Microphone circuit, device, chip, electronic device, and microphone circuit output method

Abstract

The present disclosure relates to a microphone circuit, device, chip, electronic device and microphone circuit output method, the microphone circuit comprising: when the direct current working voltage of the microphone is input into the chip, the direct current working voltage signal is denoised by a high-pass filter composed of a direct-current isolation capacitor and a low-transconductance operational amplifier, and the level difference between the direct current working voltage and the working voltage of the gain amplifier is eliminated to obtain a first voltage signal; the first voltage signal is amplified and collected by a gain amplification module; and the second voltage signal is converted into a digital audio signal by an analog-to-digital converter. The cost of the external PCB is avoided from being too high and the area is avoided from being too large, and meanwhile, the chip design is simple, the test cost is low, the hardware demand is low and the overall performance is superior.

Description

Technical Field

[0001] This disclosure relates to the field of microphone circuits, and more specifically, to a microphone circuit, device, chip, electronic device, and microphone circuit output method. Background Technology

[0002] In traditional microphone circuits, the microphone's DC operating voltage differs from the chip's gain amplifier's DC operating voltage. Therefore, an external DC blocking capacitor is needed to isolate the DC voltage, allowing only AC signals to pass. However, with traditional microphone circuit structures, the capacitance of this external DC blocking capacitor is too large, making it difficult to integrate into the chip and resulting in excessively high cost and large footprint for the external printed circuit board (PCB). While some technologies exist to reduce the need for external DC blocking capacitors, these typically rely on adding extra circuit logic, such as complex calibration logic, which increases design complexity and cost. Therefore, existing technologies for reducing external DC blocking capacitors cannot simultaneously address chip design complexity, testing costs, hardware requirements, and overall performance.

[0003] Therefore, there is an urgent need for a microphone circuit that can overcome the above problems. Summary of the Invention

[0004] The purpose of this disclosure is to provide a microphone circuit that solves the problem that existing chip-side DC blocking capacitor technology cannot simultaneously balance chip design complexity, testing costs, hardware requirements, and overall performance.

[0005] To achieve the above objectives, in a first aspect, this disclosure provides a microphone circuit, comprising: a DC blocking capacitor, a low transconductance operational amplifier, a gain amplification module, and an analog-to-digital converter; a first terminal of the DC blocking capacitor is connected to a microphone, a second terminal of the DC blocking capacitor is connected to the input terminal of the gain amplification module, a non-inverting input terminal of the low transconductance operational amplifier is connected to a reference input voltage, an inverting input terminal of the low transconductance operational amplifier is connected to the output terminal of the low transconductance operational amplifier, and the output terminal of the low transconductance operational amplifier is connected to the second terminal of the DC blocking capacitor; the output terminal of the gain amplification module is connected to the input terminal of the analog-to-digital converter.

[0006] Optionally, the microphone circuit further includes: an input follower, wherein the non-inverting input terminal of the input follower is connected to the second terminal of the DC blocking capacitor, the inverting input terminal of the input follower is connected to the output terminal of the input follower, and the output terminal of the input follower is connected to the inverting input terminal of the gain amplification module.

[0007] Optionally, the gain amplification module includes a gain amplifier, a first resistor, and a second resistor; the input terminals of the gain amplification module include a positive input terminal and an inverting input terminal of the gain amplifier; a first terminal of the first resistor is connected to the output terminal of the input follower, and a second terminal of the first resistor is connected to the inverting input terminal of the gain amplifier; a first terminal of the second resistor is connected to the inverting input terminal of the gain amplifier, and a second terminal of the second resistor is connected to the output terminal of the gain amplifier; the positive input terminal of the gain amplifier is used to connect to the reference input voltage.

[0008] Optionally, the gain amplification module includes a gain amplifier, a first resistor, and a second resistor; a first terminal of the first resistor is connected to the non-inverting input terminal of the low transconductance operational amplifier, and a second terminal of the first resistor is connected to the inverting input terminal of the gain amplifier; a first terminal of the second resistor is connected to the inverting input terminal of the gain amplifier, and a second terminal of the second resistor is connected to the output terminal of the gain amplifier.

[0009] Optionally, the microphone circuit further includes a third resistor; a first end of the third resistor is used to connect to the microphone, and a second end of the third resistor is used to connect to a power source.

[0010] Optionally, the third resistor is used to convert the current signal output by the microphone into a voltage signal; the current signal is obtained by converting the audio signal acquired by the microphone; the high-pass filter composed of the DC blocking capacitor and the low transconductance operational amplifier is used to perform noise reduction processing on the voltage signal and eliminate the level difference between the voltage signal and the operating voltage of the gain amplifier to obtain a first voltage signal; the gain amplification module is used to amplify the first voltage signal and acquire the signal to obtain a second voltage signal; the analog-to-digital converter is used to convert the second voltage signal into a digital audio signal.

[0011] Secondly, this disclosure provides a microphone circuit output method, in which a high-pass filter composed of a DC blocking capacitor and a low transconductance operational amplifier is used to denoise the voltage signal, and the DC blocking capacitor eliminates the level difference between the voltage signal and the operating voltage of the gain amplifier to obtain a first voltage signal; the voltage signal is obtained by converting an audio signal; the gain amplification module amplifies the first voltage signal to obtain a second voltage signal; and the analog-to-digital converter converts the second voltage signal into a digital audio signal.

[0012] Thirdly, a microphone device is provided, comprising: a microphone and the microphone circuit provided in the first aspect.

[0013] Fourthly, an electronic device is provided, comprising: the microphone device provided in the third aspect.

[0014] Fifthly, a chip is provided, comprising: the chip internally including the microphone circuit provided in the first aspect.

[0015] Through the above technical solution, when the microphone's DC operating voltage is input into the chip, a high-pass filter composed of a DC blocking capacitor and a low transconductance operational amplifier is used to denoise the DC operating voltage signal. The DC blocking capacitor also eliminates the level difference between the DC operating voltage and the gain amplifier's operating voltage, resulting in a first voltage signal. This first voltage signal is then amplified and acquired by the gain amplifier module, and finally converted into a digital audio signal by an analog-to-digital converter. Since the low transconductance operational amplifier can function as a large resistor at low input frequencies, forming a high-pass filter to filter out wind noise and eliminate DC level differences, it cannot keep up at high input frequencies. Therefore, the input signal passes directly through the DC blocking capacitor to the input of the gain amplifier, completing signal amplification and acquisition. This allows for the use of a smaller DC blocking capacitor, reducing its size and allowing it to be integrated into the chip. This avoids the problems of excessive chip cost and area caused by a large DC blocking capacitor. Furthermore, by avoiding the addition of complex circuit logic, the chip design is simple, testing costs are low, hardware requirements are low, and overall performance is excellent.

[0016] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0018] Figure 1 This is a schematic diagram of a traditional microphone circuit provided by related technologies;

[0019] Figure 2 This is a schematic diagram of a microphone circuit according to an exemplary embodiment;

[0020] Figure 3 This is a schematic diagram of a microphone circuit according to an exemplary embodiment;

[0021] Figure 4 This is a schematic diagram of another microphone circuit structure according to an exemplary embodiment;

[0022] Figure 5This is a block diagram illustrating an electronic device according to an exemplary embodiment. Detailed Implementation

[0023] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0024] Traditional microphone circuits, such as Figure 1 As shown: The internal microphone power generator of the chip provides power to the microphone. The output of the microphone power generator is connected to resistor R1, which in turn is connected to the microphone, which is grounded. When the microphone receives an audio signal, a current signal is generated at the microphone's output port. This current signal is converted into a voltage signal VB through resistor R1. This voltage signal is then fed into the chip via an external DC blocking capacitor C1. After passing through the chip's internal gain amplifier, it is transmitted to the analog-to-digital converter (ADC). The ADC converts the voltage signal into a digital signal, thus completing the audio signal to digital signal conversion.

[0025] Because the microphone's DC operating voltage differs from the DC operating voltage of the gain amplifier within the chip, an external DC blocking capacitor C1 is needed to isolate the DC voltage, allowing only AC signals to pass through. Simultaneously, this external DC blocking capacitor C1, together with the input resistor R2 of the gain amplifier, forms a high-pass filter to filter out noise energy within a certain range, such as noise energy in the 20-200Hz range, like wind noise. Assuming the input resistor R2 of the internal gain amplifier is 10k ohms and the capacitance of the external DC blocking capacitor C1 is 1uF, then the bandwidth of this high-pass filter, calculated as 1 / (2*pi*R2*C1), is approximately 16Hz, thus filtering out noise energy below 16Hz, where pi is the mathematical constant pi.

[0026] The input resistor value of the gain amplifier cannot be too large, otherwise it will result in a very large chip area and increase the noise in the microphone path, making it impossible to detect the energy of weak sounds. The input resistor value of the gain amplifier is generally between 2kΩ and 100kΩ, and the external DC blocking capacitor C1 is around 1uF to 0.1uF. Using a traditional microphone circuit structure, if the capacitance of the external DC blocking capacitor C1 is too large, it is difficult to integrate it into the chip, resulting in excessively high external PCB costs and a large area.

[0027] To address the aforementioned issues, several techniques have been developed that eliminate the need for external DC blocking capacitors: DC level calibration without DC blocking capacitors, equivalent resistance multiplication technique using small internal DC blocking capacitors, and DC level filtering and cancellation technique without DC blocking capacitors.

[0028] One such technique is the DC level calibration technology without DC blocking capacitors. This technology calibrates the microphone's DC operating voltage to match the internal DC operating voltage of the chip, thus eliminating the need for DC blocking capacitors. There are two implementation methods for this technology: one is to calibrate the internal DC operating voltage VREF of the chip to match the external DC operating voltage of the microphone. This is typically done using an internal digital-to-analog converter (DAC) or an FT / CP. The other method is to add a calibration module to calibrate the internal VREF voltage, ensuring that the internal DC operating level matches the external DC level of the microphone.

[0029] However, the applicant discovered several drawbacks to the aforementioned DC level calibration technology without DC blocking capacitors: First, it requires additional calibration logic or processes, increasing chip design complexity, chip area, and chip testing costs; second, calibration accuracy is difficult to control. Low calibration accuracy leads to deviations in the calibrated DC voltage, which are amplified by the gain amplifier, resulting in a loss of dynamic range performance. High calibration accuracy, on the other hand, increases chip area; third, this technology cannot filter out wind noise, thus increasing the impact of wind noise on the analog-to-digital converter (ADC); fourth, due to increasingly stringent requirements for chip power consumption (i.e., low power consumption), the internal operating voltage of the chip is decreasing, while the microphone's operating voltage needs to maintain a certain amplitude, making it increasingly impossible to calibrate the two operating voltages to the same DC voltage; fifth, changes in the external environment will render previous calibrations invalid, requiring recalibration.

[0030] Equivalent Resistance Multiplication Technology with Small Internal DC Blocking Capacitor: In traditional microphone circuits, resistor R1 and DC blocking capacitor C1 form a high-pass filter. If the DC blocking capacitor C1 is reduced to less than 100pF and integrated internally into the chip, then R1 needs to be increased by 100 to 1000 times. Therefore, directly implementing R1 would result in an excessively large chip area. This technology uses a small resistor and some logic circuits to achieve a very large equivalent resistance, i.e., resistance multiplication technology. It can be implemented using analog and sampling methods, achieving a 100 to 1000-fold amplification of the resistance through a multiplication module or a sampling method with a very small duty cycle. However, the applicant found that the additional modules in this equivalent resistance multiplication technology lead to increased power consumption or additional clock requirements, and also increase the chip design complexity, chip area, and chip testing costs.

[0031] DC level filtering and cancellation technology without DC blocking capacitors: This method involves adding DC voltage filtering and cancellation to the digital or analog modules, typically achieved by adding a filter, to prevent the DC voltage from affecting the chip's internal operating state. The applicant discovered that due to the large DC signal in the input signal, this method easily leads to a significant reduction in the ADC's input dynamic range, thus degrading the overall path performance.

[0032] In summary, the applicant has found that several technical solutions in the related technologies increase the design complexity, chip area, and chip cost, or may negatively impact the chip's performance. Therefore, to address these technical problems, this disclosure proposes a microphone circuit. The microphone circuit provided in this disclosure is described below.

[0033] Please see Figure 2 , Figure 2 This is a schematic diagram illustrating the structure of a microphone circuit according to an exemplary embodiment. Figure 2 As shown, the microphone circuit includes: a DC blocking capacitor C1, a low transconductance operational amplifier 32, a gain amplification module 33, and an analog-to-digital converter (ADC) 34; the microphone circuit is connected to an external microphone 10 and a power supply 20, and the specific connection relationship is as follows:

[0034] The first terminal of the DC blocking capacitor C1 is connected to the microphone, and the second terminal of the DC blocking capacitor C1 is connected to the input terminal of the gain amplification module 33.

[0035] The non-inverting input terminal of the low transconductance operational amplifier 32 is used to connect to the reference input voltage, the inverting input terminal of the low transconductance operational amplifier 32 is connected to the output terminal of the low transconductance operational amplifier 32, and the output terminal of the low transconductance operational amplifier 32 is connected to the second terminal of the DC blocking capacitor.

[0036] The output of the gain amplifier module 33 is connected to the input of the analog-to-digital converter 34.

[0037] In one implementation, please refer to Figure 3 , Figure 3 This is a schematic diagram illustrating the structure of a microphone circuit according to an exemplary embodiment. Figure 3 As shown, the microphone circuit includes: a DC blocking capacitor C1, a low transconductance operational amplifier 32, a gain amplification module 33, an analog-to-digital converter 34, and a third resistor R3. The gain amplification module includes a gain amplifier 331, a first resistor R1, and a second resistor R2. The microphone circuit connects to an external microphone 10 and a power supply 20. The power supply 20 can be located internally within the circuit or connected to an external power source. The specific connection relationships are as follows:

[0038] One end of the microphone is connected to the third resistor R3 to collect audio signals, which are then converted into current signals. These current signals flow through the third resistor R3 and are converted into voltage signals.

[0039] One end of the power supply is connected to the third resistor R3 to provide power to the microphone circuit inside the chip. It should be noted that... Figure 3 Although the power supply shown is inside the chip, in actual applications, the power supply can also be an external power source to supply power to the chip.

[0040] The first terminal of the DC blocking capacitor C1 is connected to the microphone, and the second terminal of the DC blocking capacitor C1 is connected to the input terminal of the gain amplifier module; the DC blocking capacitor C1 is used to eliminate the level difference between the microphone's DC operating voltage and the gain amplifier's operating voltage. In one embodiment, the capacitance value of the DC blocking capacitor C1 can be, but is not limited to, 20pF to 100pF.

[0041] The non-inverting input of the low-transconductance operational amplifier (LTA) is connected to the reference input voltage VREF, and the inverting input is connected to its output. The output is connected to the second terminal of the DC blocking capacitor C1. The LTA, together with the DC blocking capacitor, forms a high-pass filter to denoise the audio signal input from the microphone, such as filtering wind noise. For example, this high-pass filter can filter noise energy below 20–200 Hz. Assuming the LTA's transconductance Gm is 5 nS and the DC blocking capacitor C1 has a capacitance of 50 pF, the bandwidth of the high-pass filter can be calculated as 16 Hz using the formula Gm / (2*pi*C1). Therefore, the high-pass filter can filter noise energy below 16 Hz, where pi is the mathematical constant pi.

[0042] The input terminals of the gain amplifier module include the positive input terminal and the inverting input terminal of the gain amplifier; the output terminal of the gain amplifier module, i.e. the output terminal of the gain amplifier, is connected to the input terminal of the analog-to-digital converter; under high frequency signal input, the low transconductance amplifier cannot respond, so the gain amplifier module amplifies and acquires the denoised voltage signal, and then sends the acquired signal to the analog-to-digital converter, which converts the acquired signal into a digital audio signal.

[0043] In one implementation, Figure 3 The microphone circuit shown also includes an input follower 31.

[0044] The non-inverting input of the input follower is connected to the second terminal of the DC blocking capacitor C1, and the inverting input of the input follower is connected to its output. The output of the input follower is connected to the inverting input of the gain amplifier module. For example, the output of the input follower is connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is connected to the inverting input of the gain amplifier; the first terminal of the second resistor R2 is connected to the inverting input of the gain amplifier, and the second terminal of the second resistor R2 is connected to the output of the gain amplifier; the non-inverting input of the gain amplifier is used to connect to VREF.

[0045] Since the voltage signal passing through the internal DC blocking capacitor C1 and the ultra-low transconductance operational amplifier has no driving capability and cannot directly drive the gain amplifier, an input follower is added to complete the work of driving the gain amplifier.

[0046] Figure 3 The microphone circuit shown works as follows: the microphone circuit acquires the audio signal transmitted by the microphone, and the audio signal is output as a corresponding current signal from the microphone output port after passing through the microphone; the third resistor is used to convert the current signal output by the microphone into a voltage signal, and the power supply provides power to the microphone circuit inside the chip; the high-pass filter composed of the DC blocking capacitor and the low transconductance operational amplifier performs noise reduction processing on the voltage signal, such as filtering out wind noise below 20-200 Hz. High-frequency input signals, such as audio signals, will not be filtered out by this high-pass filter, and the high-frequency input signals are input to the gain amplifier inside the chip for amplification; after the DC blocking capacitor eliminates the level difference between the voltage signal and the working voltage of the gain amplifier, the first voltage signal is obtained; the input follower is used to drive the gain amplifier to work, and the gain amplification module amplifies the first voltage signal to obtain the second voltage signal; the analog-to-digital converter converts the second voltage signal into a digital audio signal.

[0047] In another implementation, this disclosure also proposes a microphone circuit that does not include an input follower, such as... Figure 4 As shown, Figure 4 This is a schematic diagram illustrating the structure of another microphone circuit according to an exemplary embodiment. For example... Figure 4 As shown, the microphone circuit includes: a DC blocking capacitor C1, a low transconductance operational amplifier 32, a gain amplification module 33, an analog-to-digital converter 34, and a third resistor R3. The gain amplification module includes a gain amplifier 331, a first resistor R1, and a second resistor R2. The microphone circuit is connected to an external microphone 10 and a power supply 20, with the specific connections as follows:

[0048] The third resistor R3 is connected to one end of the microphone 10 and is used to collect audio signals through the microphone. The microphone output terminal outputs the corresponding current signal, which flows through the third resistor R3 and is converted into a voltage signal.

[0049] One end of power supply 20 is connected to the third resistor R3 to provide power to the microphone circuit inside chip 40. It should be noted that... Figure 4 Although the power supply shown is inside the chip, in actual applications, the power supply can also be an external power source to supply power to the chip.

[0050] The first end of the DC blocking capacitor C1 is used to connect to the microphone, and the second end of the DC blocking capacitor C1 is connected to the input terminal of the gain amplifier module; the DC blocking capacitor C1 is used to eliminate the level difference between the microphone's DC operating voltage and the gain amplifier's operating voltage.

[0051] The non-inverting input of the low transconductance operational amplifier is used to connect the reference input voltage VREF, the inverting input is connected to the output, and the output is connected to the second end of the DC blocking capacitor C1. The low transconductance operational amplifier is used to form a high-pass filter with the DC blocking capacitor to denoise the voltage signal input from the microphone, such as filtering out wind noise.

[0052] The input terminals of the gain amplifier module include the positive input terminal and the inverting input terminal of the gain amplifier; the output terminal of the gain amplifier module, i.e. the output terminal of the gain amplifier, is connected to the input terminal of the analog-to-digital converter; under high frequency signal input, the low transconductance amplifier cannot respond, so the gain amplifier module amplifies and acquires the denoised voltage signal, and then sends the acquired signal to the analog-to-digital converter, which converts the acquired signal into a digital audio signal.

[0053] Optional, Figure 4 In the microphone circuit shown, the first end of the first resistor R1 is connected to the non-inverting input of the low transconductance operational amplifier, and the second end of the first resistor R1 is connected to the inverting input of the gain amplifier; the first end of the second resistor R2 is connected to the inverting input of the gain amplifier, and the second end of the second resistor R2 is connected to the output of the gain amplifier; the second end of the DC blocking capacitor C1 is connected to the non-inverting input of the gain amplifier.

[0054] Figure 4The microphone circuit shown works as follows: the microphone circuit acquires the audio signal transmitted by the microphone, and the audio signal is output as a corresponding current signal from the microphone output port after passing through the microphone; the third resistor is used to convert the current signal output by the microphone into a voltage signal, and the power supply provides power to the microphone circuit inside the chip 40; the high-pass filter composed of the DC blocking capacitor and the low transconductance operational amplifier performs noise reduction processing on the voltage signal, such as filtering out wind noise below 20-200 Hz, and high-frequency input signals such as audio signals are not filtered out by the high-pass filter. The high-frequency input signal is input to the gain amplifier inside the chip for amplification; after the DC blocking capacitor eliminates the level difference between the voltage signal and the working voltage of the gain amplifier, a first voltage signal is obtained; the gain amplification module amplifies the first voltage signal to obtain a second voltage signal; the analog-to-digital converter converts the second voltage signal into a digital audio signal.

[0055] In summary, the microphone circuit provided in this disclosure, when the microphone's DC operating voltage is input into the chip, performs noise reduction processing on the DC operating voltage signal through a high-pass filter composed of a DC blocking capacitor and a low transconductance operational amplifier, and eliminates the level difference between the DC operating voltage and the operating voltage of the gain amplifier through the DC blocking capacitor, to obtain a first voltage signal. The first voltage signal is then amplified and acquired through a gain amplification module, and the second voltage signal is converted into a digital audio signal through an analog-to-digital converter. Because a low transconductance operational amplifier can function as a large resistor at low input frequencies, forming a high-pass filter to filter out wind noise and eliminate DC level differences, it cannot keep up with high input frequencies. This allows the input signal to pass directly through the DC blocking capacitor to the input of the gain amplifier, completing signal amplification and acquisition. Therefore, a smaller capacitance value can be used for the DC blocking capacitor. This smaller capacitance reduces the size of the DC blocking capacitor, allowing it to be integrated into the chip. This avoids the problems of excessively large chip cost and area caused by a large DC blocking capacitor. Furthermore, by avoiding the addition of complex circuit logic, the chip design remains simple, testing costs are low, hardware requirements are low, and overall performance is excellent.

[0056] This disclosure also provides a microphone circuit output method, applied to... Figure 2 The microphone circuit shown includes the following method: a high-pass filter composed of a DC blocking capacitor and a low transconductance operational amplifier to denoise the voltage signal; and a first voltage signal obtained after the DC blocking capacitor eliminates the level difference between the voltage signal and the operating voltage of the gain amplifier; the voltage signal is obtained by converting an audio signal; the gain amplification module amplifies the first voltage signal to obtain a second voltage signal; and the analog-to-digital converter converts the second voltage signal into a digital audio signal.

[0057] This disclosure also provides a chip that internally includes the aforementioned microphone circuitry. This disclosure further provides a microphone device that includes a microphone and the aforementioned chip. Figure 5 This is a block diagram illustrating an electronic device 700 according to an exemplary embodiment. Figure 5 As shown, the electronic device 700 may include: a processor 701, a memory 702, and Figure 2 ,or Figure 3 ,or Figure 4 The provided microphone circuitry. The electronic device 700 may also include one or more of a multimedia component 703, an input / output (I / O) interface 704, and a communication component 705.

[0058] The processor 701 controls the overall operation of the electronic device 700 to complete all or part of the steps in the microphone circuit output method described above. The memory 702 stores various types of data to support the operation of the electronic device 700. This data may include, for example, instructions for any application or method operating on the electronic device 700, and application-related data such as contact data, sent and received messages, pictures, audio, video, etc. The memory 702 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. Multimedia component 703 may include a screen and an audio component. The screen may be, for example, a touchscreen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signals may be further stored in memory 702 or transmitted via communication component 705. The audio component also includes at least one speaker for outputting audio signals. I / O interface 704 provides an interface between processor 701 and other interface modules, such as a keyboard, mouse, buttons, etc. These buttons may be virtual or physical buttons. Communication component 705 is used for wired or wireless communication between the electronic device 700 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, NB-IoT, eMTC, or other 5G technologies, or combinations thereof, is not limited here. Therefore, the corresponding communication component 705 may include: a Wi-Fi module, a Bluetooth module, an NFC module, etc.

[0059] In an exemplary embodiment, the electronic device 700 may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the microphone circuit output method described above.

[0060] In another exemplary embodiment, a computer-readable storage medium including program instructions is also provided, which, when executed by a processor, implement the steps of the microphone circuit output method described above. For example, the computer-readable storage medium may be the memory 702 including program instructions, which may be executed by the processor 701 of the electronic device 700 to complete the microphone circuit output method described above.

[0061] In another exemplary embodiment, a computer program product is also provided, comprising a computer program executable by a programmable device, the computer program having a code portion for performing the microphone circuit output method described above when executed by the programmable device.

[0062] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0063] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0064] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A microphone circuit, characterized in that, include: DC blocking capacitors, low transconductance operational amplifiers, gain amplifier modules, and analog-to-digital converters; The first terminal of the DC blocking capacitor is connected to the microphone, and the second terminal of the DC blocking capacitor is connected to the input terminal of the gain amplification module. The non-inverting input terminal of the low transconductance operational amplifier is used to connect to the reference input voltage, the inverting input terminal of the low transconductance operational amplifier is connected to the output terminal of the low transconductance operational amplifier, and the output terminal of the low transconductance operational amplifier is connected to the second terminal of the DC blocking capacitor. The output of the gain amplifier module is connected to the input of the analog-to-digital converter.

2. The microphone circuit according to claim 1, characterized in that, Also includes: An input follower is provided, wherein the non-inverting input terminal of the input follower is connected to the second terminal of the DC blocking capacitor, the inverting input terminal of the input follower is connected to the output terminal of the input follower, and the output terminal of the input follower is connected to the input terminal of the gain amplification module.

3. The microphone circuit according to claim 2, characterized in that, The gain amplification module includes a gain amplifier, a first resistor, and a second resistor; the input terminals of the gain amplification module include the non-inverting input terminal and the inverting input terminal of the gain amplifier. The first end of the first resistor is connected to the output terminal of the input follower, and the second end of the first resistor is connected to the inverting input terminal of the gain amplifier. The first end of the second resistor is connected to the inverting input terminal of the gain amplifier, and the second end of the second resistor is connected to the output terminal of the gain amplifier. The non-inverting input of the gain amplifier is used to connect the reference input voltage.

4. The microphone circuit according to claim 1, characterized in that, The gain amplification module includes a gain amplifier, a first resistor, and a second resistor; the input terminals of the gain amplification module include the non-inverting input terminal and the inverting input terminal of the gain amplifier. The first end of the first resistor is connected to the non-inverting input of the low transconductance operational amplifier, and the second end of the first resistor is connected to the inverting input of the gain amplifier. The first end of the second resistor is connected to the inverting input of the gain amplifier, and the second end of the second resistor is connected to the output of the gain amplifier.

5. The microphone circuit according to claim 3 or 4, characterized in that, Also includes: Third resistor; The first end of the third resistor is used to connect to the microphone, and the second end of the third resistor is used to connect to the power supply.

6. The microphone circuit according to claim 5, characterized in that, The third resistor is used to convert the current signal output by the microphone into a voltage signal; the current signal is obtained by converting the audio signal acquired by the microphone. The high-pass filter composed of the DC blocking capacitor and the low transconductance operational amplifier is used to denoise the voltage signal and eliminate the level difference between the voltage signal and the operating voltage of the gain amplifier to obtain a first voltage signal. The gain amplification module is used to amplify the first voltage signal and, after signal acquisition, obtain the second voltage signal; The analog-to-digital converter is used to convert the second voltage signal into a digital audio signal.

7. A microphone circuit output method as described in any one of claims 1-6, characterized in that, include: The high-pass filter composed of the DC blocking capacitor and the low transconductance operational amplifier performs noise reduction processing on the voltage signal, and the DC blocking capacitor eliminates the level difference between the voltage signal and the operating voltage of the gain amplification module to obtain the first voltage signal; the voltage signal is obtained by converting the audio signal. The gain amplification module amplifies the first voltage signal to obtain the second voltage signal; The analog-to-digital converter converts the second voltage signal into a digital audio signal.

8. A chip, characterized in that, The chip internally includes the microphone circuit described in any one of claims 1-6.

9. A microphone device, characterized in that, include: Microphone, chip as described in claim 8.

10. An electronic device, characterized in that, include: The microphone device according to claim 9.

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