CN117394812A

CN117394812A - Terminal equipment and noise reduction circuit

Info

Publication number: CN117394812A
Application number: CN202311170048.2A
Authority: CN
Inventors: 郑铨; 秦高强
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2023-07-20
Filing date: 2023-09-08
Publication date: 2024-01-12

Abstract

The application discloses terminal equipment and a noise reduction circuit, relates to the field of circuit design, and is used for inhibiting electromagnetic noise generated by terminal equipment in a bright screen state from radiating outwards when any one of the terminal equipment connected by a cable is in the bright screen state. The terminal equipment comprises M first grounding terminals, a transmission interface with M second grounding terminals and a noise reduction circuit. The noise reduction circuit comprises M magnetic bead modules, and each magnetic bead module comprises magnetic beads. The M first grounding ends are respectively coupled to the M second grounding ends through the M magnetic bead modules. Wherein M is a positive integer.

Description

Terminal equipment and noise reduction circuit

The present application claims priority from the national intellectual property agency, application number 202310898290.5, application name "a high speed signal and fast charge compatible noise suppression method and electronic device", filed 20/07/2023, the entire contents of which are incorporated herein by reference.

Technical Field

The embodiment of the application relates to the field of circuit design, in particular to terminal equipment and a noise reduction circuit.

Background

Two terminal devices (such as mobile phones and tablet computers) can be connected through a cable (such as a universal serial bus (universal serial bus, USB) cable), when any one of the terminal devices is in a bright screen state, electromagnetic noise can be generated by a display screen (or screen) of the terminal device, and the electromagnetic noise can be radiated outwards (namely electromagnetic radiation is generated) through the cable. This can cause electromagnetic interference to other surrounding devices.

Disclosure of Invention

The application provides a terminal device and a noise reduction circuit, which are used for inhibiting electromagnetic noise generated by the terminal device in a bright screen state from radiating outwards when any terminal device is in the bright screen state in a scene that the terminal device is connected by a cable.

In order to achieve the above purpose, the present application adopts the following technical scheme:

in a first aspect, the present application provides a terminal device. The terminal device comprises M first grounding terminals, a transmission interface with M second grounding terminals and a noise reduction circuit. The noise reduction circuit includes: m magnetic bead modules, each magnetic bead module including a magnetic bead. The M first grounding ends are respectively coupled to the M second grounding ends through the M magnetic bead modules. Wherein M is a positive integer.

The noise reduction circuit is located between a second grounding end of a transmission interface of terminal equipment and a first grounding end of the terminal equipment. Thus, the noise reduction circuit filters out electromagnetic noise generated by the terminal device when the electromagnetic noise is transmitted at the ground level. Based on the above, when the terminal device is connected with other terminal devices through the cable, electromagnetic noise generated by the terminal device is not transmitted to the cable, so that electromagnetic noise generated by the terminal device can be prevented from radiating outwards through the cable connecting the two terminal devices, electromagnetic interference is generated to other surrounding devices, and the terminal device meets relevant standards.

In one possible implementation, each magnetic bead module may include L magnetic beads. The connection mode of the L magnetic beads in each magnetic bead module can comprise any one of the following conditions: if l=1, each first ground is coupled to a corresponding one of the second grounds by one of the magnetic beads. That is, the M first ground terminals are coupled to the M second ground terminals through the M magnetic beads, respectively. If L > 1, L magnetic beads may be connected in series, or L magnetic beads may be connected in parallel. If L is more than or equal to 3, after some magnetic beads in the L magnetic beads are connected in parallel, the magnetic beads are connected with the rest magnetic beads in series. The magnetic beads in the magnetic bead module can filter electromagnetic noise, provide a current return path for charging current, and provide a data signal with lower frequency (hereinafter referred to as a data signal with frequency lower than a first threshold, namely a first data signal).

In another possible implementation manner, the noise reduction circuit provided by the application may further include M data splitting modules. The M data shunt modules are respectively connected with the M magnetic bead modules in parallel. That is, the M first ground terminals are coupled to the M second ground terminals through the M data shunt modules and the M magnetic bead modules, respectively. When the frequency of the data signal transmitted by the transmission interface is larger than the second threshold value, the impedance of the M data shunt modules is smaller than the impedance of the M magnetic bead modules respectively.

Based on this, the M magnetic bead modules can filter electromagnetic noise, and since the impedance of the M data shunt modules is smaller than the impedance of the M magnetic bead modules respectively under the condition that the frequency of the data signal is greater than the second threshold value, the M data shunt modules can provide a return path for the data signal (such as the second data signal related below) with the frequency greater than the second threshold value, so that the data signal with the frequency greater than the second threshold value can be normally transmitted. However, the frequency of the electromagnetic noise is far smaller than the second threshold value, and the impedance of the M magnetic bead modules is far smaller than the impedance of the M data splitting modules respectively at the frequency of the electromagnetic noise, so that the electromagnetic noise still passes through the M magnetic bead modules and is filtered by the M magnetic bead modules.

In another possible implementation manner, each data splitting module includes Y data splitting sub-modules, where Y is a positive integer. When Y is greater than 1, the Y data splitting submodules are connected in parallel.

In another possible implementation manner, each data splitting submodule includes P capacitors, where P is a positive integer. The connection mode of the P capacitors in each data splitting sub-module may include any one of the following cases: if p=1, each bead module is connected in parallel with a capacitor. If P is more than 1, the P capacitors are connected in series and then connected in parallel with one magnetic bead module, or the P capacitors are connected in parallel and then connected in parallel with one magnetic bead module. If P is more than or equal to 3, part of the P capacitors are connected in parallel, then connected with the rest of the capacitors in series, and then connected with a magnetic bead module in parallel.

The type of the P capacitors in each data splitting sub-module, and the structure of the P capacitors, may be related to the frequency of the data signal transmitted by the transmission interface.

In another possible implementation manner, each data splitting sub-module includes P capacitors and W resistors, and W is a positive integer. The P capacitors are connected in series with the W resistors, or the P capacitors are connected in parallel with the W resistors. Taking the series connection of P capacitors and W resistors as an example, the connection manner of the W resistors in each data splitting submodule may include any one of the following cases: if W > 1, then W resistors are connected in series, or W resistors are connected in parallel. If W is more than or equal to 3, part of the W resistors are connected in parallel and then connected with the rest part of the resistors in series.

The capacitor and resistor may form a filter circuit. At this time, the data splitting submodule not only can provide a signal return path for the data signal with the frequency greater than the second threshold value, but also can filter noise signals in the data signal. The noise signal here differs from the electromagnetic noise described above. The type of the P capacitors, the signals of the W resistors, and the structures of the P capacitors and the W resistors in each data splitting submodule can be related according to the frequency of the data signal transmitted by the transmission interface and the frequency of the noise signal in the data signal.

In another possible implementation manner, each data splitting sub-module includes P capacitors and Q inductors, where Q is a positive integer. The P capacitors are connected in series with the Q inductors, or the P capacitors are connected in parallel with the Q inductors. Taking the series connection of P capacitors and Q inductors as an example, the connection mode of the Q inductors in each data splitting submodule may include any one of the following cases: if Q > 1, then Q inductors are connected in series, or Q inductors are connected in parallel. If Q is more than or equal to 3, part of the Q inductors are connected in parallel and then connected with the rest part of the inductors in series.

The capacitor and the inductor may also constitute a filter circuit. At this time, the data splitting submodule not only can provide a signal return path for the data signal with the frequency greater than the second threshold value, but also can filter noise signals in the data signal. The noise signal here differs from the electromagnetic noise described above. The type of the P capacitors, the signals of the Q inductors, and the structures of the P capacitors and the Q inductors in each data splitting submodule can be related according to the frequency of the data signal transmitted by the transmission interface and the frequency of the noise signal in the data signal.

In another possible implementation, each of the data-splitting submodules includes P capacitors, W resistors, and Q inductors. The data shunt submodule formed by the P capacitors, the W resistors and the Q inductors not only can provide a signal reflux path for a data signal with the frequency larger than a second threshold value, but also can filter noise signals in the data signal. Based on this, there may be various connection relations of the P capacitors, the W resistors, and the Q inductors.

For example, after P capacitors are connected in parallel with W resistors, the P capacitors are connected in series with Q inductors; or P capacitors are connected in parallel with Q inductors and then connected in series with W resistors; alternatively, P capacitors, W resistors, Q inductors, etc. may be connected in series, which is not limited in this application. In this application, the series connection of P capacitors, W resistors and Q inductors is described as an example. The connection mode of the P capacitors may refer to the connection mode described in the possible implementation manner, the connection mode of the W resistors may refer to the connection mode described in the possible implementation manner, and the connection mode of the Q inductors may refer to the connection mode described in the possible implementation manner. In this regard, the present application is not described in detail herein.

In another possible implementation manner, the frequency of the data signal transmitted by the transmission interface is smaller than a first threshold value.

In another possible implementation, the transmission interface is an interface adopting a USB2.0 protocol or a historical version protocol. The data signal transmitted using the USB2.0 protocol or the historical version of the interface is a relatively low frequency data signal (i.e., the first data signal).

In another possible implementation manner, the frequency of the data signal transmitted by the transmission interface is greater than a second threshold.

In another possible implementation manner, the transmission interface is at least one interface of a USB3.0 protocol or a subsequent version protocol, a high-definition multimedia interface, and a display interface. The frequency of the data signal (i.e., the second data signal) transmitted by at least one of the interface, the high-definition multimedia interface, and the display interface employing the USB3.0 protocol or the subsequent version protocol is higher than the data signal transmitted by the interface employing the USB2.0 protocol or the historical version protocol.

In a second aspect, the present application also provides a noise reduction circuit. The noise reduction circuit includes: m magnetic bead modules and M data flow distribution modules. The M magnetic bead modules are respectively connected with the M data shunt modules in parallel, the first ends of the M magnetic bead modules are used for being coupled with the grounding end of the transmission interface of the terminal equipment, and the second ends of the M magnetic bead modules are used for being coupled with the grounding end of the terminal equipment. Wherein M is a positive integer.

For example, after P capacitors are connected in parallel with W resistors, the P capacitors are connected in series with Q inductors; or P capacitors are connected in parallel with Q inductors and then connected in series with W resistors; or P capacitors, W resistors and Q inductors are connected in series, etc. In this application, the series connection of P capacitors, W resistors and Q inductors is described as an example. The connection mode of the P capacitors may refer to the connection mode described in the possible implementation manner, the connection mode of the W resistors may refer to the connection mode described in the possible implementation manner, and the connection mode of the Q inductors may refer to the connection mode described in the possible implementation manner. In this regard, the present application is not described in detail herein.

It should be appreciated that the second advantageous effect may be referred to the related description in the first aspect, and will not be described herein.

Drawings

FIG. 1 is a schematic diagram of an electromagnetic noise radiation scene in the prior art;

fig. 2 is a schematic structural diagram of a terminal device in the prior art;

FIG. 3 is a schematic diagram of a scenario of an electromagnetic compatibility radiation emission testing system according to the prior art;

FIG. 4 is a schematic diagram showing the RE test results of a terminal device according to the prior art;

fig. 5 is a schematic diagram of a signal return path of electromagnetic noise of a terminal device in the prior art;

fig. 6 is one of schematic structural diagrams of a terminal device provided in an embodiment of the present application;

fig. 7 is a schematic diagram of a signal return path of a terminal device according to an embodiment of the present application;

FIG. 8 is a schematic diagram of a characteristic curve of a magnetic bead;

FIG. 9 is a schematic structural diagram of a magnetic bead module according to an embodiment of the present disclosure;

fig. 10 is a second schematic structural diagram of a terminal device according to an embodiment of the present application;

fig. 11 is a second schematic diagram of a signal return path of a terminal device according to an embodiment of the present application;

fig. 12 is a schematic structural diagram of a data splitting module according to an embodiment of the present application;

Fig. 13 is a schematic structural diagram of a data splitting sub-module according to an embodiment of the present application;

FIG. 14 is a second schematic diagram of a data splitting sub-module according to an embodiment of the present disclosure;

FIG. 15 is a third schematic diagram of a data splitting sub-module according to an embodiment of the present disclosure;

fig. 16 is a schematic diagram comparing simulation test results of a terminal device provided in an embodiment of the present application with a terminal device in the prior art;

FIG. 17 is a second diagram showing the RE test results of a terminal device according to the prior art;

fig. 18 is a schematic diagram of a result of RE test of a terminal device according to an embodiment of the present application;

fig. 19 is a diagram showing the results of an eye diagram test of a terminal device in the prior art;

fig. 20 is a schematic diagram of an eye diagram test result of a terminal device according to an embodiment of the present application.

Detailed Description

The terms "first," "second," and the like in the embodiments of the present application are used for the purpose of distinguishing between similar features and not necessarily for the purpose of indicating a relative importance, quantity, order, or the like.

The terms "exemplary" or "such as" and the like, as used in connection with embodiments of the present application, are intended to be exemplary, or descriptive. Any embodiment or design described herein as "exemplary" or "for example" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion.

The terms "coupled" and "connected" in connection with embodiments of the present application are to be construed broadly, and may refer, for example, to a physical direct connection, or to an indirect connection via electronic devices, such as, for example, a connection via electrical resistance, inductance, capacitance, or other electronic devices.

Two terminal devices (such as a mobile phone, a tablet personal computer and the like) are connected through a cable, and if the screen of any terminal device is in a bright screen state, electromagnetic noise can be generated on the screen of the terminal device. Electromagnetic noise can radiate outward through the cable and can cause electromagnetic interference to other surrounding equipment. Meanwhile, the radiation limit value of electromagnetic noise may exceed the relevant standard (such as GB 9254), so that the terminal device cannot pass the relevant authentication.

For example, taking two terminal devices, namely a mobile phone and a notebook computer, as examples, the cable is a USB cable. As shown in fig. 1, a first end of the USB cable 110 is coupled to a transmission interface of the cellular phone 120, and a second end of the USB cable 110 is coupled to a transmission interface of the notebook computer 130. When the mobile phone 120 is in the bright screen state, electromagnetic noise is generated on the screen of the mobile phone 120, and the electromagnetic noise is transmitted to the USB cable 110 through the transmission interface of the mobile phone 120, so as to radiate outwards. Electromagnetic noise can cause electromagnetic interference to devices (e.g., speaker 140, television 150, etc.) within a certain range around. When the device is subjected to electromagnetic interference, the sensitivity of the device may be affected, and the device may be damaged in severe cases.

Fig. 2 shows a schematic structure of a terminal device according to the prior art. As shown in fig. 2, the terminal device 200 includes: transmission interface 210, processor 220, power module 230, load module 240, M first grounds 250 (e.g., gnd ₁ ～gnd _M ). Wherein the transmission interface 210 includes a data terminal a, a power terminal B, and M second ground terminals 211 (e.g., GND ₁ ～GND _M ). The data terminal a of the transmission interface 210 is coupled to the processor 220, the power terminal B of the transmission interface 210 is coupled to the power supply terminal of the power module 230, and the M second ground terminals GND of the transmission interface 210 _M M first ground terminals gnd respectively coupled to the terminal device 200 _M . The signal terminal of the processor 220 is coupled to the control terminal of the load module 240. An output of the power module 230 is coupled to a power supply of the processor 220 and a power supply of the load module 240. The processor 220, the power module 230, and the load module 240 are further coupled to the M first ground gnd of the terminal device 200 _M . Wherein M is a positive integer.

The number of the second grounding ends and the number of the first grounding ends may be the same or different. In this embodiment, the number of second ground terminals of the transmission interface is identical to the number of first ground terminals of the terminal device.

In order to determine the cause of electromagnetic noise radiating outwards, the two terminal devices connected by the cable are RE-tested by an electromagnetic compatibility radiation emission (radiated emission, RE) test system.

Fig. 3 shows a schematic view of a scenario structure of an RE test system. As shown in fig. 3, the test system includes: anechoic chamber 310, turntable 320 located in anechoic chamber 310, antenna device 330, cable 340, receiving device 350 located outside anechoic chamber 310, and control device 360. The antenna device 330 includes an antenna 331 and an antenna connection device 332, and the antenna 331 is provided on the antenna connection device 332. Antenna 331 is coupled to an input of receiving device 350, and an output of control device 360 is coupled to a control terminal of turntable 320, a control terminal of antenna connection 332.

Wherein: the inner wall surface of anechoic chamber 310 is coated with a wave absorbing material to provide a testing environment for the testing system for simulating the effect of open field. The control device 360 is used to control the rotation of the turntable 320. The control device 360 is also used to instruct the antenna connection device 332 to adjust the reception angle and the height of the antenna 331. The antenna 331 is used to receive electromagnetic signals and transmit the electromagnetic signals to the receiving device 350. The cable 340 is used to connect two terminal devices placed on the turntable.

Specifically, the type of the cable 340 is related to the type of the transmission interface of the two terminal devices. For example, the cable 340 may be any one of a USB cable, a high-definition multimedia interface (HDMI) cable, a data communication device (terminal equipment, DP) cable. Of course, the cable 340 may be a cable with an interface of one end being a USB interface and an interface of the other end being an HDMI interface; alternatively, the cable 340 may be a cable with an interface at one end being a USB interface and an interface at the other end being a DP interface; alternatively, the cable 340 may be a cable having an HDMI interface as an interface at one end and a DP interface as an interface at the other end.

For example, when both of the terminal devices are cellular phones, the cable 340 may be a USB cable. Alternatively, when the two terminal devices are a mobile phone and a television, the cable 340 may be a cable with an interface at one end being a USB interface and an interface at the other end being an HDMI interface.

Before testing, two terminal devices are placed on turret 320 with a first end of cable 340 coupled to the transmission interface of one terminal device and a second end of cable 340 coupled to the transmission interface of the other terminal device.

During the test, the control device 360 controls the turntable 320 to rotate, wherein one terminal device 200 is in a bright screen state, and the other terminal device 200' can be in a off screen state. At this time, the cable 340 corresponds to an antenna, and electromagnetic noise (or electromagnetic signal) generated by the terminal device 200 in the bright screen state is radiated outwards, that is, the cable 340 can radiate electromagnetic noise generated by the terminal device in the bright screen state outwards. The antenna 331 can receive electromagnetic signals within the anechoic chamber 310 and transmit to a receiving device 350 outside the anechoic chamber 310.

It is understood that the terminal device 200' may be in an off-screen state or a bright-screen state. Electromagnetic noise is also generated to radiate outward when the terminal device 200' is in a bright screen state. For convenience of distinction, the terminal device 200 is illustrated in a bright screen state and the terminal device 200' is illustrated in a dead screen state.

The electromagnetic compatibility radiation emission test results obtained by the receiving device in the test system are described below in different cases.

In one embodiment, two terminal devices are connected by a first cable. The first cable refers to a cable in which a signal line (or referred to as a data line), a power line and a ground line of the cable are all intact, i.e., the first cable is a conventional cable. As shown in a of fig. 4, electromagnetic noise in the anechoic chamber exceeds a noise limit (e.g., 40 noise values (decibel/. Mu.v/m, dB/. Mu.v/m)) at about 50 MHz.

In another embodiment, two terminal devices are connected by a second cable. The second cable refers to the first cable after the part of the grounding wire is separated, namely, the part of the grounding wire in the second cable is in a broken state. As shown in B of fig. 4, electromagnetic noise in the anechoic chamber exceeds the noise limit at around 50 MHz.

In another embodiment, two terminal devices are connected by a third cable, for example. The third cable refers to the first cable after all the grounding wires are cut off, namely, all the grounding wires in the third cable are in an open circuit state. As shown by C in fig. 4, electromagnetic noise in the anechoic chamber does not exceed the noise limit.

In summary, when two terminal devices are connected by a cable, electromagnetic noise generated by the screen of the terminal device is radiated outwards through the ground wire of the cable. Electromagnetic noise radiates outwards, electromagnetic interference can be generated on other surrounding equipment, and normal operation of the other surrounding equipment can be influenced when serious.

In addition, taking m=2 as an example, as shown in fig. 5, the second ground of the transmission interface of the terminal device and the first ground of the terminal device belong to the same ground plane. When the cable interface 530 and the terminal When the transmission interface 210 of the device is connected, the two third grounding ends 531 of the cable interface 530 are respectively coupled with the two second grounding ends 211 of the transmission interface 210 of the terminal device. In connection with the above analysis, it is known that when the terminal device generates electromagnetic noise at a certain frequency (e.g., about 50 MHz), the electromagnetic noise is transmitted from the first ground 250 (e.g., gnd ₁ And gnd ₂ ) A second ground 211 (e.g., GND) transmitted to the transmission interface 210 ₁ And GND (GND) ₂ ) And then the second ground end of the transmission interface is transmitted to the third ground end 531 of the cable interface 530, and the second ground end of the transmission interface is radiated outwards through the ground wire of the cable.

To this end, the embodiment of the application provides a terminal device, and the ground plane is separated by arranging a noise reduction circuit between a second ground end of a transmission interface of the terminal device and a first ground end of the terminal device. Therefore, when the electromagnetic noise is transmitted at the ground plane, the noise reduction circuit can filter the electromagnetic noise, so that the electromagnetic noise cannot be transmitted to the grounding end of the transmission interface. Based on this, when two terminal devices are connected by a cable, electromagnetic noise generated by the screen of the terminal device can be prevented from being radiated outward by the cable connecting the two terminal devices to generate electromagnetic interference to other surrounding devices, and the terminal devices can be made to satisfy the relevant standards.

The terminal device related to the embodiment of the application can be movable and portable, and has a data transmission function and a display function. The terminal device can be deployed on land (e.g., indoor or outdoor, hand-held or vehicle-mounted, etc.), on water (e.g., ship model), or in the air (e.g., unmanned aerial vehicle, etc.). The terminal device may be referred to as a User Equipment (UE), an access device, a terminal unit, a subscriber unit (subscriber unit), a terminal station, a Mobile Station (MS), a mobile station, a terminal agent, a terminal apparatus, or the like. For example, the electronic device may be a cell phone, a Virtual Reality (VR) device, an augmented reality (augmented reality, AR) device, a terminal in industrial control (industrial control), a terminal in unmanned (self driving), a terminal in remote medical (remote e-medical), a terminal in smart grid (smart grid), a terminal in transportation security (transportation safety), a terminal in smart city, a terminal in smart home (smart home), and the like. The embodiment of the application does not limit the specific type and structure of the terminal equipment.

As shown in fig. 6, a terminal device 600 provided in an embodiment of the present application may include: having M second ground terminals 211 (e.g., GND ₁ ～GND _M ) A processor 220, a power module 230, a load module 240, a noise reduction circuit 510, and M first grounds 250 (e.g., gnd ₁ ～gnd _M ). The noise reduction circuit 510 may include M magnetic bead modules 520, where each magnetic bead module 520 includes magnetic beads.

Specifically, the M second ground terminals 211 (e.g., GND ₁ ～GND _M ) Are coupled to the M first ground terminals 250 (e.g., gnd ₁ ～gnd _M ). Other connection relations in the terminal device may be referred to the description of the terminal device shown in fig. 4 above.

It should be noted that, the first grounding terminal of the terminal device and the grounding terminal of the transmission interface of the terminal device may be the same grounding terminal, or may be different grounding terminals connected together through a connection. In this embodiment, the description is given taking, as an example, that the first ground terminal of the terminal device and the ground terminal of the transmission interface of the terminal device are different ground terminals connected together.

Taking m=2, i.e. the transmission interface comprises two first ground terminals, the terminal device comprises two second ground terminals as an example. Referring to fig. 4, as shown in fig. 7, when the cable interface 530 is connected to the transmission interface 210 of the terminal device, the power source end 533 of the cable interface 530 is coupled to the power source end (not shown in fig. 7) of the transmission interface 210 of the terminal device, and the data end 532 of the cable interface 530 is coupled to the data end (not shown in fig. 7) of the transmission interface 210 of the terminal device. For convenience of description of the present solution, the ground plane of the terminal device may be divided into two ground planes based on the magnetic bead modules, as shown in fig. 7, and the ground plane of the terminal device is divided into two ground planes (which may be referred to as a first ground plane and a second ground plane, respectively) by the two magnetic bead modules. All ports of the transmission interface 210 including the second ground 211 may be located at a first ground plane and the first ground 250 of the terminal device may be located at a second ground plane. All signals between the first ground plane and the second ground plane will flow back through the two magnetic bead modules. These signals may include: electromagnetic noise, charging current, and a lower frequency data signal (which may be referred to as a first data signal). It should be noted that the first ground plane and the second ground plane are the same ground plane, and in this embodiment of the present application, the first ground plane and the second ground plane are separated for convenience of description.

Wherein the impedance of the magnetic beads in the magnetic bead module can be changed along with the change of frequency. In a low-frequency region, the magnetic beads are generally of inductive characteristics and low in impedance; in the high frequency region, the magnetic beads exhibit resistance characteristics. At a certain frequency, the impedance of the magnetic beads is maximum.

The low frequency and the high frequency are relative concepts, and are distinguished from the low frequency signal and the high frequency signal in the conventional sense. For example, 50MHz is a low frequency region relative to 240MHz, and 240MHz is a high frequency region.

By way of example, fig. 8 shows a schematic representation of the characteristic curve of a magnetic bead. As shown in fig. 8, in the frequency range of 0 to 500MHz, the impedance of the magnetic beads gradually increases with an increase in frequency; in the frequency range of 500MHz-3000MHz, the impedance of the magnetic beads gradually decreases with increasing frequency. However, the rate of decrease in the impedance of the magnetic beads in the frequency range of 500MHz or more is smaller than the rate of increase in the impedance of the magnetic beads in the frequency range of 0 to 500 MHz. It follows that the impedance of the beads is maximum at 500 MHz. As is clear from the characteristic curve of the magnetic beads, the impedance of the magnetic beads is relatively large in the frequency range of 20MHz to 3000 MHz. At this time, the magnetic beads can absorb electromagnetic noise and convert the electromagnetic noise into heat energy for dissipation, that is, the magnetic beads can filter out electromagnetic noise with a certain frequency.

In summary, in the embodiment of the present application, the second grounding end in the transmission interface originally connected together in the terminal device and the first grounding end of the terminal device are separated by the magnetic bead module. Because the magnetic beads have larger impedance in a certain frequency range (such as about 50 MHz), electromagnetic noise can be absorbed by the magnetic beads in the magnetic bead module when passing through the magnetic bead module, thereby filtering out the electromagnetic noise of 50MHz and other noises below 50MHz. Therefore, electromagnetic noise cannot be transmitted to the grounding end of the transmission interface of the terminal equipment, and the electromagnetic noise cannot radiate outwards through the ground wire of the cable, so that electromagnetic interference cannot be caused to other surrounding terminal equipment.

It should be noted that, in the embodiment of the present application, the frequency of the electromagnetic noise is not necessarily 50MHz. Electromagnetic noise may be in a certain frequency range. Typically, the frequency is in the megahertz range. For example 40MHz-60MHz.

It should be noted that, the noise reduction circuit provided in the embodiment of the present application may be located in a USB module (or referred to as a USB small board) of the terminal device, or may be located in a motherboard module, but is not limited thereto. The embodiments of the present application are not limited in this regard.

Alternatively, each of the bead modules may include L beads, where L is a positive integer. As shown in a of fig. 9, l=1, each first ground GND _M Can be coupled to a corresponding second ground gnd through a magnetic bead _M . As shown in B in FIG. 9, when L > 1, L magnetic beads can be connected in series. As shown by C in FIG. 9, when L > 1, L magnetic beads can be connected in parallel. As shown by D in FIG. 9, when L is not less than 3, N magnetic beads of the L magnetic beads can be connected in parallel and then connected in series with the rest (L-N) magnetic beads. Wherein N is a positive integer greater than or equal to 2, and N is less than L.

It should be noted that, when L is greater than 1, each of the M magnetic bead modules in the embodiment of the present application may adopt any one of structures B in fig. 9 to D in fig. 9, which is not limited in the embodiment of the present application.

Optionally, the type of each magnetic bead in the magnetic bead module, the number of the magnetic beads, and the connection structure of each magnetic bead may be determined according to the charging current of the terminal device, the frequency of electromagnetic noise, and the like.

For example, the type of the magnetic bead can be determined according to the frequency of electromagnetic noise generated by the terminal equipment, so that the magnetic bead can filter the electromagnetic noise better.

For example, the current passing capability of a single magnetic bead is generally poor, so when the charging current is large, the charging current can be split through a plurality of parallel magnetic beads, so that a current return path is provided for the charging current, and the terminal equipment can be normally charged through the transmission interface. In addition, in order to shunt a larger charging current, the magnetic beads in each magnetic bead module can select the magnetic beads with low direct current impedance and strong current capacity as far as possible. In this way, the charging of the terminal device is not affected.

Optionally, the frequency of the data signal transmitted by the transmission interface of the terminal device in the embodiment of the present application may be smaller than the first threshold.

For example, in the case where the frequency of the data signal transmitted by the transmission interface is smaller than the first threshold, the transmission interface may be an interface employing the USB2.0 protocol or the history version protocol. For example, the transmission interface may be: any one of an interface of a USB2.0 protocol, an interface of a USB1.0 protocol, an interface of a USB1.1 protocol and the like is adopted. When the transmission interface is an interface adopting the USB2.0 protocol, the frequency of the transmitted data signal is 240MHz.

For convenience of description, a data signal having a frequency less than a first threshold value is referred to as a first data signal in the embodiments of the present application.

Typically, the frequency of the electromagnetic noise may be less than the frequency of the first data signal, and the power (or energy) of the electromagnetic noise is much less than the power of the first data signal. The same magnetic bead module attenuates different signals such as noise signals and data signals to the same degree. Since the frequency of the electromagnetic noise is relatively small and the power of the electromagnetic noise is small, the electromagnetic noise can be filtered out by the bead module, but the frequency and the power of the first data signal are relatively large, so that when the first data signal passes through the bead module, the first data signal is slightly attenuated, but the signal quality of the first data signal is not affected. That is, the first data signal may be reflowed through the M magnetic bead modules, that is, each magnetic bead module in the noise reduction circuit may provide a signal reflow path for the first data signal.

Optionally, the frequency of the data signal transmitted by the transmission interface of the terminal device in the embodiment of the present application may be greater than the second threshold.

For example, in a case where the frequency of the data signal transmitted by the transmission interface is greater than the second threshold value, the transmission interface may be any one of an interface employing the USB3.0 protocol or a subsequent version of the protocol, an HDMI interface, a DP interface, and the like. The frequency of the data signals transmitted by the interface adopting the USB3.0 protocol or the subsequent version protocol, the HDMI interface and the DP interface is higher than that of the data signals transmitted by the interface adopting the USB2.0 protocol and the historical version protocol. For example, the frequency of the data signal transmitted using the interface of the USB3.0 protocol may be 2.5GHz (i.e., 2500 MHz).

For convenience of description, the data signal having the frequency greater than the second threshold value is referred to as a second data signal in the embodiment of the present application.

The impedance of the beads decreases slightly with increasing frequency over a range of frequencies, but the impedance of the beads as a whole remains relatively large. Continuing to refer to FIG. 7, in the frequency range of 500MHz-3000MHz, the impedance of the beads decreases slightly as the frequency increases, but generally the impedance of the beads remains larger. It can be seen that if the second data signal with higher frequency passes through the M magnetic bead modules, the M magnetic bead modules cause greater attenuation to the second data signal.

In conjunction with fig. 6, as shown in fig. 10, in order to reduce attenuation of the second data signal, the noise reduction circuit provided in the embodiment of the present application may further include M data splitting modules 910. The M data splitting modules 910 are respectively connected in parallel with the M magnetic bead modules 520, and at the frequency of the second data signal, the impedance of the M data splitting modules 910 is respectively far smaller than the impedance of the M magnetic bead modules, and at the frequency of about 50MHz, the impedance of the M data splitting modules 910 is respectively far greater than the impedance of the M magnetic bead modules. Based on the above, electromagnetic noise generated by the terminal device still passes through the M magnetic bead modules, so that the M magnetic bead modules 520 can filter electromagnetic noise about 50 MHz; the second data signal transmitted by the terminal device passes through the data splitting module 910, that is, the data splitting module 910 may provide a signal return path for the second data signal. That is, when the terminal device transmits the second data signal through the cable and the terminal device generates electromagnetic noise, the noise reduction circuit decouples the electromagnetic noise generated by the terminal device, so that the electromagnetic noise is absorbed by the magnetic bead module and is filtered out, and the second data signal is not radiated outwards, but the second data signal can be normally transmitted.

It should be noted that in the embodiment of the present application, a suitable type of magnetic bead and a device in the data splitting module may be selected, so that the impedance of the M data splitting modules 910 is far greater than the impedance of the M magnetic bead modules respectively at a frequency of about 50 MHz. Based on this, electromagnetic noise will pass through the M bead modules, but not through the M data shunt modules.

As shown in fig. 11, a data shunt module is connected in parallel beside each bead module. Each magnetic bead module filters electromagnetic noise and provides a current return path for charging current; each data splitting module provides a signal return path for the second data signal.

Alternatively, each of the data splitting modules may include Y data splitting sub-modules. Y is a positive integer. As shown in fig. 12, when Y is greater than 1, the Y data splitting submodules are connected in parallel. A possible structure of the data splitting sub-module 1110 will be described below with reference to fig. 13-15, taking an example in which the data splitting module includes a data splitting sub-module (i.e., y=1). At this time, the data splitting module corresponds to the data splitting sub-module.

Optionally, the data shunt sub-module may include P capacitors, where P is a positive integer. That is, each first ground terminal is coupled to a corresponding second ground terminal through P capacitors. When the frequency is less than the resonant frequency of the capacitor, the impedance of the capacitor decreases with increasing frequency. In order to ensure that the impedance of the M data shunt modules is smaller than the impedance of the M magnetic bead modules respectively at the frequency where the second data signal is located, the resonant frequency of the capacitor in the embodiment of the present application may be outside the frequency range of the second data signal, and the resonant frequency of the capacitor may be greater than the frequency of the second data signal.

The impedance versus frequency of each capacitor can be expressed by the following equation (1):

wherein Z is _C Is the impedance of the capacitor, f is the frequency, and C is the capacitance of the capacitor. As can be seen from the formula (1), the higher the frequency, the smaller the impedance of the capacitor. Possible connection structures for the P capacitors included in the data-splitting sub-module are described below.

In one embodiment, taking p=1 as an example, as shown by a in fig. 13, the data shunt sub-module 1110 includes a capacitor C. The first terminal of the capacitor C is coupled to a second ground of the transmission interface 210, and the second terminal of the capacitor C is coupled to a first ground of the terminal device. At this time, one capacitor is one data-splitting sub-module, and thus, the impedance of one data-splitting sub-module 1110 is the impedance of one capacitor C. As is clear from the above formula (1), the higher the frequency, the smaller the impedance of one capacitor. Thus, the higher the frequency of the second data signal, the lower the impedance of the data-splitting submodule 1110, and thus the second data signal may flow back through the data-splitting submodule 1110.

It should be noted that, in the prior art as shown in fig. 2 and 5, each first ground terminal is connected to the corresponding second ground terminal. In the above embodiments of the present application, the capacitor C separates one first ground terminal and the corresponding second ground terminal, which are originally connected together.

In another embodiment, taking P > 1 as an example, as shown in B of fig. 13, one data shunt submodule 1110 includes P capacitors C connected in series. The first ends of the series of P capacitors C are coupled to a second ground of the transmission interface 210, and the second ends of the series of P capacitors C are coupled to a first ground of the terminal device. At this time, the impedance of one data shunt sub-module 1110 may be the sum of the impedance of P capacitors. For the second data signal, the impedance of each capacitor is small, and thus the sum of the impedance of the P capacitors is still small. At this time, the impedance of the data-splitting submodule 1110 is still small, and thus, the second data signal may still flow back through the data-splitting submodule 1110.

In another embodiment, taking P > 1 as an example, as shown by C in FIG. 13, the data splitting submodule 1110 includes P capacitors C in parallel. The first end of each capacitor C is coupled to a second ground of the transmission interface 210 and the second end of each capacitor C is coupled to a first ground of the terminal device.

Since the plurality of capacitors are connected in parallel, the total impedance thereof is reduced. Thus, in this embodiment, the total impedance of the P parallel capacitors is reduced. That is, when the data shunt submodule includes P capacitors connected in parallel, the impedance of the data shunt submodule is also small. Thus, the second data signal may still be reflowed through the data-splitting submodule 1110.

In another embodiment, taking P.gtoreq.3 as an example, as shown by D in FIG. 13, the data splitting sub-module 1110 includes P capacitors including P1 capacitors in parallel and the remaining (P-P1) capacitors in series, and a first end of the P1 capacitors C in parallel is coupled to a first end of the (P-P1) capacitors C in series. The second end of the parallel P1 capacitors is coupled to a second ground of the transmission interface 210, and the second end of the series (P-P1) capacitors C is coupled to a first ground of the terminal device.

In this embodiment, the total impedance of the P1 parallel capacitors is smaller, the total impedance of the (P-P1) series capacitors is also smaller, and thus the impedance of the data-splitting sub-module comprising the P1 parallel capacitors, and the (P-P1) series capacitors is also smaller. Thus, the second data signal may still be reflowed through the data-splitting submodule 1110.

In the practical application process, the specific structure of the data distribution sub-module, the model number of the capacitor in the data distribution sub-module and the number of the data distribution sub-modules in the data distribution sub-module can be determined according to the frequency of the second data signal.

Alternatively, the data shunt sub-module may include P capacitors and W resistors, with the P capacitors in series with the W resistors. Wherein W is a positive integer. That is, each first ground is coupled to a corresponding second ground through P capacitors and W resistors. At this time, the P capacitors and the W resistors may correspond to a filter, so as to filter noise signals in the first frequency range in the second data signal. Wherein the first frequency range is different from the frequency range in which the electromagnetic noise is located; the impedance of each of the W resistors is small and the model of the resistor, and the model of the capacitor, is related to the frequency of the noise signal. Possible connection structures of the P capacitors and the W resistors included in the data shunt sub-module are described below.

In one embodiment, taking p=1 and w=1 as an example, in conjunction with a in fig. 13, as shown in a in fig. 14, the data shunt sub-module 1110 includes a capacitor C and a resistor R, and a first end of the capacitor C is coupled to a first end of the resistor R (i.e., the capacitor C is connected in series with the resistor R). A second terminal of the capacitor C is coupled to a second ground terminal of the transmission interface 210 and a second terminal of the resistor R is coupled to a first ground terminal of the terminal device. For the second data signal, the impedance of the capacitor is smaller, and the impedance of the resistor is smaller. That is, the impedance of the data shunt module consisting of 1 capacitor and 1 resistor is small, and thus, a data signal having a high frequency can flow back through the data shunt sub-module 1110.

In another embodiment, taking p=1 and W > 1 as an example, referring to a in fig. 13, as shown in B in fig. 14, the data splitting sub-module 1110 includes a capacitor C and W resistors R connected in series, and a first end of the capacitor C is coupled to a first end of the W resistors R connected in series (i.e. the capacitor C is connected in series with the W resistors R connected in series). A second terminal of the capacitor C is coupled to a second ground terminal of the transmission interface 210, and a second terminal of the series connection of W resistors is coupled to a first ground terminal of the terminal device.

Of course, in some embodiments, when w=1 and P > 1, the connection relationship of P capacitors may be referred to as the connection relationship in B in fig. 13. The connection relation of 1 resistor and P capacitors can be referred to as B in fig. 14, and the connection relation in B in fig. 13. In the embodiment of the present application, when w=1 and P > 1, the connection relationship between the capacitor and the resistor is not described again.

Alternatively, in other embodiments, w=p, and W and P are both positive integers greater than 1. Wherein, W resistors are connected in series, and P capacitors are connected in series.

In this embodiment, the impedance of one data shunt sub-module 1110 may be the sum of the impedance of P capacitors and the impedance of W resistors. Since the impedance of each capacitor and the impedance of each resistor are smaller, the impedance of the data shunt sub-module formed by connecting the P capacitors and the W resistors in series is smaller, and a return path can be provided for the second data signal.

In another embodiment, taking p=1 and W > 1 as an example, in conjunction with a in fig. 13, as shown in C in fig. 14, the data shunt submodule 1110 includes a capacitor C and W resistors R connected in parallel, and a first end of the capacitor C is coupled to a first end of each resistor R (i.e., the capacitor C is connected in series with the W resistors R connected in parallel). A second terminal of the capacitor C is coupled to a second ground of the transmission interface 210 and a second terminal of each resistor is coupled to a first ground of the terminal device.

Of course, in some embodiments, when w=1 and P > 1, the connection relationship of P capacitors may be referred to as the connection relationship in C in fig. 13. The connection relation of 1 resistor and P capacitors can also be referred to as C in fig. 14, and C in fig. 13. In the embodiment of the present application, when w=1 and P > 1, the connection relationship between the capacitor and the resistor is not described again.

Alternatively, in other embodiments, w=p, and W and P are both positive integers greater than 1. Wherein, W resistors are connected in parallel, and P capacitors are connected in parallel; or W resistors are connected in parallel, and P capacitors are connected in series; alternatively, W resistors are connected in series and P capacitors are connected in parallel.

In another embodiment, taking P=1 and W+.gtoreq.3 as an example, in conjunction with A in FIG. 13, as shown by D in FIG. 14, the data splitting sub-module 1110 includes a capacitor and W resistors R, and a first terminal of the capacitor C is coupled to a first terminal of the W resistors R (i.e., the capacitor C is connected in series with the W resistors R). A second terminal of the capacitor C is coupled to a second ground terminal of the transmission interface 210, and a second terminal of the W resistors R is coupled to a first ground terminal of the terminal device.

Wherein the W resistors comprise W1 resistors in series and (W-W1) resistors in parallel, and a first end of the W1 resistors in series is coupled to a first end of the (W-W1) resistors in parallel. The second end of the series connection of W1 resistors is coupled to the first end of the capacitor C, i.e. the second end of the series connection of W1 resistors is the first end of the W resistors. The second ends of the parallel (W-W1) resistors are coupled to one ground terminal of the terminal device, i.e. the second ends of the parallel (W-W1) resistors are the second ends of the W resistors.

Of course, in some embodiments, when w=1 and p+.3, the connection of P capacitors can be referred to as the connection in D in fig. 13. The connection relation of 1 resistor and P capacitors can be referred to as D in fig. 14, and D in fig. 13. In the embodiment of the application, when w=1 and P is greater than or equal to 3, the connection relationship between the capacitor and the resistor is not described again.

Alternatively, in other embodiments, w=p, and W and P are both positive integers greater than 1. The connection relation of W resistors may refer to the connection structure in D in fig. 14, and the connection relation of P capacitors may refer to the connection structure in D in fig. 13.

In the practical application process, the specific structure of the data distribution sub-module, the model of the capacitor and the model of the resistor in the data distribution sub-module and the number of the data distribution sub-modules in the data distribution sub-module can be determined according to the frequency of the second data signal.

Optionally, the data shunt sub-module may include P capacitors and Q inductors, where Q is a positive integer. That is, each first ground is coupled to a corresponding second ground through P capacitors and Q inductors. At this time, the P capacitors and the W resistors may also be equivalent to a filter, so as to filter noise signals in the second frequency range in the second data signal. The second frequency range here is distinguished from the frequency range in which electromagnetic noise is located. That is, if the frequency of the noise signal in the second data signal is large, a data shunt sub-module including P capacitors and Q inductors may be selected.

It should be noted that, when the frequency is greater than the resonant frequency of the inductor, the impedance of the inductor decreases with the increase of the frequency, so in order to ensure that the impedance of the M data shunt modules is smaller than the impedance of the M magnetic bead modules, the inductor may be selected to have a smaller inductance value, and/or the resonant frequency of the inductor may be outside the frequency range of the second data signal, and the resonant frequency of the inductor may be smaller than the frequency of the second data signal. Possible connection structures for the P capacitors and Q inductors included in the data splitting sub-module are described below.

In one embodiment, taking p=1 and q=1 as an example, in conjunction with a in fig. 13, as shown in a in fig. 15, the data shunt sub-module 1110 includes a capacitor C and an inductor L, and a first end of the capacitor C is coupled to a first end of the inductor L (i.e., the capacitor C is connected in series with the inductor L). A second terminal of the capacitor C is coupled to a second ground terminal of the transmission interface 210 and a second terminal of the inductor L is coupled to a first ground terminal of the terminal device.

In another embodiment, taking p=1 and Q > 1 as an example, referring to a in fig. 13, as shown in B in fig. 15, the data splitting sub-module 1110 includes a capacitor C and Q inductors L connected in series, and a first end of the capacitor C is coupled to a first end of the Q inductors L connected in series (i.e., the capacitor C is connected in series with the Q inductors L connected in series). A second terminal of the capacitor C is coupled to a second ground terminal of the transmission interface 210, and a second terminal of the Q inductors L in series is coupled to a first ground terminal of the terminal device.

Of course, when q=1 and P > 1, the connection relationship of P capacitances can be referred to as the connection relationship in B in fig. 13 described above. The connection relation of 1 inductance and P capacitances can be referred to B in fig. 14, and B in fig. 13. In the embodiment of the present application, when q=1 and P > 1, the connection relationship between the capacitor and the inductor is not described again.

Alternatively, in other embodiments, q=p, and Q and P are both positive integers greater than 1. Wherein, Q inductors are connected in series, and P capacitors are connected in series.

In another embodiment, taking p=1 and Q > 1 as an example, in conjunction with a in fig. 13, as shown in C in fig. 15, the data splitting sub-module 1110 includes a capacitor C and Q inductors L connected in parallel, and a first end of the capacitor C is coupled to a first end of each inductor L (i.e., the capacitor C is connected in series with Q inductors L connected in parallel). A second terminal of the capacitor C is coupled to a second ground of the transmission interface 210 and a second terminal of each inductor is coupled to a first ground of the terminal device.

Of course, when q=1 and P > 1, the connection relationship of P capacitances can be referred to as the connection relationship in C in fig. 13 described above. The connection relationship of 1 inductance and P capacitances can also be referred to as C in fig. 15, and C in fig. 13. In the embodiment of the present application, when q=1 and P > 1, the connection relationship between the capacitor and the inductor is not described again.

Alternatively, in other embodiments, q=p, and Q and P are both positive integers greater than 1. Wherein, Q inductors are connected in parallel, and P capacitors are connected in parallel; or, Q inductors are connected in parallel, and P capacitors are connected in series; alternatively, Q inductors are connected in series and P capacitors are connected in parallel.

In another embodiment, taking P=1 and Q+.gtoreq.gtoreq.3 as an example, in conjunction with A in FIG. 13, as shown by D in FIG. 15, the data splitting sub-module 1110 includes a capacitor and Q inductors L, and the capacitor C is connected in series with the Q inductors L. The capacitor C is also coupled to a second ground of the transmission interface 210 and the Q inductors L are also coupled to a first ground of the terminal device.

Wherein the Q inductors include Q1 inductors in parallel and (Q-Q1) inductors in series, and a first end of the Q1 inductors in parallel is coupled to a first end of the (Q-Q1) inductors in series. The second terminal of the Q1 inductors in parallel is coupled to the first terminal of the capacitor C. The second end of the series (Q-Q1) inductors is coupled to a ground terminal of the terminal device.

Of course, when q=1 and p≡3, the connection relation of P capacitances can be referred to as the connection relation in D in fig. 13 described above. The connection relation of 1 inductance and P capacitances can be referred to as D in fig. 15, and D in fig. 13. In the embodiment of the application, when q=1 and P is greater than or equal to 3, the connection relationship between the capacitor and the inductor is not described again.

Alternatively, in other embodiments, q=p, and Q and P are both positive integers greater than 1. The connection relation of Q inductors may refer to the connection structure in D in fig. 15, and the connection relation of P capacitors may refer to the connection structure in D in fig. 13.

In the practical application process, the specific structure of the data distribution sub-module, the model of the capacitor and the model of the inductor in the data distribution sub-module and the number of the data distribution sub-modules in the data distribution sub-module can be determined according to the frequency of the second data signal.

Alternatively, the data-splitting sub-module may include P capacitors, W resistors, and Q inductors in series. The connection structure of the P capacitors, the W resistors and the Q inductors can be referred to any combination of the above embodiments.

In one embodiment, taking the data splitting submodule as an example, it includes a capacitor: the W resistors are connected in series, and the Q inductors are connected in series; or, W resistors are connected in series, and Q inductors are connected in parallel; or, the W resistors are connected in series, and after part of the Q inductors are connected in parallel, the W resistors are connected in series with the rest of the inductors.

In another embodiment, taking the data splitting submodule as an example, the data splitting submodule includes a capacitor: w resistors are connected in parallel, and Q inductors are connected in series; or, W resistors are connected in parallel, and Q inductors are connected in parallel; or, the W resistors are connected in parallel, and after part of the Q inductors are connected in parallel, the W resistors are connected in series with the rest of the inductors.

In another embodiment, taking the data splitting submodule as an example, the data splitting submodule includes a capacitor: after partial resistors in the W resistors are connected in parallel, the W resistors are connected in series with the rest partial resistors, and Q inductors are connected in series; or, after partial resistors in the W resistors are connected in parallel, the W resistors are connected in series with the rest partial resistors, and Q inductors are connected in parallel; or, after the partial resistors in the W resistors are connected in parallel, the partial resistors are connected in series with the rest of the resistors, and after the partial inductors in the Q inductors are connected in parallel, the partial inductors are connected in series with the rest of the inductors.

It should be noted that, when the data splitting sub-module includes P capacitors, W resistors and Q inductors connected in series, the structure of the data splitting sub-module is described only as an example in the above embodiment, but the structure of the data splitting sub-module is not limited to the structure in the above embodiment.

As can be seen from the foregoing, the data shunt submodule in the embodiments of the present application is formed by capacitance, capacitance and resistance, capacitance and inductance, capacitance, inductance and resistance. The above description of the data-splitting sub-module is merely an exemplary illustration, and does not limit the structure of the data-splitting sub-module to only the above-described structure.

In the following, referring to fig. 16, taking an example that the terminal device transmits the second data signal, simulation results of the terminal device related to the embodiment of the present application and the terminal device in the prior art are compared.

As shown in fig. 16, compared with the terminal device in the prior art, the two terminal devices (including the magnetic bead module, the magnetic bead module and the data splitting module) according to the embodiments of the present application have substantially the same electromagnetic noise suppression capability in the low frequency region (see the part of the block diagram 1), and can suppress electromagnetic noise about 4 db. Compared to the terminal device in the prior art, the two terminal devices according to the embodiments of the present application may cause insertion loss to the second data signal in the high frequency region (see the part of block diagram 2). However, compared to the first terminal device (including the magnetic bead module) according to the embodiments of the present application, the second terminal device (including the magnetic bead module and the data splitting module) according to the embodiments of the present application has less insertion loss on the second data signal in the high frequency region.

It can be seen that the two terminal devices according to the embodiments of the present application can suppress electromagnetic noise with a lower frequency, so as to reduce electromagnetic radiation when data is transmitted between terminal devices connected by a cable through the cable. Meanwhile, when data signals with higher frequency (namely second data signals) are transmitted between the terminal devices through the cable, the terminal devices comprising the magnetic bead module and the data distribution module have smaller insertion loss on the data signals with higher frequency, so that the signal quality of the data signals with higher frequency is ensured.

Further, in the following, referring to fig. 17 and fig. 18, taking an example that the terminal device transmits the second data signal, the result of RE test of the terminal device and the terminal device in the prior art related to the embodiment of the present application is compared.

Fig. 17 shows a schematic diagram of the result of RE test on a terminal device in the prior art. As a result of the test, the detection margin was-0.07 dB for electromagnetic noise of about 52.5139 MHz. That is, the terminal device in the related art cannot suppress electromagnetic noise of around 50 MHz.

Wherein when the detection margin is positive, a measured value (which may be referred to as a noise value) indicating noise is smaller than a noise limit value, and when the detection margin is negative, a measured value indicating noise is larger than the noise limit value.

Fig. 18 a shows a schematic diagram of a result of RE test performed on the first terminal device according to the embodiment of the present application. From the test results, the detection margin was 8.56dB for electromagnetic noise of about 52.3057 MHz. That is, the first terminal device according to the embodiment of the present application has an electromagnetic noise suppression capability of about 50MHz of about 8.56dB. This is an improvement of about 8dB compared to prior art terminal devices.

Fig. 18B shows a schematic diagram of a result of RE test performed on the second terminal device according to the embodiment of the present application. From the test results, the detection margin was 8.26dB for electromagnetic noise of about 52.9683 MHz. That is, the second terminal device according to the embodiment of the present application has an electromagnetic noise suppression capability of about 50MHz of about 8.26dB. This is an improvement of about 8dB compared to the prior art terminal device, and is substantially consistent with the suppression capability of the first terminal device in the embodiments of the present application for electromagnetic noise.

In summary, the two terminals according to the embodiments of the present application can effectively suppress electromagnetic noise with a low frequency.

Further, in the following, taking the terminal device to transmit the second data signal as an example, in conjunction with fig. 19 and fig. 20, the eye diagram results of the terminal device related to the embodiment of the present application and the terminal device in the prior art are observed through an oscilloscope for comparison.

As shown in fig. 19, the far-end eye height in the eye pattern test result of the terminal device in the related art is 140mV. As shown in a in fig. 20, the far-end eye height in the eye test result of the first terminal device (including the magnetic bead module) according to the embodiment of the present application is 125mV. As shown in B in fig. 20, the far-end eye height in the test result of the eye pattern of the second terminal device (including the magnetic bead module and the data shunt module) according to the embodiment of the present application is 137mV.

The far-end eye height in the eye diagram can be used to indicate the quality of the signal, and the higher the far-end eye height (i.e., the larger the value of the far-end eye height), the better the signal quality.

As can be seen by comparing the values of the far-end eye heights in a in fig. 19 and 20, the first terminal device according to the embodiment of the present application has poor reflow capability for the second data signal. As can be seen by comparing the values of the far-end eye heights in B in fig. 19 and fig. 20, the second terminal device according to the embodiment of the present application has a strong capability of reflowing the second data signal, so that normal transmission of the second data signal can be ensured.

In summary, when the terminal device provided in the embodiment of the present application is connected to another terminal device through a cable and transmits a data signal through the cable, electromagnetic noise generated by the terminal device can be prevented from radiating outwards through the cable connecting the two terminal devices, and electromagnetic interference is generated to other surrounding devices, so that the terminal device meets the relevant standard. In addition, the noise reduction circuit in the embodiment of the application is formed by a plurality of basic electronic components, and the cost is low. Compared with the prior art that electromagnetic noise is filtered by adopting high-cost electric connection auxiliary materials (such as conductive foam, wave-absorbing materials and the like), the cost of the terminal equipment is greatly reduced.

In the several embodiments provided in this application, it should be understood that the disclosed circuits and devices may be implemented in other ways. For example, the above-described device embodiments are merely illustrative, e.g., the division of the modules is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple modules or components may be combined or integrated into another device, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interface, indirect coupling or communication connection of devices or modules, electrical, mechanical, or other form.

The modules described as separate components may or may not be physically separate, and components shown as modules may or may not be physically separate, i.e., may be located in one device, or may be distributed over multiple devices. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional module in each embodiment of the present application may be integrated in one device, or each module may exist alone physically, or two or more modules may be integrated in one device.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The terminal equipment is characterized by comprising M first grounding ends, a transmission interface and a noise reduction circuit, wherein the transmission interface comprises M second grounding ends, the noise reduction circuit comprises M magnetic bead modules, and each magnetic bead module comprises magnetic beads; the M first grounding ends are respectively coupled to the M second grounding ends through the M magnetic bead modules; and M is a positive integer.

2. The terminal device of claim 1, wherein each of the magnetic bead modules comprises L magnetic beads, wherein L is a positive integer; when L is greater than 1, the L magnetic beads are connected in series; alternatively, the L magnetic beads are connected in parallel; or, after some of the L magnetic beads are connected in parallel, the L magnetic beads are connected in series with the rest of the magnetic beads.

3. The terminal device according to claim 1 or 2, wherein the noise reduction circuit further comprises M data splitting modules, the M data splitting modules being respectively connected in parallel with the M magnetic bead modules; when the frequency of the data signal transmitted by the transmission interface is greater than a second threshold value, the impedance of the M data shunt modules is respectively smaller than the impedance of the M magnetic bead modules.

4. A terminal device according to claim 3, wherein each of the data splitting modules comprises Y data splitting sub-modules, Y being a positive integer; when Y is greater than 1, the Y data splitting submodules are connected in parallel.

5. The terminal device of claim 4, wherein each of the data splitting submodules includes P capacitors, wherein P is a positive integer; when the P is larger than 1, the P capacitors are connected in series; or, the P capacitors are connected in parallel; or after the partial capacitors in the P capacitors are connected in parallel, the partial capacitors are connected in series with the rest partial capacitors.

6. The terminal device of claim 5, wherein each of the data splitting sub-modules further comprises W resistors, W being a positive integer;

the P capacitors are connected in series with the W resistors, and when the W is greater than 1, the W resistors are connected in series; or,

the P capacitors are connected with the W resistors in series, and when the W is larger than 1, the W resistors are connected in parallel; or,

and the P capacitors are connected with the W resistors in series, and when the W is larger than 1, part of the W resistors are connected in parallel and then connected with the rest part of the resistors in series.

7. The terminal device of claim 5, wherein each of the data splitting sub-modules further comprises Q inductors, the Q being a positive integer;

the P capacitors are connected in series with the Q inductors, and when the Q is greater than 1, the Q inductors are connected in series; or,

the P capacitors are connected with the Q inductors in series, and when the Q is larger than 1, the Q inductors are connected in parallel; or,

and the P capacitors are connected with the Q inductors in series, and when the Q is larger than 1, part of the Q inductors are connected in parallel and then connected with the rest part of the inductors in series.

8. The terminal device of claim 5, wherein each of the data splitting sub-modules further comprises W resistors and Q inductors, wherein W and Q are positive integers, and wherein the P capacitors, the W resistors and the Q inductors are connected in series;

When the W and the Q are larger than 1, the W resistors are connected in series, and the Q inductors are connected in series; or, the W resistors are connected in series, and the Q inductors are connected in parallel; or the W resistors are connected in series, and after part of the Q inductors are connected in parallel, the W resistors are connected in series with the rest of the inductors; or,

when the W and the Q are larger than 1, the W resistors are connected in parallel, and the Q inductors are connected in series; or, the W resistors are connected in parallel, and the Q inductors are connected in parallel; or, the W resistors are connected in parallel, and after part of the Q inductors are connected in parallel, the W resistors are connected in series with the rest of the inductors; or,

when the W and the Q are larger than 1, after partial resistors in the W resistors are connected in parallel, the partial resistors are connected in series with the rest partial resistors, and the Q inductors are connected in series; or after the partial resistors in the W resistors are connected in parallel, the W resistors are connected in series with the rest partial resistors, and the Q inductors are connected in parallel; or, after being connected in parallel, part of the W resistors are connected in series with the rest of the resistors, and after being connected in parallel, part of the Q inductors are connected in series with the rest of the inductors.

9. A terminal device according to claim 1 or 2, characterized in that the frequency of the data signals transmitted by the transmission interface is smaller than a first threshold value.

10. The terminal device of claim 9, wherein the transmission interface is an interface employing a USB2.0 protocol or a history version protocol.

11. The terminal device of claim 5, wherein the frequency of the data signal transmitted by the transmission interface is greater than a second threshold.

12. The terminal device of claim 11, wherein the transmission interface is at least one of an interface using a USB3.0 protocol or a subsequent version of the protocol, a high definition multimedia interface, and a display interface.

13. The noise reduction circuit is characterized by comprising M magnetic bead modules and M data distribution modules, wherein the M magnetic bead modules are respectively connected with the M data distribution modules in parallel;

the first ends of the M magnetic bead modules are used for being coupled to the grounding end of a transmission interface of terminal equipment, and the second ends of the M magnetic bead modules are used for being coupled to the grounding end of the terminal equipment; wherein M is a positive integer.

14. The noise reduction circuit of claim 13, wherein each of the magnetic bead modules comprises L magnetic beads, wherein L is a positive integer; when L is greater than 1, the L magnetic beads are connected in series; alternatively, the L magnetic beads are connected in parallel; or, after some of the L magnetic beads are connected in parallel, the L magnetic beads are connected in series with the rest of the magnetic beads.

15. The noise reduction circuit of claim 13 or 14, wherein each of the data splitting modules comprises Y data splitting sub-modules, the Y being a positive integer; when Y is greater than 1, the Y data splitting submodules are connected in parallel.

16. The noise reduction circuit of claim 15, wherein each of the data splitting submodules includes P capacitors, the P being a positive integer; when the P is larger than 1, the P capacitors are connected in series; or, the P capacitors are connected in parallel; or after the partial capacitors in the P capacitors are connected in parallel, the partial capacitors are connected in series with the rest partial capacitors.

17. The noise reduction circuit of claim 16, wherein each of the data splitting sub-modules further comprises W resistors, W being a positive integer;

18. The noise reduction circuit of claim 16, wherein each of the data splitting sub-modules further comprises Q inductors, the Q being a positive integer;

19. The noise reduction circuit of claim 16, wherein each of the data splitting sub-modules further comprises W resistors and Q inductors, the W and Q being positive integers, the P capacitors, the W resistors and the Q inductors being in series;