in fig. 2, the surge path is an input positive electrode of the power supply port, the third rectifier bridge 113, the second diode D5, the filter capacitor C, the third rectifier bridge 113, and an input negative electrode of the power supply port. When the first diode D6 does not exist, a surge path exists from the input anode of the power port to the third rectifier bridge 113 to the second diode D5 to the input cathode of the first lightning protection device 210 to the PD chip 130 to the third rectifier bridge 113 to the power port, at this time, the internal body diode parasitic to the MOS transistor in the PD chip 130 becomes a part of the surge path, a large surge current can pass through, at this time, the PD chip 130 may be damaged or hung up, and when the first diode D6 exists, the current passing through the inside of the PD is cut off, so that the PD chip 130 is prevented from being damaged or hung up.
When the common mode surge comes in from POE network port 110 and the negative terminal of the power input is grounded, the surge path shown by the dotted line in fig. 3 is: an RJ45 interface-network transformer T-first rectifier bridge 111-capacitor C-third rectifier bridge 113-input cathode, when no first diode D6 exists, partial surge current flows to the input cathode of a power port through the first lightning protection device 210, the PD chip 130 and the third rectifier bridge 113, at the moment, an internal body diode parasitic on an MOS (metal oxide semiconductor) tube in the PD chip 130 becomes a part of a surge path, and the PD chip 130 can be damaged or hung up through large surge current, and when the D6 exists, the internal passing current of the PD is cut off, so that the PD chip 130 is prevented from being damaged or hung up.
The lightning protection circuit provided by the application is applied to a POE power supply system, the POE power supply system comprises a POE network port 110 powered by Ethernet, a power port, a direct current power supply 120 and a PD chip 130, the PD chip 130 is respectively connected with an output anode of the POE network port 110, an output cathode of the POE network port and an input cathode of the direct current power supply 120, an input anode of the direct current power supply 120 is connected with the output anode of the POE network port 110 and the output anode of the power port, the input cathode of the direct current power supply 120 is connected with the output cathode of the power port, and the lightning protection circuit comprises a first lightning protection device 210 and a first diode D6; the first lightning protection device 210 is connected between the output positive electrode and the output negative electrode of the POE gateway 110, and is configured to clamp the voltage across the PD chip 130; the cathode of the first diode D6 is connected to the output cathode of the POE gateway 110, and the anode of the first diode D6 is connected to the input cathode of the dc power supply 120 through the PD chip 130, so as to block the surge current from flowing through the PD chip 130. The PD chip 130 is connected with the first diode D6 in series and then connected with the first lightning protection device 210 in parallel, the conduction directions of the MOS tube in the first diode D6 and the PD chip 130 are the same, and the conduction directions of the first lightning protection device 210 and the first diode D6 are opposite, so that the MOS tube in the PD chip 130 is cut off to pass through surge current, the PD chip 130 is prevented from being hung and damaged, and the normal work of the circuit is ensured.
In an embodiment, to increase the protection level of the POE powered device and the EMI & EMS capability, a typical application circuit is shown in fig. 4. The lightning protection circuit further comprises a third lightning protection device 230, wherein one end of the third lightning protection device 230 is respectively connected with the positive output electrode of the POE gateway 110 and the positive input electrode of the direct current power supply 120, and the other end of the third lightning protection device 230 is grounded and used for discharging surge energy of the POE gateway 110.
In one embodiment, the third lightning protection device 230 includes any one of a TVS or a varistor. There may be one or more parallel devices, for example, the third lightning protection device 230 includes a plurality of TVSs connected in parallel, so as to better discharge the surge energy of the POE mesh port 110. In this embodiment, as shown in fig. 4, the third lightning protection device 230 is a TVS.
In an embodiment, the lightning protection circuit further includes a fourth lightning protection device 240 and a sixth lightning protection device 260 connected in series, the fourth lightning protection device 240 is connected between the input positive electrode and the input negative electrode of the power port; one end of the sixth lightning protection device 260 is connected to the input cathode of the power port, and the other end of the sixth lightning protection device 260 is grounded and used for discharging surge energy of the power port.
In an embodiment, the fourth lightning protection device 240 and the sixth lightning protection device 260 are any one of TVS or varistor. There may be one or more parallel connections, for example, the fourth lightning protection device 240 includes a plurality of TVS connected in parallel for better discharging surge energy from the power port. In this embodiment, as shown in fig. 4, both the fourth lightning protection device 240 and the sixth lightning protection device 260 are TVS.
In an embodiment, the lightning protection circuit further includes a fifth lightning protection device 250, one end of the fifth lightning protection device 250 is connected to the input positive electrode and the input negative electrode of the power port, respectively, and the other end of the fifth lightning protection device is connected to the rectifier bridge. Specifically, the fifth lightning protection element is a common-mode inductor or a common-mode inductor and a differential-mode inductor which are connected in series and used for decoupling and filtering, and the rear-stage circuit is prevented from being damaged by impact.
A Common mode inductor (Common mode Choke), also called a Common mode Choke, plays a role in EMI filtering. When the fifth lightning protection device 250 is a common mode inductor, the common mode inductor includes two common mode inductor coils La and Lb. The common mode inductor La is connected with the input anode of the power port and the rectifier bridge respectively, and the common mode inductor Lb is connected with the input cathode of the power port and the rectifier bridge respectively.
In an embodiment, the lightning protection circuit further includes a seventh lightning protection unit 270, and an anode of the seventh lightning protection unit 270 is connected to an output cathode of the POE gateway 110; the negative electrode of the seventh lightning protection unit 270 is connected to the input negative electrode of the dc power supply 120.
In one embodiment, the seventh lightning protection unit 270 includes at least one diode, and when the fifth lightning protection unit is a plurality of diodes, the plurality of diodes are connected in parallel for discharging surge energy.
When surging from power or POE net gape 110 and inrush into, the electric capacity can absorb most surge energy, and electric capacity both ends voltage can constantly rise this moment, and bearing pressure is great, can damage electric capacity or back level DC power supply 120. After the seventh lightning protection unit 270 is added, a new surge circuit is formed, most of surge current flows through the first lightning protection device 210 and the seventh lightning protection unit 270, the capacitor only bears partial energy, and meanwhile, the first lightning protection device 210 can play a clamping role, so that the capacitor and the rear-stage direct-current power supply 120 are protected.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A lightning protection circuit is applied to a POE power supply system, wherein the POE power supply system comprises a POE network port for Ethernet power supply, a power port, a direct current power supply and a PD chip, the PD chip is respectively connected with an output positive electrode and an output negative electrode of the POE network port and an input negative electrode of the direct current power supply, the input positive electrode of the direct current power supply is connected with the output positive electrode of the POE network port and the output positive electrode of the power port, and the input negative electrode of the direct current power supply is connected with the output negative electrode of the power port;
the first lightning protection device is connected between an output positive electrode and an output negative electrode of the POE network port and used for clamping voltage at two ends of the PD chip;
the negative pole of first diode with the output negative pole of POE net gape is connected, the positive pole of first diode passes through the PD chip with DC power supply's input negative pole is connected for block surge current flows through the PD chip.
2. The lightning protection circuit of claim 1, wherein the first lightning protection device comprises a transient suppression diode.
3. The lightning protection circuit of claim 1, further comprising a third lightning protection device, wherein one end of the third lightning protection device is connected to the positive output terminal of the POE gateway and the positive input terminal of the dc power supply, and the other end of the third lightning protection device is grounded and is configured to discharge the surge energy of the POE gateway.
4. The lightning protection circuit of claim 3, wherein the third lightning protection device comprises any one of a transient suppression diode or a varistor.
5. The lightning protection circuit of claim 1, wherein the POE mesh includes at least one first rectifier bridge, and wherein the positive output terminal of the POE mesh is the positive output terminal of the at least one first rectifier bridge, and wherein the negative output terminal of the POE mesh is the negative output terminal of the at least one first rectifier bridge.
6. The lightning protection circuit of claim 1, wherein the power port comprises a second rectifier bridge, a second diode, and a fifth lightning protection device,
the anode of the second diode is connected with the second rectifier bridge, and the cathode of the second diode is connected with the input anode of the direct-current power supply;
one end of the fifth lightning protection device is connected with the input anode and the input cathode of the power supply port respectively, and the other end of the fifth lightning protection device is connected with the second rectifier bridge;
the output positive pole of the power supply port is the output positive pole of the second rectifier bridge, and the output negative pole of the power supply port is the output negative pole of the second rectifier bridge.
7. The lightning protection circuit of claim 1, further comprising a fourth lightning protection device and a sixth lightning protection device connected in series, the fourth lightning protection device being connected between the input positive and input negative of the power port; one end of the sixth lightning protection device is connected with the input cathode of the power port, and the other end of the sixth lightning protection device is grounded and used for discharging surge current of the power port.
8. The lightning protection circuit of claim 7, wherein the fourth and sixth lightning protection devices are any one of transient suppression diodes or piezoresistors.
9. The lightning protection circuit of claim 1, further comprising a seventh lightning protection unit,
the positive electrode of the seventh lightning protection unit is connected with the output negative electrode of the POE port; and the negative electrode of the seventh lightning protection unit is connected with the input negative electrode of the direct-current power supply.
10. The lightning protection circuit of claim 9, wherein the seventh lightning protection unit comprises at least one diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921545679.7U CN210898527U (en) | 2019-09-17 | 2019-09-17 | Lightning protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921545679.7U CN210898527U (en) | 2019-09-17 | 2019-09-17 | Lightning protection circuit |
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| Publication Number | Publication Date |
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| CN210898527U true CN210898527U (en) | 2020-06-30 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201921545679.7U Active CN210898527U (en) | 2019-09-17 | 2019-09-17 | Lightning protection circuit |
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| CN (1) | CN210898527U (en) |
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- 2019-09-17 CN CN201921545679.7U patent/CN210898527U/en active Active
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