Sensor microphone direct current output compensation circuit, system, and method

Abstract

This invention provides a DC output compensation circuit, system, and method for a sensor microphone. The DC output compensation circuit includes a detection circuit and a preset power supply. When the sensor microphone is powered on, the detection circuit detects the extra leakage current at the output of the buffer circuit to obtain a detection signal, and sends the detection signal to the preset power supply. The preset power supply sets the output voltage of the buffer circuit according to the detection signal and outputs the output voltage to the input of the buffer circuit to compensate for the extra leakage current. This invention effectively avoids increased distortion of the sensor microphone output signal by detecting the extra leakage current and setting the output voltage of the buffer circuit according to the detection signal.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a sensor microphone DC output compensation circuit, system, and method. Background Technology

[0002] Due to the widespread application of sensor microphones in modern consumer markets such as smartphones, smart headphones, and smart homes, the demand for them has increased significantly. Traditional sensor microphones use a capacitor connected in series at the output for AC signal coupling. Only AC signals can be transmitted through the capacitor, while DC signals are blocked. The advantage is that the sensor microphone output can be used with any brand of audio codec, meaning the sensor microphone can ignore the influence of DC signals in subsequent stages. This allows the application circuitry to be designed with different DC bias voltages. Furthermore, the series AC signal coupling capacitor is a high-impedance device and does not provide a DC current path.

[0003] With the widespread application and quality improvement of smart products today, these products are developing towards multi-functionality, making system PCB circuit design more complex. Currently, the application of sensor microphones is gradually moving towards a connection method without AC signal coupling capacitors at the output end. This allows for denser component placement on the PCB and reduces costs during mass production. However, when the DC signal at the output end of the sensor microphone is at a different level than the built-in DC signal in the subsequent stage, a leakage current path will be generated in the output stage of the internal chip of the sensor microphone. Referring to the transistor current formula, as the current increases, the gate level of the NMOS transistor in the chip output stage is also increased. This causes the NMOS transistor to operate outside of its original design bias level, resulting in increased distortion of the sensor microphone output signal. Consequently, even when the total harmonic distortion is less than 10%, the maximum sound pressure level decreases.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide a DC output compensation circuit, system, and method for a sensor microphone, which aims to solve the technical problem in the prior art where the sensor microphone output signal distortion increases when the voltage values ​​of the sensor microphone and the built-in DC signal in the subsequent stage are different.

[0006] To achieve the above objectives, the present invention proposes a sensor microphone DC output compensation circuit, which includes: a detection circuit and a preset power supply;

[0007] The detection circuit is connected to the output of the preset power supply and the buffer circuit inside the sensor microphone, respectively, and the preset power supply is connected to the input of the buffer circuit.

[0008] The detection circuit is used to detect the additional leakage current at the output of the buffer circuit when the sensor microphone is powered on, obtain a detection signal, and send the detection signal to the preset power supply.

[0009] The preset power supply is used to set the output voltage of the buffer circuit according to the detection signal, and output the output voltage to the input terminal of the buffer circuit to compensate for the additional leakage current.

[0010] Optionally, the sensor microphone DC output compensation circuit further includes: a switching circuit;

[0011] The switching circuit is connected to both the detection circuit and the preset power supply.

[0012] The switching circuit is used to connect the compensation circuit between the detection circuit and the preset power supply when the sensor microphone is powered on.

[0013] The detection circuit is also used to output the detection signal to the preset power supply when the compensation circuit is turned on.

[0014] Optionally, the sensor microphone DC output compensation circuit further includes: a power reset circuit;

[0015] The power reset circuit is connected to the power supply of the switch circuit and the sensor microphone, respectively.

[0016] The power reset circuit is used to output a conduction control signal to the switching circuit when the sensor microphone is powered on.

[0017] The switching circuit is also used to connect the compensation circuit between the detection circuit and the preset power supply according to the conduction control signal.

[0018] Optionally, the power reset circuit is further configured to output a cutoff control signal to the switching circuit after compensating for the additional leakage current.

[0019] The switching circuit is also used to disconnect the compensation loop between the detection circuit and the preset power supply when the cut-off control signal is received.

[0020] Optionally, the buffer circuit includes: a first and a second switching transistor;

[0021] The control terminals of the first and second switching transistors are connected to the chip of the sensor microphone. The input terminal of the first switching transistor is connected to the power supply. The output terminal of the first switching transistor is connected to the input terminal of the second switching transistor and the subsequent load. The output terminal of the second switching transistor is grounded.

[0022] Optionally, the detection circuit includes: a third to a fifth switching transistor and a first resistor;

[0023] The control terminal of the third switch is connected to the control terminal of the second switch. The input terminal of the third switch is connected to the input terminal of the fourth switch, the output terminal of the fourth switch, and the input terminal of the fifth switch. The input terminal of the fourth switch is connected to the power supply. The input terminal of the fifth switch is connected to the power supply. The output terminal of the fifth switch is connected to the first terminal of the first resistor and the switching circuit. The second terminal of the first resistor and the output terminal of the third switch are grounded.

[0024] Optionally, the preset power supply includes: a current source and a second resistor;

[0025] The first end of the current source is connected to the power supply, the second end of the current source is connected to the output end of the fifth switching transistor and the first end of the first resistor through a switching circuit, the third end of the current source is connected to the first end of the second resistor and the input end of the buffer circuit, and the second end of the second resistor is grounded.

[0026] Optionally, the switching circuit includes: a controllable switching element;

[0027] The control terminal of the controllable switching element is connected to the output terminal of the power reset circuit, the input terminal of the controllable switching element is connected to the output terminal of the fifth switching transistor and the first terminal of the first resistor, and the output terminal of the controllable switching element is connected to the second terminal of the current source.

[0028] To achieve the above objectives, the present invention also proposes a sensor microphone DC output compensation system, which includes the aforementioned sensor microphone DC output compensation circuit.

[0029] To achieve the above objectives, the present invention also proposes a sensor microphone DC output compensation method, the sensor microphone DC output compensation method comprising:

[0030] When the sensor microphone is powered on, the additional leakage current at the output of the buffer circuit is detected to obtain a detection signal.

[0031] The output voltage of the buffer circuit is set according to the detection signal to compensate for the additional leakage current.

[0032] This invention provides a DC output compensation circuit, system, and method for a sensor microphone. The DC output compensation circuit includes a detection circuit and a preset power supply. When the sensor microphone is powered on, the detection circuit detects the extra leakage current at the output of the buffer circuit to obtain a detection signal, and sends the detection signal to the preset power supply. The preset power supply sets the output voltage of the buffer circuit according to the detection signal and outputs the output voltage to the input of the buffer circuit to compensate for the extra leakage current. This invention effectively avoids increased distortion of the sensor microphone output signal by detecting the extra leakage current and setting the output voltage of the buffer circuit according to the detection signal. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the first embodiment of the sensor microphone DC output compensation circuit proposed in this invention;

[0035] Figure 2 The circuit diagram of the buffer circuit in the first embodiment of the sensor microphone DC output compensation circuit proposed in this invention is shown.

[0036] Figure 3 This is a schematic diagram of the second embodiment of the sensor microphone DC output compensation circuit proposed in this invention;

[0037] Figure 4 This is a circuit diagram of the second embodiment of the sensor microphone DC output compensation circuit proposed in this invention;

[0038] Figure 5 This is a flowchart illustrating the first embodiment of the sensor microphone DC output compensation method proposed in this invention.

[0039] Explanation of icon numbers:

[0040] label name label name 10 Detection circuit R1~R2 First to second resistors 20 Preset power T1~T5 First to fifth switching transistors 30 Switching circuit RA Detecting resistor 40 Power reset circuit VDD Power supply IA Current source GND Grounding

[0041] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0042] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0044] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0045] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, the user should consider such a combination of technical solutions to be non-existent and not within the scope of protection claimed by this invention.

[0046] Reference Figure 1 , Figure 1 This is a schematic diagram of the first embodiment of the sensor microphone DC output compensation circuit proposed in this invention. Based on Figure 1 The first embodiment of the DC output compensation circuit for the sensor microphone of the present invention is presented.

[0047] In this embodiment, the sensor microphone DC output compensation circuit includes: a detection circuit 10 and a preset power supply 20;

[0048] The detection circuit 10 is connected to the output terminal of the preset power supply 20 and the buffer circuit inside the sensor microphone, respectively, and the preset power supply 20 is connected to the input terminal of the buffer circuit.

[0049] It should be understood that the sensor microphone's buffer contains two power transistors: a first power transistor T1 and a second power transistor T2. (Refer to...) Figure 2 When the output voltage at the sensor microphone output terminal is different from the built-in voltage of the connected downstream load, a certain amount of additional leakage current will be generated across the sensing resistor RA. During normal signal output from the sensor microphone, this additional leakage current will increase the distortion of the sensor microphone output signal.

[0050] It is understandable that after the sensor microphone is powered on, different voltages can be output to the first switch T1 and the second switch T2 through the amplifier. At this time, the first switch T1 and the second switch T2 will be turned on at a certain opening, outputting the first output voltage at the output terminal of the buffer. Compensation is performed on the first output voltage before the sensor microphone chip is powered on and before the relevant control signals are output. Compensation performed after the control signals are output will result in distortion of the signal output from the buffer.

[0051] It should be noted that the detection circuit 10 is used to collect data on whether additional leakage current is generated at the output of the sensor microphone. The detection circuit 10 can determine the presence of additional leakage current by detecting the current across the detection resistor RA. Alternatively, the detection circuit 10 can directly detect the voltage across the detection resistor RA, i.e., the voltage at the output of the buffer and the input voltage of the subsequent load. The preset power supply 20 can be used to compensate for the voltage value at the output of the sensor microphone when additional leakage current is present.

[0052] In a specific implementation, the detection circuit 10 can directly detect the additional leakage current at the output of the buffer circuit to obtain a detection signal when the sensor microphone is powered on, or it can collect and calculate the voltage at the output of the buffer circuit and the voltage of the subsequent load to obtain a detection signal, and send the detection signal to the preset power supply 20; the preset power supply 20 can set the output voltage of the buffer circuit according to the current value of the additional leakage current in the detection signal, and output the output voltage to the input of the buffer circuit to compensate for the additional leakage current.

[0053] The detection signal is used to indicate the additional leakage current. Generating the detection signal indicates that the initial voltage output by the buffer is different from the voltage of the subsequent load. In this embodiment, the buffer circuit can consist of a buffer and other related components. The detection signal includes specific current value information of the additional leakage current. The output voltage is the voltage at the output terminal of the preset power supply after adjustment. The output voltage is the same as the voltage at the input terminal of the subsequent load.

[0054] This embodiment provides a DC output compensation circuit for a sensor microphone. The circuit includes a detection circuit and a preset power supply. When the sensor microphone is powered on, the detection circuit detects the extra leakage current at the output of the buffer circuit to obtain a detection signal, and sends the detection signal to the preset power supply. The preset power supply sets the output voltage of the buffer circuit based on the detection signal and outputs the output voltage to the input of the buffer circuit to compensate for the extra leakage current. In this embodiment, by detecting the extra leakage current and setting the output voltage of the buffer circuit based on the detection signal to compensate for the extra leakage current, the distortion of the sensor microphone output signal is effectively avoided.

[0055] Reference Figure 3 , Figure 3 This is a schematic diagram of the second embodiment of the sensor microphone DC output compensation circuit proposed in this invention. Based on the first embodiment of the sensor microphone DC output compensation circuit described above, a second embodiment of the sensor microphone DC output compensation circuit of this invention is proposed.

[0056] In this embodiment, the sensor microphone DC output compensation circuit further includes a switching circuit 30;

[0057] The switching circuit 30 is connected to the detection circuit 10 and the preset power supply 20, respectively.

[0058] It should be noted that the switching circuit 30 is used to control the compensation loop between the preset power supply 20 and the detection circuit 10. When the microphone sensor is activated, the output voltage of the sensor microphone can be set according to the additional leakage current. After the setting is completed, the buffer circuit will output the set output voltage normally. At this time, in order to avoid wasting resources, the connection between the detection circuit 10 and the preset power supply 20 needs to be disconnected.

[0059] It should be understood that when the sensor microphone is powered on, the output voltage of the sensor microphone only needs to be set once. After the setting is completed, the buffer can continuously output the set output voltage.

[0060] In a specific implementation, when the sensor microphone is powered on, the switching circuit 30 can close and conduct the compensation loop between the detection circuit 10 and the preset power supply 10 through its internally configured switching components. When the compensation loop is open, the detection circuit 10 can output the detection signal to the preset power supply, thereby setting the output voltage of the sensor microphone. After setting, the buffer circuit of the sensor microphone can continuously output the set output voltage. At this time, the compensation loop between the detection circuit 10 and the preset power supply 20 can be disconnected by cutting off the switching components in the switching circuit 30 to avoid wasting resources.

[0061] In this embodiment, the sensor microphone DC output compensation circuit further includes: a power reset circuit 40;

[0062] The power reset circuit 40 is connected to the switch circuit 30 and the power supply VDD of the sensor microphone.

[0063] It should be noted that the power reset circuit 40 is used to detect the power supply VDD of the sensor microphone. When the voltage output of the sensor microphone's power supply VDD is greater than a set voltage value, it can be determined that the sensor microphone is powered on. The set voltage value can be the driving voltage of the sensor microphone.

[0064] In a specific implementation, the power reset circuit 40 can acquire the voltage value of the power supply VDD of the sensor microphone, and then determine whether the sensor microphone is powered on based on the acquired voltage value. When the sensor microphone is powered on, the power reset circuit 40 outputs a conduction control signal to the switching circuit 30; the switching circuit 30 can conduct the compensation loop between the detection circuit 10 and the preset power supply 20 according to the conduction control signal.

[0065] Of course, when the buffer circuit of the sensor microphone is normally outputting the set output voltage, that is, after compensating for the additional leakage current, the power reset circuit 40 can also output a cut-off control signal to the switch circuit 30; the switch circuit 30 can disconnect the compensation loop between the detection circuit and the preset power supply when it receives the cut-off control signal, thereby avoiding the continuous connection between the detection circuit 10 and the preset power supply 20.

[0066] In this embodiment, the buffer circuit includes: a first and a second switching transistor;

[0067] The control terminals of the first switch T1 and the second switch T2 are connected to the chip of the sensor microphone. The input terminal of the first switch T1 is connected to the power supply VDD. The output terminal of the first switch T1 is connected to the input terminal of the second switch T2 and the subsequent load. The output terminal of the second switch T2 is grounded to GND.

[0068] It should be understood that both the first switch T1 and the second switch T2 are transistors. The control logic for the first switch T1 and the second switch T2 is not the same; for example, the first switch T1 can be a PMOS transistor, and the second switch T2 can be an NMOS transistor, or other transistors, without specific limitations here. However, when the buffer circuit outputs voltage, both the first switch T1 and the second switch T2 are turned on simultaneously, working together to regulate the voltage value of the power supply VDD at the output of the buffer circuit. The DC level at the output of the buffer circuit is generated jointly by the two transistors, the first switch T1 and the second switch T2.

[0069] In this embodiment, the detection circuit 10 includes: a third to a fifth switching transistor and a first resistor R1;

[0070] In this circuit, the control terminal of the third switch T3 is connected to the control terminal of the second switch T2. The input terminal of the third switch T3 is connected to the input terminal of the fourth switch T4, the output terminal of the fourth switch T4, and the input terminal of the fifth switch T5. The input terminal of the fourth switch T4 is connected to the power supply VDD. The input terminal of the fifth switch T5 is connected to the power supply VDD. The output terminal of the fifth switch T5 is connected to the first terminal of the first resistor R1 and the switching circuit 30. The second terminal of the first resistor R1 and the output terminal of the third switch T3 are grounded to GND.

[0071] It should be noted that in this embodiment, a current mirror structure can be formed between the second switch T2 and the third switch T3 by setting a third switch T3. Before compensation, if the voltage of the downstream load is greater than the voltage at the output of the buffer circuit, there will be a certain amount of additional leakage current input to the second switch T2. Due to its own DC current plus the additional leakage current, the control terminal level of the second switch T2 will be pulled high according to the characteristics of the switch, and a detection current will be generated according to the current mirror principle.

[0072] It should be understood that the fourth switch T4 and the fifth switch T5 also form a current mirror. When the current mirror of the second switch T2 and the third switch T3 outputs a detection current, the current mirror formed by the fourth switch T4 and the fifth switch T5 generates a new detection current due to the influence of the detection current. The second switch T2 and the third switch T3 have the same control terminal bias level. Utilizing the transistor size ratio, the third switch T3 can generate a detection current. This detection current has a certain proportional relationship with the second switch T2. For example, the additional leakage current generated by the second switch T2 due to the mismatch of the subsequent load level will also be reflected proportionally in the detection current.

[0073] In specific implementation, refer to Figure 4 When the sensor microphone is powered on, the power reset circuit 40 outputs a low-level signal to the switching circuit 30 to control the conduction of the compensation loop between the detection circuit 10 and the preset power supply 20. When the additional leakage current passes through the second switch T2, the second switch T2 and the third switch T3 use the current mirror principle of transistors to output a detection current. Then, through another set of current mirror circuits composed of the fourth switch T4 and the fifth switch T5, this detection current passes through the first resistor R1, generating a detection level at the first end of the first resistor R1. The detection level is then output to the preset power supply 20 through the switching circuit 30 to set the output voltage.

[0074] In this embodiment, the preset power supply 20 includes: a current source IA and a second resistor R2;

[0075] The first terminal of the current source IA is connected to the power supply VDD. The second terminal of the current source IA is connected to the output terminal of the fifth switch T5 and the first terminal of the first resistor R1 through the switching circuit 30. The third terminal of the current source IA is connected to the first terminal of the second resistor R2 and the input terminal of the buffer circuit. The second terminal of the second resistor R2 is grounded to GND.

[0076] It should be understood that the current source IA is a component used to regulate the current output by the power supply VDD. The current source IA can determine the current requiring compensation based on the received detection level, then set the current output by the power supply VDD, thereby outputting the set output voltage at the first terminal of the second resistor R2. For example, this current source IA can be a component with an internal variable resistor. By changing the resistance value of the variable resistor, the current supplied by the power supply VDD is adjusted, thereby generating the set output voltage at the first terminal of the second resistor R2, and outputting this set output voltage through the output terminal of the buffer circuit.

[0077] In this embodiment, the switching circuit 30 includes: a controllable switching element S1;

[0078] The control terminal of the controllable switching element S1 is connected to the output terminal of the power reset circuit 30, the input terminal of the controllable switching element S1 is connected to the output terminal of the fifth switching transistor T5 and the first terminal of the first resistor R1, and the output terminal of the controllable switching element S1 is connected to the second terminal of the current source IA.

[0079] It should be noted that the controllable switching element S1 can be a switching element with a control terminal, such as a transistor, MOSFET, magnetic switch, or IGBT. In this embodiment, the specific type of the controllable switching element S1 is not limited. The power reset circuit 40 can output a cutoff signal or a conduction signal to turn the controllable switching element S1 on or off. When the sensor microphone is powered on, the power reset circuit 40 detects the additional leakage current. Upon detecting the additional leakage current, it outputs a low-level signal (i.e., a conduction signal) to the control terminal of the controllable switching element S1, controlling the controllable switching element S1 to conduct. At this time, the detected level can be output to the current source IA, thereby outputting the set output voltage. When the set output voltage is continuously output at the first terminal of the second resistor R2, the power reset circuit 40 outputs a high-level signal (i.e., a cutoff signal) to the control terminal of the controllable switching element S1, controlling the controllable switching element S1 to cut off, allowing the set output voltage to be continuously output at the output terminal of the buffer circuit.

[0080] In this embodiment, when detecting additional leakage current, if the voltage value at the buffer output terminal is the same as the voltage value of the subsequent load, no additional leakage current flows through the second switch T2. The detection level at this time is provided to the current source reference setting. Since this detection level does not include the additional leakage current, the output voltage set at the buffer circuit output terminal will not change. If the voltage value at the buffer output terminal is less than or greater than the voltage value of the subsequent load, a certain amount of additional leakage current flows through the second switch T2. The detection level at this time is provided to the current source reference setting. Since this detection level includes a certain amount of additional leakage current, there is a change between the output voltage set at the buffer circuit output terminal and the voltage output by the buffer circuit in its previous operation.

[0081] To achieve the above objectives, the present invention also proposes a sensor microphone DC output compensation system, wherein the overvoltage protection device includes the sensor microphone DC output compensation circuit as described above. The specific structure of this sensor microphone DC output compensation circuit is as described in the above embodiments. Since the sensor microphone DC output compensation system adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0082] To achieve the above objectives, the present invention also proposes a method for compensating the DC output of a sensor microphone, referring to... Figure 5 , Figure 5 This is a flowchart illustrating the first embodiment of the sensor microphone DC output compensation method proposed in this invention.

[0083] In this embodiment, the sensor microphone DC output compensation method includes:

[0084] Step S10: When the sensor microphone is powered on, detect the additional leakage current at the output of the buffer circuit to obtain a detection signal;

[0085] Step S20: Set the output voltage of the buffer circuit according to the detection signal to compensate for the additional leakage current.

[0086] It should be understood that the sensor microphone's buffer contains two power transistors, a first power transistor and a second power transistor. When the output voltage at the sensor microphone's output terminal is different from the built-in voltage of the connected downstream load, a certain amount of additional leakage current will be generated across the sensing resistor. When the sensor microphone is outputting a signal normally, this additional leakage current will cause greater distortion in the sensor microphone's output signal.

[0087] It should be noted that the detection circuit is used to collect data on whether additional leakage current is generated at the sensor microphone output. The detection circuit can determine the presence of additional leakage current by detecting the current across the detection resistor. Alternatively, the detection circuit can directly detect the voltage across the detection resistor, i.e., the voltage at the buffer output and the input voltage of the subsequent load. A preset power supply can be used to compensate for the voltage value at the sensor microphone output when additional leakage current is present.

[0088] In a specific implementation, the detection circuit can directly detect the additional leakage current at the output of the buffer circuit to obtain a detection signal when the sensor microphone is powered on, or it can collect and calculate the voltage at the output of the buffer circuit and the voltage of the subsequent load to obtain a detection signal, and send the detection signal to the preset power supply; the preset power supply can set the output voltage of the buffer circuit according to the current value of the additional leakage current in the detection signal, and output the output voltage to the input of the buffer circuit to compensate for the additional leakage current.

[0089] The detection signal is used to indicate the additional leakage current. Generating the detection signal indicates that the initial voltage output by the buffer is different from the voltage of the subsequent load. In this embodiment, the buffer circuit can consist of a buffer and other related components. The detection signal includes specific current value information of the additional leakage current. The output voltage is the voltage at the output terminal of the preset power supply after adjustment. The output voltage is the same as the voltage at the input terminal of the subsequent load.

[0090] This embodiment provides a method for compensating the DC output of a sensor microphone. This method uses a detection circuit to detect the extra leakage current at the output of the buffer circuit when the sensor microphone is powered on, obtains a detection signal, and sends the detection signal to a preset power supply. The preset power supply sets the output voltage of the buffer circuit based on the detection signal and outputs the output voltage to the input of the buffer circuit to compensate for the extra leakage current. In this embodiment, by detecting the extra leakage current and setting the output voltage of the buffer circuit based on the detection signal to compensate for the extra leakage current, the distortion of the sensor microphone output signal is effectively avoided.

[0091] In addition, the sensor microphone DC output compensation method of the present invention also includes other steps. Since the sensor microphone DC output compensation method is based on the above-mentioned sensor microphone DC output compensation system, the relevant control logic involved in the sensor microphone DC output compensation system is within the protection scope of the sensor microphone DC output compensation method of the present invention.

[0092] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A sensor microphone DC output compensation circuit, characterized in that, The sensor microphone DC output compensation circuit includes: a detection circuit and a preset power supply; The detection circuit is connected to the output of the preset power supply and the buffer circuit inside the sensor microphone, respectively. The preset power supply is connected to the input of the buffer circuit, and the output of the buffer circuit is connected to the subsequent load. The detection circuit is used to detect the additional leakage current at the output of the buffer circuit when the sensor microphone is powered on, obtain a detection signal, and send the detection signal to the preset power supply. The preset power supply is used to set the output voltage of the buffer circuit according to the detection signal, and output the output voltage to the input terminal of the buffer circuit to compensate for the additional leakage current. The buffer circuit includes: a first and a second switching transistor; The control terminals of the first and second switching transistors are connected to the chip of the sensor microphone. The input terminal of the first switching transistor is connected to the power supply of the sensor microphone. The output terminal of the first switching transistor is connected to the input terminal of the second switching transistor and the subsequent load. The output terminal of the second switching transistor is grounded. The preset power supply includes: a current source and a second resistor; The first end of the current source is connected to the power supply, the second end of the current source is connected to the detection circuit, the third end of the current source is connected to the first end of the second resistor and the input end of the buffer circuit, and the second end of the second resistor is grounded.

2. The sensor microphone DC output compensation circuit as described in claim 1, characterized in that, The sensor microphone DC output compensation circuit also includes: a switching circuit; The switching circuit is connected to both the detection circuit and the preset power supply. The switching circuit is used to connect the compensation circuit between the detection circuit and the preset power supply when the sensor microphone is powered on. The detection circuit is also used to output the detection signal to the preset power supply when the compensation circuit is turned on.

3. The sensor microphone DC output compensation circuit as described in claim 2, characterized in that, The sensor microphone DC output compensation circuit also includes: a power reset circuit; The power reset circuit is connected to the power supply of the switch circuit and the sensor microphone, respectively. The power reset circuit is used to output a conduction control signal to the switching circuit when the sensor microphone is powered on. The switching circuit is also used to connect the compensation loop between the detection circuit and the preset power supply according to the conduction control signal.

4. The sensor microphone DC output compensation circuit as described in claim 3, characterized in that, The power reset circuit is also used to output a cutoff control signal to the switching circuit after compensating for the additional leakage current. The switching circuit is also used to disconnect the compensation loop between the detection circuit and the preset power supply when the cut-off control signal is received.

5. The sensor microphone DC output compensation circuit as described in claim 4, characterized in that, The detection circuit includes: a third to a fifth switching transistor and a first resistor; The control terminal of the third switch is connected to the control terminal of the second switch. The input terminal of the third switch is connected to the input terminal of the fourth switch, the output terminal of the fourth switch, and the input terminal of the fifth switch. The input terminal of the fourth switch is connected to the power supply. The input terminal of the fifth switch is connected to the power supply. The output terminal of the fifth switch is connected to the first terminal of the first resistor and the switching circuit. The second terminal of the first resistor and the output terminal of the third switch are grounded.

6. The sensor microphone DC output compensation circuit as described in claim 5, characterized in that, The switching circuit includes: a controllable switching element; The control terminal of the controllable switching element is connected to the output terminal of the power reset circuit, the input terminal of the controllable switching element is connected to the output terminal of the fifth switching transistor and the first terminal of the first resistor, and the output terminal of the controllable switching element is connected to the second terminal of the current source.

7. A sensor microphone DC output compensation system, characterized in that, The sensor microphone DC output compensation system includes the sensor microphone DC output compensation circuit as described in any one of claims 1-6.

8. A method for compensating the DC output of a sensor microphone based on the sensor microphone DC output compensation system according to claim 7, characterized in that, The sensor microphone DC output compensation method includes: When the sensor microphone is powered on, the additional leakage current at the output of the buffer circuit is detected to obtain a detection signal. The output voltage of the buffer circuit is set according to the detection signal to compensate for the additional leakage current.

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