microphone

Abstract

The present invention provides a microphone. [Solution] The microphone includes a protective structure having an accommodating space, and an ASIC chip and a MEMS microphone chip accommodated in the accommodating space, and the microphone further includes a low-pass filter circuit, which is connected between the ASIC chip and the MEMS microphone chip, or the low-pass filter circuit is integrated into the ASIC chip, and the high-pass filter circuit has a high cut-off frequency greater than 20KHz. By providing the low-pass filter circuit, interference in the ultrasonic frequency band can be filtered out, noise can be reduced, and sound quality can be improved.

Description

[Technical field]

[0001] The present invention relates to the field of electroacoustic conversion, in particular to microphones. [Background technology]

[0002] Micro Electro Mechanical Systems (MEMS) microphones are microphones manufactured based on MEMS sensor technology. They have improved noise reduction performance, good high frequency performance and electromagnetic interference suppression capabilities, and are widely used in various electronic products such as smartphones, shift-by-wire, tablets and laptops.

[0003] At present, the high power ultrasonic transceiver is widely used, so the microphone is overloaded in the relevant sound band, which causes noise, and the noise level depends on the power level of the ultrasonic transceiver itself, the distance from the mobile phone microphone, and the sensitivity of the microphone in the relevant frequency band. In the related art, the 48KHz sampling of the encoder / decoder filters out the sound with a frequency of 24KHz or higher, but the noise is already generated inside the microphone and extends to low frequencies, which causes a pop sound that is small in amplitude but obvious to the ear.

[0004] Therefore, there is a need to provide a new microphone to solve the above technical problems. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a microphone, which is capable of filtering out interference in the ultrasonic frequency band by providing a low pass filter circuit. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a microphone, which includes a protective structure having an accommodating space, and an ASIC chip and a MEMS microphone chip accommodated in the accommodating space, and the microphone further includes a low-pass filter circuit, the low-pass filter circuit is connected between the ASIC chip and the MEMS microphone chip, or the low-pass filter circuit is integrated within the ASIC chip, and the high-pass filter circuit has a high cut-off frequency greater than 20KHz.

[0007] Furthermore, when the low-pass filter circuit is integrated into the ASIC chip, the input terminal of the low-pass filter circuit serves as the input terminal of the ASIC chip.

[0008] Furthermore, the low-pass filter circuit includes an RC circuit.

[0009] Furthermore, the low-pass filter circuit further includes an operational amplifier circuit connected to the RC circuit.

[0010] Furthermore, the low-pass filter circuit includes a field effect transistor.

[0011] Furthermore, the low-pass filter circuit includes a junction bipolar transistor.

[0012] Furthermore, the low-pass filter circuit includes a diode.

[0013] Furthermore, the protective structure has a sound hole formed therethrough, and includes a wiring board and a housing that is fitted over the wiring board to form the storage space. Effect of the Invention

[0014] Compared with the related art, the microphone of the present invention includes a protective structure having an accommodating space, and an ASIC chip and a MEMS microphone chip accommodated in the accommodating space, and the microphone further includes a low-pass filter circuit, which is connected between the ASIC chip and the MEMS microphone chip, or the low-pass filter circuit is integrated in the ASIC chip, and the high-pass filter circuit has a high cut-off frequency greater than 20KHz. Through the action of the low-pass filter circuit, interference in the ultrasonic frequency band can be filtered out, noise can be reduced, and sound quality can be improved.

[0015] In order to more clearly explain the technical solutions in the embodiments of the present invention, the following briefly introduces drawings necessary for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can further obtain other drawings based on these drawings without any creative work. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic structural diagram of a microphone according to an embodiment of the present invention; [Diagram 2] FIG. 2 is another structural schematic diagram of a microphone according to an embodiment of the present invention. [Diagram 3] 4 is an operating frequency waveform diagram of the low-pass filter circuit according to the embodiment of the present invention. [Figure 4] 10 is a waveform diagram showing the change in sensitivity with frequency before and after the installation of a low-pass filter circuit in a microphone according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The technical solutions in the embodiments of the present invention will be described below clearly and completely with reference to the drawings in the embodiments of the present invention, and obviously, the described embodiments are only some of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative labor shall fall within the scope of protection of the present invention.

[0018] 1, the microphone of the present invention includes a protective structure 10 having an accommodation space 1A, and an ASIC chip 11 and a MEMS microphone chip 12 accommodated in the accommodation space 1A. Furthermore, the protective structure 10 has a sound hole 1B penetrating therethrough, and includes a wiring board 101 and a housing 102 that is fitted over the wiring board 101 to form the accommodation space 1A.

[0019] Here, the microphone further includes a low-pass filter circuit 13, which is connected between the ASIC chip 11 and the MEMS microphone chip 12, as shown in Fig. 1, or is integrated into the ASIC chip 12, as shown in Fig. 2. Furthermore, when the low-pass filter circuit 13 is integrated into the ASIC chip 12, the input terminal of the low-pass filter circuit 13 can be the input terminal of the ASIC chip 12.

[0020] Here, as shown in FIG. 3, the upper cutoff frequency of the low-pass filter circuit 13 is greater than 20 KHz.

[0021] In some embodiments, the low pass filter circuit 13 includes an RC circuit, for example the RC circuit may be a first order RC filter circuit, i.e. a filter circuit consisting of one capacitor and one resistor, or the RC circuit may be a multi-order filter circuit.

[0022] Furthermore, the low-pass filter circuit 13 may further include an operational amplifier circuit connected to the RC circuit.

[0023] In another embodiment, the low pass filter circuit 13 includes field effect transistors, ie, the low pass filter circuit 13 uses field effect transistors to achieve the filtering function.

[0024] In another embodiment, the low pass filter circuit 13 includes junction bipolar transistors, ie, the low pass filter circuit 13 uses junction bipolar transistors to achieve the filtering function.

[0025] In another embodiment, the low pass filter circuit 13 includes a diode, and the low pass filter circuit 13 uses the diode to achieve a filtering function.

[0026] In the embodiment of the present invention, a low-pass filter circuit 13 is provided between the ASIC chip 11 and the MEMS microphone chip 12, or the low-pass filter circuit 13 is integrated in the ASIC chip 11, so that the interference in the ultrasonic frequency band can be filtered out and removed by the action of the low-pass filter circuit 13, and the noise can be reduced to improve the sound quality. As shown in Fig. 4, Fig. 4(a) is a waveform diagram showing the change in sensitivity with frequency when the microphone does not have the low-pass filter circuit 13, and Fig. 4(b) is a waveform diagram showing the change in sensitivity with frequency after the microphone has the low-pass filter circuit 13. As is clear from the comparison between Fig. 4(a) and Fig. 4(b), after the microphone has the low-pass filter circuit 13, the ultrasonic frequency band in the audio signal is largely removed, and the sound quality is greatly improved.

[0027] The above is only an embodiment of the present invention, and those skilled in the art may further improve the present invention without departing from the creative concept of the present invention, and it should be understood that all of these fall within the scope of the present invention.

Claims

1. A microphone including a protective structure having an accommodation space, and an ASIC chip and a MEMS microphone chip accommodated in the accommodation space, The microphone further includes a low pass filter circuit, the low pass filter circuit being connected between the ASIC chip and the MEMS microphone chip; The high-frequency cutoff frequency of the low-pass filter circuit is greater than 20 KHz, The protective structure has a sound hole formed therethrough, and the protective structure includes a wiring board and a housing that is fitted over the wiring board to form the accommodation space, a microphone characterized in that the ASIC chip, the MEMS microphone chip, and the low-pass filter circuit are all provided on the wiring board, the sound hole is formed through the side of the housing facing the wiring board, the thickness of the housing is smaller than the thickness of the wiring board, the sound hole is provided at a distance from each of the ASIC chip, the MEMS microphone chip, and the low-pass filter circuit, and the sound hole is configured so as not to face each of the ASIC chip, the MEMS microphone chip, and the low-pass filter circuit.

2. 2. The microphone of claim 1, wherein the low pass filter circuit includes an RC circuit.

3. 3. The microphone of claim 2, wherein the low pass filter circuit further includes an operational amplifier circuit connected to the RC circuit.

4. 2. The microphone of claim 1, wherein the low pass filter circuit includes a field effect transistor.

5. 2. The microphone of claim 1, wherein the low-pass filter circuit includes a junction bipolar transistor.

6. 2. The microphone of claim 1, wherein the low pass filter circuit includes a diode.

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