CN205092944U

CN205092944U - Microphone

Info

Publication number: CN205092944U
Application number: CN201520891260.2U
Authority: CN
Inventors: 陈志翔; 朱佳辉
Original assignee: BEIJING ACUTI MICROSYSTEMS Co Ltd
Current assignee: Shandong Gettop Acoustic Co Ltd
Priority date: 2015-11-10
Filing date: 2015-11-10
Publication date: 2016-03-16
Anticipated expiration: 2025-11-10

Abstract

The utility model discloses a microphone includes: the MEMS sensor for be the signal of telecommunication with sound signal conversion, the amplifier is configured as the receipt the signal of telecommunication to generate signal amplification, adc, be used for with signal amplification converts corresponding data signal into, pulse density modulation module, be used for with data signal converts PDM output signal into, and the model selection module, make according to first clock signal microphone switches over between a mode, the 2nd mode and the 3rd mode.

Description

Microphone

Technical field

The utility model relates to microphone, is specifically related to a kind of microphone with low-power consumption mode.

Background technology

MEMS microphone adopts MEMS (micro electro mechanical system) (MicroelectromechanicalSystems, MEMS), compared with traditional electret capacitor microphone (ECM), there is better acoustical behavior, higher signal to noise ratio, better conforming susceptibility and lower power consumption.MEMS microphone has been widely used in the fields such as voice communication, auditory prosthesis, smart mobile phone, notebook computer to provide higher voice quality.

As shown in Figure 1, existing digital MEMS microphone comprises MEMS sensor 10, amplifier 11, analog to digital converter 12 and pulse density modulated module (Pulsedensitymodulation, PDM) 13.After providing corresponding clock CLK and operating voltage VDD, microphone is started working.MEMS sensor 10 generally includes a variable capacitance and has higher output impedance.The acoustical signal in the external world is converted into the change of capacitance signal by MEMS sensor 10.First the output signal of MEMS sensor 10 is amplified and impedance transformation by amplifier 11.Signal through amplification and impedance transformation is the PDM digital signal DATA of output 1 after analog-to-digital conversion and pulse density modulated.

The MEMS microphone of prior art only has two kinds of operating states: shutdown (Powerdown) pattern and normal work (Normal) pattern.Be when zero at supply power voltage, be shutdown mode, whole microphone is in off position, at supply power voltage for operating voltage VDD and when providing effective clock signal clk, be normal mode of operation, microphone normally works.The bandwidth of microphone when identifying the voice of people is 20Hz to 8kHz, the bandwidth 20Hz to 20kHz time in running order well below microphone (i.e. normal mode of operation).

For the demand (such as wearable device) of some low-power consumption, expect the power consumption that as far as possible can reduce microphone, do not wish that again microphone quits work simultaneously, keep the function of the voice identifying people.

Utility model content

In view of this, the utility model proposes the power consumption that a kind of microphone can provide lower, be applicable to the low-power consumption application such as wearable device.

Described microphone comprises: MEMS sensor, for voice signal is converted to the signal of telecommunication; Amplifier, is configured to receive the described signal of telecommunication, and generates amplifying signal; Analog to digital converter, for being converted to corresponding digital signal by described amplifying signal; Pulse density modulated module, for being converted to PDM output signal by described digital signal; And mode selection module, make described microphone in the first mode of operation according to the first clock signal, switch between the second mode of operation and the 3rd mode of operation.

Preferably, described mode selection module comprises: oscillator, for providing the clock signal of fixed frequency; And mode decision module, for judging the frequency of the first clock signal according to the clock signal of described fixed frequency, and according to the frequency generation current control signal of described first clock signal, make mating of the frequency of the operating current of described amplifier and analog to digital converter and described first clock signal.

Preferably, in described first mode of operation, the frequency of described first clock signal is less than first frequency, and the supply power voltage of described microphone is the first voltage; In described second mode of operation, the frequency of described first clock signal is greater than first frequency and is less than second frequency, and the bandwidth of operation of described microphone is the first bandwidth, and the supply power voltage of described microphone is the first voltage; In described 3rd mode of operation, the frequency of described first clock signal is greater than second frequency, and the bandwidth of operation of described microphone is the second bandwidth, and the supply power voltage of described microphone is the first voltage.

Preferably, described first frequency is 1KHz, and described second frequency is 768KHz, and described first bandwidth is 20Hz to 8KHz, and described second bandwidth is 20Hz to 20KHz.

Described second and the 3rd mode of operation, the signal to noise ratio of microphone is consistent.

Preferably, described fixed frequency is 32KHz.

Preferably, described microphone also comprises the 4th mode of operation, and in described 4th mode of operation, the supply power voltage of described microphone is zero.

Preferably, microphone is less than the power consumption of microphone in described second mode of operation in the power consumption of described first mode of operation, and microphone is less than the power consumption of microphone in described 3rd mode of operation in the power consumption of described second mode of operation.

Microphone of the present utility model comprises multiple mode of operation, meets the requirement of low-power consumption.

Accompanying drawing explanation

By referring to the description of accompanying drawing to the utility model embodiment, above-mentioned and other objects, features and advantages of the present utility model will be more clear, in the accompanying drawings:

Fig. 1 is the schematic diagram of the microphone of prior art;

Fig. 2 is the schematic diagram of the microphone according to the utility model embodiment; And

Fig. 3 is the structured flowchart of the mode selection module according to the utility model embodiment.

Embodiment

Based on embodiment, the utility model is described below, but the utility model is not restricted to these embodiments.In hereafter details of the present utility model being described, detailedly describe some specific detail sections.Do not have the description of these detail sections can understand the utility model completely for a person skilled in the art yet.In order to avoid obscuring essence of the present utility model, known method, process, flow process, element and circuit do not describe in detail.

In addition, it should be understood by one skilled in the art that the accompanying drawing provided at this is all for illustrative purposes, and accompanying drawing is not necessarily drawn in proportion.Meanwhile, should be appreciated that in the following description, " circuit " refers to the galvanic circle connected and composed by electrical connection or electromagnetism by least one element or electronic circuit.When " being connected to " another element when claiming element or circuit or claiming element/circuit " to be connected to " between two nodes, it can be directly couple or be connected to another element or can there is intermediary element, the connection between element can be physically, in logic or its combine.On the contrary, " be directly coupled to " when claiming element or " being directly connected to " another element time, mean that both do not exist intermediary element.

Unless the context clearly requires otherwise, similar words such as " comprising ", " comprising " otherwise in whole specification and claims should be interpreted as the implication that comprises instead of exclusive or exhaustive implication; That is, be the implication of " including but not limited to ".In description of the present utility model, it is to be appreciated that term " first ", " second " etc. are only for describing object, and instruction or hint relative importance can not be interpreted as.In addition, in description of the present utility model, except as otherwise noted, the implication of " multiple " is two or more.

Fig. 2 is the schematic diagram of the microphone according to the utility model embodiment, and with reference to Fig. 2, the microphone of the present embodiment comprises: MEMS sensor 10, amplifier 11, analog to digital converter 12, pulse density modulated module 13 and mode selection module 15.

This microphone relies on suitable supply power voltage and clock signal clk work.Microphone comprises four mode of operations: dormancy (Sleep) pattern, low-power consumption (lowpower) pattern, normal work (normal) pattern, and shutdown (powerdown) pattern.

MEMS sensor 10 generally includes a variable capacitance and has larger output impedance.The acoustical signal in the external world is converted into the change of capacitance signal by MEMS sensor 10.First the output signal of MEMS sensor 10 is amplified and impedance transformation by amplifier 11.Signal through amplification and impedance transformation is the PDM digital signal DATA of output 1 after analog-to-digital conversion and pulse density modulated.

Microphone has certain bandwidth of operation, needs frequency and the operating current of the clock signal of coupling in order to obtain voice signal (namely good signal to noise ratio) clearly.Usually, when bandwidth of operation requires higher, the frequency of the clock signal of needs is higher, and operating current is larger, and power consumption is also larger.Bandwidth of operation when microphone normally works is at 20Hz to 20KHz, and microphone can receive natural various sound.Bandwidth of operation is when 20Hz to 8KHz, and microphone still can the voice of recipient.

Mode selection module 15, according to the frequency of clock signal clk, makes microphone at park mode, low-power consumption mode, normal mode of operation, and switches between shutdown mode.

The supply power voltage being supplied to microphone has two magnitudes of voltage: 0 and operating voltage VDD.

The supply power voltage of microphone is 0, and microphone is in shutdown mode, and whole microphone is in off position, and the power consumption of microphone is 0.

Be VDD at the supply power voltage of microphone, when the frequency of clock signal clk is less than 1KHz, microphone is switched to park mode by mode selection module 15.At park mode, microphone is in and low-power consumption operating state, can not identify acoustical signal, MEMS sensor 10, amplifier 11, analog to digital converter 12 and pulse density modulated module 13 are in off position, only have and just can wake microphone works up after clock signal clk promotes.At park mode, the power consumption of microphone is the first power consumption.

Be VDD at the supply power voltage of microphone, when the frequency of clock signal clk is greater than 1KHz and is less than 768KHz, microphone is switched to low-power consumption mode by mode selection module 15.At low-power consumption mode, the bandwidth of operation of microphone is reduced to 20Hz to 8KHz, and microphone can identify people's one's voice in speech, and internal operating current reduces, and microphone signal to noise ratio keeps original numerical value simultaneously.At low-power consumption mode, the power consumption of microphone is the second power consumption.At low-power consumption mode, microphone do not sacrifice sound variation detecting (VoiceActivityDetection, VDA) effect when, the lower power consumption of microphone.Such as microphone applications is on wearable device, and for receiving the sound instruction that user sends, microphone is in the operating time that low-power consumption mode can remain longer.

Be VDD at the supply power voltage of microphone, when the frequency of clock signal clk is greater than 768KHz, microphone is switched to normal mode of operation by mode selection module 15.Be in normal operating conditions at normal mode of operation microphone, bandwidth of operation, at 20Hz to 20KHz, can receive various natural sound, and microphone signal to noise ratio is optimal values simultaneously.In normal mode of operation, the power consumption of microphone is the 3rd power consumption.

First power consumption is less than the second power consumption, and the second power consumption is less than the 3rd power consumption.

With reference to Fig. 3, mode selection module 15 comprises: oscillator 16 and mode decision module 17.

Oscillator 16 is for providing the clock signal of fixed frequency.Mode decision module 17 is the clock signal of fixed frequency that provides of reception oscillator 16 and clock signal clk simultaneously.Mode decision module 17 is for judging the frequency of clock signal clk according to the clock signal of described fixed frequency and clock signal clk, and send current controling signal according to the frequency of clock signal clk to amplifier 11, analog to digital converter 12 and pulse density modulated module 13, thus switch the mode of operation of described microphone.In a preferred embodiment, described fixed frequency is 32KHz.

Such as, when the frequency of clock signal clk be less than 1 be less than 1KHz time, mode selection module 15 produces corresponding signal, and microphone is switched to park mode, informs that miscellaneous part reduces operating current; When the frequency of clock signal clk be greater than 1 be less than 1KHz and be less than 768KHz time, microphone is switched to low-power consumption mode by mode selection module 15; When the frequency of clock signal clk is greater than 768KHz, microphone is switched to normal mode by mode selection module 15.

In a preferred embodiment, microphone also comprises power-supply management system, and L/R input, for the edge of selected clock signal clk.

Microphone of the present utility model provides multiple mode of operation to reduce power consumption, is applicable to the application of wearable device.Microphone of the present utility model can be applicable to but is not limited to the fields such as voice communication, auditory prosthesis, mobile phone, notebook computer.

The foregoing is only preferred embodiment of the present utility model, be not limited to the utility model, to those skilled in the art, the utility model can have various change and change.All do within spirit of the present utility model and principle any amendment, equivalent replacement, improvement etc., all should be included within protection range of the present utility model.

Claims

1. a microphone, is characterized in that, comprising:

MEMS sensor, for being converted to the signal of telecommunication by voice signal;

Amplifier, is configured to receive the described signal of telecommunication, and generates amplifying signal;

Analog to digital converter, for being converted to corresponding digital signal by described amplifying signal;

Pulse density modulated module, for being converted to PDM output signal by described digital signal; And

Mode selection module, makes described microphone in the first mode of operation according to the first clock signal, switches between the second mode of operation and the 3rd mode of operation.

2. microphone according to claim 1, is characterized in that, described mode selection module comprises: oscillator, for providing the clock signal of fixed frequency; And

Mode decision module, for judging the frequency of the first clock signal according to the clock signal of described fixed frequency, and according to the frequency generation current control signal of described first clock signal, make mating of the frequency of the operating current of described amplifier and analog to digital converter and described first clock signal.

3. microphone according to claim 2, is characterized in that,

In described first mode of operation, the frequency of described first clock signal is less than first frequency, and the supply power voltage of described microphone is the first voltage;

In described second mode of operation, the frequency of described first clock signal is greater than first frequency and is less than second frequency, and the bandwidth of operation of described microphone is the first bandwidth, and the supply power voltage of described microphone is the first voltage;

In described 3rd mode of operation, the frequency of described first clock signal is greater than second frequency, and the bandwidth of operation of described microphone is the second bandwidth, and the supply power voltage of described microphone is the first voltage.

4. microphone according to claim 3, is characterized in that, described first frequency is 1KHz, and described second frequency is 768KHz, and described first bandwidth is 20Hz to 8KHz, and described second bandwidth is 20Hz to 20KHz.

5. microphone according to claim 3, is characterized in that, described second and the 3rd mode of operation, the signal to noise ratio of microphone is consistent.

6. microphone according to claim 2, is characterized in that, described fixed frequency is 32KHz.

7. microphone according to claim 1, is characterized in that, described microphone also comprises the 4th mode of operation, and in described 4th mode of operation, the supply power voltage of described microphone is zero.

8. microphone according to claim 3, it is characterized in that, microphone is less than the power consumption of microphone in described second mode of operation in the power consumption of described first mode of operation, and microphone is less than the power consumption of microphone in described 3rd mode of operation in the power consumption of described second mode of operation.