Audio signal mixed input circuit, earphone and Bluetooth speaker

Abstract

The present invention discloses an audio mixing input circuit, earphones and Bluetooth speakers, and relates to the technical field of audio equipment, wherein the audio mixing input circuit includes an earphone amplifier IC chip, a Bluetooth IC chip and a Line input interface. The first output end of the earphone amplifier IC chip is provided with a first speaker, and the second output end of the earphone amplifier IC chip is provided with a second speaker; and the multiple output ends of the Bluetooth IC chip are respectively connected to the input end of the corresponding earphone amplifier IC chip through different first resistor-capacitor input coupling circuit modules, and a ground load resistor is provided at the input end of the first resistor-capacitor input coupling circuit module; the first output end and the second end of the Line input interface are respectively connected to the second input end of the earphone amplifier IC chip through different second resistor-capacitor input coupling circuit modules, and a ground load resistor is provided at the input end of the second resistor-capacitor input coupling circuit module. The audio mixing input circuit can effectively solve the problem of mutual interference between Bluetooth audio signals and Line audio signals.

Description

Technical Field

[0001] The present invention relates to the field of audio equipment, and in particular to an audio mixing input circuit, earphones and a Bluetooth speaker. Background Art

[0002] The audio output of the Bluetooth IC (Integrated Circuit) chip currently used in the market is a differential balanced output, while the Line audio signal of the 3.5mm headphone jack of a mobile phone or PC (Personal Computer) is a single-ended output. In the related technology, the Bluetooth audio signal is usually converted into a single-ended output to make it compatible with the Line audio signal and the Bluetooth audio signal. However, the circuit design adopted is relatively complex and costly. Moreover, when the Bluetooth differential balanced output is converted into a single-ended output, noise is easily generated, the signal-to-noise ratio of the speaker output is low, and mutual interference is easily generated when the Bluetooth audio signal and the Line audio signal are mixed and input. Therefore, solving the problem of mixed input of Bluetooth audio signals and Line audio signals has become a difficult problem that needs to be solved urgently in this industry. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an audio mixing input circuit, earphones and Bluetooth speakers, which can effectively solve the problem of mutual interference between Bluetooth audio signals and Line audio signals.

[0004] According to the first aspect of the present invention, the audio mixing input circuit includes an earphone amplifier IC chip, a Bluetooth IC chip for outputting multiple Bluetooth audio signals, and a Line input interface for accessing Line audio signals. The first output end of the earphone amplifier IC chip is provided with a first speaker, the second output end of the earphone amplifier IC chip is provided with a second speaker, and the earphone amplifier IC chip includes a first input end, a second input end, a third input end, and a fourth input end; and the multiple output ends of the Bluetooth IC chip are respectively connected to the first input end, the second input end, the third input end, and the fourth input end of the corresponding earphone amplifier IC chip through different first resistor-capacitor input coupling circuit modules, and a ground load resistor is provided at the input end of the first resistor-capacitor input coupling circuit module; the first output end of the Line input interface is connected to the second input end of the earphone amplifier IC chip through a second resistor-capacitor input coupling circuit module, and the second output end of the Line input interface is connected to the third input end of the earphone amplifier IC chip through another second resistor-capacitor input coupling circuit module, and a ground load resistor is provided at the input end of the second resistor-capacitor input coupling circuit module.

[0005] The audio mixing input circuit according to the embodiment of the present invention has at least the following beneficial effects: through the grounded load resistor, the first RC input coupling circuit module and the second RC input coupling circuit module, the audio mixing input circuit of the present invention can effectively reduce the interference between the Bluetooth audio signal and the Line audio signal, so that the circuit can effectively output the Bluetooth audio signal and the Line audio signal, so that the user experience can be improved, and the audio mixing input circuit of the present invention has a simple structure and can effectively reduce costs.

[0006] According to some embodiments of the present invention, the first RC input coupling circuit module and the second RC input coupling circuit module both include an input coupling capacitor and an input resistor connected in series, and the input resistor is also connected to the input end of the headphone amplifier IC chip.

[0007] According to some embodiments of the present invention, a first feedback resistor is provided between the first input terminal and the first output terminal of the headphone amplifier IC chip.

[0008] According to some embodiments of the present invention, a second feedback resistor is provided between the fourth input terminal and the second output terminal of the headphone amplifier IC chip.

[0009] According to some embodiments of the present invention, a first input terminal of the first speaker is connected to a first output terminal of the headphone amplifier IC chip, and a second input terminal of the first speaker is connected to the headphone amplifier IC chip via a filtering module.

[0010] According to some embodiments of the present invention, the filtering module includes a plurality of filtering capacitors connected in parallel.

[0011] The earphone according to the second aspect of the present invention comprises the audio mixing input circuit as described in the first aspect of the present invention.

[0012] The earphone according to the embodiment of the present invention has at least the following beneficial effects: the earphone is compatible with Bluetooth audio signals and Line audio signals, can effectively reduce the mutual interference between Bluetooth audio signals and Line audio signals, and improve the user experience.

[0013] The Bluetooth speaker according to the third aspect of the present invention comprises the audio mixing input circuit as described in the first aspect of the present invention.

[0014] The Bluetooth speaker according to the embodiment of the present invention has at least the following beneficial effects: the Bluetooth speaker is compatible with Bluetooth audio signals and Line audio signals to meet user needs, and also reduces the mutual interference between Bluetooth audio signals and Line audio signals, thereby improving the user experience.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0017] Figure 1 is a principle block diagram of an audio signal mixing input circuit according to an embodiment of the present invention;

[0018] Figure 2 FIG. 4 is a schematic diagram of an audio signal mixing input circuit according to an embodiment of the present invention.

[0019] Reference numerals:

[0020] A headphone amplifier IC chip 110 , a Bluetooth IC chip 120 , a Line input interface 130 , a first speaker 140 , a second speaker 150 ; a first RC input coupling circuit module 210 , a second RC input coupling circuit module 220 , and a filter module 230 . DETAILED DESCRIPTION

[0021] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0022] In the description of the present invention, "several" means one or more, "more" means two or more, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0023] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0024] Reference Figure 1In some embodiments of the present invention, an audio signal mixing input circuit is provided, which includes an earphone amplifier IC chip 110, a Bluetooth IC chip 120 and a Line input interface 130. The first output end of the earphone amplifier IC chip 110 is provided with a first speaker 140, and the second output end of the earphone amplifier IC chip 110 is provided with a second speaker 150. It should be conceived that the first speaker 140 and the second speaker 150 are used to play left channel audio and right channel audio. For example, the first speaker 140 plays the left channel audio, and the second speaker 150 plays the right channel audio. It should be noted that the earphone amplifier IC chip 110 can adopt a CS4418 chip, a TDA1308 chip, etc.

[0025] The Bluetooth IC chip 120 outputs multiple Bluetooth audio signals, that is, the Bluetooth IC chip 120 has multiple output terminals, and each output terminal is connected to the input terminal of the headphone amplifier IC chip 110 through the first resistor-capacitor input coupling circuit module 210. It can be understood that the headphone amplifier IC chip 110 has four input terminals, namely the first input terminal, the second input terminal, the third input terminal and the fourth input terminal. The first output terminal of the Bluetooth IC chip 120 is connected to the first input terminal of the headphone amplifier IC chip 110 through the first resistor-capacitor input coupling circuit module 210. Similarly, the other output terminals of the Bluetooth IC chip 120 are connected to different input terminals of the headphone amplifier IC chip 110 through different first resistor-capacitor input coupling circuit modules 210.

[0026] The Line input interface 130 is used to access the Line audio signal, wherein the first output end of the Line input interface 130 is connected to the second input end of the headphone amplifier IC chip 110 through the second RC input coupling circuit module 220, and the second output end of the Line input interface 130 is connected to the third input end of the headphone amplifier IC chip 110 through another second RC input coupling circuit module 220. It should be noted that the second output end of the Bluetooth IC chip 120 and the first output end of the Line input interface 130 are both connected to the second input end of the headphone amplifier IC chip 110, and the third output end of the Bluetooth IC chip 120 and the second output end of the Line input interface 130 are both connected to the third input end of the headphone amplifier IC chip 110. It should be noted that the Line input interface 130 is an interface for accessing Line audio signals, such as a 3.5mm Line input female socket.

[0027] A grounded load resistor is connected before the input end of each first RC input coupling circuit module 210 and each second RC input coupling circuit module 220. It can be understood that a grounded load resistor is connected to each branch of the Bluetooth IC chip 120 that outputs a Bluetooth audio signal. Similarly, a grounded load resistor is provided on each branch of the Line input interface 130 that outputs a Line audio signal.

[0028] Through the grounded load resistor, the first RC input coupling circuit module 210 and the second RC input coupling circuit module 220, the audio mixing input circuit of the present invention can effectively reduce the interference between the Bluetooth audio signal and the Line audio signal, so that the circuit can effectively output the Bluetooth audio signal and the Line audio signal, so that the user experience can be improved, and the audio mixing input circuit of the present invention has a simple structure and can effectively reduce costs.

[0029] In some embodiments of the present invention, the first RC input coupling circuit module 210 and the second RC input coupling circuit module 220 both include an input coupling capacitor and an input resistor connected in series. Among them, one end of the input coupling capacitor in the first RC input coupling circuit module 210 is connected to the output end of the Bluetooth IC chip 120, and one end of the input resistor is connected to the headphone amplifier IC chip 110, that is, the Bluetooth audio signal output by the Bluetooth IC chip 120 enters the headphone amplifier IC chip 110 through the input coupling capacitor and the input resistor. The input coupling capacitor in the second RC input coupling circuit module 220 is connected to the output end of the Line input interface 130, and the input resistor is connected to the input end of the headphone amplifier IC chip 110, that is, the Line audio signal enters the headphone amplifier IC chip 110 after passing through the coupling capacitor and the input resistor.

[0030] In some embodiments of the present invention, a first feedback resistor is arranged between the first input terminal and the first output terminal of the headphone amplifier IC chip 110, that is, the first end of the first feedback resistor is connected to the first input terminal of the headphone amplifier IC chip 110, and the second end of the first feedback resistor is connected to the first output terminal of the headphone amplifier IC chip 110. It should be conceivable that the first end of the first feedback resistor is connected to the output terminal of the first RC input coupling circuit module 210.

[0031] In some embodiments of the present invention, a second feedback resistor is provided between the fourth input terminal and the second output terminal of the headphone amplifier IC chip 110, that is, the first end of the second feedback resistor is connected to the fourth input terminal of the headphone amplifier IC chip 110, and the second end of the first feedback resistor is connected to the second output terminal of the headphone amplifier IC chip 110. It should be conceived that the first end of the first feedback resistor is connected to the output terminal of the first RC input coupling circuit module 210.

[0032] In some embodiments of the present invention, the input end of the first speaker 140 is connected to the first output of the headphone amplifier IC chip 110, and the output end of the first speaker 140 is connected to the headphone amplifier IC chip 110 through the filter module 230. The filter module 230 filters the power supply end of the headphone amplifier IC chip 110, that is, after the power supply is connected to the power supply end of the headphone amplifier IC chip 110, the power supply is also filtered. The first end of the filter module 230 is connected to the power supply and the power supply end of the headphone amplifier IC chip 110, and the second end of the filter module 230 is connected to the protection ground end of the headphone amplifier IC chip 110 and the output end of the first speaker 140.

[0033] In some embodiments of the present invention, the filter module 230 includes a plurality of filter capacitors connected in parallel. For example, three filter capacitors are provided in the filter module 230, and the three filter capacitors are connected in parallel. The first ends of the three filter capacitors are connected to the power supply and the power supply end of the headphone amplifier IC chip 110, and the second ends of the three filter capacitors are connected to the output end of the first speaker 140 and the protection ground end of the headphone amplifier IC chip 110. It should be noted that the number of filter capacitors connected in parallel in the filter module 230 can be set according to the filtering needs of the circuit.

[0034] In some embodiments of the present invention, the audio signal mixing input circuit includes an earphone amplifier IC chip 110 , a Bluetooth IC chip 120 , a Line input interface 130 , a first speaker 140 and a second speaker 150 .

[0035] Specifically, refer to Figure 2 , the Bluetooth IC chip U2 outputs four Bluetooth audio signals, including a left channel signal and a right channel signal, such as the left channel signal includes BT_LN and BT_LP, and the right channel signal includes BT_RN and BT_RP. The BT_LN signal is connected to the first input terminal of the headphone amplifier IC chip U1 through the input coupling capacitor C5 and the input resistor R1, and a ground load resistor R11 is also connected in front of the input coupling capacitor C5; the BT_LP signal is connected to the second input terminal of the headphone amplifier IC chip U1 through the input coupling capacitor C6 and the input resistor R2, and a ground load resistor R10 is also connected in front of the input coupling capacitor C6; and the BT_RN signal is connected to the third input terminal of the headphone amplifier IC chip U1 through the input coupling capacitor C10 and the input resistor R6, and a ground load resistor R13 is also connected in front of the input coupling capacitor C10; the BT_RP signal is connected to the fourth input terminal of the headphone amplifier IC chip U1 through the input coupling capacitor C11 and the input resistor R7, and a ground load resistor R12 is also connected in front of the input coupling capacitor C11.

[0036] For the Line input interface JK1, after the Line audio signal is connected, the Line input interface JK1 outputs LINE_LIN and LINE_RIN signals. The LINE_LIN signal is connected to the second input terminal of the headphone amplifier IC chip U1 through the input coupling capacitor C7 and the input resistor R3, and a ground load resistor R16 is also connected before the input coupling capacitor C7; the INE_RIN signal input coupling capacitor C9 and the input resistor R5 are connected to the second input terminal of the headphone amplifier IC chip U1, and a ground load resistor R17 is also connected before the input coupling capacitor C9.

[0037] A first feedback resistor R4 is connected between the first input terminal and the first output terminal of the headphone amplifier IC chip U1, and a second feedback resistor R20 is connected between the fourth input terminal and the second output terminal of the headphone amplifier IC chip U1. The first input terminal and the fourth input terminal of the headphone amplifier IC chip U1 are negative input terminals, which are equivalent to the inverting input terminals in the operational amplifier, while the second input terminal and the third input terminal of the headphone amplifier IC chip U1 are positive input terminals, which are equivalent to the non-inverting input terminals in the operational amplifier.

[0038] The first output end of the headphone amplifier IC chip U1 is connected to the first speaker SPKL, and the first speaker SPKL is used to play the left channel audio, while the second output end of the headphone amplifier IC chip U1 is connected to the second speaker SPKR, and the second speaker SPKR is used to play the right channel audio. Among them, the input end of the first speaker SPKL is connected to the first output end of the headphone amplifier IC chip U1, and the output end of the first speaker SPKL is connected to the protection ground end of the headphone amplifier IC chip U1, wherein the power supply end and the protection ground end of the headphone amplifier IC chip U1 are connected to the filter module 230 formed by the parallel connection of the filter capacitor C1, the filter capacitor C2 and the filter capacitor C3, that is, the power supply PVDD is connected to the first end of the filter module 230, and the first speaker SPKL is connected to the second end of the filter module 230.

[0039] It can be understood that the left channel signal in the Bluetooth audio signal is input into the headphone amplifier IC chip U1 through the coupling input capacitor C5, input resistor R1, coupling input capacitor C6, input resistor R2, and is amplified by the headphone amplifier IC chip U1 and output to the first speaker SPKL; the right channel signal in the Bluetooth audio signal is input into the headphone amplifier IC chip U1 through the coupling input capacitor C10, input resistor R6, coupling input capacitor C11, input resistor R7, and is amplified by the headphone amplifier IC chip U1 and output to the second speaker SPKR.

[0040] The left channel signal of the Line audio signal is input into the headphone amplifier IC chip U1 through the coupling input capacitor C7 and the input resistor R3, and is amplified by the headphone amplifier IC chip U1 and output to the first speaker SPKL; the right channel signal of the Line audio signal is input into the headphone amplifier IC chip U1 through the coupling input capacitor C9 and the input resistor R5, and is amplified by the headphone amplifier IC chip U1 and output to the second speaker SPKR.

[0041] When Bluetooth is not connected or Bluetooth is connected and stops playing audio, the Bluetooth audio signal is disconnected, which will affect the size of the Line audio signal input to the headphone amplifier IC chip U1, that is, interference is formed. The circuit design in the present invention can, when the Line audio signal is input, the left channel signal of the Line audio signal can be input into the headphone amplifier IC chip U1 under the voltage division effect of the input resistor R3, the input resistor R2 and the ground load resistor R10, and the right channel signal of the Line audio signal can be input into the headphone amplifier IC chip U1 under the voltage division effect of the input resistor R5, the input resistor R6 and the ground load resistor R13, thereby reducing the interference effect of the Bluetooth audio signal on the Line audio signal.

[0042] When the Line audio signal is not input, the left channel signal of the Bluetooth audio signal can be input into the headphone amplifier IC chip U1 under the voltage division effect of the input resistor R2, the input resistor R3 and the ground load resistor R16, and the right channel signal of the Bluetooth audio signal can be input into the headphone amplifier IC chip U1 under the voltage division effect of the input resistor R6, the input resistor R5 and the ground load resistor R17, thereby reducing the interference effect of the Line audio signal on the Bluetooth audio signal.

[0043] In some embodiments of the present invention, an earphone is provided, which includes the audio mixing input circuit as described in the above embodiments. The earphone is compatible with Bluetooth audio signals and Line audio signals, and can effectively reduce the mutual interference between Bluetooth audio signals and Line audio signals, that is, it can effectively reduce the interference effect of Bluetooth audio signal input on Line audio signal input and the interference effect of Line audio signal input on Bluetooth audio signals, thereby improving the user experience.

[0044] In some embodiments of the present invention, a Bluetooth speaker is provided, which includes the audio mixing input circuit as described in the above embodiments. It should be conceived that the Bluetooth speaker can also be compatible with Bluetooth audio signals and Line audio signals, adapt to user needs, reduce mutual interference between Bluetooth audio signals and Line audio signals, and enhance user experience.

[0045] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. An audio signal mixing input circuit, characterized in that: include: An earphone amplifier IC chip, wherein a first output terminal of the earphone amplifier IC chip is provided with a first speaker, a second output terminal of the earphone amplifier IC chip is provided with a second speaker, and the earphone amplifier IC chip includes a first input terminal, a second input terminal, a third input terminal and a fourth input terminal; A Bluetooth IC chip, used for outputting multiple Bluetooth audio signals, wherein the multiple output terminals of the Bluetooth IC chip are respectively connected to the first input terminal, the second input terminal, the third input terminal and the fourth input terminal of the corresponding headphone amplifier IC chip through different first resistance-capacitance input coupling circuit modules, and a grounded load resistor is provided at the input terminal of each of the first resistance-capacitance input coupling circuit modules; A Line input interface is used to access a Line audio signal, wherein a first output end of the Line input interface is connected to a second input end of the headphone amplifier IC chip through a second RC input coupling circuit module, and a second output end of the Line input interface is connected to a third input end of the headphone amplifier IC chip through another second RC input coupling circuit module, and a grounded load resistor is provided at the input end of each of the second RC input coupling circuit modules.

2. The audio signal mixing input circuit according to claim 1, characterized in that: The first RC input coupling circuit module and the second RC input coupling circuit module both include an input coupling capacitor and an input resistor which are sequentially connected in series, and the input resistor is also connected to the input end of the headphone amplifier IC chip.

3. The audio signal mixing input circuit according to claim 1, characterized in that: A first feedback resistor is arranged between the first input terminal and the first output terminal of the headphone amplifier IC chip.

4. The audio signal mixing input circuit according to claim 1, characterized in that: A second feedback resistor is arranged between the fourth input terminal and the second output terminal of the headphone amplifier IC chip.

5. The audio signal mixing input circuit according to claim 1, characterized in that: The first input end of the first speaker is connected to the first output end of the headphone amplifier IC chip, and the second input end of the first speaker is connected to the headphone amplifier IC chip through a filter module.

6. The audio signal mixing input circuit according to claim 5, characterized in that: The filter module includes a plurality of filter capacitors connected in parallel.

7. A headset, characterized in that: The invention comprises the audio signal mixing input circuit as claimed in any one of claims 1 to 6.

8. A Bluetooth speaker, characterized in that: The invention comprises the audio signal mixing input circuit as claimed in any one of claims 1 to 6.

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