Sensor microphone circuit, sensor microphone, and electronic device

Abstract

The present disclosure provides a sensor microphone circuit, comprising: a signal input end, a control module, a voltage stabilizing module, a conversion module, a capacitor and a signal output end, wherein: a first input end of the control module is connected with the signal input end, a second input end of the control module is connected with an output end of the voltage stabilizing module, an output end of the control module is connected with a control end of the voltage stabilizing module; the output end of the voltage stabilizing module is connected with a first input end of the conversion module; a second input end of the conversion module is connected with the signal input end, an output end of the conversion module is connected with the signal output end; and the capacitor is connected between the signal input end and a ground end. The sensor microphone circuit provided by the present disclosure can realize suppression of power supply noise of the sensor microphone circuit.

Description

Technical Field

[0001] This disclosure relates to the field of acoustic technology, and more specifically, to a sensor microphone circuit, a sensor microphone, and an electronic device. Background Technology

[0002] With the widespread use of electronic devices with voice interaction capabilities (such as smartphones and smart home devices), the demand for sensor microphones in these devices is increasing.

[0003] Taking smartphones as an example, in GSM (Global System for Mobile Communications) phone applications, the 217Hz switching frequency is a major noise source for the sensor microphone's power supply. Suppressing power supply noise can improve the output signal quality of the sensor microphone, thus enhancing the clarity of smartphone voice interaction. Therefore, how to suppress power supply noise in sensor microphones has become an urgent technical problem to be solved. Summary of the Invention

[0004] One object of the present disclosure is to provide a new technical solution for a sensor microphone circuit.

[0005] According to a first aspect of the present disclosure, a sensor microphone circuit is provided, comprising:

[0006] The signal input terminal, control module, voltage regulator module, conversion module, capacitor, and signal output terminal include:

[0007] The first input terminal of the control module is connected to the signal input terminal, the second input terminal of the control module is connected to the output terminal of the voltage regulator module, and the output terminal of the control module is connected to the control terminal of the voltage regulator module.

[0008] The output terminal of the voltage regulator module is connected to the first input terminal of the conversion module;

[0009] The second input terminal of the conversion module is connected to the signal input terminal, and the output terminal of the conversion module is connected to the signal output terminal;

[0010] The capacitor is connected between the signal input terminal and the ground terminal;

[0011] Specifically, when the amplitude of the input signal at the signal input terminal is less than or equal to the amplitude of the output signal of the voltage regulator module, the control module controls the amplitude of the output signal of the voltage regulator module to remain unchanged; and when the amplitude of the input signal at the signal input terminal is greater than or equal to the amplitude of the output signal of the voltage regulator module, the control module controls the amplitude of the output signal of the voltage regulator module to be greater than or equal to the amplitude of the input signal at the signal input terminal.

[0012] Optionally, the control module includes at least one first comparison unit, a second comparison unit, and a control unit, wherein:

[0013] For any of the first comparison units, the first input terminal of the first comparison unit is connected to the output terminal of the corresponding reference voltage source, and the second input terminal of the first comparison unit is connected to the signal input terminal.

[0014] The first input terminal of the second comparison unit is connected to the signal input terminal, and the second input terminal of the second comparison unit is connected to the output terminal of the voltage regulator module;

[0015] The output terminal of the second comparison unit and the output terminal of any of the first comparison units are respectively connected to the corresponding input terminal of the control unit;

[0016] The output terminal of the control unit is connected to the control terminal of the voltage regulator module.

[0017] Optionally, the control unit is an encoder.

[0018] Optionally, the control module is a comparator.

[0019] Optionally, the voltage regulator module is a linear voltage regulator.

[0020] Optionally, the linear regulator is a low-dropout linear regulator.

[0021] Optionally, the circuit further includes an operating voltage source, wherein:

[0022] The input terminal of the operating voltage source is connected to the power supply terminal of the voltage regulator module.

[0023] Optionally, the circuit further includes a sound sensor, wherein:

[0024] The input terminal of the sound sensor is connected to the signal input terminal.

[0025] According to a second aspect of the present disclosure, a sensor microphone is provided, the sensor microphone including the sensor microphone circuit as described in any one of the first aspects.

[0026] According to a third aspect of the present disclosure, an electronic device is provided, the electronic device including a sensor microphone as described in the second aspect.

[0027] This disclosure discloses a sensor microphone circuit comprising: a signal input terminal, a control module, a voltage regulator module, a conversion module, a capacitor, and a signal output terminal. The control module has a first input terminal connected to the signal input terminal, a second input terminal connected to the output terminal of the voltage regulator module, and an output terminal connected to the control terminal of the voltage regulator module. The voltage regulator module's output terminal is connected to the first input terminal of the conversion module. The conversion module's second input terminal is connected to the signal input terminal, and its output terminal is connected to the signal output terminal. The capacitor is connected between the signal input terminal and a ground terminal. When the amplitude of the input signal at the sound signal input terminal is less than or equal to the amplitude of the output signal of the voltage regulator module, the control module keeps the amplitude of the voltage regulator module's output signal constant. This allows for suppression of power supply noise in a quiet environment with low sound pressure input, thereby improving the PSRR performance of the sensor microphone circuit. Furthermore, when the amplitude of the input signal at the signal input terminal is greater than the amplitude of the output signal of the voltage regulator module, by controlling the amplitude of the output signal of the voltage regulator module to be greater than or equal to the amplitude of the input signal at the audio signal input terminal, it is possible to reduce THD distortion in noisy environments with high sound pressure input, thereby improving AOP performance and thus improving the clarity of voice interaction.

[0028] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0030] Figure 1 This is a schematic diagram of the sensor microphone circuit provided according to an embodiment of the present disclosure. Figure 1 ;

[0031] Figure 2 This is a schematic diagram of the sensor microphone circuit provided according to an embodiment of the present disclosure. Figure 2 ;

[0032] Figure 3 This is a schematic diagram of the sensor microphone circuit provided according to an embodiment of the present disclosure. Figure 3 ;

[0033] Figure label:

[0034] Signal input terminal—101; Control module—102; Voltage regulator module—103; Conversion module—104; Signal output terminal—105; Capacitor—106; Working voltage source—107; Comparator—1021; First comparison unit—1022-1, 1022-2, 1022-3; Second comparison unit—1022-4; Reference voltage source—1023-1, 1023-2, 1023-3; Low dropout linear regulator—1031; Control unit—1024; Buffer—1041. Detailed Implementation

[0035] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the embodiments of the present disclosure.

[0036] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0037] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0038] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0040] <Circuit Example>

[0041] This disclosure provides a sensor microphone circuit, such as... Figure 1 As shown, the circuit includes: a signal input terminal 101, a control module 102, a voltage regulator module 103, a conversion module 104, a capacitor 106, and a signal output terminal 105, wherein:

[0042] The first input terminal of the control module 102 is connected to the signal input terminal 101, the second input terminal of the control module 102 is connected to the output terminal of the voltage regulator module 103, and the output terminal of the control module 102 is connected to the control terminal of the voltage regulator module 103.

[0043] The output terminal of the voltage regulator module 103 is connected to the first input terminal of the conversion module 104;

[0044] The second input terminal of the conversion module 104 is connected to the signal input terminal, and the output terminal of the conversion module 104 is connected to the signal output terminal 105.

[0045] Capacitor 106 is connected between signal input terminal 101 and ground terminal;

[0046] Specifically, when the amplitude of the input signal at the signal input terminal 101 is less than or equal to the amplitude of the output signal of the voltage regulator module 103, the control module 102 controls the amplitude of the output signal of the voltage regulator module 103 to remain unchanged; and when the amplitude of the input signal at the signal input terminal 101 is greater than or equal to the amplitude of the output signal of the voltage regulator module 103, the control module 102 controls the amplitude of the output signal of the voltage regulator module 103 to be greater than or equal to the amplitude of the input signal at the signal input terminal 101.

[0047] In this embodiment, the signal input terminal 101 is used to receive an input signal. The input signal is a weak voltage signal generated by a sound sensor connected to the signal input terminal 101, which converts ambient sound into voltage.

[0048] In one embodiment, the sensor microphone circuit provided in this disclosure further includes a sound sensor. The input terminal of the sound sensor is connected to the signal input terminal 101.

[0049] In this embodiment, a sound sensor is used to convert ambient sound into a weak voltage signal. Furthermore, in this embodiment, the sound sensor is integrated into the sensor microphone circuit, which improves the integration level of the sensor microphone circuit.

[0050] In this embodiment, capacitor 106 is used to filter out high-frequency noise in the input signal to reduce the interference of high-frequency noise on the input signal.

[0051] In this embodiment, the voltage regulator module 103 is a module that ensures the output signal of the conversion module 104 is within a set voltage range. The upper limit of the set voltage range is the maximum output voltage value of the voltage regulator module 103, and the lower limit is the minimum output voltage value of the voltage regulator module 103. Furthermore, the set voltage range is typically set to the voltage range capable of driving the subsequent circuitry of the sensor microphone circuit.

[0052] It is understood that the voltage regulator module 103 also includes a power supply terminal, which is used to connect to the operating power supply of the voltage regulator module 103. Based on this, in one embodiment, such as... Figure 2 As shown in Figure 3, the sensor microphone circuit provided in this embodiment of the present disclosure also includes a working voltage source 107, the input terminal of which is connected to the power supply terminal of the voltage regulator module 103.

[0053] In this embodiment, the output voltage of the operating voltage source 107 is typically 2.0V. In this embodiment, the operating voltage source 107 is integrated into the sensor microphone circuit, which improves the integration of the sensor microphone circuit and thus reduces dependence on an external voltage source.

[0054] In one embodiment, the voltage regulator module 103 is a linear regulator. When the voltage regulator module 103 is a linear regulator, the output signal ripple of the voltage regulator module 103 is small.

[0055] Furthermore, in one embodiment, such as Figure 2 As shown in Figure 3, the above-mentioned linear regulator is a low dropout linear regulator (LDO) 1031. When the linear regulator is a low dropout linear regulator 1031, the regulator module 103 has low self-dissipation, low inherent noise, and high power supply rejection ratio.

[0056] In this embodiment, the conversion module 104 is used to perform impedance conversion on the input signal at the signal input terminal 101 according to the output signal of the voltage regulator module 103, so as to obtain an output signal within a corresponding set voltage range. In one embodiment, such as Figure 2 As shown in Figure 3, the conversion module 104 can be implemented by the buffer 1041.

[0057] In this embodiment, the signal output terminal 105 is used to output the output signal of the conversion module 104 to the subsequent circuit of the sensor microphone circuit.

[0058] In this embodiment, the control module 102 is used to detect the magnitude of the input signal amplitude at the signal input terminal 101 and the magnitude of the output signal amplitude at the voltage regulator module 103, and determine the method of controlling the output signal amplitude of the voltage regulator module 103 based on the relationship between the two.

[0059] Specifically, when the amplitude of the input signal at signal input terminal 101 is less than or equal to the amplitude of the output signal of voltage regulator module 103, it indicates that the sensor microphone circuit is in a low sound pressure input environment, i.e., a low-volume voice interaction environment. It is understandable that low-volume voice interaction typically occurs in a quiet environment. In a quiet environment, the power supply noise of the sensor microphone becomes the main factor interfering with the output signal of the sensor microphone circuit. By setting the voltage regulator module 103 and keeping its output signal amplitude constant, the power supply noise of the sensor microphone circuit can be suppressed, thus improving the PSRR (Power Supply Rejection Ratio) performance of the sensor microphone circuit. Furthermore, in a quiet environment, the output signal amplitude of the sensor microphone circuit is relatively small. Therefore, although a voltage regulator module 103 is provided, the output signal at signal output terminal 105 will not be clipped.

[0060] It should be noted that PSRR represents the ratio of the voltage gains obtained when the input and power supply are considered as two independent signal sources. The formula for calculating PSRR is as follows:

[0061] PSRR = 20log[(Ripple(in) / Ripple(out))].

[0062] Where Ripple(in) represents the input signal amplitude, and Ripple(out) represents the power supply amplitude. In this embodiment, the Ripple(out) corresponding to the voltage regulator module 103 is smaller, therefore, the PSRR is larger.

[0063] Furthermore, if the amplitude of the input signal at signal input terminal 101 is greater than the amplitude of the output signal at voltage regulator module 103, it indicates that the sensor microphone circuit is operating in a high sound pressure level (SPL) input environment, i.e., a high-volume voice interaction environment. It is understandable that high-volume voice interaction typically occurs in noisy environments. In noisy environments, the amplitude of the sensor microphone circuit's output signal is relatively large. Based on this, by controlling the amplitude of the output signal at voltage regulator module 103 to be greater than the amplitude of the input signal at sound signal input terminal 101, the originally clipped output signal can be adjusted to an un-clipped output signal, thereby reducing THD (Total Harmonic Distortion) and improving AOP (Acoustic Overload Point) performance, thus improving the clarity of voice interaction. Additionally, in noisy environments, the amplitude of the sensor microphone circuit's output signal is relatively large, and the impact of power supply noise on the sensor microphone circuit's output signal is small, therefore power supply noise can be ignored.

[0064] It should be noted that AOP refers to the sound pressure level at which the THD output of the sensor microphone circuit is equal to 10%. Sound pressure levels higher than AOP will cause severe nonlinear distortion in the output signal.

[0065] This disclosure discloses a sensor microphone circuit comprising: a signal input terminal, a control module, a voltage regulator module, a conversion module, a capacitor, and a signal output terminal. The control module has a first input terminal connected to the signal input terminal, a second input terminal connected to the output terminal of the voltage regulator module, and an output terminal connected to the control terminal of the voltage regulator module. The voltage regulator module's output terminal is connected to the first input terminal of the conversion module. The conversion module's second input terminal is connected to the signal input terminal, and its output terminal is connected to the signal output terminal. The capacitor is connected between the signal input terminal and a ground terminal. When the amplitude of the input signal at the sound signal input terminal is less than or equal to the amplitude of the output signal of the voltage regulator module, the control module keeps the amplitude of the voltage regulator module's output signal constant. This allows for suppression of power supply noise in a quiet environment with low sound pressure input, thereby improving the PSRR performance of the sensor microphone circuit. Furthermore, when the amplitude of the input signal at the signal input terminal is greater than the amplitude of the output signal of the voltage regulator module, by controlling the amplitude of the output signal of the voltage regulator module to be greater than or equal to the amplitude of the input signal at the audio signal input terminal, it is possible to reduce THD distortion in noisy environments with high sound pressure input, thereby improving AOP performance and thus improving the clarity of voice interaction.

[0066] In one embodiment, such as Figure 2 As shown, the control module 102 can be a comparator 1021.

[0067] In this embodiment, taking the minimum output signal amplitude of the voltage regulator module 103 as 1.5V and the maximum output signal amplitude as VxV (greater than 1.5V), and the initial output signal amplitude of the voltage regulator module 103 as 1.5V as an example: When the input signal amplitude at the signal input terminal 101 is less than or equal to 1.5V, the comparator 1021 outputs a low level. At this time, the voltage regulator module 103 maintains its output signal amplitude under the control of the low level. When the input signal amplitude at the signal input terminal 101 is greater than 1.5V, the comparator 1021 outputs a high level. At this time, the voltage regulator module 103 increases its output signal amplitude to VxV under the control of the high level.

[0068] In another embodiment, such as Figure 3 As shown, the control module 102 includes at least one first comparison unit, a second comparison unit 1022-4, and a control unit 1024, wherein:

[0069] For any first comparison unit, the first input terminal of the first comparison unit is connected to the output terminal of the corresponding reference voltage source, and the second input terminal of the first comparison unit is connected to the signal input terminal 101.

[0070] The first input terminal of the second comparison unit 1022-4 is connected to the signal input terminal 101, and the second input terminal of the second comparison unit 1022-4 is connected to the output terminal of the voltage regulator module 103.

[0071] The output terminal of the second comparison unit 1022-4 and the output terminal of any of the first comparison units are respectively connected to the corresponding input terminal of the control unit 1024;

[0072] The output terminal of the control unit 1024 is connected to the control terminal of the voltage regulator module 103.

[0073] It should be noted that, Figure 3 The example shown uses three first comparison units, and the "\" in "2" represents a multi-bit signal. It is understood that this embodiment does not limit the number of first comparison units. Furthermore, the voltage output from the reference voltage source can be set based on the developer's experience.

[0074] Furthermore, the three first comparison units are first comparison unit 1022-1, first comparison unit 1022-2, and first comparison unit 1022-3, respectively. The reference voltage sources corresponding to the three first comparison units are 1023-1, 1023-2, and 1023-3, respectively.

[0075] In this embodiment, with Figure 3 For example, the reference voltages provided by the corresponding reference voltage sources of the three first comparison units are 1.8V, 1.7V and 1.6V, respectively.

[0076] With the input signal amplitude at signal input terminal 101 being 1.4V and the initial output signal amplitude of voltage regulator module 103 being 1.5V, the three first comparison units and one second comparison unit 1022-4 respectively output low level L, low level L, low level L, and low level L to control unit 1024. Control unit 1024, based on the low level L, low level L, low level L, and low level L, outputs low level L, low level L, and low level L to voltage regulator module 103. Voltage regulator module 103, based on the low level L, low level L, and low level L, outputs a 1.5V output signal.

[0077] With the input signal amplitude at signal input terminal 101 being 1.55V and the initial output signal amplitude of voltage regulator module 103 being 1.5V, the three first comparison units and one second comparison unit 1022-4 respectively output low level L, low level L, low level L, and high level H to control unit 1024. Control unit 1024, based on the low level L, low level L, low level L, and high level H, outputs low level L, low level L, and high level H to voltage regulator module 103. Voltage regulator module 103, based on the low level L, low level L, and high level H, outputs a 1.6V output signal.

[0078] With the input signal amplitude at signal input terminal 101 being 1.65V and the initial output signal amplitude of voltage regulator module 103 being 1.5V, the three first comparison units and one second comparison unit 1022-4 respectively output low level L, low level L, high level H, and high level H to control unit 1024. Control unit 1024, based on low level L, low level L, high level H, and high level H, outputs low level L, high level H, and low level L to voltage regulator module 103. Voltage regulator module 103, based on low level L, high level H, and low level L, outputs a 1.7V output signal.

[0079] With the input signal amplitude at signal input terminal 101 being 1.75V and the initial output signal amplitude of voltage regulator module 103 being 1.5V, the three first comparison units and one second comparison unit 1022-4 respectively output low level L, high level H, high level H, and high level H to control unit 1024. Control unit 1024, based on the low level L, high level H, high level H, and high level H, outputs low level L, high level H, and high level H to voltage regulator module 103. Voltage regulator module 103, based on the low level L, high level H, and high level H, outputs a 1.8V output signal.

[0080] With the input signal amplitude at signal input terminal 101 being 1.85V and the initial output signal amplitude of voltage regulator module 103 being 1.5V, the three first comparison units and one second comparison unit 1022-4 respectively output high level H, high level H, high level H, and high level H to control unit 1024. Control unit 1024, based on the high level H, high level H, high level H, and high level H, outputs high level H, low level L, and low level L to voltage regulator module 103. Voltage regulator module 103, based on the high level H, low level L, and low level L, can output an output signal greater than 1.85V, specifically 1.9V.

[0081] Furthermore, as can be seen from the above examples, through the sensor microphone circuit provided in this embodiment, under the control of the control module 102, the amplitude of the input signal at the signal input terminal 101 is less than the amplitude of the output signal at the voltage regulator module 103. Therefore, the input signal at the signal input terminal 101 will not be clipped, and thus will not cause distortion of the output signal at the conversion module 104.

[0082] In this embodiment, precise control of the output signal amplitude of the voltage regulator module 103 can be achieved through at least one first comparison unit, one second comparison unit 1022-4, and one control unit 1024. Furthermore, the voltage regulator module 103 can be reduced from four inputs to three inputs, which reduces the circuit complexity of the voltage regulator module 103.

[0083] In one embodiment, the control unit 1024 described above can be an encoder. Of course, the control unit 1024 described above can also be a microcontroller (MCU).

[0084] In one embodiment, the first comparison unit and the second comparison unit 1022-4 described above can both be implemented by a comparator.

[0085] <Equipment Example 1>

[0086] This disclosure also provides a sensor microphone, which includes the sensor microphone circuit provided in any of the above embodiments.

[0087] <Equipment Example 2>

[0088] This disclosure also provides an electronic device that includes the sensor-microphone circuit provided in the first embodiment of the device described above.

[0089] In one embodiment, the aforementioned electronic device may be a smartphone, tablet computer, smart wearable device, etc.

[0090] The above embodiments mainly focus on the differences from other embodiments, but those skilled in the art should understand that the above embodiments can be used alone or in combination as needed.

[0091] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein. The scope of this disclosure is defined by the appended claims.

Claims

1. A sensor microphone circuit, characterized by The circuit comprises a signal input end, a control module, a voltage stabilizing module, a conversion module, a capacitor and a signal output end, wherein: a first input end of the control module is connected with the signal input end, a second input end of the control module is connected with an output end of the voltage stabilizing module, and an output end of the control module is connected with a control end of the voltage stabilizing module; an output end of the voltage stabilizing module is connected with a first input end of the conversion module; a second input end of the conversion module is connected with the signal input end, and an output end of the conversion module is connected with the signal output end; the capacitor is connected between the signal input end and a ground end; wherein, when an input signal amplitude of the signal input end is less than or equal to an output signal amplitude of the voltage stabilizing module, the control module controls the output signal amplitude of the voltage stabilizing module to be unchanged, and when the input signal amplitude of the signal input end is greater than the output signal amplitude of the voltage stabilizing module, the control module controls the output signal amplitude of the voltage stabilizing module to be greater than or equal to the input signal amplitude of the signal input end. The control module comprises at least one first comparison unit, a second comparison unit and a control unit, wherein:

2. The circuit of claim 1, wherein, for any first comparison unit, a first input end of the first comparison unit is connected with an output end of a corresponding reference voltage source, and a second input end of the first comparison unit is connected with the signal input end; a first input end of the second comparison unit is connected with the signal input end, and a second input end of the second comparison unit is connected with the output end of the voltage stabilizing module; an output end of the second comparison unit and an output end of any first comparison unit are respectively connected with corresponding input ends of the control unit; an output end of the control unit is connected with the control end of the voltage stabilizing module. The control unit is an encoder.

3. The circuit of claim 2, wherein, The control module is a comparator.

4. The circuit of claim 1, wherein, The voltage stabilizing module is a linear voltage stabilizer.

5. The circuit of claim 1, wherein, The linear voltage stabilizer is a low-dropout linear voltage stabilizer.

6. The circuit of claim 5, wherein, The circuit further comprises a working voltage source, wherein:

7. The circuit of claim 1, wherein, an input end of the working voltage source is connected with a power supply end of the voltage stabilizing module. The circuit further comprises a sound sensor, wherein:

8. The circuit of claim 1, wherein, an input end of the sound sensor is connected with the signal input end. The sensor microphone comprises the sensor microphone circuit according to any one of claims 1-8.

9. A sensor microphone, characterized by The electronic device comprises the sensor microphone according to claim 9.

10. An electronic device, comprising: ​

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