Terminal device and noise reduction circuit

Abstract

The present application relates to the field of circuit design, and discloses a terminal device and a noise reduction circuit, used for suppressing, when any one of terminal devices connected by using a cable is in a screen-on state, outward radiation of electromagnetic noise generated by the terminal device in the screen-on state. The terminal device comprises M first ground terminals, a transmission interface having M second ground terminals, and a noise reduction circuit. The noise reduction circuit comprises M magnetic bead modules, and each magnetic bead module comprises a magnetic bead. The M first ground terminals are respectively coupled to the M second ground terminals by means of the M magnetic bead modules, wherein M is a positive integer.

Description

Terminal device and noise reduction circuit

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on July 20, 2023, with application number 202310898290.5, and invention name “A noise suppression method and electronic device compatible with high-speed signals and fast charging”, and the Chinese patent application filed with the State Intellectual Property Office on September 8, 2023, with application number 202311170048.2, and invention name “A terminal device and noise reduction circuit”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of circuit design, and in particular to a terminal device and a noise reduction circuit. Background Art

[0003] Two terminal devices (such as mobile phones and tablets) can be connected via a cable (such as a universal serial bus (USB) cable). When either terminal device is in the on-screen state, the terminal device's display (or screen) generates electromagnetic noise and radiates outward through the cable (i.e., generates electromagnetic radiation). This can cause electromagnetic interference to other nearby devices.

[0004] Summary of the Invention

[0005] The present application provides a terminal device and a noise reduction circuit, which are used in a scenario where the terminal devices are connected by cables. When any terminal device is in a screen-on state, the circuit suppresses the outward radiation of electromagnetic noise generated by the terminal device in the screen-on state.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a terminal device. The terminal device includes M first ground terminals, a transmission interface having M second ground terminals, and a noise reduction circuit. The noise reduction circuit includes M ferrite bead modules, each of which includes a ferrite bead. The M first ground terminals are respectively coupled to the M second ground terminals via the M ferrite bead modules. M is a positive integer.

[0008] The noise reduction circuit provided in the present application is located between the second ground terminal of the transmission interface of the terminal device and the first ground terminal of the terminal device. In this way, when the electromagnetic noise generated by the terminal device is transmitted on the ground plane, the noise reduction circuit will filter out the electromagnetic noise. Based on this, when the terminal device is connected to other terminal devices through a cable, the electromagnetic noise generated by the terminal device will not be transmitted to the cable, thereby preventing the electromagnetic noise generated by the terminal device from radiating outward through the cable connecting the two terminal devices and causing electromagnetic interference to other surrounding devices, and ensuring that the terminal device meets relevant standards.

[0009] In one possible implementation, each magnetic bead module may include L magnetic beads. The connection method of the L magnetic beads in each magnetic bead module may include any of the following situations: If L=1, each first ground terminal is coupled to a corresponding second ground terminal through a magnetic bead. That is to say, the M first ground terminals are coupled to the M second ground terminals through M magnetic beads respectively. If L>1, the L magnetic beads can be connected in series, or the L magnetic beads can be connected in parallel. If L≥3, some of the L magnetic beads are connected in parallel and then connected in series with the remaining part of the magnetic beads. The magnetic beads in the magnetic bead module can not only filter out electromagnetic noise, but also provide a current return path for the charging current, as well as lower frequency data signals (such as the data signal with a frequency lower than the first threshold mentioned below, i.e., the first data signal).

[0010] In another possible implementation, the noise reduction circuit provided in the present application may further include M data shunt modules. The M data shunt modules are respectively connected in parallel with the M magnetic bead modules. In other words, the M first ground terminals are respectively coupled to the M second ground terminals via the M data shunt modules and the M magnetic bead modules. When the frequency of the data signal transmitted by the transmission interface is greater than the second threshold, the impedance of the M data shunt modules is respectively less than the impedance of the M magnetic bead modules.

[0011] Based on this, the M magnetic bead modules can filter out electromagnetic noise. Since the impedance of the M data shunt modules is respectively less than the impedance of the M magnetic bead modules when the frequency of the data signal is greater than the second threshold, the M data shunt modules can provide a return path for data signals with a frequency greater than the second threshold (such as the second data signal mentioned below), so that the data signals with a frequency greater than the second threshold can be transmitted normally. However, the frequency of the electromagnetic noise is much less than the second threshold, and at the frequency of the electromagnetic noise, the impedance of the M magnetic bead modules is respectively much less than the impedance of the M data shunt modules. Therefore, the electromagnetic noise will still pass through the M magnetic bead modules and be filtered out by the M magnetic bead modules.

[0012] In another possible implementation, each of the above-mentioned data distribution modules includes Y data distribution sub-modules, where Y is a positive integer. When Y is greater than 1, the Y data distribution sub-modules are connected in parallel.

[0013] In another possible implementation, each of the above-mentioned data splitting sub-modules includes P capacitors, where P is a positive integer. The connection method of the P capacitors in each data splitting sub-module can include any of the following situations: If P=1, each magnetic bead module is connected in parallel with a capacitor. If P>1, the P capacitors are connected in series and then in parallel with a magnetic bead module, or the P capacitors are connected in parallel and then in parallel with a magnetic bead module. If P≥3, some of the P capacitors are connected in parallel, then connected in series with the remaining capacitors, and then connected in parallel with a magnetic bead module.

[0014] The types and structures of the P capacitors in each data splitting submodule may be related to the frequency of the data signal transmitted by the transmission interface.

[0015] In another possible implementation, each of the above-mentioned data splitting sub-modules includes P capacitors and W resistors, where W is a positive integer. P capacitors are connected in series with W resistors, or P capacitors are connected in parallel with W resistors. Taking P capacitors and W resistors in series as an example, the connection method of the W resistors in each data splitting sub-module may include any of the following situations: if W>1, then the W resistors are connected in series, or, the W resistors are connected in parallel. If W≥3, then some of the W resistors are connected in parallel and then connected in series with the remaining resistors.

[0016] The capacitors and resistors can form a filter circuit. In this case, the data shunt submodule can not only provide a signal return path for the data signal with a frequency greater than the second threshold, but also filter out the noise signal in the data signal. The noise signal here is different from the electromagnetic noise mentioned above. The model of the P capacitors, the signal of the W resistors, and the structure of the P capacitors and W resistors in each data shunt submodule can be related to the frequency of the data signal transmitted by the transmission interface and the frequency of the noise signal in the data signal.

[0017] In another possible implementation, each of the above-mentioned data splitting sub-modules includes P capacitors and Q inductors, where Q is a positive integer. P capacitors are connected in series with Q inductors, or P capacitors are connected in parallel with Q inductors. Taking P capacitors and Q inductors connected in series as an example, the connection method of the Q inductors in each data splitting sub-module may include any of the following situations: if Q>1, then the Q inductors are connected in series, or, the Q inductors are connected in parallel. If Q≥3, then some of the Q inductors are connected in parallel and then connected in series with the remaining inductors.

[0018] Capacitors and inductors can also form a filtering circuit. In this case, the data shunt submodule can not only provide a signal return path for the data signal with a frequency greater than the second threshold, but also filter out the noise signal in the data signal. The noise signal here is different from the electromagnetic noise mentioned above. The model of the P capacitors, the signal of the Q inductors, and the structure of the P capacitors and Q inductors in each data shunt submodule can be related to the frequency of the data signal transmitted by the transmission interface and the frequency of the noise signal in the data signal.

[0019] In another possible implementation, each of the aforementioned data splitter modules includes P capacitors, W resistors, and Q inductors. The data splitter modules comprised of the P capacitors, W resistors, and Q inductors can not only provide a signal return path for data signals with a frequency greater than the second threshold, but can also filter out noise signals from the data signals. Based on this, the connection relationships among the P capacitors, W resistors, and Q inductors can be various.

[0020] For example, P capacitors are connected in parallel with W resistors and then 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., and this application does not limit this. In this application, P capacitors, W resistors and Q inductors are connected in series as an example. Among them, the connection method of P capacitors can refer to the connection method described in the above possible implementation method, the connection method of W resistors can refer to the connection method described in the above possible implementation method, and the connection method of Q inductors can refer to the connection method described in the above possible implementation method. In this regard, this application will not go into details here.

[0021] In another possible implementation, the frequency of the data signal transmitted by the transmission interface is less than a first threshold.

[0022] In another possible implementation, the transmission interface is an interface using the USB 2.0 protocol or a previous version of the protocol. The data signal transmitted by the interface using the USB 2.0 protocol or a previous version of the protocol is a data signal with a relatively low frequency (ie, a first data signal).

[0023] In another possible implementation, the frequency of the data signal transmitted by the transmission interface is greater than a second threshold.

[0024] In another possible implementation, the transmission interface is at least one of an interface using the USB 3.0 protocol or a later version, a high-definition multimedia interface, and a display interface. Compared to data signals transmitted using an interface using the USB 2.0 protocol or a previous version, the data signal (i.e., the second data signal) transmitted using the at least one of the interfaces using the USB 3.0 protocol or a later version, the high-definition multimedia interface, and the display interface has a higher frequency.

[0025] In a second aspect, the present application further provides a noise reduction circuit. The noise reduction circuit comprises: M magnetic bead modules and M data shunt modules. The M magnetic bead modules are connected in parallel with the M data shunt modules, respectively. The first ends of the M magnetic bead modules are coupled to the ground terminal of the transmission interface of the terminal device, and the second ends of the M magnetic bead modules are coupled to the ground terminal of the terminal device. Wherein, M is a positive integer.

[0026] In one possible implementation, each magnetic bead module may include L magnetic beads. The connection method of the L magnetic beads in each magnetic bead module may include any of the following situations: If L=1, each first ground terminal is coupled to a corresponding second ground terminal through a magnetic bead. That is to say, the M first ground terminals are coupled to the M second ground terminals through M magnetic beads respectively. If L>1, the L magnetic beads can be connected in series, or the L magnetic beads can be connected in parallel. If L≥3, some of the L magnetic beads are connected in parallel and then connected in series with the remaining part of the magnetic beads. The magnetic beads in the magnetic bead module can not only filter out electromagnetic noise, but also provide a current return path for the charging current, as well as lower frequency data signals (such as the data signal with a frequency lower than the first threshold mentioned below, i.e., the first data signal).

[0027] In another possible implementation, each of the above-mentioned data distribution modules includes Y data distribution sub-modules, where Y is a positive integer. When Y is greater than 1, the Y data distribution sub-modules are connected in parallel.

[0028] In another possible implementation, each of the above-mentioned data splitting sub-modules includes P capacitors, where P is a positive integer. The connection method of the P capacitors in each data splitting sub-module can include any of the following situations: If P=1, each magnetic bead module is connected in parallel with a capacitor. If P>1, the P capacitors are connected in series and then in parallel with a magnetic bead module, or the P capacitors are connected in parallel and then in parallel with a magnetic bead module. If P≥3, some of the P capacitors are connected in parallel, then connected in series with the remaining capacitors, and then connected in parallel with a magnetic bead module.

[0029] In another possible implementation, each of the above-mentioned data splitting sub-modules includes P capacitors and W resistors, where 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 example of P capacitors and W resistors connected in series, the connection method of the W resistors in each data splitting sub-module may include any of the following situations: if W>1, then the W resistors are connected in series, or the W resistors are connected in parallel. If W≥3, then some of the W resistors are connected in parallel and then connected in series with the remaining resistors.

[0030] In another possible implementation, each of the above-mentioned data splitting sub-modules includes P capacitors and Q inductors, where Q is a positive integer. P capacitors are connected in series with Q inductors, or P capacitors are connected in parallel with Q inductors. Taking P capacitors and Q inductors connected in series as an example, the connection method of the Q inductors in each data splitting sub-module may include any of the following situations: if Q>1, then the Q inductors are connected in series, or, the Q inductors are connected in parallel. If Q≥3, then some of the Q inductors are connected in parallel and then connected in series with the remaining inductors.

[0031] In another possible implementation, each of the aforementioned data splitter modules includes P capacitors, W resistors, and Q inductors. The data splitter modules comprised of the P capacitors, W resistors, and Q inductors can not only provide a signal return path for data signals with a frequency greater than the second threshold, but can also filter out noise signals from the data signals. Based on this, the connection relationships among the P capacitors, W resistors, and Q inductors can be various.

[0032] For example, P capacitors are connected in parallel with W resistors and then 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, P capacitors, W resistors, and Q inductors are connected in series as an example. Among them, the connection method of the P capacitors can refer to the connection method described in the above possible implementation method, the connection method of the W resistors can refer to the connection method described in the above possible implementation method, and the connection method of the Q inductors can refer to the connection method described in the above possible implementation method. In this regard, this application will not go into details here.

[0033] It should be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a schematic diagram of an electromagnetic noise radiation scenario in the prior art;

[0035] FIG2 is a schematic structural diagram of a terminal device in the prior art;

[0036] FIG3 is a schematic diagram of a scene structure of an electromagnetic compatibility radiation emission test system in the prior art;

[0037] FIG4 is a schematic diagram showing one of the results of an RE test of a terminal device in the prior art;

[0038] FIG5 is a schematic diagram of a signal return path of electromagnetic noise of a terminal device in the prior art;

[0039] FIG6 is a schematic diagram of a structure of a terminal device according to an embodiment of the present application;

[0040] FIG7 is a schematic diagram of a signal return path of a terminal device provided in an embodiment of the present application;

[0041] FIG8 is a schematic diagram of a characteristic curve of a magnetic bead;

[0042] FIG9 is a schematic structural diagram of a magnetic bead module provided in an embodiment of the present application;

[0043] FIG10 is a second structural diagram of a terminal device provided in an embodiment of the present application;

[0044] FIG11 is a second schematic diagram of a signal return path of a terminal device provided in an embodiment of the present application;

[0045] FIG12 is a schematic structural diagram of a data diversion module provided in an embodiment of the present application;

[0046] FIG13 is a structural diagram of a data splitting submodule according to an embodiment of the present application;

[0047] FIG14 is a second structural diagram of a data splitting submodule provided in an embodiment of the present application;

[0048] FIG15 is a third structural diagram of a data splitting submodule provided in an embodiment of the present application;

[0049] FIG16 is a schematic diagram showing comparison of simulation test results of a terminal device provided in an embodiment of the present application and a terminal device in the prior art;

[0050] FIG17 is a second schematic diagram of the results of an RE test of a terminal device in the prior art;

[0051] FIG18 is a schematic diagram showing the results of an RE test of a terminal device provided in an embodiment of the present application;

[0052] FIG19 is a schematic diagram showing the results of an eye diagram test of a terminal device in the prior art;

[0053] Figure 20 is a schematic diagram of the results of an eye diagram test of a terminal device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0054] The terms "first", "second", etc. involved in the embodiments of the present application are only used to distinguish features of the same type and cannot be understood as indicating relative importance, quantity, order, etc.

[0055] The terms "exemplary" or "for example" in the embodiments of this application are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0056] The terms "coupling" and "connection" involved in the embodiments of this application should be understood in a broad sense. For example, they may refer to a physical direct connection, or an indirect connection achieved through electronic devices, such as a connection achieved through resistors, inductors, capacitors or other electronic devices.

[0057] If two devices (such as mobile phones and tablets) are connected via a cable and the screen of either device is on, electromagnetic noise will be generated on that device's screen. This electromagnetic noise will radiate outward through the cable, causing electromagnetic interference to other nearby devices. Furthermore, the electromagnetic noise emission limit may exceed relevant standards (such as GB9254), causing the device to fail certification.

[0058] For example, take the two terminal devices, a mobile phone and a laptop computer, and a USB cable as an example. As shown in Figure 1, the first end of the USB cable 110 is coupled to the transmission interface of the mobile phone 120, and the second end of the USB cable 110 is coupled to the transmission interface of the laptop computer 130. When the mobile phone 120 is in the screen-on state, the screen of the mobile phone 120 will generate electromagnetic noise, and the electromagnetic noise will be transmitted to the USB cable 110 through the transmission interface of the mobile phone 120, and then radiated outward. Electromagnetic noise can cause electromagnetic interference to devices within a certain range (such as speakers 140, TVs 150, etc.). When a device is subjected to electromagnetic interference, it may affect the sensitivity of the device, and in severe cases, it may damage the device.

[0059] Figure 2 shows a schematic diagram of the structure of a terminal device in the prior art. As shown in Figure 2, the terminal device 200 includes a transmission interface 210, a processor 220, a power module 230, a load module 240, and M first ground terminals 250 (e.g., gnd1 to gndM). The transmission interface 210 includes a data terminal A, a power terminal B, and M second ground terminals 211 (e.g., GND1 to GNDM). 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 GNDM of the transmission interface 210 are respectively coupled to the M first ground terminals gndM of the terminal device 200. The signal terminal of the processor 220 is coupled to the control terminal of the load module 240. The output terminal of the power module 230 is coupled to the power supply terminal of the processor 220 and the power supply terminal of the load module 240. The processor 220, the power module 230, and the load module 240 are also coupled to the M first ground terminals gndM of the terminal device 200. Wherein, M is a positive integer.

[0060] The number of the second grounding terminals may be the same as or different from the number of the first grounding terminals. In the embodiment of the present application, the example in which the number of the second grounding terminals of the transmission interface is the same as the number of the first grounding terminals of the terminal device is used for description.

[0061] In order to determine the cause of the electromagnetic noise being radiated outward, an electromagnetic compatibility radiated emission (RE) test is performed on the two terminal devices connected by the cable using an RE test system.

[0062] Figure 3 shows a schematic diagram of a RE test system scenario. As shown in Figure 3, the test system includes an anechoic chamber 310, a turntable 320 located within the chamber, an antenna device 330, and a cable 340. A receiving device 350 and a control device 360 ​​are located outside the chamber 310. Antenna device 330 includes an antenna 331 and an antenna connector 332, with antenna 331 mounted on antenna connector 332. Antenna 331 is coupled to the input of receiving device 350, and the output of control device 360 ​​is coupled to the control terminals of turntable 320 and antenna connector 332.

[0063] The inner wall of the anechoic chamber 310 is coated with absorbing material, providing a test environment for the test system, simulating the effects of an open field. A control device 360 ​​controls the rotation of the turntable 320. It also instructs the antenna connector 332 to adjust the receiving angle and height of the antenna 331. Antenna 331 receives electromagnetic signals and transmits them to a receiving device 350. A cable 340 connects two terminal devices placed on the turntable.

[0064] Specifically, the type of cable 340 is related to the type of transmission interface of the above-mentioned two terminal devices. For example, cable 340 can be any one of a USB cable, a high-definition multimedia interface (HDMI) cable, and a data communication equipment (terminal equipment, DP) cable. Of course, cable 340 can also be a cable with a USB interface at one end and an HDMI interface at the other end; or, cable 340 can also be a cable with a USB interface at one end and a DP interface at the other end; or, cable 340 can also be a cable with an HDMI interface at one end and a DP interface at the other end.

[0065] For example, when the two terminal devices are both mobile 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 have a USB interface at one end and an HDMI interface at the other end.

[0066] Before testing, two terminal devices are placed on the turntable 320 , and a first end of the cable 340 is coupled to a transmission interface of one terminal device, and a second end of the cable 340 is coupled to a transmission interface of the other terminal device.

[0067] During the test, the control device 360 ​​controls the rotation of the turntable 320. One terminal device 200 is in the screen-on state, while the other terminal device 200' can be in the screen-off state. At this time, the cable 340 acts as an antenna, radiating the electromagnetic noise (or electromagnetic signal) generated by the terminal device 200 in the screen-on state. In other words, the cable 340 can radiate the electromagnetic noise generated by the terminal device in the screen-on state. The antenna 331 can receive the electromagnetic signal within the anechoic chamber 310 and transmit it to the receiving device 350 outside the anechoic chamber 310.

[0068] It is understood that the terminal device 200' can be in the screen-off state or the screen-on state. When the terminal device 200' is in the screen-on state, electromagnetic noise will also be radiated outward. For ease of distinction, the following examples are taken as an example of the terminal device 200 in the screen-on state and the terminal device 200' in the screen-off state.

[0069] The following describes the electromagnetic compatibility radiation emission test results obtained by the receiving equipment in the above test system under different conditions.

[0070] In one embodiment, two terminal devices are connected via a first cable. The first cable refers to a cable in which the signal line (or data line), power line, and ground line are all intact, i.e., the first cable is a conventional cable. As shown in A in FIG4 , at approximately 50 MHz, the electromagnetic noise in the anechoic chamber exceeds a noise limit (e.g., 40 decibel / μV / m, dB / μV / m).

[0071] In another embodiment, two terminal devices are connected via a second cable. The second cable is the first cable with a portion of the ground wire cut off, meaning that the ground wire in the second cable is partially disconnected. As shown in Figure 4, B, at around 50 MHz, the electromagnetic noise in the anechoic chamber still exceeds the noise limit.

[0072] In another embodiment, two terminal devices are connected via a third cable. The third cable is the first cable after all ground wires have been disconnected, meaning all ground wires in the third cable are disconnected. As shown in C in Figure 4 , the electromagnetic noise in the anechoic chamber does not exceed the noise limit.

[0073] In summary, when two terminal devices are connected via a cable, the electromagnetic noise generated by the terminal device's screen radiates outward through the cable's ground wire. This radiated electromagnetic noise can cause electromagnetic interference to other nearby devices, and in severe cases, can affect their normal operation.

[0074] Furthermore, taking M=2 as an example, as shown in FIG5 , the second ground terminal of the terminal device's transmission interface and the first ground terminal of the terminal device belong to the same ground plane. When the cable interface 530 is connected to the terminal device's transmission interface 210, the two third ground terminals 531 of the cable interface 530 are respectively coupled to the two second ground terminals 211 of the terminal device's transmission interface 210. Based on the above analysis, it can be seen that when the terminal device generates electromagnetic noise of a certain frequency (e.g., approximately 50 MHz), the electromagnetic noise is transmitted from the terminal device's first ground terminal 250 (e.g., gnd1 and gnd2) to the second ground terminal 211 (e.g., GND1 and GND2) of the transmission interface 210 on the terminal device's ground plane. The noise is then transmitted through the transmission interface's second ground terminal to the third ground terminal 531 of the cable interface 530, and then radiated outward through the cable's ground wire.

[0075] To this end, an embodiment of the present application provides a terminal device that separates the ground plane by providing a noise reduction circuit between the second ground terminal of the terminal device's transmission interface and the first ground terminal of the terminal device. In this way, when electromagnetic noise is transmitted on the ground plane, the noise reduction circuit will filter out the electromagnetic noise, so that the electromagnetic noise cannot be transmitted to the ground terminal of the transmission interface. Based on this, when two terminal devices are connected by a cable, the electromagnetic noise generated by the screen of the terminal device can be prevented from radiating outward through the cable connecting the two terminal devices and causing electromagnetic interference to other surrounding devices, and the terminal device can meet the relevant standards.

[0076] The terminal device involved in the embodiments of the present application can be movable and portable, and the terminal device has data transmission and display functions. The terminal device can be deployed on land (for example, indoors or outdoors, handheld or vehicle-mounted, etc.), on the water (for example, a ship model), or in the air (for example, a drone, etc.). The terminal device can be referred to as user equipment (UE), access device, terminal unit, subscriber unit, terminal station, mobile station (MS), mobile station, terminal agent or terminal device, etc. For example, the electronic device can be a mobile phone, virtual reality (VR) device, augmented reality (AR) device, terminal in industrial control (industrial control), terminal in self-driving (self-driving), terminal in remote medical (remote medical), terminal in smart grid (smart grid), terminal in transportation safety (transportation safety), terminal in smart city (smart city), terminal in smart home (smart home), etc. The embodiments of the present application do not limit the specific type and structure of the terminal device.

[0077] As shown in FIG6 , a terminal device 600 provided in an embodiment of the present application may include: a transmission interface 210 having M second ground terminals 211 (e.g., GND1 to GNDM), a processor 220, a power module 230, a load module 240, a noise reduction circuit 510, and M first ground terminals 250 (e.g., gnd1 to gndM). The noise reduction circuit 510 may include M magnetic bead modules 520, each of which includes a magnetic bead.

[0078] Specifically, the M second ground terminals 211 (e.g., GND1 to GNDM) of the transmission interface 210 are respectively coupled to the M first ground terminals 250 (e.g., gnd1 to gndM) of the terminal device 600 via M magnetic bead modules. For other connection relationships in the terminal device, refer to the description of the terminal device shown in FIG. 4 above.

[0079] It should be noted that the first ground terminal of the terminal device and the ground terminal of the transmission interface of the terminal device can be the same ground terminal, or they can be different ground terminals connected together. In the embodiment of the present application, 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 as an example.

[0080] Take M=2, that is, the transmission interface includes two first ground terminals and the terminal device includes two second ground terminals as an example. In combination with Figure 4, as shown in Figure 7, when the cable interface 530 is connected to the transmission interface 210 of the terminal device, the power terminal 533 of the cable interface 530 is coupled with the power terminal of the transmission interface 210 of the terminal device (not shown in Figure 7), and the data terminal 532 of the cable interface 530 is coupled with the data terminal of the transmission interface 210 of the terminal device (not shown in Figure 7). In order to facilitate the introduction of this solution, the ground plane of the terminal device can be separated into two ground planes based on the magnetic bead module. As shown in Figure 7, the ground plane of the terminal device is separated into two ground planes (which can be referred to as the first ground plane and the second ground plane, respectively) by two magnetic bead modules. All ports of the transmission interface 210 including the second ground terminal 211 can be located on the first ground plane, and the first ground terminal 250 of the terminal device can be located on the second ground plane. All signals between the first ground plane and the second ground plane will be returned through the two magnetic bead modules. These signals may include: electromagnetic noise, charging current, and data signals with lower frequencies (which can be referred to as first data signals). It should be noted that the first ground plane and the second ground plane are the same ground plane. In order to facilitate the introduction of this solution in the embodiment of the present application, they are separated.

[0081] The impedance of the ferrite beads in a ferrite bead module can change with frequency. Typically, at low frequencies, the beads exhibit inductive properties, resulting in low impedance; at high frequencies, they exhibit resistive properties. At a certain frequency, the impedance of the beads reaches its maximum.

[0082] It should be noted that the terms "low frequency" and "high frequency" are relative terms, different from the conventional low-frequency and high-frequency terms. For example, 50 MHz is considered low-frequency relative to 240 MHz, while 240 MHz is considered high-frequency.

[0083] For example, Figure 8 shows a schematic diagram of the characteristic curve of a magnetic bead. As shown in Figure 8, within the frequency range of 0-500MHz, the impedance of the magnetic bead gradually increases as the frequency increases; within the frequency range of 500MHz-3000MHz, the impedance of the magnetic bead gradually decreases as the frequency increases. However, the rate of decrease of the impedance of the magnetic bead in the frequency range above 500MHz is less than the rate of increase of the impedance of the magnetic bead in the frequency range of 0-500MHz. It can be seen that the impedance of the magnetic bead is the largest at 500MHz. It can be seen from the characteristic curve of the magnetic bead that the impedance of the magnetic bead is relatively large in the frequency range of 20MHz-3000MHz. At this time, the magnetic bead can absorb electromagnetic noise and convert the electromagnetic noise into heat energy for dissipation. In other words, the magnetic bead can filter out electromagnetic noise of a certain frequency.

[0084] To sum up, in the embodiment of the present application, the second ground terminal in the transmission interface originally connected together in the terminal device and the first ground terminal of the terminal device are separated by a magnetic bead module. Since the magnetic beads have a large impedance within a certain frequency range (such as around 50MHz), the electromagnetic noise will be absorbed by the magnetic beads in the magnetic bead module when passing through the magnetic bead module, thereby filtering out the 50MHz electromagnetic noise and other noise below 50MHz. In this way, the electromagnetic noise cannot be transmitted to the ground terminal of the transmission interface of the terminal device, nor will it radiate outward through the ground wire of the cable, thereby not causing electromagnetic interference to other terminal devices around it.

[0085] It should be noted that in the embodiments of the present application, the frequency of the electromagnetic noise is not necessarily 50 MHz. The electromagnetic noise can be within a certain frequency range. Typically, the frequency is in the megahertz range, for example, 40 MHz to 60 MHz.

[0086] It should be noted that the noise reduction circuit provided in the embodiment of the present application can be located in the USB module (or USB board) of the terminal device, or in the main board module, but is not limited thereto. The embodiment of the present application does not limit this.

[0087] Optionally, each of the above-mentioned magnetic bead modules may include L magnetic beads, where L is a positive integer. As shown in A of Figure 9, L=1, each first ground terminal GNDM can be coupled to a corresponding second ground terminal gndM through a magnetic bead. As shown in B of Figure 9, when L>1, the L magnetic beads can be connected in series. As shown in C of Figure 9, when L>1, the L magnetic beads can be connected in parallel. As shown in D of Figure 9, when L≥3, N magnetic beads out of the L magnetic beads can be connected in parallel and then connected in series with the remaining (LN) magnetic beads. Wherein, N is a positive integer greater than or equal to 2, and N is less than L.

[0088] 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 can adopt any structure from B in FIG. 9 to D in FIG. 9 , and the embodiment of the present application does not limit this.

[0089] Optionally, the model of each magnetic bead in the magnetic bead module, the number of magnetic beads, and the connection structure of each magnetic bead can be determined according to the charging current of the terminal device, the frequency of electromagnetic noise, etc.

[0090] For example, the type of magnetic beads can be determined according to the frequency of the electromagnetic noise generated by the terminal device, so that the magnetic beads can better filter out the electromagnetic noise.

[0091] For example, a single magnetic bead usually has poor current carrying capacity. Therefore, when the charging current is large, the charging current can be shunted by multiple magnetic beads connected in parallel, thereby providing a current return path for the charging current so that the terminal device can charge normally through the transmission interface. In addition, in order to shunt the large charging current, the magnetic beads in each magnetic bead module can be selected as low DC impedance and high current carrying capacity as much as possible. In this way, it will not affect the charging of the terminal device.

[0092] Optionally, the frequency of the data signal transmitted by the transmission interface of the terminal device involved in the embodiments of the present application may be less than the first threshold.

[0093] Exemplarily, when the frequency of the data signal transmitted by the transmission interface is less than the first threshold, the transmission interface may be an interface using the USB 2.0 protocol or a previous version of the protocol. For example, the transmission interface may be any one of an interface using the USB 2.0 protocol, an interface using the USB 1.0 protocol, and an interface using the USB 1.1 protocol. When the transmission interface uses the USB 2.0 protocol, the frequency of the transmitted data signal is 240 MHz.

[0094] For the convenience of description, in the embodiment of the present application, a data signal whose frequency is less than the first threshold is referred to as a first data signal.

[0095] Typically, the frequency of electromagnetic noise may be lower than the frequency of the first data signal, and the power (or energy) of electromagnetic noise is much lower than the power of the first data signal. For the same magnetic bead module, the degree of attenuation of different signals such as noise signals and data signals is the same. Since the frequency of electromagnetic noise is relatively small and the power of electromagnetic noise is relatively small, the electromagnetic noise can be filtered out by the magnetic bead module. However, the frequency and power of the first data signal are relatively large. Therefore, when the first data signal passes through the magnetic bead module, the first data signal will be slightly attenuated, but it does not affect the signal quality of the first data signal. In other words, the first data signal can be refluxed through M magnetic bead modules, that is, each magnetic bead module in the noise reduction circuit will provide a signal reflux path for the first data signal.

[0096] Optionally, the frequency of the data signal transmitted by the transmission interface of the terminal device involved in the embodiment of the present application may be greater than the second threshold.

[0097] Exemplarily, when the frequency of the data signal transmitted by the transmission interface is greater than the second threshold, the transmission interface may be any one of an interface adopting the USB 3.0 protocol or a later version of the protocol, an HDMI interface, a DP interface, etc. The frequency of the data signal transmitted by the interface adopting the USB 3.0 protocol or a later version of the protocol, the HDMI interface, and the DP interface is higher than the frequency of the data signal transmitted by the interface adopting the USB 2.0 protocol and previous versions of the protocol. For example, the frequency of the data signal transmitted by the interface adopting the USB 3.0 protocol may be 2.5 GHz (i.e., 2500 MHz).

[0098] For the convenience of description, in the embodiment of the present application, a data signal with a frequency greater than the second threshold is referred to as a second data signal.

[0099] Within a certain frequency range, the impedance of the ferrite bead decreases slightly as the frequency increases, but overall the impedance remains relatively high. Continuing with Figure 7, within the frequency range of 500MHz-3000MHz, the impedance of the ferrite bead decreases slightly as the frequency increases, but overall the impedance remains relatively high. This shows that if a second data signal with a higher frequency passes through M ferrite bead modules, these M ferrite bead modules will significantly attenuate the second data signal.

[0100] In conjunction with FIG6 , as shown in FIG10 , in order to reduce the attenuation of the second data signal, the noise reduction circuit provided in the embodiment of the present application may further include M data diversion modules 910. The M data diversion 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 diversion modules 910 is respectively much smaller than the impedance of the M magnetic bead modules. At a frequency of approximately 50 MHz, the impedance of the M data diversion modules 910 is respectively much larger than the impedance of the M magnetic bead modules. Based on this, the electromagnetic noise generated by the terminal device will still pass through the M magnetic bead modules, so that the M magnetic bead modules 520 can filter out electromagnetic noise of approximately 50 MHz; the second data signal transmitted by the terminal device will pass through the data diversion module 910, that is, the data diversion module 910 can provide a signal return path for the second data signal. That is to say, when the terminal device transmits the second data signal through the cable and the terminal device generates electromagnetic noise, the noise reduction circuit will decouple the electromagnetic noise generated by the terminal device so that it is absorbed by the magnetic bead module and filtered out, and then does not radiate outward, but the second data signal can be transmitted normally.

[0101] It should be noted that in the embodiment of the present application, appropriate models of magnetic beads and components in the data shunt module can be selected so that at a frequency of approximately 50 MHz, the impedance of the M data shunt modules 910 is significantly greater than the impedance of the M magnetic bead modules. Based on this, electromagnetic noise will pass through the M magnetic bead modules but will not be transmitted outward through the M data shunt modules.

[0102] As shown in Figure 11, a data shunt module is connected in parallel next to each magnetic bead module. Each magnetic bead module filters out electromagnetic noise and provides a current return path for the charging current; each data shunt module provides a signal return path for the second data signal.

[0103] Optionally, each of the above-mentioned data diversion modules may include Y data diversion sub-modules. Y is a positive integer. As shown in Figure 12, when Y is greater than 1, the Y data diversion sub-modules are connected in parallel. The following, in conjunction with Figures 13-15, takes the example of a data diversion module including one data diversion sub-module (i.e., Y = 1) to introduce the possible structure of the data diversion sub-module 1110. In this case, the data diversion module is equivalent to the data diversion sub-module.

[0104] Optionally, the data shunt submodule may include P capacitors, where P is a positive integer. That is, each first ground terminal is coupled to the 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 as the frequency increases. At the frequency of the second data signal, in order to ensure that the impedance of the M data shunt modules is less than the impedance of the M magnetic bead modules, the resonant frequency of the capacitor involved 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.

[0105] The relationship between the impedance of each capacitor and the frequency can be expressed by the following formula (1):

[0106] Among them, Z C is the impedance of the capacitor, f is the frequency, and C is the capacitance of the capacitor. Formula (1) shows that, given a constant capacitance, the higher the frequency, the smaller the capacitor impedance. The following describes possible connection structures for the P capacitors included in the data splitter module.

[0107] In one embodiment, taking P=1 as an example, as shown in A in FIG13 , the data splitting submodule 1110 includes a capacitor C. The first end of the capacitor C is coupled to a second ground terminal of the transmission interface 210, and the second end of the capacitor C is coupled to a first ground terminal of the terminal device. In this case, one capacitor is a data splitting submodule, and therefore, the impedance of one data splitting submodule 1110 is the impedance of this capacitor C. As can be seen from the above formula (1), for a capacitor, the higher the frequency, the smaller the impedance of the capacitor. Therefore, for the second data signal, the higher its frequency, the smaller the impedance of the data splitting submodule 1110, and therefore, the second data signal can flow back through the data splitting submodule 1110.

[0108] It should be noted that, in the prior art shown in Figures 2 and 5, each first ground terminal is connected to the corresponding second ground terminal. In the above embodiment of the present application, the capacitor C separates a first ground terminal and the corresponding second ground terminal that were originally connected together.

[0109] In another embodiment, taking P>1 as an example, as shown in B in FIG13 , a data splitting submodule 1110 includes P capacitors C connected in series. The first ends of the P capacitors C connected in series are coupled to a second ground terminal of the transmission interface 210, and the second ends of the P capacitors C connected in series are coupled to a first ground terminal of the terminal device. In this case, the impedance of a data splitting submodule 1110 can be the sum of the impedances of the P capacitors. For the second data signal, the impedance of each capacitor is relatively small, so the sum of the impedances of the P capacitors is still relatively small. In this case, the impedance of the data splitting submodule 1110 is still relatively small, so the second data signal can still flow back through the data splitting submodule 1110.

[0110] In another embodiment, taking P>1 as an example, as shown by C in FIG13 , the data splitting submodule 1110 includes P capacitors C connected in parallel. A first end of each capacitor C is coupled to a second ground terminal of the transmission interface 210 , and a second end of each capacitor C is coupled to a first ground terminal of the terminal device.

[0111] Since the total impedance of multiple capacitors connected in parallel is reduced, in this embodiment, the total impedance of the P capacitors connected in parallel is reduced. In other words, when the data splitting submodule includes P capacitors connected in parallel, the impedance of the data splitting submodule is also relatively small. Therefore, the second data signal can still flow back through the data splitting submodule 1110.

[0112] In another embodiment, taking P ≥ 3 as an example, as shown in D in FIG13 , the data splitting submodule 1110 includes P capacitors, including P1 capacitors connected in parallel and the remaining (P-P1) capacitors connected in series, and the first end of the P1 capacitors C connected in parallel is coupled to the first end of the (P-P1) capacitors C connected in series. The second end of the P1 capacitors connected in parallel is coupled to a second ground terminal of the transmission interface 210, and the second end of the (P-P1) capacitors C connected in series is coupled to a first ground terminal of the terminal device.

[0113] In this embodiment, the total impedance of the P1 parallel capacitors is relatively low, as is the total impedance of the (P-P1) series capacitors. Therefore, the impedance of the data splitting submodule, which includes the P1 parallel capacitors and the (P-P1) series capacitors, is also relatively low. Therefore, the second data signal can still flow back through the data splitting submodule 1110.

[0114] In actual application, the specific structure of the data diversion submodule, the type of capacitor in the data diversion submodule, and the number of data diversion submodules in the data diversion submodule can be determined according to the frequency of the second data signal.

[0115] Optionally, the data diversion submodule may include P capacitors and W resistors, and the P capacitors and the W resistors are connected in series. Wherein, W is a positive integer. That is to say, each first ground terminal is coupled to the corresponding second ground terminal through P capacitors and W resistors. At this time, the P capacitors and W resistors can be equivalent to a filter, thereby filtering out the noise signal within 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, as well as the model of the capacitor, is related to the frequency of the noise signal. The following introduces the possible connection structure of the P capacitors and W resistors included in the data diversion submodule.

[0116] In one embodiment, taking P=1 and W=1 as an example, in combination with A in FIG13 , as shown in A in FIG14 , the data shunt submodule 1110 includes a capacitor C and a resistor R, and the first end of the capacitor C is coupled to the first end of the resistor R (i.e., the capacitor C and the resistor R are connected in series). The second end of the capacitor C is coupled to a second ground terminal of the transmission interface 210, and the second end 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 small, and at this time, the impedance of the resistor is also small. In other words, the impedance of the data shunt module composed of one capacitor and one resistor is small, so that data signals with higher frequencies can flow back through the data shunt submodule 1110.

[0117] In another embodiment, taking P=1 and W>1 as an example, in combination with A in FIG13 , as shown in B in FIG14 , the data splitting submodule 1110 includes a capacitor C and W resistors R connected in series, and the first end of the capacitor C is coupled to the first end of the W resistors R connected in series (i.e., the capacitor C is connected in series with the W resistors R). The second end of the capacitor C is coupled to a second ground terminal of the transmission interface 210, and the second ends of the W resistors connected in series are coupled to a first ground terminal of the terminal device.

[0118] Of course, in some embodiments, when W=1 and P>1, the connection relationship between the P capacitors can refer to the connection relationship in B of Figure 13 above. The connection relationship between one resistor and the P capacitors can refer to B of Figure 14 and the connection relationship in B of Figure 13. The connection relationship between the capacitors and resistors when W=1 and P>1 is not further described in the embodiments of the present application.

[0119] Alternatively, in some other embodiments, W=P, and both W and P are positive integers greater than 1. W resistors are connected in series, and P capacitors are connected in series.

[0120] In this embodiment, the impedance of a data splitting submodule 1110 may be the sum of the impedances of P capacitors and W resistors. Since the impedance of each capacitor and each resistor is relatively small, the impedance of the data splitting submodule consisting of P capacitors and W resistors in series is relatively small, thereby providing a return path for the second data signal.

[0121] In another embodiment, taking P=1 and W>1 as an example, in combination with A in FIG13 , as shown in C in FIG14 , the data splitting submodule 1110 includes a capacitor C and W resistors R connected in parallel, with the first end of the capacitor C coupled to the first end of each resistor R (i.e., the capacitor C is connected in series with the W parallel resistors R). The second end of the capacitor C is coupled to a second ground terminal of the transmission interface 210, and the second end of each resistor is coupled to a first ground terminal of the terminal device.

[0122] Of course, in some embodiments, when W=1 and P>1, the connection relationship between the P capacitors can refer to the connection relationship in C in Figure 13 above. The connection relationship between one resistor and the P capacitors can also refer to C in Figure 14 and the connection relationship in C in Figure 13. The connection relationship between the capacitors and resistors when W=1 and P>1 is not further described in the embodiments of the present application.

[0123] Alternatively, in some other embodiments, W=P, and both W and P are positive integers greater than 1. Here, 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; or, W resistors are connected in series, and P capacitors are connected in parallel.

[0124] In another embodiment, taking P=1 and W≥3 as an example, in combination with A in FIG13 , as shown in D in FIG14 , the data splitting submodule 1110 includes a capacitor and W resistors R, and the first end of the capacitor C is coupled to the first ends of the W resistors R (i.e., the capacitor C and the W resistors R are connected in series). The second end of the capacitor C is coupled to a second ground terminal of the transmission interface 210, and the second ends of the W resistors R are coupled to a first ground terminal of the terminal device.

[0125] The W resistors include W1 resistors connected in series and (W-W1) resistors connected in parallel, and the first end of the W1 resistor connected in series is coupled to the first end of the (W-W1) resistors connected in parallel. The second end of the W1 resistor connected in series is coupled to the first end of the capacitor C, that is, the second end of the W1 resistor connected in series is the first end of the W resistors. The second end of the (W-W1) resistors connected in parallel is coupled to a ground terminal of the terminal device, that is, the second end of the (W-W1) resistors connected in parallel is the second end of the W resistors.

[0126] Of course, in some embodiments, when W = 1 and P ≥ 3, the connection relationship of the P capacitors can refer to the connection relationship in D in Figure 13 above. The connection relationship between 1 resistor and P capacitors can refer to D in Figure 14 and the connection relationship in D in Figure 13. The connection relationship between the capacitors and resistors when W = 1 and P ≥ 3 is not further described in the embodiments of the present application.

[0127] Alternatively, in some other embodiments, W=P, and both W and P are positive integers greater than 1. The connection relationship of the W resistors can refer to the connection structure in D of FIG14 , and the connection relationship of the P capacitors can refer to the connection structure in D of FIG13 .

[0128] In actual application, the specific structure of the data diversion submodule, the type of capacitors and resistors in the data diversion submodule, and the number of data diversion submodules in the data diversion submodule can be determined according to the frequency of the second data signal.

[0129] Optionally, the data shunt submodule may include P capacitors and Q inductors, where Q is a positive integer. That is, each first ground terminal is coupled to the corresponding second ground terminal through P capacitors and Q inductors. At this time, the P capacitors and W resistors can also be equivalent to a filter, thereby filtering out the noise signal within the second frequency range in the second data signal. The second frequency range here is different from the frequency range in which the electromagnetic noise is located. That is to say, if the frequency of the noise signal in the second data signal is large, a data shunt submodule including P capacitors and Q inductors can be selected.

[0130] It should be noted that when the frequency is greater than the resonant frequency of the inductor, the impedance of the inductor decreases as the frequency increases. Therefore, to ensure that the impedance of the M data shunt modules is less than the impedance of the M magnetic bead modules, the inductor can be selected to have a smaller inductance value, and / or the resonant frequency of the inductor can be outside the frequency range of the second data signal and less than the frequency of the second data signal. The following describes possible connection structures of the P capacitors and Q inductors included in the data shunt sub-module.

[0131] In one embodiment, taking P=1 and Q=1 as an example, in combination with A in FIG13 , as shown in A in FIG15 , the data splitting submodule 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 and the inductor L are connected in series). The second end of the capacitor C is coupled to a second ground terminal of the transmission interface 210, and the second end of the inductor L is coupled to a first ground terminal of the terminal device.

[0132] In another embodiment, taking P=1 and Q>1 as an example, in combination with FIG13A , as shown in FIG15B , the data splitting submodule 1110 includes a capacitor C and Q inductors L connected in series, with the first end of the capacitor C coupled to the first ends of the Q inductors L connected in series (i.e., the capacitor C is connected in series with the Q inductors L). The second end of the capacitor C is coupled to a second ground terminal of the transmission interface 210 , and the second ends of the Q inductors L connected in series are coupled to a first ground terminal of the terminal device.

[0133] Of course, when Q = 1 and P > 1, the connection relationship between the P capacitors can refer to the connection relationship in B in Figure 13 above. The connection relationship between one inductor and P capacitors can refer to B in Figure 14 and the connection relationship in B in Figure 13. The connection relationship between the capacitor and the inductor when Q = 1 and P > 1 is not further described in this embodiment of the application.

[0134] Alternatively, in some other embodiments, Q=P, and both Q and P are positive integers greater than 1. Q inductors are connected in series, and P capacitors are connected in series.

[0135] In another embodiment, taking P=1 and Q>1 as an example, in combination with A in FIG13 , as shown in C in FIG15 , the data splitting submodule 1110 includes a capacitor C and Q inductors L connected in parallel, with the first end of the capacitor C coupled to the first end of each inductor L (i.e., the capacitor C is connected in series with the Q parallel inductors L). The second end of the capacitor C is coupled to a second ground terminal of the transmission interface 210, and the second end of each inductor is coupled to a first ground terminal of the terminal device.

[0136] Of course, when Q = 1 and P > 1, the connection relationship between the P capacitors can refer to the connection relationship in C in Figure 13 above. The connection relationship between one inductor and P capacitors can also refer to C in Figure 15 and the connection relationship in C in Figure 13. In this embodiment of the application, the connection relationship between the capacitor and the inductor when Q = 1 and P > 1 is not further described.

[0137] Alternatively, in some other embodiments, Q=P, and both Q and P are positive integers greater than 1. Here, 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; or, Q inductors are connected in series, and P capacitors are connected in parallel.

[0138] In another embodiment, taking P=1 and Q≥3 as an example, in combination with A in FIG13 , as shown in D in FIG15 , the data splitting submodule 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 further coupled to a second ground terminal of the transmission interface 210, and the Q inductors L are further coupled to a first ground terminal of the terminal device.

[0139] The Q inductors include Q1 inductors connected in parallel and (Q-Q1) inductors connected in series, and the first end of the Q1 inductors connected in parallel is coupled to the first end of the (Q-Q1) inductors connected in series. The second end of the Q1 inductors connected in parallel is coupled to the first end of the capacitor C. The second end of the (Q-Q1) inductors connected in series is coupled to a ground terminal of the terminal device.

[0140] Of course, when Q = 1 and P ≥ 3, the connection relationship of the P capacitors can refer to the connection relationship in D in Figure 13 above. The connection relationship between 1 inductor and P capacitors can refer to D in Figure 15 and the connection relationship in D in Figure 13. The embodiment of the present application does not further describe the connection relationship between the capacitor and the inductor when Q = 1 and P ≥ 3.

[0141] Alternatively, in some other embodiments, Q=P, and both Q and P are positive integers greater than 1. The connection relationship of the Q inductors can refer to the connection structure in D in FIG15 , and the connection relationship of the P capacitors can refer to the connection structure in D in FIG13 .

[0142] In actual application, the specific structure of the data diversion submodule, the type of capacitors and inductors in the data diversion submodule, and the number of data diversion submodules in the data diversion submodule can be determined according to the frequency of the second data signal.

[0143] Optionally, the data splitting submodule may include P capacitors, W resistors, and Q inductors connected in series. The connection structure of the P capacitors, W resistors, and Q inductors may refer to any combination of the above embodiments.

[0144] In one embodiment, taking the data splitter module including a capacitor as an example: W resistors are connected in series, and Q inductors are connected in series; or, W resistors are connected in series, and Q inductors are connected in parallel; or, W resistors are connected in series, and some of the Q inductors are connected in parallel and then connected in series with the remaining inductors.

[0145] In another embodiment, taking the data splitter module including a capacitor as an example: 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, W resistors are connected in parallel, and some of the Q inductors are connected in parallel and then in series with the remaining inductors.

[0146] In another embodiment, taking the data splitter module including a capacitor as an example: some of the W resistors are connected in parallel and then connected in series with the remaining resistors, and Q inductors are connected in series; or, some of the W resistors are connected in parallel and then connected in series with the remaining resistors, and Q inductors are connected in parallel; or, some of the W resistors are connected in parallel and then connected in series with the remaining resistors, and some of the Q inductors are connected in parallel and then connected in series with the remaining inductors.

[0147] It should be noted that when the data splitter module includes P capacitors, W resistors and Q inductors connected in series, the above embodiment only introduces the structure of the data splitter module by way of example, but the structure of the data splitter module is not limited to the structure in the above embodiment.

[0148] As can be seen from the above, the data splitting submodule in the embodiment of the present application is composed of a capacitor, a capacitor and a resistor, a capacitor and an inductor, or a capacitor, an inductor, and a resistor. The above description of the data splitting submodule is only an exemplary introduction, and does not limit the structure of the data splitting submodule to only the above structure.

[0149] 16 , taking the transmission of the second data signal by the terminal device as an example, simulation results of the terminal device involved in the embodiment of the present application and the terminal device in the prior art are compared.

[0150] As shown in FIG16 , compared to the terminal devices in the prior art, the two terminal devices involved in the embodiment of the present application (including the magnetic bead module, including the magnetic bead module and the data shunt module) have basically the same ability to suppress electromagnetic noise in the low-frequency region (see the portion of block diagram 1), and can suppress electromagnetic noise of about 4 decibels. Compared to the terminal devices in the prior art, the two terminal devices involved in the embodiment of the present application will cause insertion loss to the second data signal in the high-frequency region (see the portion of block diagram 2). However, compared to the first terminal device involved in the embodiment of the present application (including the magnetic bead module), the second terminal device involved in the embodiment of the present application (including the magnetic bead module and the data shunt module) causes less insertion loss to the second data signal in the high-frequency region.

[0151] Thus, it can be seen that the two terminal devices involved in the embodiments of the present application can suppress lower-frequency electromagnetic noise, thereby reducing electromagnetic radiation when data is transmitted via the cable between terminal devices connected by the cable. At the same time, when a higher-frequency data signal (i.e., the second data signal) is transmitted via the cable between the terminal devices, the terminal device including both the magnetic bead module and the data shunt module has a low insertion loss for the higher-frequency data signal, thereby ensuring the signal quality of the higher-frequency data signal.

[0152] Furthermore, in combination with Figures 17 and 18, taking the terminal device transmitting the second data signal as an example, the results of the RE test of the terminal device involved in the embodiment of the present application and the terminal device in the prior art are compared.

[0153] Figure 17 shows a schematic diagram of the results of an RE test on a conventional terminal device. The test results show that for electromagnetic noise around 52.5139 MHz, the detection margin is -0.07 dB. This means that conventional terminal devices are unable to suppress electromagnetic noise around 50 MHz.

[0154] When the detection margin is a positive value, it indicates that the measured value of the noise (which may be referred to as the noise value) is less than the noise limit value. When the detection margin is a negative value, it indicates that the measured value of the noise is greater than the noise limit value.

[0155] Figure 18, A, shows the results of an RE test on the first terminal device according to an embodiment of the present application. The test results show that the detection margin for electromagnetic noise around 52.3057 MHz is 8.56 dB. In other words, the first terminal device according to an embodiment of the present application has a suppression capability of approximately 8.56 dB for electromagnetic noise around 50 MHz. This represents an improvement of approximately 8 dB compared to conventional terminal devices.

[0156] Figure 18B shows a schematic diagram of the results of an RE test on the second terminal device involved in the embodiment of the present application. The test results show that the detection margin for electromagnetic noise around 52.9683 MHz is 8.26 dB. In other words, the second terminal device involved in the embodiment of the present application has a suppression capability of approximately 8.26 dB for electromagnetic noise around 50 MHz. This is an improvement of approximately 8 dB compared to terminal devices in the prior art and is essentially consistent with the electromagnetic noise suppression capability of the first terminal device in the embodiment of the present application.

[0157] In summary, the two terminals involved in the embodiments of the present application can effectively suppress electromagnetic noise with lower frequencies.

[0158] Furthermore, in combination with Figures 19 and 20, taking the terminal device transmitting the second data signal as an example, the eye diagram results of the terminal device involved in the embodiment of the present application and the terminal device in the prior art are observed by an oscilloscope and compared.

[0159] As shown in FIG19 , the far-end eye height in the eye diagram test results of a terminal device in the prior art is 140 mV. As shown in FIG20A , the far-end eye height in the eye diagram test results of the first terminal device (including the ferrite bead module) involved in the embodiment of the present application is 125 mV. As shown in FIG20B , the far-end eye height in the eye diagram test results of the second terminal device (including the ferrite bead module and the data diversion module) involved in the embodiment of the present application is 137 mV.

[0160] The far-end eye height in the eye diagram can be used to indicate signal quality, and the higher the far-end eye height (ie, the larger the value of the far-end eye height), the better the signal quality.

[0161] By comparing the values ​​of the far-end eye height in A in Figures 19 and 20 , it can be seen that the first terminal device involved in the embodiment of the present application has a poor reflux capability for the second data signal. By comparing the values ​​of the far-end eye height in B in Figures 19 and 20 , it can be seen that the second terminal device involved in the embodiment of the present application has a strong reflux capability for the second data signal, which can ensure normal transmission of the second data signal.

[0162] In summary, the terminal device provided in the embodiment of the present application is connected to another terminal device via a cable, and when a data signal is transmitted via the cable, the electromagnetic noise generated by the terminal device can be prevented from radiating outward through the cable connecting the two terminal devices, thereby causing electromagnetic interference to other surrounding devices, and the terminal device can meet the relevant standards. In addition, the noise reduction circuit in the embodiment of the present application is composed of some basic electronic components and has a low cost. Compared with the prior art that uses more expensive electrical connection auxiliary materials (such as conductive foam, absorbing materials, etc.) to filter out electromagnetic noise, this greatly reduces the cost of the terminal device.

[0163] In the several embodiments provided in this application, it should be understood that the disclosed circuits and devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules is merely a logical function division. In actual implementation, there may be other division methods, such as multiple modules or components can be combined or integrated into another device, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0164] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located on a single device or distributed across multiple devices. Some or all of the modules may be selected to achieve the purpose of this embodiment based on actual needs.

[0165] In addition, the functional modules in the various embodiments of the present application may be integrated into one device, or each module may exist physically separately, or two or more modules may be integrated into one device.

[0166] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A terminal device, characterized in that: The terminal device includes M first ground terminals, a transmission interface and a noise reduction circuit, the transmission interface includes M second ground terminals, the noise reduction circuit includes M magnetic bead modules, each of the magnetic bead modules includes a magnetic bead; the M first ground terminals are respectively coupled to the M second ground terminals through the M magnetic bead modules; M is a positive integer.

2. The terminal device according to claim 1, characterized in that: Each of the magnetic bead modules includes L magnetic beads, where L is a positive integer; when L is greater than 1, the L magnetic beads are connected in series; or, the L magnetic beads are connected in parallel; or, some of the L magnetic beads are connected in parallel and then connected in series with the remaining beads.

3. The terminal device according to claim 1 or 2, characterized in that: The noise reduction circuit also includes M data diversion modules, which are 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, the impedance of the M data diversion modules is respectively less than the impedance of the M magnetic bead modules.

4. The terminal device according to claim 3, characterized in that: Each of the data distribution modules includes Y data distribution sub-modules, where Y is a positive integer; when Y is greater than 1, the Y data distribution sub-modules are connected in parallel.

5. The terminal device according to claim 4, characterized in that: Each of the data splitting submodules includes P capacitors, where P is a positive integer; when P is greater than 1, the P capacitors are connected in series; or, the P capacitors are connected in parallel; Alternatively, some of the P capacitors are connected in parallel and then connected in series with the remaining capacitors.

6. The terminal device according to claim 5, characterized in that: Each of the data splitting sub-modules further includes W resistors, where W is a positive integer; The P capacitors are connected in series with the W resistors, and when W is greater than 1, the W resistors are connected in series; or, The P capacitors are connected in series with the W resistors, and when W is greater than 1, the W resistors are connected in parallel; or, The P capacitors are connected in series with the W resistors, and when W is greater than 1, some of the W resistors are connected in parallel and then connected in series with the remaining resistors.

7. The terminal device according to claim 5, characterized in that: Each of the data splitting submodules further includes Q inductors, where Q is a positive integer; The P capacitors are connected in series with the Q inductors, and when Q is greater than 1, the Q inductors are connected in series; or, The P capacitors are connected in series with the Q inductors, and when Q is greater than 1, the Q inductors are connected in parallel; or, The P capacitors are connected in series with the Q inductors, and when Q is greater than 1, some of the Q inductors are connected in parallel and then connected in series with the remaining inductors.

8. The terminal device according to claim 5, characterized in that: Each of the data splitting sub-modules further includes W resistors and Q inductors, where W and Q are positive integers, and the P capacitors, the W resistors, and the Q inductors are connected in series; When W and Q are greater 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 some of the Q inductors are connected in parallel and then connected in series with the remaining inductors; or, When W and Q are greater 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 some of the Q inductors are connected in parallel and then connected in series with the remaining inductors; or, When W and Q are greater than 1, some of the W resistors are connected in parallel and then connected in series with the remaining resistors, and the Q inductors are connected in series; or, some of the W resistors are connected in parallel and then connected in series with the remaining resistors, and the Q inductors are connected in parallel; or, some of the W resistors are connected in parallel and then connected in series with the remaining resistors, and some of the Q inductors are connected in parallel and then connected in series with the remaining inductors.

9. The terminal device according to claim 1 or 2, characterized in that: The frequency of the data signal transmitted by the transmission interface is less than a first threshold.

10. The terminal device according to claim 9, characterized in that: The transmission interface is an interface using the USB 2.0 protocol or a historical version protocol.

11. The terminal device according to claim 5, characterized in that: The frequency of the data signal transmitted by the transmission interface is greater than a second threshold.

12. The terminal device according to claim 11, characterized in that: The transmission interface is at least one of an interface adopting the USB 3.0 protocol or a subsequent version of the protocol, a high-definition multimedia interface, and a display interface.

13. A noise reduction circuit, characterized in that: The noise reduction circuit includes M magnetic bead modules and M data shunt modules, and the M magnetic bead modules are respectively connected in parallel with the M data shunt modules; The first ends of the M magnetic bead modules are used to couple to the ground end of the transmission interface of the terminal device, and the second ends of the M magnetic bead modules are used to couple to the ground end of the terminal device; wherein M is a positive integer.

14. The noise reduction circuit according to claim 13, characterized in that: Each of the magnetic bead modules includes L magnetic beads, where L is a positive integer; when L is greater than 1, the L magnetic beads are connected in series; or, the L magnetic beads are connected in parallel; or, some of the L magnetic beads are connected in parallel and then connected in series with the remaining beads.

15. The noise reduction circuit according to claim 13 or 14, characterized in that: Each of the data distribution modules includes Y data distribution sub-modules, where Y is a positive integer; when Y is greater than 1, the Y data distribution sub-modules are connected in parallel.

16. The noise reduction circuit according to claim 15, characterized in that: Each of the data splitting submodules includes P capacitors, where P is a positive integer; when P is greater than 1, the P capacitors are connected in series; or, the P capacitors are connected in parallel; Alternatively, some of the P capacitors are connected in parallel and then connected in series with the remaining capacitors.

17. The noise reduction circuit according to claim 16, characterized in that: Each of the data splitting sub-modules further includes W resistors, where W is a positive integer; The P capacitors are connected in series with the W resistors, and when W is greater than 1, the W resistors are connected in series; or, The P capacitors are connected in series with the W resistors, and when W is greater than 1, the W resistors are connected in parallel; or, The P capacitors are connected in series with the W resistors, and when W is greater than 1, some of the W resistors are connected in parallel and then connected in series with the remaining resistors.

18. The noise reduction circuit according to claim 16, characterized in that: Each of the data splitting submodules further includes Q inductors, where Q is a positive integer; The P capacitors are connected in series with the Q inductors, and when Q is greater than 1, the Q inductors are connected in series; or, The P capacitors are connected in series with the Q inductors, and when Q is greater than 1, the Q inductors are connected in parallel; or, The P capacitors are connected in series with the Q inductors, and when Q is greater than 1, some of the Q inductors are connected in parallel and then connected in series with the remaining inductors.

19. The noise reduction circuit according to claim 16, characterized in that: Each of the data splitting sub-modules further includes W resistors and Q inductors, where W and Q are positive integers, and the P capacitors, the W resistors, and the Q inductors are connected in series; When W and Q are greater 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 some of the Q inductors are connected in parallel and then connected in series with the remaining inductors; or, When W and Q are greater 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 some of the Q inductors are connected in parallel and then connected in series with the remaining inductors; or, When W and Q are greater than 1, some of the W resistors are connected in parallel and then connected in series with the remaining resistors, and the Q inductors are connected in series; or, some of the W resistors are connected in parallel and then connected in series with the remaining resistors, and the Q inductors are connected in parallel; or, some of the W resistors are connected in parallel and then connected in series with the remaining resistors, and some of the Q inductors are connected in parallel and then connected in series with the remaining inductors.

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