Loudspeaker driving circuit, loudspeaker module and electronic equipment

Abstract

The invention discloses a driving circuit of a loudspeaker, a loudspeaker module and electronic equipment, and belongs to the technical field of signal processing. The driving circuit of the loudspeaker comprises a signal detection circuit, an interference processing circuit and an audio signal power amplifier circuit, the audio signal power amplifier circuit is connected with a loudspeaker and is used for preprocessing an input audio signal to obtain an output audio signal and outputting the output audio signal to the loudspeaker; the signal detection circuit is connected with the interference processing circuit and is used for detecting a working electric signal of the loudspeaker and outputting the working electric signal to the interference processing circuit, and the working electric signal comprises a superposed signal of the output audio signal and an external interference signal; and the interference processing circuit is connected with the loudspeaker, and is used for receiving the input audio signal, obtaining a reverse signal of the external interference signal according to processing of the input audio signal and the working electric signal, and outputting the reverse signal to the loudspeaker.

Description

Technical Field

[0001] The present application belongs to the field of signal processing technology, and specifically relates to a speaker driving circuit, a speaker module and an electronic device. Background Art

[0002] The speaker is one of the indispensable components in a mobile terminal. Figure 1 As shown, the speaker 10 generally includes a diaphragm assembly 101, a voice coil 102, a magnetic circuit assembly 103, and a basin frame 104 for fixing the various components of the speaker. The working principle of the speaker 10 is: by passing a changing audio signal into the voice coil 102, the voice coil 102 is vibrated by the changing Ampere force in the magnetic field generated by the magnetic circuit assembly 103, thereby driving the diaphragm assembly 101 to vibrate, and then the diaphragm assembly 101 vibrates and radiates sound outward.

[0003] Although currently the speakers are usually arranged at the edge of the mobile terminal to prevent the high-power devices in the mobile terminal from causing signal interference to the speakers, due to the size of the mobile terminal, the speakers are still relatively easy to couple to interference signals, thus affecting the sound playback effect. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a speaker driving circuit, a speaker module and an electronic device, which can solve the problem that the current speakers are more easily coupled to interference signals, thereby affecting the sound playback effect.

[0005] In a first aspect, an embodiment of the present application provides a driving circuit of a speaker, the driving circuit comprising: a signal detection circuit, an interference processing circuit and an audio signal power amplifier circuit;

[0006] The audio signal power amplifier circuit is connected to the speaker, and is used to pre-process the input audio signal to obtain an output audio signal, and output the output audio signal to the speaker;

[0007] The signal detection circuit is connected to the interference processing circuit, and is used to detect the working electrical signal of the speaker, and output the working electrical signal to the interference processing circuit, wherein the working electrical signal includes a superimposed signal of the output audio signal and an external interference signal;

[0008] The interference processing circuit is connected to the speaker, and is used for receiving the input audio signal, obtaining a reverse signal of the external interference signal according to the input audio signal and the working electrical signal, and outputting the reverse signal to the speaker.

[0009] In a second aspect, an embodiment of the present application provides a speaker module, comprising: a speaker and any driving circuit described in the first aspect.

[0010] In a third aspect, an embodiment of the present application provides an electronic device, wherein the electronic device includes the driving circuit described in any one of the first aspects, or includes the speaker module described in any one of the second aspects.

[0011] In an embodiment of the present application, the driving circuit of the speaker includes: a signal detection circuit, an interference processing circuit and an audio signal amplifier circuit. Among them, the audio signal amplifier circuit can be used to pre-process the input audio signal to obtain an output audio signal, and output the output audio signal to the speaker. The signal detection circuit can be used to detect the working electrical signal of the speaker and output the working electrical signal to the interference processing circuit. The interference processing circuit can be used to receive the input audio signal, process the input audio signal and the working electrical signal to obtain a reverse signal of the external interference signal, and output the reverse signal to the speaker.

[0012] In this technical solution, the speaker is easily affected by the interference magnetic field generated by the high-power device and generates an external interference signal, so that the working electrical signal of the speaker includes the output audio signal and the superposition signal of the external interference signal. The interference processing circuit in the present application can be used to receive the working electrical signal of the speaker detected by the signal detection circuit, and then obtain the reverse signal of the external interference signal according to the input audio signal and the working electrical signal of the speaker, and output the reverse signal to the speaker. In this way, the speaker can receive the reverse signal of the external interference signal to offset the interference signal in the original working electrical signal, thereby effectively avoiding the interference sound formed by the external interference signal in the speaker and improving the sound playback effect.

[0013] Furthermore, since the driving circuit of the speaker of the present application can effectively cancel the interference signal in the original working electrical signal of the speaker, the interference sound of the speaker caused by the external interference signal can be avoided. Therefore, the speaker driven by the driving circuit of the present application and its signal processing circuit can be freely laid out, which is beneficial to the structure and appearance design of the electronic device. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is one of the structural schematic diagrams of the loudspeaker provided by the related art;

[0015] Figure 2 It is one of the structural schematic diagrams of a mobile terminal provided by the related art;

[0016] Figure 3 It is one of the schematic diagrams for generating interference current signals provided by the relevant technology;

[0017] Figure 4 This is one of the structural schematic diagrams of the driving circuit of the speaker provided in the embodiment of the present application;

[0018] Figure 5 This is a second structural schematic diagram of a driving circuit of a speaker provided in an embodiment of the present application;

[0019] Figure 6 This is the third structural schematic diagram of the driving circuit of the speaker provided in the embodiment of the present application;

[0020] Figure 7 This is one of the schematic diagrams of the arrangement of the detection coil provided in the embodiment of the present application;

[0021] Figure 8 This is the second schematic diagram of the arrangement of the detection coil provided in the embodiment of the present application;

[0022] Fig. 9 It is one of the schematic diagrams of the working electrical signals of the speaker provided in the embodiment of the present application;

[0023] Fig.10 This is a fourth structural diagram of a driving circuit of a speaker provided in an embodiment of the present application;

[0024] Fig.11 It is one of the circuit schematic diagrams of the differential amplifier provided in the embodiment of the present application;

[0025] Fig.12 It is one of the signal processing principle diagrams of the interference processing circuit provided in the embodiment of the present application;

[0026] Fig.13 This is a fifth structural diagram of a driving circuit of a speaker provided in an embodiment of the present application;

[0027] Fig.14 It is one of the circuit schematic diagrams of the reverse processing unit provided in the embodiment of the present application;

[0028] Fig.15 It is one of the signal processing principle diagrams of the reverse processing unit provided in the embodiment of the present application;

[0029] Fig.16 This is the sixth structural schematic diagram of the driving circuit of the speaker provided in the embodiment of the present application. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0031] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0032] The speaker driving circuit, speaker module and electronic device provided in the embodiments of the present application are described in detail below with reference to specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0033] The speaker is one of the indispensable components in a mobile terminal. Figure 1 As shown, the speaker 10 generally includes a diaphragm assembly 101, a voice coil 102, a magnetic circuit assembly 103, and a basin frame 104 for fixing the various components of the speaker. The working principle of the speaker 10 is: by passing a changing audio signal into the voice coil 102, the voice coil 102 is vibrated by the changing Ampere force in the magnetic field generated by the magnetic circuit assembly 103, thereby driving the diaphragm assembly 101 to vibrate, and then the diaphragm assembly 101 vibrates and radiates sound outward.

[0034] However, currently the speakers are usually arranged at the edge area of ​​the mobile terminal to prevent the high-power devices in the mobile terminal from causing signal interference to the speakers. Figure 2 As shown, the mobile terminal 1 includes two speakers 10, a battery 20, and a main printed circuit board (PCB) 30 and a sub-PCB 40 disposed on opposite sides of the battery 20. One speaker 10 is disposed at an edge area of ​​the main PCB 30, and the other speaker 10 is disposed at an edge area of ​​the sub-PCB 40 to be as far away from the current routing on the PCB as possible, thereby preventing the current routing of the high-power device from interfering with the speaker 10.

[0035] Specifically, since the voice coil 102 in the speaker 10 is made of a metal wire wound multiple times. Therefore, when the voice coil 102 is arranged in an environment where an interfering magnetic field exists, an interfering current signal will be coupled to the voice coil 102. Then, when the speaker is working, the speaker and its driving circuit will form a low-resistance closed loop. The induced current (i.e., the interfering current signal) generated by the voice coil 102 coupled under the interfering magnetic field will form a changing Ampere force in the magnetic field generated by the magnetic circuit assembly 103, driving the diaphragm assembly 101 to vibrate to form an interfering sound, which can then be heard by the human ear.

[0036] For example, Figure 3 As shown, current mobile terminals such as mobile phones, tablet computers, and laptop computers usually include high-power devices. When the high-power device is working, there will be intermittent large current draws. The draws of these large currents I1 will cause the circuit loop 301 in which it is located to generate a correspondingly changing interference magnetic field E1. When the speaker is working, the voice coil 102 is coupled under the interference magnetic field E1 to generate an interference current signal I2. The interference current signal I2 will form a changing Ampere force in the magnetic field generated by the magnetic circuit component 103 and drive the diaphragm component 101 to vibrate to form an interference sound with a frequency of 20-20Khz. The interference sound is within the hearing range of the human ear and is easily perceived by the human ear. Especially in mobile terminals with increasingly compact layout space, the closer the speaker is to the motherboard, the more obvious the phenomenon of interference sound in the speaker. Therefore, limited by the volume of the mobile terminal, the speaker is still relatively easy to couple to the interference signal, affecting the sound playback effect and the user experience.

[0037] Please refer to Figure 4 , which shows a schematic diagram of the structure of a speaker driving circuit provided by an embodiment of the present application. The driving circuit can solve the problems existing in the above-mentioned speakers to a certain extent. Figure 4 As shown, the driving circuit 50 of the speaker includes: a signal detection circuit 501 , an interference processing circuit 502 and an audio signal amplifier circuit 503 .

[0038] The audio signal amplifier circuit 503, namely, an audio power amplifier (PA) circuit, is connected to the speaker 10. The audio signal amplifier circuit 503 is used to pre-process the input audio signal to be played to obtain an output audio signal, and output the output audio signal to the speaker.

[0039] The signal detection circuit 501 is connected to the interference processing circuit 502. The signal detection circuit 501 is used to detect the working electrical signal of the speaker 10 and output the working electrical signal to the interference processing circuit 502. The working electrical signal includes a superimposed signal of the output audio signal and the external interference signal.

[0040] The interference processing circuit 502 is connected to the speaker 10. The interference processing circuit 502 is used to receive an input audio signal, process the input audio signal and the working electrical signal to obtain a reverse signal of the external interference signal, and output the reverse signal to the speaker.

[0041] Optionally, the preprocessing of the input audio signal by the audio signal amplifier circuit 503 mainly includes power amplification processing to increase the amplitude of the input audio signal, improve the loudness of the speaker, and ensure that the sound can be clearly and accurately conveyed to the audience. In addition, the preprocessing can also include adjustment processing of key parameters such as distortion, frequency response and dynamic performance of the input audio signal to effectively improve the sound quality of the speaker to provide a better sound experience.

[0042] Furthermore, as mentioned above, during operation, the speaker 10 can not only receive the output audio signal output by the audio signal amplifier circuit 503, but the voice coil of the speaker 10 can also generate an interference electrical signal (i.e., an external interference signal) under an external interference magnetic field. Based on this, the speaker 10 will output sound according to the superposition signal of the output audio signal and the external interference signal during actual operation. Therefore, it can be considered that the working electrical signal of the speaker 10 includes the superposition signal of the output audio signal transmitted by the external interference signal and the audio signal amplifier circuit 503.

[0043] In the present application embodiment, Figure 5 As shown, in the working process of driving the speaker 10, the audio signal amplifier circuit 503 can pre-process the input audio signal of the sound to be played to obtain the output audio signal, and output the output audio signal to the speaker 10. The signal detection circuit 501 can detect the working electrical signal of the speaker 10, and output the working electrical signal to the interference processing circuit 502. The interference processing circuit 502 can receive the input audio signal, and obtain the reverse signal of the external interference signal according to the input audio signal and the working electrical signal, and output the reverse signal to the speaker 10. Therefore, at the signal input end of the speaker 10, it can receive the output audio signal transmitted by the audio signal amplifier circuit 503 and the reverse signal of the external interference signal transmitted by the interference processing circuit 502. Based on this, the external interference signal in the original working electrical signal on the voice coil of the speaker 10 can be offset after being superimposed with the reverse signal of the external interference signal transmitted by the interference processing circuit 502. In this way, the output audio signal can be retained on the voice coil of the speaker 10, and then a clean sound can be output according to the output audio signal, effectively avoiding the interference sound formed on the speaker by the external interference signal.

[0044] In summary, the driving circuit of the speaker provided in the embodiment of the present application includes: a signal detection circuit, an interference processing circuit and an audio signal amplifier circuit. Among them, the audio signal amplifier circuit can be used to pre-process the input audio signal to obtain an output audio signal, and output the output audio signal to the speaker. The signal detection circuit can be used to detect the working electrical signal of the speaker, and output the working electrical signal to the interference processing circuit. The interference processing circuit can be used to receive the input audio signal, and obtain the reverse signal of the external interference signal according to the input audio signal and the working electrical signal, and output the reverse signal to the speaker.

[0045] In this technical solution, the speaker is easily affected by the interference magnetic field generated by the high-power device and generates an external interference signal, so that the working electrical signal of the speaker includes the output audio signal and the superposition signal of the external interference signal. The interference processing circuit in the present application can be used to receive the working electrical signal of the speaker detected by the signal detection circuit, and then obtain the reverse signal of the external interference signal according to the input audio signal and the working electrical signal of the speaker, and output the reverse signal to the speaker. In this way, the speaker can receive the reverse signal of the external interference signal to offset the interference signal in the original working electrical signal, thereby effectively avoiding the interference sound formed by the external interference signal in the speaker and improving the sound playback effect.

[0046] In an optional case, the signal detection circuit 501 may include: a magnetic induction sensor. The magnetic induction sensor is arranged close to the speaker 10 and connected to the interference processing circuit 502 .

[0047] The magnetic induction sensor is used to sense the external interference electromagnetic signal and the target electromagnetic signal generated by the speaker, convert the external interference signal and the target electromagnetic signal into a working electrical signal, and output the working electrical signal to the interference processing circuit 502.

[0048] Among them, the external interference electromagnetic signal is used to make the speaker 10 generate an external interference signal. That is, the external interference electromagnetic signal can be understood as the interference magnetic field of the speaker 10. For example, the external interference electromagnetic signal can be the magnetic field generated when a high-power device near the speaker 10 draws a large current, and this magnetic field will interfere with the sound of the speaker 10 and cause it to produce noise. In addition, the voice coil of the speaker 10 will also generate an electromagnetic signal when receiving the output audio signal due to the electromagnetic induction effect. The target electromagnetic signal is the electromagnetic signal generated by the voice coil of the speaker 10 due to the output audio signal.

[0049] Based on this, the magnetic induction sensor of the signal detection circuit 501 can sense the electromagnetic signals (including external interference electromagnetic signals and target electromagnetic signals) near the speaker 10 to convert the electromagnetic signals into electrical signals to obtain the working electrical signals of the speaker 10, so as to effectively pick up the electromagnetic signals near the speaker 10 and obtain the working electrical signals of the speaker 10.

[0050] Alternatively, if Figure 6 As shown, the magnetic induction sensor includes: a detection coil L. The coil winding direction of the detection coil L is the same as or opposite to the target direction. The target direction is the coil winding direction of the voice coil in the speaker 10. That is, the detection coil L can be set close to the speaker 10 and parallel to the voice coil in the speaker 10. For example, Figure 6 As shown, one end of the detection coil L is connected to the interference processing circuit 502, and the other end of the detection coil L is grounded through the first resistor R61. The detection coil L is used to sense external interference electromagnetic signals and target electromagnetic signals, convert the external interference signals and the target electromagnetic signals into working electrical signals, and output the working electrical signals to the interference processing circuit 502. In this optional embodiment, since the detection coil L has the ability to pick up the working electrical signal of the speaker 10, it also has the advantages of small size and simple setting. Therefore, the drive circuit 50 can effectively reduce the circuit volume of the drive circuit 50 on the basis of effectively avoiding the interference sound generated by the speaker, so that the drive circuit 50 can achieve a certain degree of layout freedom in a mobile terminal with a smaller volume.

[0051] In an alternative case, if Figure 7 As shown, the driving circuit 50 of the speaker 10 is arranged in a speaker module, and the speaker module includes a printed circuit board (PCB) 70. The speaker 10 and the PCB 70 are stacked. The detection coil L can be arranged on the metal layer of the PCB 70. Specifically, the PCB 70 can include a plurality of metal layers and insulating layers that are staggered and stacked. The detection coil L can be arranged on any metal layer of the PCB 70.

[0052] For example, the detection coil L can be disposed on the metal layer of the PCB 70 by an etching process. Alternatively, the detection coil L can be disposed on the metal layer of the PCB 70 by a printing process. It should be noted that, Figure 7 The PCB 70 in the mobile terminal 1 may be the main PCB 30 in the mobile terminal 1 mentioned above, or may be the sub-PCB 40.

[0053] In another alternative case, if Figure 8 As shown, the detection coil L can also be independently arranged at one side of the speaker 10 and arranged in parallel with the voice coil in the speaker 10 . Figure 8In the example, the detection coil L is independently arranged above the speaker 10.

[0054] In this way, when the detection coil L is arranged close to the speaker 10, the coil winding direction of the detection coil L is set to be the same as or opposite to the target direction, which can ensure that the external interference electromagnetic signal passes through the detection coil L and the voice coil coil synchronously, so as to form the same external interference signal in the detection coil L and the voice coil coil. In this way, it is ensured that the detection coil L can sense the external interference electromagnetic signal and the target electromagnetic signal, and then effectively convert them into the following: Fig. 9 The working electrical signal of the speaker shown in the figure. The working electrical signal 900 detected by the detection coil L includes: the output audio signal radiated outward by the voice coil of the speaker 10 and the external interference signal.

[0055] It should be noted that when it is clear that the interference source that generates the external interference electromagnetic signal is on the PCB, the solution of placing the detection coil L on the PCB is better than the solution of independently setting it on the speaker 10. At this time, when the detection coil L is set on the PCB, not only can the external interference signal be detected more effectively, but also other irrelevant signals that will not interfere with the speaker 10 can be prevented from being picked up by the detection coil L, effectively ensuring the detection effect of the detection coil L on the external interference signal of the speaker 10. When it is not clear that the interference source is on the PCB, the solution of independently setting the detection coil L on the speaker 10 is better than the solution of placing the detection coil L on the PCB. In this way, the electromagnetic signal radiated on the PCB that will not interfere with the speaker 10 can be prevented from being picked up by the detection coil L as much as possible. The setting scheme that the detection coil L and the speaker 10 are as close as possible can also make the external interference signal sensed by the detection coil L largely consistent with the external interference signal sensed by the voice coil of the speaker 10, effectively ensuring the detection effect of the detection coil L on the external interference signal of the speaker 10. In some embodiments, the magnetic induction sensor may also include: a magnetoresistive sensor, a Hall sensor, etc.

[0056] Further optionally, the interference processing circuit 502 may include: an interference processing unit. The interference processing unit is connected to the speaker 10. The interference processing unit is used to receive an input audio signal, separate an external interference signal from the working electrical signal according to the input audio signal, and reversely process the external interference signal to obtain a reverse signal. Optionally, the interference processing unit is used to separate the external interference signal from the working electrical signal after subtracting the input audio signal from the working electrical signal, and reversely process the external interference signal to obtain a reverse signal, thereby facilitating the subsequent cancellation of the interference signal in the original working electrical signal of the speaker, and effectively preventing the speaker from generating interference sound due to the external interference signal.

[0057] In an alternative case, if Fig.10As shown, the interference processing unit includes: a differential amplifier 5021. The first input end of the differential amplifier 5021 is connected to the signal detection circuit 501, and is used to receive the working electrical signal output by the signal detection circuit 501. The second input end of the differential amplifier 5021 is used to receive the input audio signal. The output end of the differential amplifier 5021 is connected to the speaker 10. The differential amplifier 5021 is used to separate the external interference signal from the working electrical signal according to the input audio signal.

[0058] Specifically, optionally, the differential amplifier 5021 can be directly used to separate the reverse signal of the external interference signal from the working electrical signal according to the input audio signal, and output the reverse signal of the external interference signal. Obviously, in this case, the interference processing unit can only include the differential amplifier 5021 to output the reverse signal of the external interference signal to the speaker 10.

[0059] Alternatively, the differential amplifier 5021 can be used to separate the external interference signal from the working electrical signal according to the input audio signal. Obviously, in this case, the interference processing unit also needs to include other circuits to cooperate with the differential amplifier 5021 to output the reverse signal of the external interference signal to the speaker 10, as described later.

[0060] For example, Fig.11 As shown, the differential amplifier 5021 is also called a differential amplifier circuit, a signal elimination / amplification circuit, and includes: an operational amplifier OPA1, a first input resistor R11, a second input resistor R12, a third input resistor R13 and a feedback resistor R15.

[0061] The positive input terminal of the operational amplifier OPA1 is connected to the first target input terminal through the first input resistor R11, and the first target input terminal is used to receive the first input signal Vi1. The positive input terminal of the operational amplifier OPA1 is also grounded through the third input resistor R13. The inverting input terminal of the operational amplifier OPA1 is connected to the second target input terminal through the second input resistor R12, and the second target input terminal is used to receive the second input signal Vi2. The output terminal of the operational amplifier OPA1 is also connected to the inverting input terminal of the operational amplifier OPA1 through the feedback resistor R15.

[0062] Among them, the following relationship (1) exists between the first input signal Vi1, the second input signal Vi2 and the output signal Vo at the output end of the operational amplifier OPA1:

[0063]

[0064] In the relation (1), Vi1 represents the first input signal. Vi2 represents the second input signal. Vo represents the output signal of the output terminal of the operational amplifier OPA1. r11 represents the resistance of the first input resistor R11. r12 represents the resistance of the second input resistor R12. r13 represents the resistance of the third input resistor R13. r15 represents the resistance of the feedback resistor R15.

[0065] Furthermore, since usually, the resistance of the first input resistor R11 is equal to the resistance of the third input resistor R13, and the resistance of the second input resistor R12 is equal to the resistance of the feedback resistor R15, therefore, the relation (1) can be simplified to the relation (2).

[0066]

[0067] It can be clearly seen from the relation (2) that the output signal Vo at the output terminal of the operational amplifier OPA1 is the amplified result of the difference between the first input signal Vi1 and the second input signal Vi2 of the operational amplifier OPA1.

[0068] It should be noted that by adjusting the gain r15 / r13 of the operational amplifier OPA1, the amplitude of the output signal Vo of the operational amplifier OPA1 can be made the same as the amplitude of the external interference signal of the speaker 10. In this way, the output signal Vo at the output end of the operational amplifier OPA1 can be the external interference signal of the speaker 10, or the inverted signal of the external interference signal of the speaker 10. In some embodiments, the gain r15 / r13 of the operational amplifier OPA1 can be determined by repeated experimental tests.

[0069] Based on this, in some embodiments, such as Fig.12 As shown, the differential amplifier 5021 can be used to separate the external interference signal from the working electrical signal according to the input audio signal.

[0070] The first target input terminal is the first input terminal of the differential amplifier 5021, and the second target input terminal is the second input terminal of the differential amplifier 5021. That is, the positive input terminal of the operational amplifier OPA1 can be connected to the signal detection circuit 501 to receive the working electrical signal (i.e., the first input signal Vi1) output by the signal detection circuit 501. The reverse input terminal of the operational amplifier OPA1 can be used to receive the input audio signal (i.e., the second input signal Vi2). The output signal Vo of the operational amplifier OPA1 is the result of amplifying the difference between the working electrical signal and the input audio signal, which is the external interference signal of the speaker 10.

[0071] In other embodiments, the differential amplifier 5021 may be directly used to separate the reverse signal of the external interference signal from the working electrical signal according to the input audio signal, and output the reverse signal of the external interference signal.

[0072] The first target input terminal is the second input terminal of the differential amplifier 5021, and the second target input terminal is the first input terminal of the differential amplifier 5021. That is, the positive input terminal of the operational amplifier OPA1 can be used to receive the input audio signal (i.e., the first input signal Vi1). The reverse input terminal of the operational amplifier OPA1 can be connected to the signal detection circuit 501 to receive the working electrical signal (i.e., the second input signal Vi2) output by the signal detection circuit 501. The output signal Vo of the operational amplifier OPA1 is the result of amplifying the difference between the input audio signal and the working electrical signal, that is, the inverted signal of the external interference signal of the speaker 10.

[0073] It should be noted that whether the coil winding direction of the detection coil L is the same as the coil winding direction of the voice coil of the speaker 10 (i.e., the target direction) can also determine whether the working electrical signal detected by the detection coil L is in phase with the actual working electrical signal of the speaker 10. When the coil winding direction of the detection coil L is the same as the target direction, the working electrical signal detected by the detection coil L is in phase with the actual working electrical signal of the speaker 10. When the coil winding direction of the detection coil L is opposite to the target direction, the working electrical signal detected by the detection coil L is in phase with the actual working electrical signal of the speaker 10.

[0074] Based on this, the connection relationship of the aforementioned differential amplifier 5021 is illustrated by taking the coil winding direction of the detection coil L as the same as the target direction, and taking the actual working electrical signal of the speaker 10 as an example. Of course, the relationship between the coil winding direction of the detection coil L and the target direction can also be adjusted to control whether the differential amplifier 5021 outputs an external interference signal or outputs a reverse signal of the external interference signal.

[0075] By way of further example, Fig.11 As shown, the differential amplifier 5021 further includes: an output resistor R14 and an output capacitor C11. The output end of the operational amplifier OPA1 is connected to the output end of the differential amplifier 5021 through the output resistor R14. The output end of the operational amplifier OPA1 is also connected to one end of the output capacitor C11 through the output resistor R14, and the other end of the output capacitor C11 is grounded.

[0076] Among them, the output resistor R14 and the output capacitor C11 can form a resistor-capacitor filter (i.e., an RC filter). The resistor-capacitor filter is used to adjust the cutoff frequency by adjusting the values ​​of the output resistor R14 and the output capacitor C11, so as to filter the output signal Vo of the operational amplifier OPA1 according to the cutoff frequency to obtain the processed output signal Vout. The signal frequency of the processed output signal Vout is less than the cutoff frequency. That is, the resistor-capacitor filter is used to adjust the cutoff frequency by adjusting the values ​​of the output resistor R14 and the output capacitor C11, so that the output signal Vo of the operational amplifier OPA1 below the cutoff frequency can be output through the resistor-capacitor filter.

[0077] In some embodiments, the cutoff frequency of the resistor-capacitor filter can be adjusted according to the actual needs of the speaker 10, so as to further adjust the external interference signal output by the operational amplifier OPA1, or the reverse signal of the external interference signal, through the resistor-capacitor filter.

[0078] Optionally, when the differential amplifier 5021 is used to separate the external interference signal from the working electrical signal according to the input audio signal, the external interference signal is in phase with the external interference signal of the speaker 10. In this way, the interference processing circuit 502 also needs to perform reverse processing on the external interference signal to obtain a reverse signal of the external interference signal. Based on this, Fig.13 As shown, the interference processing circuit 502 also includes: a reverse processing unit 5022. The reverse processing unit 5022 is connected to the output end of the differential amplifier 5021. The reverse processing unit 5022 is used to perform reverse processing on the external interference signal to obtain a reverse signal. In this way, when the differential amplifier can only be used to separate the external interference signal from the working electrical signal according to the input audio signal, the reverse processing function of the interference processing unit on the external interference signal can be supplemented, so as to facilitate the subsequent cancellation of the interference signal in the original working electrical signal of the speaker, and effectively avoid the speaker from generating interference sound due to the external interference signal.

[0079] Further optionally, if Fig.14 As shown, the reverse processing unit 5022 may include: an operational amplifier OPA2, a feedback resistor R22 and an input resistor R21. The first input terminal of the operational amplifier OPA2 is used to receive the bias voltage signal Vref. The second input terminal of the operational amplifier OPA2 is connected to the output terminal of the differential amplifier OPA2 through the input resistor R21. The output terminal of the operational amplifier OPA2 is respectively connected to one end of the feedback resistor R22 and the speaker 10. The other end of the feedback resistor R22 is also connected to the second input terminal of the operational amplifier OPA2. For example, in Fig.14In the embodiment, the positive input terminal of the operational amplifier OPA2 is used to receive the bias voltage signal Vref. The negative input terminal of the operational amplifier OPA2 is connected to the output terminal of the differential amplifier OPA2 through the input resistor R21, and is used to receive the external interference signal. The output terminal of the operational amplifier OPA2 is connected to the speaker 10.

[0080] There exists the following relationship (3) between the input signal Vi3 and the output signal Vout2 of the reverse processing unit 5022:

[0081]

[0082] In equation (3), Vout2 represents the output signal of the reverse processing unit 5022, that is, the bias reverse signal. Vref represents the bias voltage signal. Vi3 represents the input signal of the reverse processing unit 5022, that is, the external interference signal output by the differential amplifier OPA2. r22 represents the resistance value of the feedback resistor R22. r21 represents the resistance value of the input resistor R21. Based on this, Fig.15 As shown, the reverse processing unit 5022 can be used to perform reverse processing on the external interference signal based on the bias voltage signal Vref to obtain a bias reverse signal Vout2. The bias reverse signal Vout2 is a superposition signal of the reverse signal of the external interference signal and the bias voltage signal.

[0083] Among them, by setting the bias voltage signal Vref, the reverse processing unit 5022 can prevent the loss of some external interference signals with a signal size less than 0 during the reverse processing of the external interference signal, thereby effectively ensuring the integrity of the reverse signal of the processed external interference signal.

[0084] Based on this, the interference processing circuit 502 also needs to be used to further extract the reverse signal of the external interference signal from the bias reverse signal to output the reverse signal of the external interference signal to the speaker 10. Fig.13 As shown, the interference processing circuit 502 further includes: a capacitor C31. The capacitor C31 is connected to the output end of the operational amplifier OPA2 and the speaker 10 respectively. The capacitor C31 is used to couple the reverse signal in the bias reverse signal Vout2 to the transmission path between the speaker 10 and the audio signal power amplifier circuit 503, so as to output the reverse signal to the speaker 10.

[0085] In this way, by utilizing the DC isolation function of capacitor C31, the bias voltage signal of the DC signal in the bias reverse signal Vout2 can be prevented from flowing to the speaker 10, so as to output the reverse signal of the external interference signal to the speaker 10. The signal input end of the speaker 10 can receive the output audio signal transmitted by the audio signal amplifier circuit 503 and the inverted signal of the external interference signal. Based on this, the external interference signal in the original working electrical signal on the voice coil of the speaker 10 can be offset after being superimposed with the inverted signal of the external interference signal transmitted by the interference processing circuit 502. In this way, the output audio signal can be retained on the voice coil of the speaker 10, and then a clean sound can be output according to the output audio signal, effectively avoiding the interference sound formed on the speaker by the external interference signal.

[0086] In an alternative case, if Fig.16 As shown, the signal detection circuit 501 may include: a signal sampling unit 5012. The signal sampling unit 5012 is respectively connected to the voice coil of the speaker 10 and the interference processing circuit 502. The signal sampling unit 5012 is used to collect the working electrical signal on the voice coil and output the working electrical signal to the interference processing circuit 502.

[0087] As shown above, the voice coil of the speaker 10 will generate an external interference signal under the influence of the interference magnetic field, that is, the magnetic lines of force of the interference magnetic field will form an interference induced electromotive force at both ends of the voice coil when passing through the voice coil of the speaker 10, thereby generating an external interference signal. In this way, a working electrical signal in which the external interference signal and the output audio signal are superimposed will exist in the circuit loop formed by the audio signal amplifier circuit 503 and the voice coil. The signal sampling unit 5012 can be connected to the voice coil of the speaker 10 to collect the working electrical signal, thereby effectively picking up the working electrical signal of the speaker 10.

[0088] Alternatively, if Fig.16 As shown, the signal sampling unit 5012 includes: an analog-to-digital conversion (ADC) sampling module 5012. The ADC sampling module 5012 is respectively connected to the voice coil of the speaker 10 and the interference processing circuit 502. The ADC sampling module 5012 is used to collect the working electrical signal on the voice coil, perform analog-to-digital conversion on the working electrical signal, and obtain a digital working signal.

[0089] Based on this, the interference processing circuit 502 is used to receive an input audio signal, perform analog-to-digital conversion on the input audio signal to obtain a digital audio signal, perform signal difference extraction on the digital audio signal and the digital working signal to obtain a difference signal, perform reverse processing on the difference signal to obtain a target reverse signal of the difference signal, perform digital-to-analog conversion on the target reverse signal to obtain a reverse signal of the external interference signal, and output the reverse signal to the speaker 10.

[0090] For example, Fig.16 As shown, the interference processing circuit 502 includes: an ADC unit 5023, a digital processing unit 5024 and a digital-to-analog conversion (DAC) unit 5025. The digital processing unit 5024 is connected to the ADC unit 5023 and the DAC unit 5025 respectively, and the DAC unit 5025 is also used to connect to the speaker 10.

[0091] The ADC unit 5023 is used to receive an input audio signal, perform analog-to-digital conversion processing on the input audio signal to obtain a digital audio signal, and output the digital audio signal to the digital processing unit 5024. The digital processing unit 5024 is used to perform signal difference extraction processing on the digital audio signal and the digital working signal to obtain a difference signal, perform reverse processing on the difference signal to obtain a target reverse signal of the difference signal, and output the target reverse signal to the DAC unit 5025. The digital processing unit 5024 can be used to perform signal difference extraction processing on the waveform corresponding to the digital audio signal and the waveform corresponding to the digital working signal to obtain a difference signal having a difference waveform between the digital audio signal and the digital working signal, perform reverse processing on the difference signal to obtain a target reverse signal of the difference signal, and output the target reverse signal to the DAC unit 5025. The DAC unit 5025 is used to perform digital-to-analog conversion processing on the target reverse signal to obtain a reverse signal of the external interference signal, and output the reverse signal to the speaker 10.

[0092] In this way, at the signal input end of the speaker 10, it can receive the output audio signal transmitted by the audio signal power amplifier circuit 503 and the inverted signal of the external interference signal transmitted by the DAC unit 5025. Based on this, the external interference signal in the original working electrical signal on the voice coil of the speaker 10 can be offset after being superimposed with the inverted signal of the external interference signal transmitted by the interference processing circuit 502. In this way, the output audio signal can be retained on the voice coil of the speaker 10, and then a clean sound can be output according to the output audio signal, effectively avoiding the interference sound formed on the speaker by the external interference signal.

[0093] In summary, the driving circuit of the speaker provided in the embodiment of the present application includes: a signal detection circuit, an interference processing circuit and an audio signal amplifier circuit. Among them, the audio signal amplifier circuit can be used to pre-process the input audio signal to obtain an output audio signal, and output the output audio signal to the speaker. The signal detection circuit can be used to detect the working electrical signal of the speaker, and output the working electrical signal to the interference processing circuit. The interference processing circuit can be used to receive the input audio signal, and obtain the reverse signal of the external interference signal according to the input audio signal and the working electrical signal, and output the reverse signal to the speaker.

[0094] In this technical solution, the speaker is easily affected by the interference magnetic field generated by the high-power device and generates an external interference signal, so that the working electrical signal of the speaker includes the output audio signal and the superposition signal of the external interference signal. The interference processing circuit in the present application can be used to receive the working electrical signal of the speaker detected by the signal detection circuit, and then obtain the reverse signal of the external interference signal according to the input audio signal and the working electrical signal of the speaker, and output the reverse signal to the speaker. In this way, the speaker can receive the reverse signal of the external interference signal to offset the interference signal in the original working electrical signal, thereby effectively avoiding the interference sound formed by the external interference signal in the speaker and improving the sound playback effect.

[0095] Furthermore, since the driving circuit of the speaker of the present application can effectively cancel the interference signal in the original working electrical signal of the speaker, the interference sound of the speaker caused by the external interference signal can be avoided. Therefore, the speaker driven by the driving circuit of the present application and its signal processing circuit can be freely laid out, which is beneficial to the structure and appearance design of the electronic device.

[0096] The embodiment of the present application also provides a speaker module. The speaker module includes: a speaker and any driving circuit provided in the embodiment of the present application. Optionally, the speaker module may include Figure 4 , Figure 5 , Figure 6 , Fig.10 , Fig.13 or Fig.16 The speaker driving circuit is shown.

[0097] Optionally, when the signal detection circuit includes a detection coil, the speaker module further includes: a PCB, and the detection coil is arranged on a metal layer of the PCB. The speaker module includes the driving circuit provided in the embodiment of the present application, thereby achieving the same technical effect.

[0098] In the speaker module provided in the embodiment of the present application, the speaker is easily affected by the interference magnetic field generated by the high-power device and generates an external interference signal, so that the working electrical signal of the speaker includes the output audio signal and the superposition signal of the external interference signal. The interference processing circuit in the present application can be used to receive the working electrical signal of the speaker detected by the signal detection circuit, and then obtain the reverse signal of the external interference signal according to the input audio signal and the working electrical signal of the speaker, and output the reverse signal to the speaker. In this way, the speaker can receive the reverse signal of the external interference signal to offset the interference signal in the original working electrical signal, thereby effectively avoiding the interference sound formed by the external interference signal on the speaker and improving the sound playback effect.

[0099] Furthermore, since the driving circuit of the speaker of the present application can effectively cancel the interference signal in the original working electrical signal of the speaker, the interference sound of the speaker caused by the external interference signal can be avoided. Therefore, the speaker driven by the driving circuit of the present application and its signal processing circuit can be freely laid out, which is beneficial to the structure and appearance design of the electronic device.

[0100] The present application also provides an electronic device, the electronic device comprising any driving circuit provided in the present application. Alternatively, the electronic device comprises the speaker module provided in the present application. Optionally, the electronic device may comprise Figure 4 , Figure 5 , Figure 6 , Fig.10 , Fig.13 or Fig.16 The electronic device includes the driving circuit provided by the embodiment of the present application, thereby achieving the same technical effect.

[0101] In the speaker module provided in the embodiment of the present application, the speaker is easily affected by the interference magnetic field generated by the high-power device and generates an external interference signal, so that the working electrical signal of the speaker includes the output audio signal and the superposition signal of the external interference signal. The interference processing circuit in the present application can be used to receive the working electrical signal of the speaker detected by the signal detection circuit, and then obtain the reverse signal of the external interference signal according to the input audio signal and the working electrical signal of the speaker, and output the reverse signal to the speaker. In this way, the speaker can receive the reverse signal of the external interference signal to offset the interference signal in the original working electrical signal, thereby effectively avoiding the interference sound formed by the external interference signal on the speaker and improving the sound playback effect.

[0102] Furthermore, since the driving circuit of the speaker of the present application can effectively cancel the interference signal in the original working electrical signal of the speaker, the interference sound of the speaker caused by the external interference signal can be avoided. Therefore, the speaker driven by the driving circuit of the present application and its signal processing circuit can be freely laid out, which is beneficial to the structure and appearance design of the electronic device.

[0103] In the embodiments of the present application, the electronic device may be a terminal, or may be other devices other than a terminal. For example, the electronic device may be a mobile phone, a tablet computer, a laptop computer, a PDA, a vehicle-mounted electronic device, a mobile Internet Device (MID), an augmented reality (AR) / virtual reality (VR) device, a robot, a wearable device, an ultra-mobile personal computer (UMPC), a netbook or a personal digital assistant (PDA), etc. It may also be a server, a network attached storage (NAS), a personal computer (PC), a television (TV), a teller machine or a self-service machine, etc., which is not specifically limited in the embodiments of the present application.

[0104] The electronic device in the embodiment of the present application may be a device having an operating system. The operating system may be an Android operating system, an iOS operating system, or other possible operating systems, which are not specifically limited in the embodiment of the present application.

[0105] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0106] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, a disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0107] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A speaker driving circuit, characterized in that: The driving circuit comprises: a signal detection circuit, an interference processing circuit and an audio signal power amplifier circuit; The audio signal power amplifier circuit is connected to the speaker, and is used to pre-process the input audio signal to obtain an output audio signal, and output the output audio signal to the speaker; The signal detection circuit is connected to the interference processing circuit, and is used to detect the working electrical signal of the speaker, and output the working electrical signal to the interference processing circuit, wherein the working electrical signal includes a superimposed signal of the output audio signal and an external interference signal; The interference processing circuit is connected to the speaker, and is used for receiving the input audio signal, obtaining a reverse signal of the external interference signal according to the input audio signal and the working electrical signal, and outputting the reverse signal to the speaker.

2. The driving circuit according to claim 1, characterized in that: The signal detection circuit comprises: a magnetic induction sensor; The magnetic induction sensor is arranged close to the speaker and connected to the interference processing circuit, and is used to sense the external interference electromagnetic signal and the target electromagnetic signal generated by the speaker, convert the external interference signal and the target electromagnetic signal to obtain the working electrical signal, and output the working electrical signal to the interference processing circuit. The external interference electromagnetic signal is used to cause the speaker to generate the external interference signal, and the target electromagnetic signal is an electromagnetic signal generated by the voice coil of the speaker due to the output audio signal.

3. The driving circuit according to claim 2, characterized in that: The magnetic induction sensor comprises: a detection coil; The coil winding direction of the detection coil is the same as or opposite to the target direction, and the target direction is the coil winding direction of the voice coil in the speaker.

4. The driving circuit according to claim 2 or 3, characterized in that: The interference processing circuit comprises: an interference processing unit; The interference processing unit is connected to the speaker, and is used to receive the input audio signal, separate the external interference signal from the working electrical signal according to the input audio signal, and reversely process the external interference signal to obtain the reverse signal.

5. The driving circuit according to claim 4, characterized in that: The interference processing unit includes: a differential amplifier, the differential amplifier is used to separate the external interference signal from the working electrical signal according to the input audio signal; The first input end of the differential amplifier is connected to the signal detection circuit, the second input end of the differential amplifier is used to receive the input audio signal, and the output end of the differential amplifier is connected to the speaker.

6. The driving circuit according to claim 5, characterized in that: The interference processing circuit further includes: a reverse processing unit; The reverse processing unit is connected to the output end of the differential amplifier and is used to perform reverse processing on the external interference signal to obtain the reverse signal.

7. The driving circuit according to claim 6, characterized in that: The reverse processing unit includes: an operational amplifier, a feedback resistor and an input resistor; The first input terminal of the operational amplifier is used to receive a bias voltage signal, the second input terminal of the operational amplifier is connected to the output terminal of the differential amplifier through the input resistor, the output terminal of the operational amplifier is respectively connected to one end of the feedback resistor and the speaker, and the other end of the feedback resistor is also connected to the second input terminal of the operational amplifier. The reverse processing unit is used to perform reverse processing on the external interference signal based on the bias voltage signal to obtain a bias reverse signal, where the bias reverse signal is a superposition signal of the reverse signal of the external interference signal and the bias voltage signal; The interference processing circuit also includes: a capacitor, which is respectively connected to the output end of the operational amplifier and the speaker, and is used to couple the reverse signal in the biased reverse signal to the transmission path between the speaker and the audio signal power amplifier circuit to output the reverse signal to the speaker.

8. The driving circuit according to claim 1, characterized in that: The signal detection circuit comprises: a signal sampling unit; The signal sampling unit is connected to the voice coil of the speaker and the interference processing circuit respectively, and is used to collect the working electrical signal on the voice coil and output the working electrical signal to the interference processing circuit.

9. The driving circuit according to claim 8, characterized in that: The signal sampling unit comprises: an analog-to-digital conversion sampling module; The analog-to-digital conversion sampling module is connected to the voice coil of the speaker and the interference processing circuit respectively, and is used to collect the working electrical signal on the voice coil, perform analog-to-digital conversion processing on the working electrical signal, and obtain a digital working signal; The interference processing circuit is used to receive the input audio signal, perform analog-to-digital conversion on the input audio signal to obtain a digital audio signal, perform signal difference extraction on the digital audio signal and the digital working signal to obtain a difference signal, perform reverse processing on the difference signal to obtain a target reverse signal of the difference signal, perform digital-to-analog conversion on the target reverse signal to obtain a reverse signal of the external interference signal, and output the reverse signal to the speaker.

10. The driving circuit according to claim 3, characterized in that: The driving circuit is arranged on a speaker module including a printed circuit board PCB, and the detection coil is arranged on a metal layer of the PCB.

11. A speaker module, characterized in that: The speaker module comprises: a speaker and a driving circuit as described in any one of claims 1 to 10.

12. The speaker module according to claim 11, characterized in that: The signal detection circuit includes the detection coil; the speaker module also includes: a printed circuit board PCB, and the detection coil is arranged on the metal layer of the PCB.

13. An electronic device, characterized in that: The electronic device comprises the driving circuit described in any one of claims 1 to 10, or comprises the speaker module described in any one of claims 11 to 12.

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