USB3.0 composite filter circuit and electronic product
By setting up a balanced dual-line filter and a common-mode filter in parallel on the USB 3.0 interface, and connecting ferrite beads in parallel across the common-mode filter, the filtering frequency band is extended, the problem of excessive EMC noise is solved, and a wider range of noise suppression effects are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2026-03-24
AI Technical Summary
In existing USB 3.0 filtering solutions, the common-mode inductor has a limited filtering frequency band, resulting in excessive EMC noise and failing to effectively solve noise problems in other frequency bands.
Set up transmit and receive differential pair transmission ports on the USB 3.0 interface, connect the first and second balanced dual-line filters and the common-mode filter in parallel, and connect ferrite beads in parallel across the common-mode filter to enhance the filtering range to hundreds of kHz to 2.5 GHz.
This achieved a reduction in EMC noise values across all test frequency bands during radiation testing, meeting EMC noise requirements.
Smart Images
Figure CN224037335U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to electromagnetic compatibility radiation emission technical field more specifically, relate to a kind of composite filter circuit and electronic product of USB3.0. BACKGROUND
[0002] At present, computer peripheral equipment, storage device, audio and video playback equipment etc. will not meet the speed transmission of USB2.0 due to the increase of data volume, so more and more electronic products will use the transmission mode of USB3.0, and some new cars will also use the transmission mode of USB3.0, so that the car can read the high-definition video, lossless file etc. in U disk more quickly.
[0003] In the prior art, the USB3.0 filtering scheme generally connects a common mode inductor to the transmission line of USB3.0, and the filtering frequency band of the common mode inductor is limited, generally about 100MHz, and the EMC noise of the remaining frequency band cannot be solved, so a composite filter circuit for reducing EMC noise of USB3.0 is needed. UTILITY MODEL CONTENT
[0004] The technical problem to be solved by the utility model is EMC noise exceeding the standard, and the utility model provides a composite filter circuit for USB3.0 and an electronic product to solve the above-mentioned defects of the prior art.
[0005] The utility model solves the technical problem by adopting the following technical scheme:
[0006] On the one hand
[0007] A composite filter circuit for USB3.0 comprises a USB3.0 interface, a transmitting differential pair transmission port and a receiving differential pair transmission port are arranged on the USB3.0 interface, a first balanced double-line filter, a common mode filter and a second balanced double-line filter are sequentially connected to the transmitting differential pair transmission port and the receiving differential pair transmission port from near to far, and a magnetic bead is connected in parallel to the positive input pin and the negative input pin of the common mode filter.
[0008] Preferably, the transmitting differential pair transmission port comprises a TX+ pin and a TX- pin.
[0009] The TX+ pin and the TX- pin are connected with the positive input pin and the negative input pin of the corresponding first balanced twin-lead filter respectively, the positive output pin and the negative output pin of the first balanced twin-lead filter are grounded, the positive input pin and the negative input pin of the first balanced twin-lead filter corresponding to the transmitting differential pair transmission port are connected with the positive input pin and the negative input pin of the corresponding common mode filter, the output pins of the two magnetic beads corresponding to the common mode filter are connected with the positive input pin and the negative input pin of the corresponding second balanced twin-lead filter, and the positive output pin and the negative output pin of the second balanced twin-lead filter are grounded.
[0010] Preferably, the receiving differential pair transmission port comprises an RX+ pin and an RX- pin.
[0011] The RX+ pin and the RX- pin are connected with the positive input pin and the negative input pin of the corresponding first balanced twin-lead filter respectively, the positive output pin and the negative output pin of the first balanced twin-lead filter are grounded, the positive input pin and the negative input pin of the first balanced twin-lead filter corresponding to the receiving differential pair transmission port are connected with the positive input pin and the negative input pin of the corresponding common mode filter, the output pins of the two magnetic beads corresponding to the common mode filter are connected with the positive input pin and the negative input pin of the corresponding second balanced twin-lead filter, and the positive output pin and the negative output pin of the second balanced twin-lead filter are grounded.
[0012] Preferably, the USB3.0 interface is provided with a D+ pin and a D- pin.
[0013] The D+ pin and the D- pin are connected with the positive input pin and the negative input pin of the corresponding first balanced twin-lead filter respectively, the positive output pin and the negative output pin of the first balanced twin-lead filter are grounded, the pins of the first balanced twin-lead filter corresponding to the D+ pin and the D- pin are connected with the positive output pin and the negative output pin of the corresponding common mode filter, the output pins of the two magnetic beads corresponding to the common mode filter are connected with the positive input pin and the negative input pin of the corresponding second balanced twin-lead filter, and the positive output pin and the negative output pin of the second balanced twin-lead filter are grounded.
[0014] Preferably, the USB3.0 interface is provided with a VCC pin and a GND pin.
[0015] The VCC pin and the GND pin are connected with positive input pins and negative input pins of a corresponding first balanced twin-lead filter respectively, positive output pins and negative output pins of the first balanced twin-lead filter are grounded, pins of the first balanced twin-lead filter corresponding to the VCC pin and the GND pin are connected with positive output pins and negative output pins of a corresponding common mode filter, output pins of two magnetic beads corresponding to the common mode filter are connected with positive input pins and negative input pins of a corresponding second balanced twin-lead filter, and positive output pins and negative output pins of the second balanced twin-lead filter are grounded.
[0016] Preferably, the first balanced twin-lead filter is used for filtering noise in a frequency band of 30MHz-1GHz.
[0017] Preferably, the common mode filter is used for filtering noise in a frequency band of 50MHz-200MHz.
[0018] Preferably, the magnetic bead is used for filtering noise in a frequency band of 1GHz-3GHz.
[0019] Preferably, the second balanced twin-lead filter is used for filtering noise in a frequency band of 0.15MHz-30MHz.
[0020] Another aspect
[0021] An electronic product is provided with any one of the composite filter circuits.
[0022] The utility model discloses the beneficial effect lies in: on the basis of common mode filter, parallel two magnetic beads in common mode filter both ends, parallel first balanced twin-lead filter and second balanced twin-lead filter close to chip and close to port, thereby making common mode filter from the original filter range dozens of MHz to 200MHz change into hundreds of KHz to 2.5GHz, make in radiation test, all test frequency band EMC noise value is at the lower value. BRIEF DESCRIPTION OF DRAWINGS
[0023] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the present application will be further described below with reference to the drawings and embodiments, and the drawings in the following description are only part of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings:
[0024] Figure 1 It is a schematic diagram of the composite filter of the embodiment of the present application in the specific access circuit.
[0025] Figure 2 It is a schematic diagram of the composition structure of the filter circuit of the embodiment of the present application.
[0026] Figure 3 is the X2Y electrical schematic diagram with structural features of the balanced dual-line filter BDL of the embodiment of the present application.
[0027] Figure 4 is the X2Y electrical schematic diagram with structural features of the balanced dual-line filter BDL of the embodiment of the present application. DETAILED DESCRIPTION
[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the following will make a clear and complete description of the technical scheme in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.
[0029] Embodiment 1
[0030] The embodiment of the present application discloses a composite filter circuit of USB3.0, referring to Figure 1 and Figure 2 The composite filter circuit of USB3.0 includes a USB3.0 interface, and a sending differential pair transmission port, a receiving differential pair transmission port, a D+ pin, a D- pin, a VCC pin and a GND pin are arranged on the USB3.0 interface; a first balanced dual-line filter, a common-mode filter and a second balanced dual-line filter are sequentially connected from near to far on the sending differential pair transmission port, the receiving differential pair transmission port, the D+ pin, the D- pin, the VCC pin and the GND pin, and magnetic beads are connected in parallel on the positive input pin and the negative input pin of the common-mode filter. The two pins of the first balanced dual-line filter and the second balanced dual-line filter are both grounded.
[0031] The working voltage on the VCC pin is generally 5V. A shielding layer Shield is further arranged on the USB3.0 interface.
[0032] The sending differential pair transmission port includes a TX+ pin and a TX- pin, the TX+ pin and the TX- pin are respectively connected with the positive input pin and the negative input pin of the corresponding first balanced dual-line filter BDL1, the positive output pin and the negative output pin of the first balanced dual-line filter BDL1 are both grounded, the positive input pin and the negative input pin of the first balanced dual-line filter BDL1 corresponding to the sending differential pair transmission port are connected with the positive input pin and the negative input pin of the corresponding common-mode filter L1, the output pins of the two magnetic beads corresponding to the corresponding common-mode filter L1 are connected with the positive input pin and the negative input pin of the corresponding second balanced dual-line filter BDL2, and the positive output pin and the negative output pin of the second balanced dual-line filter BDL2 are both grounded.
[0033] The VCC pin and the GND pin are connected to the positive input pin and the negative input pin of the corresponding balanced double-line first balanced double-line filter BDL3 respectively, the positive output pin and the negative output pin of the first balanced double-line filter BDL3 are grounded, the positive input pin and the negative input pin of the balanced double-line first balanced double-line filter BDL3 corresponding to the balanced double-line VCC pin and the balanced double-line GND pin are connected to the positive input pin and the negative input pin of the corresponding common-mode filter L2, the output pins of the two magnetic beads corresponding to the corresponding balanced double-line common-mode filter L2 are connected to the positive input pin and the negative input pin of the corresponding second balanced double-line filter BDL4, and the positive output pin and the negative output pin of the second balanced double-line filter BDL4 are grounded.
[0034] The D+ pin and the D- pin are a pair of differential data transmission ports, the D+ pin and the balanced double-line D- pin are connected to the positive input pin and the negative input pin of the corresponding balanced double-line first balanced double-line filter BDL5 respectively, the positive output pin and the negative output pin of the first balanced double-line filter BDL5 are grounded, the positive input pin and the negative input pin of the balanced double-line first balanced double-line filter BDL5 corresponding to the balanced double-line D+ pin and the balanced double-line D- pin are connected to the positive input pin and the negative input pin of the corresponding common-mode filter L3, the output pins of the two magnetic beads corresponding to the corresponding balanced double-line common-mode filter L3 are connected to the positive input pin and the negative input pin of the corresponding second balanced double-line filter BDL6, and the positive output pin and the negative output pin of the second balanced double-line filter BDL6 are grounded.
[0035] The receiving differential pair transmission port includes an RX+ pin and an RX- pin, the RX+ pin and the RX- pin are connected to the positive input pin and the negative input pin of the corresponding first balanced double-line filter BDL7 respectively, the positive output pin and the negative output pin of the first balanced double-line filter BDL7 are grounded, the positive input pin and the negative input pin of the first balanced double-line filter BDL7 corresponding to the receiving differential pair transmission port are connected to the positive input pin and the negative input pin of the corresponding common-mode filter L4, the output pins of the two magnetic beads corresponding to the corresponding common-mode filter L4 are connected to the positive input pin and the negative input pin of the corresponding second balanced double-line filter BDL8, and the positive output pin and the negative output pin of the second balanced double-line filter BDL8 are grounded.
[0036] The first balanced twin filter is used for low-frequency band filtering of 30MHz-1GHz frequency band noise. The common mode filter is used for filtering 50MHz-200MHz frequency band noise, and filters out common mode noise. The balanced twin magnetic bead is used for filtering 1GHz-3GHz frequency band noise, and has low impedance in other frequency bands, thereby filtering out noise above 1G. The second balanced twin filter is used for filtering 0.15MHz-30MHz frequency band noise.
[0037] With reference to Figure 3 and Figure 4 The X2Y electric principle of the balanced twin filter relates to using an X2Y capacitor to realize the filtering function. The X2Y capacitor is a three-terminal capacitor, has two input terminals Cy and one output terminal Cx, and forms a low-impedance path by connecting the two input terminals to the output terminal, guides common mode noise to the ground, and thereby suppresses common mode noise. Meanwhile, the X2Y capacitor forms a differential filter through the two capacitors inside the X2Y capacitor, and thereby suppresses differential mode noise.
[0038] Embodiment 2
[0039] An electronic product is provided with the USB3.0 composite filter circuit described in Embodiment 1.
[0040] The implementation principle of the USB3.0 composite filter circuit according to the embodiment is that two sharp magnetic beads FB are connected in parallel at both ends of the common mode filter L, and two balanced twin filters BDL are connected in parallel near the chip and near the port, so that the common mode filter L changes from the original filtering range of tens of MHz to 200MHz to hundreds of KHz to 2.5GHz, and when the radiation test is performed, all test frequency band EMC noise values are at a low value.
[0041] It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the utility model.
Claims
1. A USB3.0 composite filter circuit comprising a USB3.0 interface, characterized in that, The USB3.0 interface is provided with a sending differential pair transmission port and a receiving differential pair transmission port, the sending differential pair transmission port and the receiving differential pair transmission port are sequentially connected with a first balanced double-line filter, a common-mode filter and a second balanced double-line filter from near to far, and the positive input pin and the negative input pin of the common-mode filter are both connected with a magnetic bead in parallel.
2. The USB3.0 composite filter circuit of claim 1, wherein, The sending differential pair transmission port comprises a TX+ pin and a TX- pin; The TX+ pin and the TX- pin are respectively connected with the positive input pin and the negative input pin of the corresponding first balanced double-line filter, the positive output pin and the negative output pin of the first balanced double-line filter are both grounded, the positive input pin and the negative input pin of the first balanced double-line filter corresponding to the sending differential pair transmission port are connected with the positive input pin and the negative input pin of the corresponding common-mode filter, the output pins of the two magnetic beads corresponding to the common-mode filter are connected with the positive input pin and the negative input pin of the corresponding second balanced double-line filter, and the positive output pin and the negative output pin of the second balanced double-line filter are both grounded.
3. The USB3.0 composite filter circuit of claim 1, wherein, The receiving differential pair transmission port comprises an RX+ pin and an RX- pin; The RX+ pin and the RX- pin are respectively connected with the positive input pin and the negative input pin of the corresponding first balanced double-line filter, the positive output pin and the negative output pin of the first balanced double-line filter are both grounded, the positive input pin and the negative input pin of the first balanced double-line filter corresponding to the receiving differential pair transmission port are connected with the positive input pin and the negative input pin of the corresponding common-mode filter, the output pins of the two magnetic beads corresponding to the common-mode filter are connected with the positive input pin and the negative input pin of the corresponding second balanced double-line filter, and the positive output pin and the negative output pin of the second balanced double-line filter are both grounded.
4. The USB3.0 composite filter circuit of claim 1, wherein, The USB3.0 interface is provided with a D+ pin and a D- pin; The D+ pin and the D- pin are respectively connected with the positive input pin and the negative input pin of the corresponding first balanced double-line filter, the positive output pin and the negative output pin of the first balanced double-line filter are both grounded, the pins of the first balanced double-line filter corresponding to the D+ pin and the D- pin are connected with the positive output pin and the negative output pin of the corresponding common-mode filter, the output pins of the two magnetic beads corresponding to the common-mode filter are connected with the positive input pin and the negative input pin of the corresponding second balanced double-line filter, and the positive output pin and the negative output pin of the second balanced double-line filter are both grounded.
5. The USB3.0 composite filter circuit of claim 1, wherein, The USB3.0 interface is provided with a VCC pin and a GND pin; The VCC pin and the GND pin are connected with the positive input pin and the negative input pin of the corresponding first balanced dual-line filter respectively, the positive output pin and the negative output pin of the first balanced dual-line filter are grounded, the pins of the first balanced dual-line filter corresponding to the VCC pin and the GND pin are connected with the positive output pin and the negative output pin of the corresponding common-mode filter, the output pins of the two magnetic beads corresponding to the common-mode filter are connected with the positive input pin and the negative input pin of the corresponding second balanced dual-line filter, and the positive output pin and the negative output pin of the second balanced dual-line filter are grounded.
6. The USB3.0 composite filter circuit of claim 1, wherein, The first balanced dual-line filter is used for filtering noise in the frequency band of 30MHz-1GHz.
7. The USB3.0 composite filter circuit of claim 1, wherein, The common-mode filter is used for filtering noise in the frequency band of 50MHz-200MHz.
8. The USB3.0 composite filter circuit of claim 1, wherein, The magnetic beads are used for filtering noise in the frequency band of 1GHz-3GHz.
9. The USB3.0 composite filter circuit of claim 1, wherein, The second balanced dual-line filter is used for filtering noise in the frequency band of 0.15MHz-30MHz.
10. An electronic product, characterized by comprising: The electronic product is provided with the USB3.0 composite filter circuit as claimed in any one of claims 1-9.