CN112492475B - MEMS microphone and working control method thereof - Google Patents
MEMS microphone and working control method thereof Download PDFInfo
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- CN112492475B CN112492475B CN202011372109.XA CN202011372109A CN112492475B CN 112492475 B CN112492475 B CN 112492475B CN 202011372109 A CN202011372109 A CN 202011372109A CN 112492475 B CN112492475 B CN 112492475B
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- mems microphone
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R19/00—Electrostatic transducers
- H04R19/04—Microphones
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/005—Circuits for transducers, loudspeakers or microphones for combining the signals of two or more microphones
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
- H04R2201/003—Mems transducers or their use
Abstract
The invention relates to the technical field of microphones, in particular to an MEMS (micro-electromechanical systems) microphone and a working control method thereof. According to the MEMS microphone, the first MEMS microphone unit and the second MEMS microphone unit with different sensitivities are arranged to obtain two paths of electric signals with different sensitivities, the two paths of electric signals are converted into two paths of digital signals by the two analog-to-digital converters respectively, and the two paths of digital signals are superposed and output, so that the ultra-large dynamic range is realized, and the high AOP is realized while the signal-to-noise ratio is high.
Description
[ technical field ] A method for producing a semiconductor device
The invention relates to the technical field of microphones, in particular to an MEMS (micro-electromechanical system) microphone and a working control method thereof.
[ background of the invention ]
The MEMS microphone mainly includes a MEMS sensor and an ASIC (Application-Specific Integrated Circuit) chip, which are electrically connected to convert a sound signal into an electrical signal, thereby implementing the function of the microphone.
In the prior art, a MEMS microphone mostly amplifies and outputs an electrical signal through an amplifier in an ASIC chip, and cannot simultaneously consider a high signal-to-noise ratio and a high AOP (Acoustic Overload Point).
Therefore, there is a need to provide a new MEMS microphone to solve the above technical problems.
[ summary of the invention ]
The invention aims to provide an MEMS microphone and a working control method thereof, and aims to solve the technical problem that the MEMS microphone in the prior art cannot simultaneously give consideration to high signal-to-noise ratio and high AOP.
The technical scheme of the invention is as follows: the MEMS microphone comprises a first MEMS microphone unit, a second MEMS microphone unit and an ASIC chip, wherein the sensitivity of the second MEMS microphone unit is greater than that of the first MEMS microphone unit, the ASIC chip comprises a first amplifier electrically connected with the first MEMS microphone unit, a first analog-to-digital converter electrically connected with the first amplifier, a second amplifier electrically connected with the second MEMS microphone unit, a second analog-to-digital converter electrically connected with the second amplifier and output ends respectively electrically connected with the first analog-to-digital converter and the second analog-to-digital converter.
Preferably, the first MEMS microphone unit is a first MEMS chip, and the second MEMS microphone unit is a second MEMS chip.
Preferably, the ASIC chip further comprises a first bias voltage module for providing a bias voltage to the first MEMS chip and a second bias voltage module for providing a bias voltage to the second MEMS chip.
Preferably, the first MEMS microphone unit includes a first diaphragm, the second MEMS microphone unit includes a second diaphragm, and the first MEMS microphone unit and the second MEMS microphone unit are integrated on a third MEMS chip.
Preferably, the input of the first MEMS microphone unit and the input of the second MEMS microphone unit are connected to each other and are both grounded.
Preferably, a first input terminal of the first amplifier is connected with an output terminal of the first MEMS microphone unit, and a second input terminal of the first amplifier is grounded; the first input end of the second amplifier is connected with the output end of the second MEMS microphone unit, and the second input end of the second amplifier is grounded.
The other technical scheme of the invention is as follows: the method for controlling the operation of the MEMS microphone is provided, and the MEMS microphone is the MEMS microphone and comprises the following steps:
the MEMS microphone device comprises a first MEMS microphone unit and a second MEMS microphone unit, wherein the first MEMS microphone unit and the second MEMS microphone unit respectively convert sound signals input to the MEMS microphones into a first electrical signal and a second electrical signal, and the sensitivity of the second electrical signal is greater than that of the first electrical signal;
a first analog-to-digital converter converts a first electric signal processed by a first amplifier into a first digital signal, and a second analog-to-digital converter converts a second electric signal processed by a second amplifier into a second digital signal, wherein the first analog-to-digital converter operates by a first clock signal, the second analog-to-digital converter operates by a second clock signal, and the first clock signal and the second clock signal have the same period and are delayed in phase by one or more periods;
and outputting the first digital signal and the second digital signal after superposition.
Preferably, the first digital signal is located in a high order range and the second digital signal is located in a low order range.
Preferably, the sensitivity of the first MEMS microphone unit is-68 dBFS, the sensitivity of the second MEMS microphone unit is-20 dBFS, and the dynamic range of the superimposed signal of the first digital signal and the second digital signal is-144 dBFS-0 dBFS.
Preferably, the sound pressure of the superimposed signal of the first digital signal and the second digital signal is 18dBSPL to 162 dBSPL.
The invention has the beneficial effects that: according to the MEMS microphone, the first MEMS microphone unit and the second MEMS microphone unit with different sensitivities are arranged to obtain two paths of electric signals with different sensitivities, the two paths of electric signals are converted into two paths of digital signals by the two analog-to-digital converters respectively, and the two paths of digital signals are superposed and output, so that the ultra-large dynamic range is realized, and the high AOP is realized while the signal-to-noise ratio is high.
[ description of the drawings ]
Fig. 1 is a schematic structural diagram of a MEMS microphone according to a first embodiment of the present invention;
fig. 2 is a schematic structural diagram of a preferred implementation of a MEMS microphone according to a first embodiment of the present invention;
fig. 3 is a schematic diagram illustrating the operation of a MEMS microphone according to a first embodiment of the present invention;
fig. 4 is a flowchart of an operation control method of a MEMS microphone according to a second embodiment of the present invention;
fig. 5 is a schematic diagram illustrating an operation control method of a MEMS microphone according to a second embodiment of the present invention.
[ detailed description ] embodiments
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
First embodiment
Referring to fig. 1 to 3, a MEMS microphone according to a first embodiment of the present invention includes a first MEMS microphone unit 10, a second MEMS microphone unit 20, and an ASIC chip 30, wherein a sensitivity of the second MEMS microphone unit 20 is greater than a sensitivity of the first MEMS microphone unit 10, and the ASIC chip 30 includes a first amplifier 31 electrically connected to the first MEMS microphone unit 10, a first analog-to-digital converter 32 electrically connected to the first amplifier 31, a second amplifier 33 electrically connected to the second MEMS microphone unit 20, a second analog-to-digital converter 34 electrically connected to the second amplifier 33, and an output terminal 35 electrically connected to the first analog-to-digital converter 32 and the second analog-to-digital converter 34, respectively.
In the present embodiment, the first MEMS microphone unit 10 is a low-sensitivity microphone sensor, and the converted electrical signal is a low-sensitivity electrical signal; the second MEMS microphone unit 20 is a high-sensitivity microphone sensor, and the converted electrical signal is a high-sensitivity electrical signal; the first amplifier 31 amplifies the low-sensitivity electric signal, and the second amplifier 33 amplifies the high-sensitivity electric signal; referring to fig. 3, the first analog-to-digital converter 32 converts the low-sensitivity electrical signal into a digital signal, the second analog-to-digital converter 34 converts the high-sensitivity electrical signal into a digital signal, the digital signal output by the first analog-to-digital converter 32 and the digital signal output by the second analog-to-digital converter 34 are transmitted on the same data line with high bits and low bits, respectively, and high AOP and high signal-to-noise ratio are simultaneously achieved.
In a first alternative embodiment, the first MEMS microphone unit 10 is a first MEMS chip and the second MEMS microphone unit 20 is a second MEMS chip. Further, the first MEMS chip and the second MEMS chip may adopt the same MEMS chip, and the adjustment of the sensitivity of the first MEMS chip and the second MEMS chip is achieved by providing different bias voltages to the first MEMS chip and the second MEMS chip, respectively. Thus, referring to fig. 2, in the present embodiment, the ASIC chip 30 further includes a first bias voltage module 36 for providing a bias voltage to the first MEMS chip and a second bias voltage module 37 for providing a bias voltage to the second MEMS chip.
In a second alternative embodiment, the first MEMS microphone unit 10 includes a first diaphragm, and the second MEMS microphone unit 20 includes a second diaphragm, wherein the first diaphragm and the second diaphragm have different structures and sizes, so as to achieve different sensitivities of the first MEMS microphone unit 10 and the second MEMS microphone unit 20, and the first MEMS microphone unit 10 and the second MEMS microphone unit 20 may be integrated on the same MEMS chip.
As shown in fig. 1, the input terminal 11 of the first MEMS microphone unit 10 and the input terminal 21 of the second MEMS microphone unit 20 are connected to each other and are grounded. The first input 311 of the first amplifier 31 is connected to the output 12 of the first MEMS microphone unit 10, and the second input 312 of the first amplifier 31 is grounded; the first input 331 of the second amplifier 33 is connected to the output 22 of the second MEMS microphone unit 20, and the second input 332 of the second amplifier 33 is connected to ground. The input 321 of the first analog-to-digital converter 32 is connected to the output 313 of the first amplifier 31, the input 341 of the second analog-to-digital converter 34 is connected to the output 333 of the second amplifier 33, and the output 322 of the first analog-to-digital converter 32 and the output 342 of the second analog-to-digital converter 34 are both connected to the output 35 of the ASIC chip 30.
Second embodiment
An embodiment of the present invention provides a method for controlling an operation of an MEMS microphone, which is applied to the MEMS microphone of the first embodiment, and as shown in fig. 4, the method includes the following steps:
s101, the first MEMS microphone unit 10 and the second MEMS microphone unit 20 respectively convert a sound signal input to the MEMS microphone into a first electrical signal and a second electrical signal, wherein the sensitivity of the second electrical signal is greater than the sensitivity of the first electrical signal.
S102, the first analog-to-digital converter 33 converts the first electrical signal processed by the first amplifier 31 into a first digital signal, and the second analog-to-digital converter 34 converts the second electrical signal processed by the second amplifier 32 into a second digital signal, wherein the first analog-to-digital converter 33 operates with a first clock signal, the second analog-to-digital converter 34 operates with a second clock signal, and the first clock signal and the second clock signal have the same period and are phase-delayed by one or more periods.
And S103, outputting the first digital signal and the second digital signal after superposition.
In step S101, the first MEMS microphone unit 10 and the second MEMS microphone unit 20 respectively process the same sound signal to obtain a first electrical signal and a second electrical signal. In step S102, one of the first analog-to-digital converter 33 and the second analog-to-digital converter 34 may be delayed from the other by several clock cycles, for example, the phase of the first clock signal is delayed by one or more cycles from the second clock signal, or the phase of the second clock signal is delayed by one or more cycles from the first clock signal. In step S103, the first digital signal is written into the high bit, the second digital signal is written into the low bit, and the two digital signals are superimposed and output from the output terminal 35.
In the present embodiment, when the sound is small, the first electric signal of low sensitivity is small, and the first digital signal converted by the first analog-to-digital converter 33 is written in the high order, and the high order data is kept at 0; the second electrical signal with high sensitivity is written to the lower bits by the second digital signal converted by the second analog-to-digital converter 34. When the sound is large, the first digital signal converted from the second electric signal with high sensitivity reaches the full scale, and the second digital signal converted from the first electric signal with low sensitivity is written into the high order.
Specifically, in a typical operation mode, the high-order data is 8 bits, the low-order data is 16 bits, the sensitivity of the first MEMS microphone unit 10 is-68 dBFS, and the sensitivity of the second MEMS microphone unit 20 is-20 dBFS. For a 16-bit digital signal, the maximum value is 65536 and the calculation formula for the Full decibel Scale (dBFS) is
Wherein, the sample is 1-65536, and the dynamic range of the second digital signal is-96 dBFS-0 dBFS. Similarly, the dynamic range of the first digital signal is obtained to be-48 dBFS to 0 dBFS. Thus, the dynamic range of the superimposed signal of the first digital signal and the second digital signal is-144 dBFS to 0 dBFS. The sound pressure of the superimposed signal of the first digital signal and the second digital signal is 18 dBSPL-162 dBSPL.
While the foregoing is directed to embodiments of the present invention, it will be understood by those skilled in the art that various changes may be made without departing from the spirit and scope of the invention.
Claims (10)
1. A MEMS microphone is characterized by comprising a first MEMS microphone unit, a second MEMS microphone unit and an ASIC chip, the sensitivity of the second MEMS microphone unit is greater than the sensitivity of the first MEMS microphone unit, the ASIC chip comprises a first amplifier electrically connected with the first MEMS microphone unit, a first analog-to-digital converter electrically connected with the first amplifier, a second amplifier electrically connected with the second MEMS microphone unit, a second analog-to-digital converter electrically connected with the second amplifier and output ends respectively electrically connected with the first analog-to-digital converter and the second analog-to-digital converter, wherein the first analog-to-digital converter operates with a first clock signal and the second analog-to-digital converter operates with a second clock signal, the first clock signal and the second clock signal are the same period and phase delayed by one or more of the periods.
2. The MEMS microphone of claim 1, wherein the first MEMS microphone unit is a first MEMS chip and the second MEMS microphone unit is a second MEMS chip.
3. The MEMS microphone of claim 2, wherein the ASIC chip further comprises a first bias voltage module for providing a bias voltage to the first MEMS chip and a second bias voltage module for providing a bias voltage to the second MEMS chip.
4. The MEMS microphone of claim 1, wherein the first MEMS microphone unit comprises a first diaphragm, the second MEMS microphone unit comprises a second diaphragm, and the first MEMS microphone unit and the second MEMS microphone unit are integrated on a third MEMS chip.
5. The MEMS microphone of claim 1, wherein the input of the first MEMS microphone unit and the input of the second MEMS microphone unit are connected to each other and are both grounded.
6. The MEMS microphone of claim 5, wherein a first input of the first amplifier is connected to an output of the first MEMS microphone unit, and a second input of the first amplifier is grounded; the first input end of the second amplifier is connected with the output end of the second MEMS microphone unit, and the second input end of the second amplifier is grounded.
7. An operation control method of a MEMS microphone according to any one of claims 1 to 6, comprising:
the MEMS microphone device comprises a first MEMS microphone unit and a second MEMS microphone unit, wherein the first MEMS microphone unit and the second MEMS microphone unit respectively convert sound signals input to the MEMS microphones into a first electrical signal and a second electrical signal, and the sensitivity of the second electrical signal is greater than that of the first electrical signal;
a first analog-to-digital converter converts a first electric signal processed by a first amplifier into a first digital signal, and a second analog-to-digital converter converts a second electric signal processed by a second amplifier into a second digital signal, wherein the first analog-to-digital converter operates by a first clock signal, the second analog-to-digital converter operates by a second clock signal, and the first clock signal and the second clock signal have the same period and are delayed in phase by one or more periods;
and outputting the first digital signal and the second digital signal after superposition.
8. The method of claim 7, wherein the first digital signal is in a high range and the second digital signal is in a low range.
9. The method of claim 8, wherein the sensitivity of the first MEMS microphone unit is-68 dBFS, the sensitivity of the second MEMS microphone unit is-20 dBFS, and the dynamic range of the superimposed signal of the first digital signal and the second digital signal is-144 dBFS-0 dBFS.
10. The method of controlling an operation of a MEMS microphone according to claim 9, wherein the sound pressure of the superimposed signal of the first digital signal and the second digital signal is 18dBSPL to 162 dBSPL.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011372109.XA CN112492475B (en) | 2020-11-30 | 2020-11-30 | MEMS microphone and working control method thereof |
| PCT/CN2020/138835 WO2022110421A1 (en) | 2020-11-30 | 2020-12-24 | Mems microphone and working control method therefor |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011372109.XA CN112492475B (en) | 2020-11-30 | 2020-11-30 | MEMS microphone and working control method thereof |
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| CN112492475A CN112492475A (en) | 2021-03-12 |
| CN112492475B true CN112492475B (en) | 2022-01-11 |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0820210A3 (en) * | 1997-08-20 | 1998-04-01 | Phonak Ag | A method for elctronically beam forming acoustical signals and acoustical sensorapparatus |
| US20060013412A1 (en) * | 2004-07-16 | 2006-01-19 | Alexander Goldin | Method and system for reduction of noise in microphone signals |
| TW200904222A (en) * | 2007-02-26 | 2009-01-16 | Yamaha Corp | Sensitive silicon microphone with wide dynamic range |
| US9380380B2 (en) * | 2011-01-07 | 2016-06-28 | Stmicroelectronics S.R.L. | Acoustic transducer and interface circuit |
| CN103402160B (en) * | 2013-07-10 | 2016-12-28 | 瑞声声学科技(深圳)有限公司 | MEMS microphone and operation control method thereof |
| CN104284275B (en) * | 2013-07-12 | 2018-10-09 | 钰太芯微电子科技（上海）有限公司 | A kind of microphone array system of super low noise high amplitude audio capturing |
| US20150208165A1 (en) * | 2014-01-21 | 2015-07-23 | Knowles Electronics, Llc | Microphone Apparatus and Method To Provide Extremely High Acoustic Overload Points |
| CN105101024A (en) * | 2014-04-22 | 2015-11-25 | 钰太芯微电子科技（上海）有限公司 | Multi-diaphragm MEMS (Micro-Electro-Mechanical System) microphone structure |
| CN105611474B (en) * | 2014-11-24 | 2019-01-29 | 山东共达电声股份有限公司 | A kind of silicon capacitor microphone |
| CN105744452B (en) * | 2014-12-12 | 2019-04-02 | 瑞声声学科技(深圳)有限公司 | MEMS microphone circuit |
| CN105050013B (en) * | 2015-07-28 | 2019-03-05 | 瑞声声学科技(深圳)有限公司 | A kind of operation control method of MEMS microphone and the MEMS microphone |
| CN107040831A (en) * | 2016-02-04 | 2017-08-11 | 北京卓锐微技术有限公司 | A kind of microphone for having a delay feature |
| US10250980B2 (en) * | 2016-10-19 | 2019-04-02 | Fortemedia, Inc. | Digital microphone and control method therefor |
| CN106658323A (en) * | 2017-02-28 | 2017-05-10 | 浙江诺尔康神经电子科技股份有限公司 | Dual microphone noise reduction system and method for cochlear implants and hearing aids |
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| CN112492475A (en) | 2021-03-12 |
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