Vehicle-mounted sound equipment control circuit with double-isolation function

Abstract

The utility model relates to a vehicle-mounted sound equipment control circuit with a double-isolation function, which comprises an audio input interface which comprises a first sound channel input end, a second sound channel input end and a sound channel grounding end, the first sound channel input end and the sound channel grounding end are sequentially connected with a first common mode inductor and a first audio transformer, and the second sound channel input end is connected with a second common mode inductor and a second audio transformer. The second sound channel input end and the sound channel grounding end are sequentially connected with a second common mode inductor, a second audio transformer and an audio ground isolation amplification chip, and the audio ground isolation amplification chip comprises a first operational amplifier, a second operational amplifier, a first grounding end and a positive power supply input end. The vehicle-mounted sound equipment control circuit with the double-isolation function can effectively isolate spurious signals and current in a ground wire loop, reduce the influence of noise and interference, and improve the quality of audio signals.

Description

TECHNICAL FIELD

[0001] The utility model relates to vehicle audio circuit, especially a kind of vehicle audio control circuit with double isolation function. BACKGROUND

[0002] Vehicle audio is set up to reduce the dullness of driver and passenger during travel. The earliest use is automobile amplitude modulation radio, then amplitude modulation frequency modulation radio, tape player, to CD player and compatible DCC, DAT digital audio. With the rise of off-road vehicle and all-terrain vehicle, all-terrain vehicle refers to the vehicle that can travel on any terrain, and walk freely on the terrain that ordinary vehicle is difficult to maneuver.

[0003] The vehicle audio circuit design in the market does not fully consider the need to isolate the current in the stray signal and ground loop and the factors that the ground loop may cause interference and noise, therefore, the audio input signal in the audio input module of the car audio has the possibility of improvement. According to the deficiencies of the prior art, it is necessary to propose a new technical scheme. SUMMARY

[0004] The utility model provides a kind of vehicle audio control circuit with double isolation function, to at least solve one of the technical problems existing in prior art.

[0005] The technical scheme of the utility model is a kind of vehicle audio control circuit with double isolation function, it includes: audio input interface, the audio input includes first sound channel input end, second sound channel input end and sound channel ground end, the first sound channel input end and sound channel ground end are sequentially connected with first common mode inductance and first audio transformer, the second sound channel input end and sound channel ground end are sequentially connected with second common mode inductance and second audio transformer, audio ground isolation amplification chip, the audio ground isolation amplification chip includes first operational amplifier, second operational amplifier, first ground end and positive power input end, wherein, the output end of the first audio transformer is connected with the input end of the first operational amplifier, the output end of the second audio transformer is connected with the input end of the second operational amplifier, the output end of the first operational amplifier outputs first sound channel processing signal, the output end of the second operational amplifier outputs second sound channel processing signal, and wherein, the first ground end is connected with a common ground end, and the positive power input end is connected with the positive pole of a power supply.

[0006] Further, the first common mode inductor and the first audio transformer in series between the positive output terminal and the positive input terminal, the second common mode inductor and the second audio transformer in series between the positive output terminal and the positive input terminal, the first audio transformer and the first audio transformer in parallel between the positive input terminal and the negative input terminal, the second audio transformer and the second audio transformer in parallel between the positive input terminal and the negative input terminal.

[0007] Further, the audio input interface is an AUX audio interface, and the audio input interface further comprises an auxiliary detection interface for detecting whether the AUX interface is connected with an audio device.

[0008] Further, the first operational amplifier and the common ground terminal in parallel between the output terminal and the common ground terminal, the first RC circuit comprising a sixth capacitor and a fourteenth resistor connected in parallel, the second operational amplifier and the common ground terminal in parallel between the output terminal and the common ground terminal, and the second RC circuit comprising a sixth capacitor and a fifteenth resistor connected in parallel.

[0009] Further, the audio signal distribution module for selecting different audio sources, the audio signal distribution module comprising an analog switch chip and a plurality of audio input terminals and audio output terminals arranged on the analog switch chip, wherein the first channel input terminal and the second channel input terminal are connected with a plurality of audio input terminals respectively.

[0010] Further, a plurality of audio input terminals are further connected with a radio audio module and a microphone input module respectively.

[0011] Further, the analog switch chip is a 4052 chip.

[0012] Further, the audio ground isolation amplifier chip is a BA3121 chip.

[0013] Further, the first audio transformer and the second audio transformer are both EI-14 audio transformers.

[0014] The beneficial effects of the utility model include:

[0015] The audio input interface connects the audio output of MP3 player, mobile phone, tablet computer, notebook computer and other devices to the vehicle audio, plays the audio content on the devices, and the first common mode inductor and the first audio transformer connected to the two-way first channel input end and the second channel input end of the audio input interface can effectively isolate the stray signal and the current in the ground loop, reduce the influence of noise and interference, and improve the quality of the audio signal.

[0016] In addition, the additional aspects and advantages of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a circuit schematic diagram of the vehicle audio control circuit with double isolation function according to the embodiment of the present application.

[0018] Figure 2 is a circuit schematic diagram of the audio signal distribution module according to the embodiment of the present application.

[0019] Figure 3 is a circuit schematic diagram of the radio audio module according to the embodiment of the present application.

[0020] Figure 4 is a circuit schematic diagram of the audio ground isolation amplification chip according to the embodiment of the present application. Figure 1

[0021] Figure 5 is a vehicle audio structure diagram corresponding to the vehicle audio control circuit with double isolation function according to the embodiment of the present application. DETAILED DESCRIPTION

[0022] The concept, specific structure and generated technical effects of the present application will be described clearly and completely in the following embodiments and drawings, so as to fully understand the purpose, scheme and effect of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0023] ​It should be noted that, unless otherwise specified, when a certain feature is referred to as being "fixed", "connected" to another feature, it can be directly fixed, connected to the other feature, or indirectly fixed, connected to the other feature. In addition, the up, down, left, right, top, bottom and other descriptions used in the utility model are only relative to the mutual position relationship of the components of the utility model in the drawings.

[0024] In addition, 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 technology belongs. The terminology used in the description herein is for describing specific embodiments only and is not intended to be limiting of the utility model. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0025] It should be understood that, although the terms first, second, third, etc. can be employed in this disclosure to describe various elements, these elements should not be limited to these terms. These terms are only used to distinguish one element from another. For example, a first element could also be referred to as a second element without departing from the scope of the disclosure, and similarly, a second element could also be referred to as a first element.

[0026] Referring to Figures 1 to 5 As shown in some embodiments, the utility model discloses a kind of vehicle-mounted audio control circuit with double isolation function, it includes:

[0027] Referring to Figure 1 The audio input interface J21 in the circuit schematic diagram, the audio input includes first sound channel input end AUS_RIN, second sound channel input end AUS_LIN and sound channel ground AUS_GND. Preferably, the audio input interface J21 is AUX audio interface, the audio input interface J21 also includes the auxiliary detection interface AUS_DET for detecting whether AUX interface is connected audio equipment. AUX audio interface is input 4 section 3.6mm earphone seat.

[0028] Continue to refer to Figure 1 The first sound channel input end AUS_RIN and sound channel ground AUS_GND are sequentially connected with first common mode inductance L05 and first audio transformer T1, and the second sound channel input end AUS_LIN and sound channel ground AUS_GND are sequentially connected with second common mode inductance L06 and second audio transformer T2, as shown in the circuit schematic diagram in Figure 1 Combined with Figure 4The audio ground isolation amplifier chip U03 shown is a BA3121 chip. The main function of the BA3121 audio ground isolation IC in this circuit is to improve the quality of the audio signal by isolating and suppressing noise, ensuring that the audio system outputs a clear and pure audio signal.

[0029] The audio ground isolation amplifier chip U03 includes a first operational amplifier OP1, a second operational amplifier OP2, a first ground terminal, and a positive power input terminal. The output terminal of the first audio transformer T1 is connected to the input terminal of the first operational amplifier OP1, and the output terminal of the second audio transformer T2 is connected to the input terminal of the second operational amplifier OP2. The output terminal of the first operational amplifier OP1 outputs a first channel processing signal AUS-R, and the output terminal of the second operational amplifier OP2 outputs a second channel processing signal AUS-L. The first ground terminal is connected to a common ground terminal AGND, and the positive power input terminal is connected to the positive terminal of a power supply.

[0030] The aforementioned audio input interface connects the audio output of devices such as MP3 players, mobile phones, tablets, and laptops to... Figure 5 In car audio systems, when playing audio content from these devices, the first common-mode inductor and the first audio transformer connected to the two audio input interfaces (first and second channel inputs) can effectively isolate stray signals and current in the ground loop, reducing the impact of noise and interference and improving the quality of the audio signal. In addition, the two audio signals at the output of the first audio transformer are connected to the audio ground isolation amplifier chip. The audio isolation transformer can convert high-impedance signals to low-impedance signals or unbalanced signals to balanced signals, achieving signal matching between different impedances and ensuring signal transmission effect and quality.

[0031] Continue to refer to Figure 1 As shown in the circuit diagram, a fifth resistor R5 is connected in series between the positive output terminal of the first common-mode inductor L05 and the positive input terminal of the first audio transformer T1; a sixteenth resistor R16 is connected in series between the positive output terminal of the second common-mode inductor L06 and the positive input terminal of the second audio transformer T2. The resistors connected between the common-mode inductors and the audio transformers can be used to adjust the circuit's input impedance to match the output impedance of the source device, thereby optimizing signal transmission and reducing reflections. If the input signal is too strong, the series connection of the fifth and sixteenth resistors can limit the current, protecting sensitive components in the circuit from damage. (Continue referring to...) Figure 1As shown in the circuit principle diagram, the first audio transformer T1 has a fifty-fourth capacitor C54 connected in parallel between the positive input end and the negative input end of the first audio transformer T1; the second audio transformer T2 has a fifty-fifth capacitor C55 connected in parallel between the positive input end and the negative input end of the second audio transformer T2. The parallel resistance and bypass capacitor of the two audio signals described above are used in combination to form a low-pass filter, which helps to suppress high-frequency noise on the power line.

[0032] With continued reference to Figure 1 As shown in the circuit principle diagram, the first RC circuit includes a sixty-second capacitor C62 and a fifteenth resistor R15 connected in parallel in sequence between the output end and the common ground end AGND of the second operational amplifier OP2. The two audio signals at this place are used as a low-pass filter to reduce high-frequency noise at the output end, smooth the output signal, and improve the quality of the audio signal.

[0033] With reference to Figure 1 In combination Figure 2 As shown in the circuit principle diagram, the audio signal distribution module for selecting different audio sources includes an analog switch chip U8 and a plurality of audio input ends and an audio output end provided on the analog switch chip U8, and the first channel input end AUS_RIN and the second channel input end AUS_LIN are connected to the plurality of audio input ends, respectively. Specifically, the analog switch chip U8 is a 4052 chip. The 4052 chip can be used as a 4:1 multiplexer to allow selection of one signal from four input signals. In a sound system, this can be used to select different audio sources, such as selecting one audio signal from a plurality of input devices (such as the AUX interface audio signal in the first channel input end AUS_RIN and the second channel input end AUS_LIN described above, the radio audio module and the microphone input module below, etc.) for amplification and output. The plurality of audio input ends are also respectively connected to a radio audio module and a microphone input module, Figure 3 The circuit principle diagram of the radio audio module is shown in the following figure.

[0034] In some embodiments, the first audio transformer and the second audio transformer are both EI-14 audio transformers. The first audio transformer of this type can use parameters of 4 soft feet 50HZ-100KHZ.

[0035] The above merely describes preferred embodiments of the present application, and the present application is not limited to the above-described embodiments, as long as the same technical effects are achieved by the same means, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure. All shall belong to the protection scope of the present application. The technical solutions and / or embodiments within the protection scope of the present application can have various modifications and changes.

Claims

1. A vehicle audio control circuit with dual isolation function, characterized in that, Comprise: audio input interface, the audio input includes first sound track input end, second sound track input end and sound track ground, the first sound track input end and sound track ground are connected with first common mode inductance and first audio transformer in turn, the second sound track input end and sound track ground are connected with second common mode inductance and second audio transformer in turn, audio ground isolation amplifier chip, the audio ground isolation amplifier chip includes first operational amplifier amplifier, second operational amplifier amplifier, first ground and positive power input, wherein, the output of the first audio transformer is connected with the input of the first operational amplifier amplifier, the output of the second audio transformer is connected with the input of the second operational amplifier amplifier, the output of the first operational amplifier amplifier outputs first sound track processing signal, the output of the second operational amplifier amplifier outputs second sound track processing signal, And wherein, the first ground is connected with a common ground, and the positive power input is connected with the positive electrode of a power supply.

2. The vehicle-mounted audio control circuit with double isolation function according to claim 1, wherein, the positive output of the first common mode inductance and the positive input of the first audio transformer are connected in series with a fifth resistor, the positive output of the second common mode inductance and the positive input of the second audio transformer are connected in series with a sixteenth resistor, the positive input and the negative input of the first audio transformer are connected in parallel with a fifty-fourth capacitor, the positive input and the negative input of the second audio transformer are connected in parallel with a fifty-fifth capacitor.

3. The vehicle-mounted audio control circuit with double isolation function according to claim 1, wherein, the audio input interface is an AUX audio interface, and the audio input interface further comprises an auxiliary detection interface for detecting whether the AUX interface is connected with an audio device.

4. The vehicle-mounted audio control circuit with double isolation function according to claim 1, wherein, the output of the first operational amplifier amplifier and the common ground are connected in parallel with a first RC circuit, and the first RC circuit comprises a sixtieth capacitor and a fourteenth resistor connected in parallel in turn, the output of the second operational amplifier amplifier and the common ground are connected in parallel with a second RC circuit, and the first RC circuit comprises a sixty-second capacitor and a fifteenth resistor connected in parallel in turn.

5. The vehicle audio control circuit having a dual isolation function according to claim 1, wherein, Further comprise: an audio signal distribution module for selecting different audio sources, the audio signal distribution module comprising an analog switch chip and a plurality of audio input terminals and an audio output terminal arranged on the analog switch chip, wherein, the first sound track input end and the second sound track input end are respectively connected with a plurality of the audio input terminals.

6. The vehicle-mounted audio control circuit with double isolation function according to claim 5, wherein, a plurality of the audio input terminals are further respectively connected with a radio audio module and a microphone input module.

7. The vehicle-mounted audio control circuit with double isolation function according to claim 5, wherein, the analog switch chip is a 4052 chip.

8. The vehicle-mounted audio control circuit with double isolation function according to claim 1, wherein, The model of the audio ground isolation amplification chip is BA3121 chip.

9. The vehicle audio control circuit with double isolation function according to claim 1, characterized in that, The model of the first audio transformer and the second audio transformer is EI-14 audio transformer.

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