Vibration sensor, control method thereof and electronic equipment

Abstract

The invention discloses a vibration sensor, a control method thereof and electronic equipment. The vibration sensor comprises a substrate and a shell, the substrate is covered with the shell, and the shell and the substrate form a containing cavity; the vibration assembly is arranged on the substrate and located in the containing cavity; the functional assembly is arranged in the containing cavity and comprises an MEMS chip and an ASIC chip, the MEMS is electrically connected with the vibration assembly, and the ASIC chip is electrically connected with the MEMS chip and the substrate; wherein the ASIC chip comprises a chopping denoising circuit, and the chopping denoising circuit comprises a modulation circuit, an amplification circuit, a demodulation circuit, a high-pass filter circuit and a low-pass filter circuit. The vibration sensor provided by the invention has the advantage of low noise.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic devices, and more particularly, to a vibration sensor, a control method thereof, and an electronic device. BACKGROUND

[0002] A vibration sensor is a sensor that detects a flow signal by using a vibrating diaphragm to drive air flow. Conventional vibration sensors have poor acoustic performance due to product structure and external circuit, which affects the user experience of the product.

[0003] In the prior art, in order to improve the acoustic performance of the vibration sensor, the size and position of the vibrating diaphragm and other hardware structures are usually adjusted, but such adjustment is usually limited, resulting in poor improvement effect. SUMMARY

[0004] An object of the present application is to provide a new technical solution of a vibration sensor, a control method thereof, and an electronic device.

[0005] According to a first aspect of the present application, a vibration sensor is provided, comprising: a substrate and a shell, the shell being arranged on the substrate and forming a containing cavity with the substrate; a vibration assembly arranged on the substrate and located in the containing cavity; a functional assembly arranged in the containing cavity and comprising a MEMS chip and an ASIC chip, the MEMS chip being electrically connected to the vibration assembly, and the ASIC chip being electrically connected to the MEMS chip and the substrate, respectively; wherein the ASIC chip comprises a chopping denoising circuit, and the chopping denoising circuit comprises a modulation circuit, an amplification circuit, a demodulation circuit, a high-pass filter circuit, and a low-pass filter circuit.

[0006] Optionally, the ASIC chip further comprises a high-frequency noise suppression module.

[0007] Optionally, the high-pass filter circuit and the low-pass filter circuit both adopt a second-order Butterworth filter.

[0008] Optionally, the ASIC chip comprises a modem, and the modem adopts an analog switch.

[0009] Optionally, the vibration sensor is an air-conducted vibration sensor.

[0010] Optionally, the vibration component comprises a first substrate, a diaphragm and a mass, the first substrate is arranged on the substrate, the diaphragm is arranged on the first substrate, and the mass is suspended on the diaphragm and between the diaphragm and the substrate; and / or, The functional component further comprises a second substrate, the second substrate is stacked on the first substrate and has a gap between the second substrate and the diaphragm, and the MEMS chip and the ASIC chip are arranged on the second substrate. The second substrate is provided with a through hole, and the MEMS chip is opposite to the through hole.

[0011] Optionally, a groove is arranged on a side of the substrate close to the diaphragm, and a projection of the mass on the substrate falls into the groove.

[0012] According to a second aspect of the present application, a control method of the vibration sensor of the first aspect is provided, comprising: The vibration component picks up external vibration information, and the MEMS chip receives the vibration information. The MEMS chip converts the vibration information into an electrical signal and outputs the electrical signal to the ASIC chip to form an initial signal. The initial signal is modulated to a high frequency band by the modulation circuit, amplified by the amplification circuit, and then filtered to remove low-frequency noise and electrical noise of the amplification circuit by the high-pass filter circuit, and demodulated back to a base frequency by the demodulation circuit. The initial signal demodulated back to the base frequency is filtered to remove high-frequency noise by the low-pass filter circuit to form an output signal.

[0013] Optionally, the frequency of the square wave signal emitted by the chopper denoising circuit is greater than the peak frequency of the vibration sensor.

[0014] According to a third aspect of the present application, an electronic device is provided, comprising the vibration sensor of the first aspect.

[0015] According to an embodiment of the present application, by integrating the chopper denoising circuit on the ASIC chip, after the MEMS chip converts the vibration signal into an electrical signal and inputs the electrical signal to the ASIC chip, the ASIC chip can filter high-frequency noise and low-frequency noise in the electrical signal at the same time through the chopper denoising circuit, thereby reducing the noise of each frequency band of the vibration sensor and improving the performance of the vibration sensor.

[0016] In addition, by integrating the chopper denoising circuit on the ASIC chip, the structure of the original vibration sensor is not affected, and the iteration cost of the product is reduced.

[0017] Other features and advantages of the present application will become apparent from the following detailed description of illustrative embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings incorporated in and forming a part of the specification, illustrate embodiments of the present application and, together with the description, serve to explain the principles of the application.

[0019] Figure 1 is a structural schematic diagram of a vibration sensor provided by the present application.

[0020] Figure 2 is a schematic diagram of a signal transmission mode of an ASIC chip provided by the present application.

[0021] BRIEF DESCRIPTION OF DRAWINGS 1, substrate; 11, groove; 2, housing; 3, vibration assembly; 31, first substrate; 32, diaphragm; 33, mass; 4, functional assembly; 41, second substrate; 42, MEMS chip; 43, ASIC chip. DETAILED DESCRIPTION

[0022] Various illustrative embodiments of the present application will now be described in detail with reference to the accompanying figures. It should be noted that the relative arrangements, numerical expressions, and numerical values of components and steps set forth in these embodiments are not limiting to the scope of the present application unless specifically stated otherwise.

[0023] The following description of at least one illustrative embodiment is merely exemplary in nature and is in no way intended to limit the application or its application or uses.

[0024] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein. However, where appropriate, such techniques, methods, and apparatus should be considered as falling within the scope of the present application.

[0025] In all of the examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as a limitation. Thus, other examples of the illustrative embodiments can have different values.

[0026] It should be noted that like reference numerals and letters refer to like items throughout the drawings, and thus, once an item is defined in one drawing, it is not necessary to discuss it further in subsequent drawings.

[0027] As Figure 1 and Figure 2As shown, according to the first aspect of the present application, a vibration sensor is provided, comprising: a substrate 1 and a shell 2, the shell 2 is arranged on the substrate 1 and forms a containing cavity with the substrate 1; a vibration assembly 3, the vibration assembly 3 is arranged on the substrate 1 and located in the containing cavity; a functional assembly 4, the functional assembly 4 is arranged in the containing cavity and comprises a MEMS chip 42 (Micro-Electro-Mechanical Systems) and an ASIC chip 43 (Application-Specific Integrated Circuit), the MEMS chip 42 is electrically connected with the vibration assembly 3, and the ASIC chip 43 is electrically connected with the MEMS chip 42 and the substrate 1 respectively; wherein the ASIC chip 43 comprises a chopping denoising circuit, the chopping denoising circuit comprises a modulation circuit, an amplification circuit, a demodulation circuit, a high-pass filter circuit and a low-pass filter circuit.

[0028] Specifically, the vibration assembly 3 generally comprises a diaphragm 32, the vibration sensor senses the external vibration signal through the vibration assembly 3 and squeezes / stretches the air between the diaphragm 32 and the MEMS chip 42; the functional assembly 4 converts the air pressure change generated by the vibration of the vibration assembly 3 into an electrical signal to express the vibration information. In this embodiment, the electrical signal can be transmitted to the ASIC chip 43 through the MEMS chip 42, and after being processed by the chopping denoising circuit, an output signal is formed.

[0029] In the chopping denoising circuit, the modulation circuit is used to load the baseband signal (such as audio, digital signal) onto a high-frequency carrier, realize signal spectrum shift to adapt to the transmission medium or improve the anti-interference ability; the amplification circuit compensates the attenuation of the signal in the transmission or processing process by amplifying the amplitude of the weak signal, ensures that the signal strength meets the needs of the subsequent circuit; the demodulation circuit is used to extract the original baseband signal from the modulated signal, complete the reverse shift of the signal spectrum, and restore the information content before transmission; the high-pass filter circuit allows high-frequency signals to pass and suppresses low-frequency signals, which is used to separate high-frequency components or eliminate low-frequency interference (such as power supply noise); the low-pass filter circuit allows low-frequency signals to pass and attenuates high-frequency signals, which is used to extract useful low-frequency signals or suppress high-frequency noise (such as electromagnetic interference).

[0030] Reference Figure 2In the process of processing the electrical signal, the electrical signal is transmitted into the ASIC chip 43 in turn through a modulation circuit, an amplification circuit, a demodulation circuit, a high-pass filter circuit and a low-pass filter circuit, so that the modulation circuit modulates the electrical signal to a high frequency band, and then the electrical signal is amplified through the amplification circuit, and the low frequency noise in the electrical signal is filtered out through the high-pass filter circuit, and the electrical noise generated by the amplification circuit is also filtered out. Then, the electrical signal is demodulated to a base frequency through the demodulation circuit, and the high frequency noise in the electrical signal is removed through the low-pass filter, and then an output signal without low frequency noise and high frequency noise is formed, and the noise of the output signal of the vibration sensor in the whole frequency band is reduced.

[0031] In actual application, the design of the modulation circuit, the amplification circuit, the demodulation circuit, the high-pass filter circuit and the low-pass filter circuit can be matched and designed on the ASIC chip 43 according to actual needs, and the application does not limit this. In addition, the chopper denoising circuit is integrated in the ASIC chip 43, which has little effect on the structural layout of the vibration sensor, and the performance of the vibration sensor and the rationalization of the layout are considered.

[0032] Optionally, the ASIC chip 43 further comprises a high frequency noise suppression module.

[0033] Specifically, the high frequency noise suppression module can filter out or greatly weaken the high frequency noise components higher than the target frequency band in the signal through low-pass filtering, frequency band selective attenuation or active cancellation, while preserving the integrity and energy of the useful signal as much as possible, thereby improving the signal-to-noise ratio, reducing signal distortion, and ensuring stable and reliable transmission or processing of low frequency key information in a complex electromagnetic environment.

[0034] In this embodiment, the electrical signal is filtered and output by the high frequency noise suppression module after being processed by the high-pass filter circuit, so as to remove the device noise introduced by the chopper denoising circuit, further reduce the noise of the output signal, and improve the performance of the vibration sensor.

[0035] Optionally, the high-pass filter circuit and the low-pass filter circuit both adopt a second-order Butterworth filter.

[0036] Specifically, the second-order Butterworth filter is a linear time-invariant filter with maximum flat amplitude response characteristics, and its design is based on the Butterworth polynomial. It can provide nearly undamped signal transmission in the passband (below the cutoff frequency), while smoothly attenuating high frequency noise in the stopband (above the cutoff frequency), and the phase response is close to linear. Its structure is simple and the performance is balanced, which can effectively suppress high frequency interference and retain the key characteristics of the signal.

[0037] In the embodiment, the high-pass filter circuit and the low-pass filter circuit both adopt the second-order Butterworth filter, which can further improve the processing effect on high-frequency noise and low-frequency noise. In addition, when the ASIC chip 43 also includes a high-frequency noise suppression module, the second-order Butterworth filter can also be used to achieve the high-frequency noise suppression module.

[0038] Optionally, the ASIC chip 43 includes a modem, and the modem adopts an analog switch.

[0039] Specifically, the modem is a key communication device for converting digital signals and analog signals, and its core function is to load the digital signal generated by the computer or digital device on the high-frequency carrier through modulation technology (such as QAM, PSK) at the sending end, and convert it into an analog signal suitable for transmission in analog media such as telephone lines, optical fibers or wireless channels; at the receiving end, the original digital signal is recovered from the analog signal through demodulation technology, so as to realize the bidirectional and reliable transmission of digital data in the analog communication network, and is the bridge connecting the digital terminal and the analog communication infrastructure.

[0040] In the embodiment, the modem can be used for modulation and demodulation circuits to realize modulation and demodulation of the electrical signal, realize efficient adaptation of the electrical signal and the analog channel, improve the anti-interference ability and transmission distance of the electrical signal through modulation technology, and accurately restore the original data through demodulation technology, thereby ensuring the reliability and compatibility of the output signal. The modem can adopt a four-way analog electronic switch, and the low-pass and high-pass amplifiers can select low-noise and low-offset voltage chips. Through simulation verification, the structure has obvious improvement in noise and SNR, overcomes the 1 / f low-frequency noise that cannot be filtered out by the traditional hardware scheme at low frequency, and reduces the thermal noise and the product power consumption.

[0041] Optionally, the vibration sensor is an air-conducted vibration sensor.

[0042] In actual application, the MEMS chip 42 can be arranged in the space formed between the vibration assembly 3 and the substrate 1, or in the space formed between the vibration assembly 3 and the shell 2, that is, the MEMS chip 42 can be arranged above or below the vibration assembly 3. In addition, in some embodiments, the vibration assembly 3 can also be arranged in different spaces relative to the MEMS chip 42, that is, the MEMS chip 42 can be arranged inside or outside the vibration assembly 3, and the specific design can be made according to the specific type of the air-conducted vibration sensor, and the specific design is not limited.

[0043] Optionally, as Figure 1As shown, the vibration assembly 3 comprises a first substrate 31, a diaphragm 32 and a mass 33, the first substrate 31 is arranged on the substrate 1, the diaphragm 32 is arranged on the first substrate 31, and the mass 33 is suspended on the diaphragm 32 and between the diaphragm 32 and the substrate 1.

[0044] Specifically, in the embodiment, the diaphragm 32 is supported on the substrate 1 by the first substrate 31, and the mass 33 is suspended on the diaphragm 32, so that when the vibration sensor is subjected to vibration, the vibration assembly 3 can sense the vibration information, so that the vibration of the mass 33 drives the diaphragm 32 to deform, and the deformation of the diaphragm 32 can realize the compression or stretching of the space between the MEMS chip 42, thereby transmitting the vibration information to the MEMS chip 42. The structure of the vibration assembly 3 effectively improves the vibration sensitivity and signal response speed, while enhancing the structural stability and reducing the energy loss.

[0045] Optionally, as shown in Figure 1 The functional assembly 4 further comprises a second substrate 41, the second substrate 41 is stacked on the first substrate 31 and has a gap between the second substrate 41 and the diaphragm 32, and the MEMS chip 42 and the ASIC chip 43 are arranged on the second substrate 41; the second substrate 41 is provided with a through hole, and the MEMS chip 42 is opposite to the through hole.

[0046] Specifically, in the embodiment, the second substrate 41 is used to arrange the MEMS chip 42 and the ASIC chip 43 on the vibration assembly 3, which on the one hand facilitates the MEMS chip 42 to receive the vibration information of the vibration assembly 3 and convert it into an electrical signal, and on the other hand facilitates the reduction of the lateral size of the vibration sensor by the stacking method, which is conducive to the miniaturization of the product. The through hole on the second substrate 41 is used for the vibration assembly 3 to transmit the vibration signal to the MEMS chip 42. The gap between the diaphragm 32 and the second substrate 41 is usually greater than the amplitude of the diaphragm 32 to avoid affecting the performance of the vibration assembly 3.

[0047] Optionally, as shown in Figure 1 The side of the substrate 1 close to the diaphragm 32 is provided with a groove 11, and the projection of the mass 33 on the substrate 1 falls into the groove 11.

[0048] Specifically, in the embodiment, the groove 11 is arranged on the side of the substrate 1 close to the diaphragm 32, which not only ensures the vibration space of the vibration assembly 3 when vibrating, but also saves the occupied space of the vibration sensor in the vibration direction, which is conducive to the miniaturization of the product.

[0049] According to the second aspect of the present application, referring to Figure 1 and Figure 2, a control method of the vibration sensor of the first aspect is provided, comprising: the vibration component 3 picks up external vibration information, and the MEMS chip 42 receives the vibration information; the MEMS chip 42 converts the vibration information into an electrical signal and outputs the electrical signal to the ASIC chip 43 to form an initial signal Vin; the initial signal Vin is modulated to a high frequency band by a modulation circuit, amplified by an amplification circuit, and then filtered to remove low frequency noise and electrical noise of the amplification circuit, and demodulated back to a base frequency by a demodulation circuit; the initial signal Vin demodulated back to the base frequency is filtered to remove high frequency noise by a low pass filter circuit to form an output signal Vout. Wherein, the initial signal Vin is modulated to a high frequency band by a multiplier after being superimposed with a modulation signal M1(t), and after the low frequency noise and the electrical noise of the amplification circuit are removed by a high pass filter circuit, the initial signal Vin is demodulated back to a base frequency with a square wave signal M1(t), and Figure 2 .

[0050] Specifically, in this embodiment, the functional component 4 is taken as a microphone component, the MEMS chip 42 has a variable capacitor, the vibration component 3 has a diaphragm 32 and a mass 33, and a chopper denoising circuit is integrated on the ASIC chip 43. On the one hand, the ASIC chip 43 can provide an initial direct current voltage for the capacitor, Vbias is connected to a movable electrode plate to provide an initial sensitivity of the product, and on the other hand, the ASIC chip 43 is used to read the output voltage value of the capacitor, Vin is connected to a fixed electrode, and after processing, an output is output. The addition of the chopper denoising circuit reduces the high frequency noise and the low frequency noise of the output signal, and also improves the SNR (Signal-to-Noise Ratio) of the vibration sensor.

[0051] In the above control process, the main working principle of the vibration sensor is that when the vibration sensor is excited by vibration, the mass 33 receives the signal to vibrate, generates a displacement amount ΔX, triggers the diaphragm 32 to deform, changes the back electrode spacing of the MEMS chip 42, generates a capacitance ΔC, a voltage amount ΔU, and then obtains a low-noise output signal after the ASIC signal amplification conditioning. And because the electrical signal is processed by the modulation circuit, the amplification circuit, the demodulation circuit, the high pass filter circuit and the low pass filter circuit in turn, the high frequency noise, the low frequency noise and the harmonic component of the vibration sensor are greatly reduced, the SNR, the sensitivity and the bandwidth are improved, and the performance of the vibration sensor is ensured.

[0052] Optionally, the frequency of the square wave signal emitted by the chopper denoising circuit is greater than the peak frequency of the vibration sensor.

[0053] Specifically, in this embodiment, the low frequency noise (especially 1 / f noise) is moved to a high frequency band by high frequency modulation, and then the signal SNR (Signal-to-Noise Ratio) is significantly improved after low pass filtering, while the effective low frequency signal of the sensor output is retained.

[0054] According to a third aspect of the present application, an electronic device is provided, comprising the vibration sensor of the first aspect.

[0055] Specifically, in the present embodiment, the vibration sensor of the first aspect has obvious improvement in noise and SNR, overcomes the 1 / f and other low-frequency noise that the conventional hardware scheme cannot filter out at low frequencies, and reduces the thermal noise to reduce the power consumption of the product. When applied to an electronic device, the performance of the electronic device can be improved.

[0056] The differences between the various embodiments are mainly described in the above embodiments. The optimization features that are different between the various embodiments can be combined to form a more optimal embodiment as long as they are not contradictory. In view of the brevity of the writing, they will not be described here.

[0057] Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A vibration sensor, characterized in that, include: A substrate and a housing, wherein the housing is disposed on the substrate and forms a receiving cavity with the substrate; A vibration assembly, which is disposed on the substrate and located within the receiving cavity; A functional component is disposed within the receiving cavity and includes a MEMS chip and an ASIC chip. The MEMS chip is electrically connected to the vibration component, and the ASIC chip is electrically connected to the MEMS chip and the substrate, respectively. The ASIC chip includes a chopper noise reduction circuit, which comprises a modulation circuit, an amplification circuit, a demodulation circuit, a high-pass filter circuit, and a low-pass filter circuit.

2. The vibration sensor according to claim 1, characterized in that, The ASIC chip also includes a high-frequency noise suppression module.

3. The vibration sensor according to claim 1, characterized in that, Both the high-pass filter circuit and the low-pass filter circuit employ second-order Butterworth filters.

4. The vibration sensor according to claim 1, characterized in that, The ASIC chip includes a modem, which employs an analog switch.

5. The vibration sensor according to claim 1, characterized in that, The vibration sensor is a gas-conducting vibration sensor.

6. The vibration sensor according to claim 5, characterized in that, The vibration assembly includes a first substrate, a diaphragm, and a mass block. The first substrate is disposed on the substrate, the diaphragm is disposed on the first substrate, and the mass block is suspended on the diaphragm and located between the diaphragm and the substrate; and / or, The functional component further includes a second substrate, which is stacked on the first substrate and has a gap with the diaphragm. The MEMS chip and the ASIC chip are both disposed on the second substrate. The second substrate has a through-hole, and the MEMS chip is opposite to the through-hole.

7. The vibration sensor according to claim 5, characterized in that, A groove is provided on the side of the substrate near the diaphragm, and the projection of the mass block on the substrate falls into the groove.

8. A control method for a vibration sensor as described in any one of claims 1-7, characterized in that, include: The vibration component picks up external vibration information, and the MEMS chip receives the vibration information. The MEMS chip converts the vibration information into an electrical signal and outputs the electrical signal to the ASIC chip to form an initial signal; The initial signal is modulated to a high frequency band by the modulation circuit, amplified by the amplifier circuit, and then filtered out by the high-pass filter circuit to remove low-frequency noise and electrical noise of the amplifier circuit. Finally, it is demodulated back to the base frequency by the demodulation circuit. The initial signal, demodulated back to the base frequency, is filtered by the low-pass filter circuit to remove high-frequency noise and form the output signal.

9. The control method for the vibration sensor according to claim 8, characterized in that, The square wave signal emitted by the chopper noise reduction circuit has a frequency greater than the peak frequency of the vibration sensor.

10. An electronic device, characterized in that, include: The vibration sensor according to any one of claims 1-7.

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