CN105764017B - A kind of silicon capacitor microphone - Google Patents
A kind of silicon capacitor microphone Download PDFInfo
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- CN105764017B CN105764017B CN201410782518.5A CN201410782518A CN105764017B CN 105764017 B CN105764017 B CN 105764017B CN 201410782518 A CN201410782518 A CN 201410782518A CN 105764017 B CN105764017 B CN 105764017B
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Abstract
The present invention provides a kind of silicon capacitor microphone, sensitive structure is matched with the frequency characteristic of mating integrated circuit；Wherein sensitive structure specifies the high 3dB or more of response of the response ratio microphone low frequency flat segments of frequency point in encapsulating housing in microphone works bandwidth, and this point can be realized by the way that size and the material parameter of the sensitive structure is arranged；And corresponding setting is also made in the response of mating integrated circuit frequency range near silicon capacitor microphone bandwidth of operation, to guarantee that microphone frequency characteristic is smooth in bandwidth of operation, this point can amplify the frequency characteristic with processing links by adjusting the signal of mating integrated circuit to realize.Under existing technological level, the signal-to-noise ratio of silicon capacitor microphone is improved 1dB or more due to applying design means of the invention.
Description
Technical field
It is especially a kind of by adjusting sensitive structure and mating integrated circuit the present invention relates to a kind of silicon capacitor microphone
Frequency characteristic obtains the silicon capacitor microphone of more excellent signal-to-noise ratio.
Background technique
Micro electronmechanical (MEMS, Micro-Electro-Mechanical System) microphone or silicon capacitor microphone because
The advantages that its is small in size, suitable for surface mount and the sound collection for being widely used in tablet electronic device, such as: mobile phone, MP3,
Recording pen and monitoring equipment etc..Generally, MEMS system includes to convert the micro- of electric signal for other physical signals in front end
Mechanical sensitive structure, or in micro mechanical structure actuator of the rearmost end comprising converting electrical signals to other physical signals.It is micro-
Mechanical sensitive structure plays the role of the translation interface of electric signal Yu other physical signals in MEMS system.To meet people group
Many growing material and cultural needs, the indexs such as volume, cost, sensitivity, linearity of MEMS system are also excellent constantly
Change and improves.In related optimisation technique scheme, it is no lack of numerous effort, constantly converts the progress of manufacturing process to silicon capacitor wheat
The raising of gram wind signal-to-noise ratio.Due to the application of high s/n ratio microphone, at present in far-field acoustic, speech recognition, echo cancellor, master
There is significant progress in the fields such as dynamic noise reduction, but then under prior art means, the items of silicon capacitor microphone
Can index beyond tradition microphone, therefore some unprecedented technical problems are also emerged, so that further increasing silicon
The difficulty of the signal-to-noise ratio of capacitance microphone is higher and higher.
On the other hand, for the frequency characteristic in microphone works bandwidth, general application is required in microphone
Frequency response in bandwidth of operation is relatively flat；Otherwise, microphone collects the tone color of voice signal corresponding uneven
Frequency range can also be deformed, to influence whole sense of hearing.
For guarantee silicon capacitor microphone low cost and miniaturization feature, generally in the industry by dedicated IC chip with
Sensitive structure matches.For working principle, integrated circuit is close but not exactly the same with traditional circuit.For existing
For integrated circuit is horizontal, the planarization that bandwidth is very easy to be made wide to guarantee inband signaling transmission, frequency characteristic
Curve is very smooth in microphone works frequency band, and in fact this is also the most common circuit realization side under state of the art
Formula.Meanwhile the links such as filtering are increased to integrated circuit biggish technical difficulty will be encountered when controlling its frequency characteristic: such as right
The capacitor that needs are filtered for analog circuit, which will increase cost even, influences encapsulation characteristic, needs to increase for digital circuit specially
The filtering link of door simultaneously develops dedicated filtering algorithm.Therefore, in order to ensure that integrated circuit cooperates the versatility of various sensitive structures,
Only need to its frequency characteristic be arranged smooth in microphone works frequency band.
Therefore, in traditional silicon capacitor microphone, not by the frequency characteristic curve of sensitive structure and mating integrated circuit into
The fixed cooperation of row, but respectively respective frequency characteristic is arranged smooth in bandwidth, to meet microphone entirety
The requirement smooth in bandwidth of the frequency characteristic of output.Such as Chinese patent CN201509310U and Chinese patent
CN203301696U, when being limited when sensitive structure frequency characteristic curve is arranged by structural parameters, by the way that encapsulating structure is arranged
Mode keep the frequency characteristic of its sensitive structure smooth in bandwidth of operation, to ensure that and frequency characteristic is in work
When making integrated circuit matching smooth in bandwidth, final silicon capacitor microphone frequency characteristic is smooth in bandwidth of operation.
It is quick by being matched to encapsulating structure although this kind of conventional solution matches versatility with encapsulating structure by abandoning sensitive structure
The change for feeling structure, makes microphone frequency characteristic reach requirement smooth in bandwidth of operation, but also lose and further increase
The space of microphone signal-to-noise ratio.
Summary of the invention
The present invention provides the silicon capacitor Mikes that the frequency characteristic of a kind of sensitive structure and mating integrated circuit is mutually matched
Wind can guarantee silicon by the way that the frequency characteristic of sensitive structure and mating integrated circuit is respectively set and is mutually matched it
Under the premise of capacitance microphone frequency characteristic meets application requirement, its letter is further increased under the limitation of original process conditions
It makes an uproar ratio.
To solve the above problems, the technical solution adopted by the present invention is that:
A kind of silicon capacitor microphone, sensitive structure are matched with the frequency characteristic of mating integrated circuit, described quick
Feel structure specifies the response of the response ratio microphone low frequency flat segments of frequency point high in encapsulating housing in microphone works bandwidth
3dB or more, and corresponding matching setting is also made in response of the mating integrated circuit near this frequency point.By sensitive structure
Made with the frequency characteristic of mating integrated circuit and match setting, be in order to both guarantee matching work after, silicon capacitor Mike
The frequency characteristic of wind itself is flat in bandwidth of operation.And will in its bandwidth of operation specify frequency point response be arranged compared with
Height is because of that best to the reducing effect of silicon capacitor microphone noise when doing, which should be according to the work of each parameter
The skill limit is up to principle to the sensitive structure frequency characteristic curve integrated value after normalization with microphone noise in working band
It determines.And the response for being assigned frequency point is arranged 3dB or more higher than the response of low frequency flat segments, is because just can guarantee in this way
Reduce silicon capacitor microphone noise by 1dB or more.
Preferred silicon capacitor microphone, wherein the sensitive structure refers in microphone works bandwidth in encapsulating housing
The high 3dB or more of response for determining the response ratio microphone low frequency flat segments of frequency point, by the way that the sensitive structure is arranged in encapsulating housing
In size and material parameter realize.Although can also be existed by setting encapsulating structure size and shape to adjust sensitive structure
Frequency characteristic in encapsulating housing, but the versatility for abandoning sensitive structure and encapsulating housing thus adversely affects: encapsulation
Due to occurring directly in application, if the interface (such as sound inlet) with application certainly will influence shell by modifying
The application range of encapsulating housing.
Preferred silicon capacitor microphone, wherein the mating integrated circuit specifies frequency point in microphone works bandwidth
Corresponding matching setting is also made in response, comes by adjusting the signal amplification of mating integrated circuit and the frequency characteristic of processing links
It realizes.In the inventive solutions, sensitive structure is by the capacitance change signal generated after voice signal excitation, and inputs
To after integrated circuit, capacitance change signal can be converted to voltage change signal by integrated circuit first, then can pass through amplification and place
Reason link handles voltage signal.Due to the reason of the relatively more convenient processing of electrical signal, mating integrated circuit is adjusted
Frequency characteristic can be realized by adjusting frequency characteristic of the amplification with processing links.In traditional integrated circuit technique scheme,
Due to realizing the difficulty of corresponding function in integrated circuits and guaranteeing that integrated circuit frequency characteristic in working band itself is smooth
The reason additionally filtered is not needed, only has pooling feature or full frequency band indifference enlarging function with processing links in amplification, even
The amplification and processing links of signal is not present in some schemes, directly exports after being converted to voltage signal.
Preferred silicon capacitor microphone, wherein the frequency of the signal amplification and processing links of the mating integrated circuit of adjustment
Rate characteristic, by being realized in the amplification of the signal of circuit with a filter link is increased in processing links.As low-pass filter,
Bandstop filter, digital filter (mainly including finite impulse response filter FIR and infinite impulse response filter IIR) etc.
Common filter is the mode of the more convenient realization of prior art means, though and the technical solutions such as multiplier, modem
The frequency characteristic of right also adjustable circuit, but it is complex due to implementing, not as the first choice of technical solution.
Preferred silicon capacitor microphone, wherein the filter, is realized by digital circuit means.It is integrated for simulating
For circuit, realize that filter function needs the extremely difficult realization in Analogous Integrated Electronic Circuits of the capacitor used and cost is very high, such as
Fruit increases capacitor in encapsulating structure, will increase corresponding material cost, process costs and verifying cost, and first in encapsulating structure
The increase of device can bring the change of encapsulation cavity geometry and volume, to frequency characteristic of the sensitive structure when wherein working itself
It will cause influence again.Therefore Analogous Integrated Electronic Circuits realizes that filter is complex and cost is also higher.And for digital circuit and
The problem of speech, not only there is no filter capacitors, can more be optimized filter effect by various modern filtering methods；Furthermore
Same money digital circuit can also match the parameter fluctuation of the same multiple sensitive structures of batch by the methods of auto-adaptive parameter.
It is proposed of the invention, so that the signal-to-noise ratio of silicon capacitor microphone is due to applying this hair under existing technological level
Bright design means are improved the signal-to-noise ratio of 1dB or more microphone, increase the market competitiveness of silicon capacitor microphone.This
Although outer technical solution of the present invention is to guarantee that microphone frequency characteristic abandons silicon capacitor microphone sensitive structure and made-up set
The versatility being mutually matched at circuit, but by by sensitive structure and the respective frequency characteristic complex optimum of integrated circuit
Configuration obtains the technical effect of further improvement microphone signal-to-noise ratio.For conventional solution, due to integrated circuit
Unit cost it is lower than encapsulating structure, protected and abandoning the matching of sensitive structure and encapsulating structure compared to other schemes
For demonstrate,proving microphone frequency characteristic, technical solution of the present invention is suitable for the encapsulating structure of sizes, and the scope of application is wider.
Detailed description of the invention
Fig. 1 is each link frequency characteristic and its match condition schematic diagram of traditional silicon capacitor microphone；
Fig. 2 is that the sensitive structure of one embodiment of the invention and the mating integrated matched scheme of channel frequency characteristic curve are shown
It is intended to；
Fig. 3 is the control system characteristic schematic diagram of each link signal transmitting of the preferred embodiment of the present invention；
Fig. 4 is the Analysis of Noise Properties schematic diagram in each link signal transmitting of the preferred embodiment of the present invention；
Fig. 5 is three kinds of selection example schematic diagrams of the prestage frequency characteristic of the preferred embodiment of the present invention；
Fig. 6 is the prestage and the matched scheme schematic diagram of back-end circuit frequency characteristic of another embodiment of the present invention.
Specific embodiment
Present invention is mainly used for a kind of frequency characteristics by adjusting sensitive structure and mating integrated circuit to obtain
The silicon capacitor microphone of more excellent signal-to-noise ratio can keep the original appearance of silicon capacitor microphone, package dimension and subsequent technique real
Under the premise of existing mode, by abandoning the versatility of sensitive structure Yu mating integrated Circuit Matching, come so that silicon capacitor microphone
Signal-to-noise ratio under the limitation of original process conditions further increases, and makees the present invention into one below with reference to specific drawings and examples
Walk explanation.
As shown in Figure 1, in traditional silicon capacitor microphone scheme, to guarantee sensitive structure and mating integrated circuit respectively
Versatility, generally respectively its frequency characteristic is arranged more smooth in bandwidth of operation, and fit together use.Letter
Number by sensitive structure mechanics link T1After be converted into motor message, then pass through the T of sensitive structure itself2Link is converted into
Electrical signal, and pass through IC capacitor-voltage conversion links T3Voltage signal is converted by electrical signal.In traditional collection
At in circuit solutions, due to realizing the difficulty of corresponding function in integrated circuits and guaranteeing integrated circuit itself in work frequency
The smooth reason for not needing additionally to filter of in-band frequency characteristic, in amplification and processing links T4Only pooling feature or full frequency band without
Difference enlarging function is (with T straight always2Link is similar) in addition some schemes there is no signal amplification and processing links T4,
It is directly exported after being converted to voltage signal.
As shown in Fig. 2, technical solution proposed by the present invention be by sensitive structure in encapsulating housing in microphone works band
The high 3dB or more of response of the response ratio microphone low frequency flat segments of frequency point is specified in width, and the mating integrated circuit is in phase
Corresponding matching setting is also made with the response near frequency point.It is in this way that the frequency characteristic of sensitive structure and mating integrated circuit is bent
Line makes matching setting, and after not only ensure that the two matching work, the frequency response of silicon capacitor microphone itself is in bandwidth of operation
It is flat, more make silicon capacitor microphone because of that improving the technical effect of whole signal-to-noise ratio 1dB or more.Wherein sound inlet
100, sensitive structure 200, encapsulating structure inner cavity 300 have codetermined sensitive structure work in silicon capacitor microphone system and have encapsulated
The frequency characteristic of inside configuration, also constitute acoustic signals to sensitive structure diaphragm displacement signal mechanics link 001；It is quick
Feel structure 200 and convert its capacitance change signal for the displacement signal of its diaphragm, and constitutes electrical rings together with integrated circuit 400
Capacitance change signal is converted voltage signal by section 002, electricity link 002, and final output characterizes the voltage signal of acoustic signals.
Fig. 3, Fig. 4 and Fig. 5 are a preferred embodiment of the present invention.Acoustic signals show as the variation of the sound intensity in space
Δ p, by being converted into power Δ F after diaphragm of the effective area for the sensitive structure 200 of A；And sensitive structure is shown as on mechanics
Quality m, stiffness K, damped coefficient are the mass-spring-damper system of b, transmission function are as follows:
Power Δ F signal after through this system is converted into the displacement signal Δ x of diaphragm, and the displacement signal Δ x of diaphragm is again
Capacitance change signal Δ C is converted to by sensitive structure itself, if in sensitive structure capacitor C0Both ends apply fixed voltage
Δ U drops, then capacitance change signal Δ C can be exchanged into charge variation signal delta Q=Δ U Δ C, evaluate when investigating signal-to-noise ratio
Under the standard sound intensity, this displacement signal Δ x is relative to sensitive structure natural capacity gap d0It is one a small amount of, it is believed that this displacement
Conversion approximately linear of the signal delta x to charge signal Δ Q, scale factor are as follows:
T2(s)=C0·ΔU/d0
This link is that sensitive structure is determined as sensor feature itself, in the frequency range of concern and is measured
Within the scope of the sound intensity of signal-to-noise ratio, amplification factor is flat always.
As shown in figure 3, charge variation Δ Q signal enters a similar matter in the capacitance-voltage conversion links of integrated circuit
Amount-spring-damper system resistance (R)-inductance (L)-capacitor (C0) system (RLC system), electricity is converted to through this system
Press signal delta V.Its transmission function is as follows:
This link in the specific implementation, due to using the elements such as triode, field-effect tube in integrated circuit, is transmitted
Function model also compares T3(s) more complicated, cannot be simply by the RLC System describe of the present embodiment, but principle is close therewith.
In addition, in the present embodiment, the frequency characteristic of voltage signal Δ V not necessarily meets the frequency of silicon capacitor microphone again
The requirement planarized in the bandwidth of operation of characteristic, therefore need signal amplification and processing links T using integrated circuit4(s)
Filtering processing, 0~ω of last output services frequency band0Interior flat voltage signal Δ Vout。
Noise in lower surface analysis signals transmission.From the point of view of energy system, energy is from " power-displacement " corresponding machinery
It can be converted into " charge-voltage " corresponding electric energy, this is also the reason that sensitive structure is also known as " energy converter ".Its energy transfer process
In energy loss mainly as mechanical damping and electrical damping to caused by dissipation of energy, the loss of this portion of energy corresponds to phase
It can increase in the molecular thermalmotion answered, so being white noise, mechanics link 001 and electricity link 002 in the frequency band of concern
Noise be respectivelyWithAnd the former corresponding unit is power noise unitThe latter
Corresponding unit is voltage noise unitWherein kBIt is Boltzmann constant, heat when T is silicon capacitor microphone work
Mechanics temperature.In addition, in sensitive structure capacitor C0Both ends apply fixed voltage drop Δ U, so that capacitance change signal Δ C be turned
It is changed to charge variation signal delta Q=Δ U Δ C, this itself can introduce the noise N of fixed voltage drop Δ UU, this electricity
Pressing noise is also white noise in the frequency band of concern, and unit is alsoCan be added to electrical noise
The capacitance-voltage conversion links of sensitive structure 200 itself and integrated circuit 400, constitute the prestage of circuit,
Also the noise of silicon capacitor microphone is determined.In the present embodiment, prestage transmission function is S (s)=T1(s)·T2(s)·T3
(s), signal amplification and the processing links T of integrated circuit 400 are eventually passed through4(s) it after, ultimately forms planarization in bandwidth of operation and rings
The silicon capacitor microphone Input output Relationship IO (s) answered.And signal amplification and processing links T4(s) due to being not belonging to prestage
Link, corresponding noise can be neglected in the present embodiment.
When measuring signal-to-noise ratio, generally from 0~ω of working band of silicon capacitor microphone0One Frequency point of interior flat place
ωcThe sound intensity signal delta P of normal intensity is inputted, test obtains signal strength IO (ωc) Δ PA, and to working band 0~
ω0Interior noise is integrated, and measuring its aggregate noise level (allows some weightings acoustically to handle, but do not influence this implementation
The technical solution of example), using ratio between two as the signal-to-noise ratio of silicon capacitor microphone.Therefore this implementation can be derived according to this model
The silicon capacitor microphone Signal to Noise Ratio (SNR) of example are as follows:
In this formula, in 0~ω of working band0It is interior to be believed that IO (ω)=IO (ωc), meet professional standard
Constant, Δ P are the sound intensity signals of normal intensity in the industry, and A is the effective diaphragm area of sensitive structure 200, after fixed it is also contemplated that
It is constant, and three kinds of 0~ω of working band0Interior white noise NF,NV,NU, all respectively have its own the physics pole under technological parameter limitation
Limit.So adjustment prestage transmission function S (s) makes it in 0~ω of working band under the premise of other parameters are fixed0Interior one
A little frequency range responses are higher, are beneficial for improving Signal to Noise Ratio (SNR).
Due to can generally use the elements such as triode, field-effect tube, circuit noise N in integrated circuit 400V、NUIt is working
It is not necessarily white noise again in bandwidth, and may also includes that pink noise (1/f noise), brown noise (Brownian noise) etc. are coloured
Noise contribution.It therefore, can be according to specific circuit noise N before specific implementationV、NUActual distribution situation in band,
In bandwidth of operation similar to Figure 5 in a plurality of frequency characteristic of certain frequency point response higher than low-frequency range 3dB, in process conditions
In allowed band, maximum frequency characteristic after selection circuit noise integrates S (ω), according to given encapsulation cavity body structure
300 parameter, then the parameter of corresponding sensitive structure 200 is arranged.The capacitance-voltage conversion ring of integrated circuit 400 has been determined
After the design parameter of section, it can amplify and processing links T by adjusting the signal of integrated circuit 4004(s), work belt is ultimately formed
The silicon capacitor microphone Input output Relationship IO (s) of planarization response in wide, and IO (s) is to meet industry in bandwidth of operation
The curve of the flat and frequency response intensity of interior relevant criterion.
Specified frequency point above-mentioned can be made an uproar according to the technological limits of each parameter of sensitive structure with microphone in working band
Sound is up to principle to the sensitive structure frequency characteristic curve integrated value after normalization and determines；Wherein normalization, which refers to, ties sensitivity
All multiplied by a same coefficient, making response at its 1KHz is 0dB (i.e. 1 times) for the response of each frequency point of structure frequency characteristic,
To exclude the different interference of its sensitivity in the characteristic of more a plurality of frequency characteristic itself.Wherein, technological limits packet
In terms of including much and as the time is in progress, different types of concrete technology limit is also different.For example, A process pole
Limit is 0.1 micron, and the B process limit is 0.01 micron, and C technology stress control limit is 100MPa, D technology stress control electrode
Limit is 10MPa.Dimension limit and the limiting range of stress determine K and m, this after having selected technique it was determined that and b parameter not only
It is determined by above-mentioned technique, is also determined by the displacement that diaphragm stress after the completion of technique discharges, and be displaced and not only depend on technological limits,
Additionally depend on specific structure type and parameter.On how to determine specified frequency point be also it is similar, actually according to above-mentioned
The technological limits available K of each parameter of sensitive structure, b, the limitation range of m parameter are specified, and when specific implementation can lead to
The noise calculated limit in range under each different parameters is crossed to the sensitive structure frequency characteristic curve integrated value after normalization, choosing
A maximum value corresponding K, b, m parameter.It also can choose a biggish product when maximizing is relatively complicated, in engineering
The corresponding parameter of score value is come approximate.
In this embodiment, due to having used silicon capacitor microphone operational frequency bandwidth ω0Neighbouring frequency characteristic
Higher prestage transmission function S (s), and pass through the amplification of the signal of integrated circuit 400 and processing links T4(s) it adjusts, finally
The silicon capacitor microphone Input output Relationship IO (s) of planarization response is obtained, the signal-to-noise ratio of silicon capacitor microphone is improved.From
From the point of view of technology is realized, prestage transmission function S (s) is in 0~ω of operational frequency bandwidth0Interior specified frequency point response is compared with low-frequency range
It is high, it is easier to which that parameter when being worked in enclosed construction by the way that sensitive structure is arranged is realized, is difficult by the way that integrated circuit is arranged
The frequency characteristic of 400 capacitance-voltage conversion links is realized.Therefore it is believed that frequency curve setting method of the invention is approximate
It is equal to " sensitive structure response ratio microphone low frequency flat segments of frequency range near microphone works bandwidth in encapsulating housing
Response is high, and the mating integrated circuit also makes corresponding matching setting in the response of this frequency range " way.And it is such
Approximation is conducive to respectively determine technical solution when sensitive structure and integrated circuit parameter are arranged, thus clear sensitive structure 200
It is enhanced respectively each with the respective parameter interface of integrated circuit 400 so that sensitive structure 200 and integrated circuit 400 are mutually indepedent
From the versatility as silicon capacitor microphone component.Still further aspect, integrated circuit 400 have modified signal amplification and processing links
Frequency characteristic after, still can keep the electrically and mechanically interface of original silicon capacitor microphone input and output, remain
Its application range.
Fig. 6 is the prestage and back-end circuit (the signal amplification and processing of integrated circuit 400 of another embodiment of the present invention
Link) the matched scheme schematic diagram of frequency characteristic.It is that the response of frequency ranges certain in working band is positioned below low frequency
Section response, and be disposed higher than by signal amplification in integrated circuit 400 and processing links the responses of these frequency ranges is corresponding
Low-frequency range preferably reduces noise effects after comprehensive with acquirement and meets the requirement of industry frequency characteristic.Such comparison
The technical effect of the optimization silicon capacitor microphone of embodiment may theoretically be better than the present embodiment, but in specific implementation,
Although signal amplification and processing links T4(s) it is not belonging to prestage link, but responds and improves as frequency increases due to existing
Part (this portion link is referred to as differentiation element or differentiation element), correspondingly can also be introduced in integrated circuit 400 additional
Noise, therefore need to comprehensively consider when selecting technical solution corresponding with this embodiment.
With another embodiment of technical solution of the present invention comparison, it is another to be that inventor attempts in the implementation of the present invention
A kind of scheme.It is by modification sound inlet 100 or encapsulating structure inner cavity 300 so that the frequency characteristic of sensitive structure 200 to exist
0~ω of working band0The technical solution for inside modifying flat.The way of this comparative example is equal to modification mechanics link
001 K, m, the parameters such as b, although the frequency characteristic of mechanical ring section 001 can be made in 0~ω of working band in this way0Interior change
It is smooth, but its damped coefficient b modified after due to being limited by physics limit, will not reduce, or even can increased, this just makes
Its mechanics noise NFNot anti-reflection increases, and the frequency response curve of its mechanics link 001 is relatively flat, so that its S (ω) curve is in working band 0
~ω0Interior is also to meet the flat of professional standard, this has no inhibiting effect to electrical noise, therefore to the entirety of silicon capacitor microphone
Noise do not improve.Due to having modified sound inlet 100 or encapsulating structure inner cavity 300, sensitive structure for matching sensitive structure
It is mutually matched between encapsulating structure, loses versatility, and modified sound inlet 100 is due to being related to extraneous input sound letter
Number mechanical interface change, reduce the application range of silicon capacitor microphone.
It is that full frequency band increases in working band by S (ω) curve with the another embodiment of technical solution of the present invention comparison,
And in the amplification of the signal of integrated circuit 400 and processing links T4Give full frequency band decaying in (ω) again to guarantee the frequency of silicon microphone
The satisfactory technical solution of rate characteristic curve.This way is worthless, although doing so is beneficial to silicon capacitor microphone
The reduction of noise and the raising of signal-to-noise ratio, but when low-frequency range is acted on by the larger sound intensity, the saturation of sensitive structure 200 can be too early
Ground occurs, even if signal amplification and processing links T in integrated circuit 4004Decayed again in (ω), the signal of output is also
Serious distortion, this maximum sound intensity that silicon capacitor microphone can be made to can be applied to reduces, and reduces the suitable of silicon capacitor microphone
Use range.For the solution of the present invention, increases, can also be directed to due to simply meaning to determine the frequency range response near frequency point
Some Nonlinear Processing means such as this frequency range application AW (Anti-Windup, anti-saturation) method, prevent sensitive structure 200
Saturation can prematurely occur in this frequency range, while not interfere with other performance indicators of silicon capacitor microphone, will not shadow
Ring the scope of application to the silicon capacitor microphone in terms of the maximum sound intensity.
The above description of this invention is illustrative and not restrictive, those skilled in the art understand that wanting in right
Ask it can be carried out within the spirit and scope of restriction it is many modification, variation or it is equivalent, but they fall within it is of the invention
In protection scope.
Claims (4)
1. a kind of silicon capacitor microphone, sensitive structure including encapsulating housing and in the encapsulating housing and with the sensitivity
The integrated circuit that structure matches, it is characterised in that: the frequency characteristic of the sensitive structure and the integrated circuit matches
Close, the sensitive structure in the encapsulating housing in silicon capacitor microphone bandwidth of operation specify frequency point response ratio its in silicon
The high 3dB or more of response of capacitance microphone low frequency flat segments, and response of the integrated circuit near the specified frequency point
Corresponding matching setting is made, by adjusting the frequency characteristic of the signal amplification and processing links of the integrated circuit, keeps silicon electric
Hold frequency response curve planarization of the microphone in bandwidth of operation；
The frequency characteristic of the signal amplification and processing links of the adjustment integrated circuit passes through the signal amplification in circuit
It is realized with a filter link is increased in processing links.
2. silicon capacitor microphone according to claim 1, it is characterised in that: the sensitive structure is in the encapsulating housing
In silicon capacitor microphone bandwidth of operation specify frequency point response ratio its silicon capacitor microphone low frequency flat segments the high 3dB of response
More than, by the way that dimensional parameters and material parameter of the sensitive structure in the encapsulating housing are arranged to adjust the sensitive knot
The mechanics transmission function of structureTo realize, wherein the sensitive structure shows as quality on mechanics and is
M, rigidity K, damped coefficient are the mass-spring-damper system of b.
3. silicon capacitor microphone according to claim 1, it is characterised in that: the filter link passes through digital circuit hand
Duan Shixian.
4. silicon capacitor microphone according to claim 1, it is characterised in that: the specified frequency point, according to the sensitive knot
The technological limits of each parameter of structure, it is bent to the sensitive structure frequency characteristic after normalization with silicon capacitor microphone noise in working band
Line integral value is up to principle and determines.
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| CN106658287A (en) * | 2016-11-11 | 2017-05-10 | 北京卓锐微技术有限公司 | Microphone system and amplifying circuit |
| CN106658303A (en) * | 2016-12-01 | 2017-05-10 | 北京卓锐微技术有限公司 | Microphone system and amplifying circuit |
| CN108807286A (en) * | 2018-07-06 | 2018-11-13 | 武汉耐普登科技有限公司 | sensor LGA package structure |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201509310U (en) * | 2009-09-14 | 2010-06-16 | 瑞声声学科技(常州)有限公司 | Condenser microphone |
| CN203301696U (en) * | 2013-06-08 | 2013-11-20 | 歌尔声学股份有限公司 | Microphone |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8965027B2 (en) * | 2013-02-15 | 2015-02-24 | Invensense, Inc. | Packaged microphone with frame having die mounting concavity |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201509310U (en) * | 2009-09-14 | 2010-06-16 | 瑞声声学科技(常州)有限公司 | Condenser microphone |
| CN203301696U (en) * | 2013-06-08 | 2013-11-20 | 歌尔声学股份有限公司 | Microphone |
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