A USB audio filtering circuit, junction box, USB audio system and filtering method

Abstract

This application relates to the field of audio signal processing, specifically a USB audio filtering circuit. The circuit includes a transient voltage suppressor, an LC filter circuit, and an RC filter circuit. The transient voltage suppressor is connected to the power input terminal and is used to initially filter out electrostatic discharge and interference signals from the power supply during the reception of USB audio signals by the audio device. The LC filter circuit is connected between the transient voltage suppressor and the RC filter circuit to filter out high-frequency signals in the interference signal. The RC filter circuit is connected between the LC filter circuit and the cable harness interface to filter out low-frequency signals in the interference signal. This application also relates to a junction box, a USB audio system, and a filtering method. The technical solution provided by this application can improve the anti-interference capability of EFT interference signals from power lines and simplify device interfaces.

Description

Technical Field

[0001] This application relates to the field of audio signal processing technology, and more specifically, to a USB audio filtering circuit, a junction box, a USB audio system, and a filtering method. Background Technology

[0002] With the rapid development of modern electronic technology and integrated circuits, electronic devices are becoming increasingly miniaturized, multifunctional, and intelligent. Various electronic products now feature audio playback capabilities, such as mobile phones, portable multimedia players, laptops, desktop computers, and radios. Currently, mainstream USB audio products typically have multiple input / output interfaces, separating power supply and data transmission using different interfaces, thus separating the power and data cables. While this prevents USB signals from being affected by EFT (Electrical Fast Transient) interference, resulting in signal abnormalities or interruptions, the large number of interfaces leads to complex and messy wiring, lacking simplicity. Therefore, simplifying device interfaces while maintaining the anti-interference capabilities of USB audio products is a pressing issue that needs to be addressed. Summary of the Invention

[0003] The technical problem to be solved by the embodiments of this application is that the related technologies have many device interfaces, many complex and messy wiring, and are not simple enough.

[0004] To address the aforementioned technical problems, this application provides a USB audio filtering circuit, employing the following technical solution:

[0005] Transient voltage suppressor, LC filter circuit and RC filter circuit;

[0006] The transient voltage suppressor is connected to the power input terminal and is used to initially filter out electrostatic discharge and interference signals from the power supply during the process of the audio device receiving USB audio signals.

[0007] The LC filter circuit is connected between the transient voltage suppressor and the RC filter circuit, and is used to filter out high-frequency signals in the interference signal.

[0008] The RC filter circuit is connected between the LC filter circuit and the wiring harness interface to filter out low-frequency signals in the interference signal.

[0009] Furthermore, the transient voltage suppressor includes a TVS diode, the cathode of which is connected to the first power supply pin of the power input terminal and the LC filter circuit, respectively.

[0010] The anode of the TVS diode is connected to the second power supply pin of the power input terminal and the LC filter circuit, respectively.

[0011] Furthermore, the LC filter circuit includes a filter inductor and a first filter capacitor, and the filter inductor is provided with a first inductor pin, a second inductor pin, a third inductor pin, and a fourth inductor pin;

[0012] The fourth inductor pin is connected to the cathode of the TVS diode, the third inductor pin is connected to the anode of the TVS diode, the first inductor pin is connected to one end of the first filter capacitor, and the second inductor pin is connected to the other end of the first filter capacitor.

[0013] The first filter capacitor is connected in parallel across the two ends of the RC filter circuit.

[0014] Furthermore, the first filter capacitor includes a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor, which are connected in parallel.

[0015] Furthermore, the capacitance values ​​of the first capacitor, the second capacitor, the third capacitor, and the fourth capacitor are different.

[0016] Furthermore, the RC filter circuit includes a filter resistor and a second filter capacitor, which are connected in series.

[0017] The first end of the filter resistor is connected to the wire harness interface and one end of the first filter capacitor, respectively, and the second end of the filter resistor is connected to the first end of the second filter capacitor.

[0018] The second terminal of the second filter capacitor is grounded and connected to the other terminal of the first filter capacitor.

[0019] Furthermore, the filter inductor is a common-mode inductor.

[0020] To address the aforementioned technical problems, this application also provides a junction box, employing the technical solution described below:

[0021] The junction box includes the USB audio filtering circuit, power input terminal, communication circuit and wire harness interface as described above, and the filtering circuit is connected between the power input terminal and the wire harness interface;

[0022] The communication circuit is connected to the wiring harness interface and is used to transmit the received USB audio signal to the audio device through the wiring harness interface;

[0023] One end of the wiring harness interface is connected to the filtering circuit and the communication circuit respectively, and the other end of the wiring harness interface is connected to the audio device.

[0024] To address the aforementioned technical problems, this application also provides a USB audio system, which employs the following technical solution:

[0025] The audio system includes, as described above, a junction box, audio equipment, communication equipment, and a power adapter;

[0026] The power input terminal of the junction box is connected to the power adapter, and the communication circuit of the junction box is connected to the communication device.

[0027] The audio device is connected to the junction box via a wiring harness and is used to receive USB audio signals transmitted from the communication circuit.

[0028] To address the aforementioned technical problems, this application also provides a filtering method, employing the technical solution described below:

[0029] The power input terminal of the junction box receives the power signal transmitted through the power adapter and transmits the power signal to the filtering circuit of the junction box.

[0030] The filtering circuit filters out interference signals in the power supply signal;

[0031] The communication circuit of the junction box receives the USB audio signal transmitted through the communication device and sends it to the wiring harness interface of the junction box.

[0032] The junction box's wiring harness interface transmits the USB audio signal to the audio device via the wiring harness.

[0033] Compared with the prior art, the embodiments of this application have the following main advantages:

[0034] The USB audio filtering circuit provided in this application includes a transient voltage suppressor, an LC filter circuit, and an RC filter circuit. The transient voltage suppressor is connected to the power input terminal and is used to initially filter out electrostatic discharge and interference signals from the power supply during the process of the audio device receiving USB audio signals. The LC filter circuit is connected between the transient voltage suppressor and the RC filter circuit and is used to filter out high-frequency signals in the interference signals. The RC filter circuit is connected between the LC filter circuit and the wire harness interface and is used to filter out low-frequency signals in the interference signals. Through the transient voltage suppressor, LC filter circuit, and RC filter circuit of the filtering circuit, this application can further improve the anti-interference capability of the EFT interference signal of the power line.

[0035] The junction box provided in this application combines the power cord and data cable into a bundle before connecting them to the audio device, which simplifies the device interface and makes the device look more concise and aesthetically pleasing. Attached Figure Description

[0036] To more clearly illustrate the solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the USB audio filtering circuit according to an embodiment of this application;

[0038] Figure 2 This is a schematic diagram of the structure of a USB audio system according to an embodiment of this application. Detailed Implementation

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0040] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0041] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0042] This application provides a USB audio filtering circuit; see [link to relevant documentation]. Figure 1 and Figure 2As shown, the filter circuit 11 includes a transient voltage suppressor 111, an LC filter circuit 112, and an RC filter circuit 113. The transient voltage suppressor 111 is connected to the power input terminal DC_IN and is used to initially filter out electrostatic discharge and interference signals from the power supply during the process of the audio device 20 receiving USB audio signals. The LC filter circuit 112 is connected between the transient voltage suppressor 111 and the RC filter circuit 113 and is used to filter out high-frequency signals in the interference signals. The RC filter circuit 113 is connected between the LC filter circuit 112 and the wire harness interface 13 and is used to filter out low-frequency signals in the interference signals.

[0043] In this embodiment, the EFT interference signal is input from the power input terminal DC_IN. The EFT interference signal is filtered out by the transient voltage suppressor 111, the LC filter circuit 112 and the RC filter circuit 113, which can improve the EFT interference caused by the power line.

[0044] EFT (Electrical Fast Transient) refers to a finite number of clearly distinguishable pulse sequences or oscillations of finite duration. Individual pulses within the pulse group have specific repetition periods, voltage amplitudes, rise times, and pulse widths. EFT interference typically occurs in power grids due to the switching processes of numerous mechanical switches (disconnecting inductive loads, relay contact bouncing, etc.). This type of interference is characterized by: clusters of narrow pulses, high pulse repetition frequencies (kHz-MHz), steep rise edges (ns level), short durations of individual pulses (10-100ns level), and amplitudes reaching the kV level. Clusters of narrow pulses can charge the junction capacitance of semiconductor devices; when the energy accumulates to a certain level, it can cause errors in the circuit or equipment. Therefore, it is necessary to filter out EFT interference signals.

[0045] In this embodiment, the transient voltage suppressor 111 includes a TVS (Transient Voltage Suppressor) diode D200. The cathode of the TVS diode D200 is connected to the first power supply pin of the power input terminal DC_IN and the LC filter circuit 112, respectively. The anode of the TVS diode D200 is connected to the second power supply pin of the power input terminal DC_IN and the LC filter circuit 112, respectively.

[0046] TVS diodes have a much faster transient response and surge absorption capacity than ordinary Zener diodes. They can quickly absorb surge pulses and effectively protect circuits from damage caused by surge pulses.

[0047] It should be understood that the power input terminal DC_IN is connected to the power adapter, so that power is transmitted to the power input terminal DC_IN through the power adapter to power the circuit.

[0048] In this embodiment, the LC filter circuit 112 includes a filter inductor L200 and a first filter capacitor. The filter inductor is provided with a first inductor pin 1, a second inductor pin 2, a third inductor pin 3 and a fourth inductor pin 4. The fourth inductor pin 4 is connected to the cathode of the TVS diode D200, the third inductor pin 3 is connected to the anode of the TVS diode D200, the first inductor pin 1 is connected to one end of the first filter capacitor, and the second inductor pin 2 is connected to the other end of the first filter capacitor.

[0049] Common-mode current is one of the factors of conducted interference. The filter inductor L200 can specifically be a common-mode inductor. When a common-mode current flows through the coil of the common-mode inductor, due to the same direction of the common-mode current, a magnetic field in the same direction will be generated in the coil, which will increase the inductive reactance of the coil, making the coil exhibit high impedance and producing a strong damping effect, thereby attenuating the common-mode current and achieving the purpose of filtering.

[0050] It should be noted that the first filter capacitor includes at least two capacitors connected in parallel, each with a different capacitance value, to achieve a better filtering effect. The capacitance value of each capacitor can be selected according to actual needs.

[0051] For details, see Figure 1 The first filter capacitor includes a first capacitor C203, a second capacitor C204, a third capacitor C205, and a fourth capacitor C206, which are connected in parallel.

[0052] In this embodiment, the RC filter circuit 113 includes a filter resistor R206 and a second filter capacitor C207. The filter resistor R206 and the second filter capacitor C207 are connected in series. The first end of the filter resistor R206 is connected to the wire harness interface 13 and one end of the first filter capacitor, respectively. The second end of the filter resistor R206 is connected to the first end of the second filter capacitor C207. The second end of the second filter capacitor C207 is grounded and connected to the other end of the first filter capacitor.

[0053] LC filter circuit 112 is generally used to filter high-frequency interference signals, while RC filter circuit 113 is used to filter low-frequency interference signals, further improving the filtering capability.

[0054] This application also provides a junction box, including the USB audio filtering circuit 11, power input terminal DC_IN, communication circuit 12, and wire harness interface 13 as described above. The filtering circuit 11 is connected between the power input terminal DC_IN and the wire harness interface 13. The communication circuit 12 is connected to the wire harness interface 13 and is used to transmit the received USB audio signal to the audio device 20 through the wire harness interface 13. One end of the wire harness interface 13 is connected to the filtering circuit 11 and the communication circuit 12 respectively, and the other end of the wire harness interface 13 is connected to the audio device 20.

[0055] Specifically, the communication circuit 12 can be a Micro USB.

[0056] The EFT interference signal is loaded from the power grid, and after passing through the power adapter, it is transmitted to the junction box. The filter circuit 11 in the junction box attenuates and filters out the EFT interference signal, so that the EFT interference signal cannot or can only enter the wiring harness in small amounts, thereby reducing the impact on USB communication.

[0057] In this embodiment, the power cord and data cable are combined into a single cable harness via a junction box and then connected to the audio device. This method simplifies the interface and makes the device look cleaner and more aesthetically pleasing.

[0058] This application also provides a USB audio system, including a junction box 10, an audio device 20, a power adapter 30, and a communication device 40 as described above. The power input terminal DC_IN of the junction box 10 is connected to the power adapter 30, the communication circuit 12 of the junction box 10 is connected to the communication device 40, and the audio device 20 is connected to the junction box 10 via a wiring harness to receive USB audio signals transmitted from the communication circuit 12.

[0059] In this embodiment, the audio device 20 is also provided with a wire harness interface 21. The wire harness interface 13 of the splitter box 10 and the wire harness interface 21 of the audio device 20 are connected by a wire harness, so that the audio device 20 can play the USB audio signal received from the communication device 40. The communication device 40 controls the audio device 20 to record via the USB signal.

[0060] Among them, the communication device 40 includes, but is not limited to, computers, tablets and mobile phones, and the audio device 20 can be a USB audio device with a speaker and a microphone.

[0061] This application also provides a filtering method for use with the audio system described above. The filtering method includes the following steps:

[0062] In step S10, the power input terminal DC_IN of the junction box 10 receives the power signal transmitted through the power adapter 30 and transmits the power signal to the filter circuit 11 of the junction box 10.

[0063] Step S20: The filter circuit 11 filters out interference signals in the power supply signal;

[0064] In step S30, the communication circuit 12 of the junction box 10 receives the USB audio signal transmitted through the communication device 40 and sends it to the wiring harness interface 13 of the junction box 10.

[0065] In step S40, the wiring harness interface 13 of the junction box 10 transmits the USB audio signal to the audio device 20 through the wiring harness.

[0066] The junction box 10 simultaneously receives the power signal transmitted through the power adapter 30 and the USB audio signal transmitted through the communication device 40. When there is interference in the power signal, the filtering circuit 11 filters the interference signal, greatly attenuating the strength of the interference signal, so that the interference signal will not directly enter the wiring harness, thereby causing the USB audio signal to be interrupted and communication to be abnormal. At the same time, it can prevent the interference signal from being transmitted to the audio device 20, causing the audio device 20 to malfunction, such as freezing, USB controller malfunction leading to playback or recording function problems, etc.

[0067] In this embodiment, the status of the communication circuit 12 can also be monitored by software. When the status of the communication circuit 12 is abnormal or unresponsive, the software can reset the communication circuit 12, which can further improve EFT interference.

[0068] The communication circuit 12 malfunctions or becomes unresponsive because interference signals may enter it. When interference is present, the communication circuit 12 cannot recognize the USB audio signal, leading to malfunction or unresponsiveness. By monitoring the status of the communication circuit 12 through software, it automatically resets the circuit when malfunctions or becomes unresponsive, re-identifying the USB audio signal and preventing abnormal USB audio signal transmission due to interference.

[0069] It should be noted that the software's monitoring and reset operations on communication circuit 12 will not affect the operation of the filter circuit.

[0070] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A junction box, comprising a USB audio filtering circuit, a power input terminal, a communication circuit, and a wire harness interface, characterized in that: The filter circuit is connected between the power input terminal and the wiring harness interface; The communication circuit is connected to the wiring harness interface and is used to transmit the received USB audio signal to the audio device through the wiring harness interface; One end of the wiring harness interface is connected to the filtering circuit and the communication circuit respectively, and the other end of the wiring harness interface is connected to the audio device; The USB audio filtering circuit includes: Transient voltage suppressor, LC filter circuit and RC filter circuit; The transient voltage suppressor is connected to the power input terminal and is used to initially filter out electrostatic discharge and interference signals from the power supply during the process of the audio device receiving USB audio signals. The LC filter circuit is connected between the transient voltage suppressor and the RC filter circuit, and is used to filter out high-frequency signals in the interference signal. The RC filter circuit is connected between the LC filter circuit and the wiring harness interface to filter out low-frequency signals in the interference signal.

2. The junction box according to claim 1, characterized in that, The transient voltage suppressor includes a TVS diode, the cathode of which is connected to the first power supply pin of the power input terminal and the LC filter circuit, respectively. The anode of the TVS diode is connected to the second power supply pin of the power input terminal and the LC filter circuit, respectively.

3. The junction box according to claim 2, characterized in that, The LC filter circuit includes a filter inductor and a first filter capacitor. The filter inductor is provided with a first inductor pin, a second inductor pin, a third inductor pin, and a fourth inductor pin. The fourth inductor pin is connected to the cathode of the TVS diode, the third inductor pin is connected to the anode of the TVS diode, the first inductor pin is connected to one end of the first filter capacitor, and the second inductor pin is connected to the other end of the first filter capacitor. The first filter capacitor is connected in parallel across the two ends of the RC filter circuit.

4. The junction box according to claim 3, characterized in that, The first filter capacitor includes a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor, which are connected in parallel.

5. The junction box according to claim 4, characterized in that, The capacitance values ​​of the first capacitor, the second capacitor, the third capacitor, and the fourth capacitor are different.

6. The junction box according to claim 3, characterized in that, The RC filter circuit includes a filter resistor and a second filter capacitor, which are connected in series. The first end of the filter resistor is connected to the wire harness interface and one end of the first filter capacitor, respectively, and the second end of the filter resistor is connected to the first end of the second filter capacitor. The second terminal of the second filter capacitor is grounded and connected to the other terminal of the first filter capacitor.

7. The junction box according to any one of claims 3-6, characterized in that, The filter inductor is a common-mode inductor.

8. A USB audio system, comprising a junction box, audio device, communication device, and power adapter as described in any one of claims 1-7, characterized in that: The power input terminal of the junction box is connected to the power adapter, and the communication circuit of the junction box is connected to the communication device. The audio device is connected to the junction box via a wiring harness and is used to receive USB audio signals transmitted from the communication circuit.

9. A filtering method, comprising the USB audio system of claim 8, characterized in that, The method includes the following steps: The power input terminal of the junction box receives the power signal transmitted through the power adapter and transmits the power signal to the filtering circuit of the junction box. The filtering circuit filters out interference signals in the power supply signal; The communication circuit of the junction box receives the USB audio signal transmitted through the communication device and sends it to the wiring harness interface of the junction box. The junction box's wiring harness interface transmits the USB audio signal to the audio device via the wiring harness.

Images