CN112187271A - MEMS sensor system and use method thereof - Google Patents
MEMS sensor system and use method thereof Download PDFInfo
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- CN112187271A CN112187271A CN202011133654.3A CN202011133654A CN112187271A CN 112187271 A CN112187271 A CN 112187271A CN 202011133654 A CN202011133654 A CN 202011133654A CN 112187271 A CN112187271 A CN 112187271A
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Abstract
The invention discloses a MEMS sensor system, which comprises: a MEMS sensor, comprising: an upper polar plate, a middle polar plate and a lower polar plate; the preamplifier is used for converting the electric charge output by the MEMS sensor into an analog voltage signal to be output; the preamplifier comprises an operational amplifier and a feedback capacitor; the first end of the compensation capacitor is electrically connected with the middle pole plate, and the second end of the compensation capacitor is connected with a common-mode voltage for storing part of the charge quantity of the MEM sensor; the analog-to-digital converter is used for converting the analog voltage signal into a digital voltage signal and outputting the digital voltage signal; the digital signal processor is used for carrying out noise suppression processing on the digital voltage signal output by the analog-to-digital converter, generating a time sequence signal according to the digital voltage signal after the noise suppression processing and outputting the time sequence signal; the pulse generator is used for generating a pulse signal according to the timing signal so as to drive the MEMS sensor to work. The invention can effectively improve the noise performance of the MEMS sensor, reduce the power consumption of the system and improve the precision of the system.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to an MEMS sensor system and a using method thereof.
Background
The existing MEMS (Micro Electro Mechanical Systems ) sensor architecture is mostly implemented by using a switched capacitor circuit, the switched capacitor circuit has more switching states, the MEMS sensor system is easily affected by switching noise, such as switching thermal noise, and the like, and the precision of the MEMS sensor is limited, such as the application of the precision up to 10ng/rt (hz). In seismic exploration and other applications, high-precision MEMS sensors are needed, and sensors using switched capacitor circuit structures cannot meet requirements.
In some existing technical solutions, a single power supply system is also adopted, the reference voltage of the readout circuit is also a single voltage, such as 5V, and if the input end of the operational amplifier is grounded (or 0V), because the MEMS sensor is directly connected to the readout circuit, the output voltage of the readout circuit is close to the supply voltage, i.e., 5V, due to the amplification effect of the readout circuit, the conventional circuit structure is easily saturated.
Therefore, it is necessary to develop a new sensor system, which can eliminate the switch requirement in the readout circuit to the maximum, suppress the thermal noise of the switch, effectively improve the noise performance of the MEMS sensor, reduce the system power consumption, and improve the system precision.
Disclosure of Invention
The MEMS sensor system and the use method thereof can effectively improve the noise performance of the MEMS sensor, reduce the power consumption of the system and improve the precision of the system.
The present invention provides a MEMS sensor system, comprising:
a MEMS sensor, comprising: an upper polar plate, a middle polar plate and a lower polar plate;
the preamplifier is used for converting the electric charge quantity output by the MEMS sensor into an analog voltage signal to be output; the preamplifier comprises an operational amplifier and a feedback capacitor, the feedback capacitor is connected between a negative input end of the operational amplifier and an output end of the operational amplifier in parallel, the negative input end of the operational amplifier is electrically connected with the output end of the MEMS sensor, and a positive input end of the operational amplifier is grounded;
a first end of the compensation capacitor is electrically connected with the middle pole plate, and a second end of the compensation capacitor is connected with a common mode voltage for storing part of the charge quantity of the MEM sensor and adjusting the common mode voltage value connected with the second end of the compensation capacitor;
the analog-to-digital converter is electrically connected with the output end of the MEMS sensor and is used for converting the analog voltage signal into a digital voltage signal and outputting the digital voltage signal;
the digital signal processor is electrically connected with the analog-to-digital converter and used for performing noise suppression processing on the digital voltage signal output by the analog-to-digital converter, generating a time sequence signal according to the digital voltage signal after the noise suppression processing and outputting the time sequence signal;
and the pulse generator is electrically connected with the digital signal processor and the MEMS sensor respectively and is used for generating a pulse signal according to the time sequence signal so as to drive the MEMS sensor to work.
Preferably, the method further comprises the following steps: a digital-to-analog converter;
the input end of the digital-to-analog converter is electrically connected with the output end of the analog-to-digital converter, and the output end of the digital-to-analog converter is electrically connected with the second end of the compensation capacitor and used for generating the common-mode voltage according to the digital voltage signal output by the analog-to-digital converter.
Preferably, the digital signal processor is further configured to generate a digital sequence for canceling the dc offset signal, and output the digital sequence to the digital-to-analog converter.
Preferably, the pulse generator is further configured to control the upper plate to be connected to a reference voltage or the lower plate to be connected to the reference voltage according to the pulse signal, when the upper plate is connected to the reference voltage, the lower plate is grounded or connected to 0V, and when the lower plate is connected to the reference voltage, the upper plate is grounded or connected to 0V.
Preferably, the digital signal processor is further configured to subtract the first digital voltage signal and the second digital voltage signal output by the analog-to-digital converter, and then output a changed pulse signal; the first digital voltage signal is a signal output by the analog-to-digital converter when the upper plate is connected with the reference voltage, and the second digital voltage signal is a signal output by the analog-to-digital converter when the lower plate is connected with the reference voltage.
Preferably, the pulse signal is a pulse signal having a fixed width, or a pulse signal having a width adjusted according to a change in the timing signal.
Preferably, the pulse generator further comprises a clock jitter filter for reducing clock jitter noise.
The invention also provides a use method of the MEMS sensor system, wherein the MEMS sensor system is the sensor system, and the method comprises the following steps:
converting the electric charge output by the MEMS sensor into an analog voltage signal through a preamplifier and outputting the analog voltage signal;
storing a portion of the charge of the MEM sensor via a compensation capacitor;
converting the analog voltage signal into a digital voltage signal through an analog-to-digital converter and outputting the digital voltage signal;
carrying out noise suppression processing on the digital voltage signal output by the analog-to-digital converter through a digital signal processor, generating a time sequence signal according to the digital voltage signal after the noise suppression processing, and outputting the time sequence signal;
and generating a pulse signal by a pulse generator according to the timing signal so as to drive the MEMS sensor to work.
Preferably, the method further comprises the following steps:
and generating the common-mode voltage according to the digital voltage signal output by the analog-to-digital converter through a digital-to-analog converter.
Preferably, the pulse signal is a pulse signal having a fixed width, or a pulse signal having a width adjusted according to a change in the timing signal.
The implementation of the invention has the following beneficial effects: in the system and the method provided by the invention, the preamplifier only needs to be composed of the operational amplifier and the capacitor, has no switch, no switch thermal noise, low noise and no switch state switching, and supplies power for the single power supply, thereby having low power consumption. In addition, the invention also adopts the compensation capacitor, and the compensation capacitor stores part of the charge quantity of the MEM sensor, thereby effectively removing the influence of the common-mode voltage deviation of the input end of the operational amplifier and improving the system precision.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a schematic diagram of a MEMS sensor system in an embodiment provided by the present invention;
FIG. 2 is a schematic diagram of a MEMS sensor system in another embodiment provided by the present invention;
FIG. 3 is a waveform diagram of a pulse signal and sampling timing of an analog-to-digital converter according to an embodiment of the present invention;
FIG. 4 is a waveform diagram illustrating the timing of the sensing and feedback of the MEMS sensor driven by the pulse signal according to an embodiment of the present invention.
Detailed Description
In order to make the present application more clearly understood by those skilled in the art to which the present application pertains, the following detailed description of the present application is made with reference to the accompanying drawings by way of specific embodiments.
The present invention provides a MEMS sensor system, as shown in fig. 1, comprising: MEMS sensor 1, preamplifier 2, compensation capacitor CcomAn analog-to-digital converter 3, a digital signal processor 4 and a pulse generator 5.
The MEMS sensor 1 includes: an upper polar plate, a middle polar plate and a lower polar plate.
The preamplifier 2 is used for converting the electric charge quantity output by the MEMS sensor 1 into an analog voltage signal and outputting the analog voltage signal; the preamplifier 2 comprises an operational amplifier OP and a feedback capacitor CfFeedback capacitance CfThe operational amplifier OP is connected in parallel between the negative input end of the operational amplifier OP and the output end of the operational amplifier OP, the negative input end of the operational amplifier OP is electrically connected with the output end of the MEMS sensor 1, and the positive input end of the operational amplifier OP is grounded. In other embodiments, a resistor may be connected in parallel between the negative input terminal and the output terminal of the operational amplifier OP, and the feedback capacitor C is prevented by the resistorfCreating saturation and providing a dc bias to the output of the operational amplifier.
Compensation capacitor CcomThe first end of the compensating capacitor is electrically connected with the middle pole platecomA second terminal of the voltage regulator is connected with a common mode voltage VcomCompensating capacitor CcomFor storing a portion of the charge of the MEMS sensor 1, adjusting the compensation capacitance CcomThe common mode voltage value accessed by the second end is large or small.
Connected common mode voltage VcomThe value is used for offsetting the voltage value of the middle electrode plate of the MEMS sensor 1 to be 0V, and the virtual ground is realized with the positive input end of the operational amplifier OP. Applied common mode voltage VcomThe value can be adjusted according to the compensation capacitance VcomThe size and MEMS sensor system output are calculated.
The analog-to-digital converter 3 (i.e., ADC) is electrically connected to the output terminal of the MEMS sensor 1, and is configured to convert the analog voltage signal into a digital voltage signal and output the digital voltage signal.
The analog voltage signal output by the preamplifier 2 is subjected to digital signal processing by adopting a digital correlation double sampler technology. The number of bits of the analog-to-digital converter 3 depends on the magnitude of the analog voltage amplitude to be quantized, such as 10-bit/12-bit.
The digital signal processor 4 is electrically connected to the analog-to-digital converter 3, and is configured to perform noise suppression processing on the digital voltage signal output by the analog-to-digital converter 3, generate a timing signal according to the digital voltage signal after the noise suppression processing, and output the timing signal.
In an embodiment, the digital signal processor 4 may be a digital processing chip such as a DSP/FPGA, and performs digital signal processing such as noise suppression on the digital signal output from the analog-to-digital converter 3 in a digital domain, and generates a timing signal applied to the pulse generator 5.
In another embodiment, the digital signal processor 4 may perform digital signal processing on the analog voltage signal output by the preamplifier 2 by using a best fit technique, such as a moving average technique, a genetic algorithm, or the like.
The digital signal processor 4 is also used for generating a digital sequence for canceling the direct current offset signal and outputting the digital sequence to the digital-to-analog converter. For example, the digital signal processor 4 may generate a digital sequence of dc offset signals for counteracting gravitational acceleration, etc., which acts on a digital-to-analog converter for counteracting fixed offsets such as gravitational acceleration, etc.
The pulse generator 5 is electrically connected to the digital signal processor 4 and the MEMS sensor 1, respectively, and is configured to generate a pulse signal according to the timing signal to drive the MEMS sensor 1 to operate.
The pulse signal here is a pulse signal having a fixed width or a pulse signal whose width is adjusted according to a change in the timing signal.
In an embodiment, the pulse signal generated by the pulse generator 5 may output an open-loop pulse or a closed-loop pulse according to a loop setting. The open-loop pulse is a pulse with a fixed width, and the closed-loop pulse can adjust the pulse width according to the digital voltage signal output by the digital signal processor 4 to realize closed-loop feedback.
In another embodiment, the pulse generator 5 may include a clock jitter filter in order to reduce noise such as clock jitter in the pulse generator 5. In yet another embodiment, pulse generator 5 may comprise a phase-locked loop (PLL).
The MEMS sensor system provided by the invention can output an analog voltage signal proportional to the detected acceleration according to the requirement, and can also output a digital voltage signal according to the requirement.
In another embodiment, as shown in fig. 2, the MEMS sensor system described above further includes: digital-to-analog converters (i.e., DACs); the input end of the digital-to-analog converter is electrically connected with the output end of the analog-to-digital converter 3, and the output end of the digital-to-analog converter and the compensation capacitor VcomIs electrically connected to generate a common mode voltage V according to the digital voltage signal output by the analog-to-digital converter 3com. In this embodiment, the common mode voltage may be a fixed input voltage value for driving the compensation capacitor to store charge.
The pulse generator 5 is further configured to control the upper plate to be connected to the reference voltage or the lower plate to be connected to the reference voltage according to the pulse signal, wherein when the upper plate is connected to the reference voltage, the lower plate is connected to the ground or connected to the 0V voltage, and when the lower plate is connected to the reference voltage, the upper plate is connected to the ground or connected to the 0V voltage.
For example: the upper polar plate is connected with a reference voltage, and the lower polar plate is grounded; or the upper polar plate is connected with a reference voltage, and the lower polar plate is connected with 0V voltage; or the lower polar plate is connected with the reference voltage, and the upper polar plate is grounded; or the lower polar plate is connected with the reference voltage, and the upper polar plate is connected with the 0V voltage.
In another embodiment, the digital signal processor 4 is further configured to subtract the first digital voltage signal and the second digital voltage signal output by the analog-to-digital converter 3, and then output a changed pulse signal; the first digital voltage signal is a signal output by the analog-to-digital converter 3 when the upper plate is connected with the reference voltage, and the second digital voltage signal is a signal output by the analog-to-digital converter 3 when the lower plate is connected with the reference voltage.
Specifically, the MEMS sensor 1 starts to operate under the pulse signal output from the pulse generator 5, and the pulse signals applied to the upper plate and the lower plate are as shown in the following figure. For convenience of description, the operating state of the MEMS sensor 1 is divided into two states.
The first state: the upper plate is connected with a reference voltage VrefThe capacitor formed by the middle pole plate and the upper pole plate is charged, the lower pole plate is grounded (or 0V), meanwhile, the capacitor formed by the middle pole plate and the upper pole plate is charged to a stable state and is converted into a stable voltage through the preamplifier 2, and the voltage is sampled by the analog-to-digital converter 3 and then the voltage value is stored.
And a second state: the lower pole plate is connected with a reference voltage VrefAnd charging a capacitor formed by the middle polar plate and the lower polar plate, grounding (or 0V) the upper polar plate, converting the charged capacitor formed between the middle polar plate and the lower polar plate to voltage through the preamplifier 2 at the same time, and storing the voltage value after sampling the voltage by the analog-to-digital converter 3.
In the first state and the second state, the voltage values sampled by the analog-to-digital converter 3 are respectively Vo1And Vo2The two voltages are subtracted from each other to eliminate low-frequency signals such as offset voltage and 1/f noise stored in the memory, and a changed digital voltage signal is output. The timing of the pulse signal and the sampling of the analog-to-digital converter 3 is shown in fig. 3.
The digital signal processor 4 controls the pulse generator 5 to generate a pulse signal according to the signal processing result thereof, so as to control the power-up condition of the upper and lower plates of the MEMS sensor 1 and the sampling timing sequence of the analog-to-digital converter 3 in the next period.
Status of stateFirstly, the method comprises the following steps: assuming that the capacitance formed between the middle plate and the upper plate is CtAnd the capacitance formed between the middle plate and the lower plate is CbIn this state, the output voltage of the preamplifier 2 is Vo1And no offset voltage, i.e. VoffsetWhen equal to 0.
The middle polar plate and the upper polar plate store charge: qt1＝-Vref*Ct
The middle polar plate and the lower polar plate store charge: qb1＝Voffset*Cb＝0*Cb＝0
Compensation capacitor CcomStorage of charge: qcom1＝(Voffset-Vcom)*Ccom＝-Vcom*Ccom
Feedback capacitance CfUpper stored charge: qf1＝(Vo1-Voffset)*Cf＝Vo1*Cf
From the law of conservation of charge, one can derive: qt1+Qb1+Qf1+Qcom1＝0
The stabilized output voltage of the operational amplifier OP is:
and a second state: assuming that the capacitance formed by the middle plate and the upper plate is CtAnd the capacitance formed between the middle plate and the lower plate is CbIn this state, the output voltage of the preamplifier 2 is Vo2。
The middle polar plate and the upper polar plate store charge: qt2＝Voffset*Ct＝0*Ct＝0
The middle polar plate and the lower polar plate store charge: qb2＝-Vref*Cb
Compensation capacitor CcomStorage of charge: qcom1＝(Voffset-Vcom)*Ccom＝-Vcom*Ccom
Feedback capacitance CfUpper stored charge: qf2＝(Vo2-Voffset)*Cf
From the law of conservation of charge, one can derive: qt2+Qb2+Qf2+Qcom2＝0
The stabilized output voltage of the operational amplifier OP is:
at the end of the two states, the analog-to-digital converter 3 samples the V acquired by the time sequenceo1And Vo2After entering the digital signal processor 4, the following operations can be obtained by performing subtraction operation:
assuming that the displacement of the mass block of the MEM sensor from the center position is x, which represents the dielectric constant of the medium, a represents the facing area of the two polar plates, and d represents the vertical distance between the two polar plates, it can be obtained:
when the displacement x < d, C can be approximatedt＝C0+ΔC，Cb＝C0Δ C, so that:
the above equation shows that the signal amplitude output by the digital signal processor 4 is doubled, and the output signal does not contain a direct current signal, thereby improving the signal-to-noise ratio of the output signal.
In addition to the above-mentioned operating states, the MEMS sensor system further includes a pulse width modulation feedback control, as shown in fig. 4, and fig. 4 is a waveform diagram of the read-out and feedback timing of the pulse signal driven MEMS sensor 1. The feedback control effect is achieved by controlling the pulse signal width of the voltage applied to the upper polar plate and the lower polar plate. The average time of the difference value of the pulse signal widths applied to the upper polar plate and the lower polar plate is inversely proportional to the input acceleration signal.
Preferably, the reference voltage of the MEMS sensor system provided by the present invention may be a power supply voltage, that is, the system reference source and the system supply voltage are the same voltage, and there is no need to separately generate the reference voltage, which saves the design cost. Both the supply voltage and the reference voltage are required to meet the system noise performance requirements.
Based on the same inventive concept, the invention also provides a use method of the MEMS sensor system, wherein the MEMS sensor system is the sensor system, and the method comprises the following steps:
converting the electric charge output by the MEMS sensor 1 into an analog voltage signal through a preamplifier 2 and outputting the analog voltage signal;
by compensating for capacitance CcomStoring part of the charge quantity of the MEM sensor, and adjusting the common-mode voltage value of the input end connected with the preamplifier;
converting the analog voltage signal into a digital voltage signal through an analog-to-digital converter 3 and outputting the digital voltage signal;
performing noise suppression processing on the digital voltage signal output by the analog-to-digital converter 3 through the digital signal processor 4, generating a time sequence signal according to the digital voltage signal after the noise suppression processing, and outputting the time sequence signal; the pulse signal is a pulse signal with a fixed width or a pulse signal with a width adjusted along with the change of the time sequence signal;
and generating a pulse signal by a pulse generator 5 according to the timing signal so as to drive the MEMS sensor 1 to work.
The digital signal processor 4 in the above method may be a digital processing chip such as a DSP/FPGA, and performs digital signal processing such as noise suppression on the digital signal output from the analog-to-digital converter 3 in a digital domain, and generates a timing signal applied to the pulse generator 5.
In another embodiment, the method further comprises: a digital sequence of the offset dc offset signal is generated by the digital signal processor 4 and output to the digital to analogue converter. For example, the digital signal processor 4 may generate a digital sequence of dc offset signals for counteracting gravitational acceleration, etc., which acts on a digital-to-analog converter for counteracting fixed offsets such as gravitational acceleration, etc.
In the above embodiment, the pulse signal generated by the pulse generator 5 may output an open-loop pulse or a closed-loop pulse according to the loop setting. The open-loop pulse is a pulse with a fixed width, and the closed-loop pulse can adjust the pulse width according to the digital voltage signal output by the digital signal processor 4 to realize closed-loop feedback. In another embodiment, the pulse generator 5 may include a clock jitter filter in order to reduce noise such as clock jitter in the pulse generator 5. In yet another embodiment, the pulse generator 5 may generate the pulse signal through a Phase Locked Loop (PLL).
A method of using a MEMS sensor system, further comprising:
generating a common-mode voltage V by a digital-to-analog converter according to the digital voltage signal output by the analog-to-digital converter 3com。
Preferably, the method for using the MEMS sensor system further comprises: after subtracting the second digital voltage signal from the first digital voltage signal output by the analog-to-digital converter 3 through the digital signal processor 4, outputting a changed pulse signal; the first digital voltage signal is a signal output by the analog-to-digital converter 3 when the upper plate is connected with the reference voltage, and the second digital voltage signal is a signal output by the analog-to-digital converter 3 when the lower plate is connected with the reference voltage.
In summary, in the system and method provided by the present invention, the preamplifier 2 only needs to be composed of the operational amplifier OP and the capacitor, and has no switch, no switch thermal noise, low noise, and no switch state switching, so that the power consumption is lowcomAnd storing part of the charge quantity of the MEMS sensor so as to effectively remove the influence of common-mode voltage deviation of the input end of the operational amplifier OP and improve the system precision. Moreover, the invention adopts single power supply, single reference source and single-pole detection, and is easy to realize low powerAnd furthermore, low power consumption is realized.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A MEMS sensor system, comprising:
a MEMS sensor, comprising: an upper polar plate, a middle polar plate and a lower polar plate;
the preamplifier is used for converting the electric charge quantity output by the MEMS sensor into an analog voltage signal to be output; the preamplifier comprises an operational amplifier and a feedback capacitor, the feedback capacitor is connected between a negative input end of the operational amplifier and an output end of the operational amplifier in parallel, the negative input end of the operational amplifier is electrically connected with the output end of the MEMS sensor, and a positive input end of the operational amplifier is grounded;
a first end of the compensation capacitor is electrically connected with the middle pole plate, and a second end of the compensation capacitor is connected with a common mode voltage for storing part of the charge quantity of the MEM sensor and adjusting the common mode voltage value connected with the second end of the compensation capacitor;
the analog-to-digital converter is electrically connected with the output end of the MEMS sensor and is used for converting the analog voltage signal into a digital voltage signal and outputting the digital voltage signal;
the digital signal processor is electrically connected with the analog-to-digital converter and used for performing noise suppression processing on the digital voltage signal output by the analog-to-digital converter, generating a time sequence signal according to the digital voltage signal after the noise suppression processing and outputting the time sequence signal;
and the pulse generator is electrically connected with the digital signal processor and the MEMS sensor respectively and is used for generating a pulse signal according to the time sequence signal so as to drive the MEMS sensor to work.
2. The MEMS sensor system of claim 1, further comprising: a digital-to-analog converter;
the input end of the digital-to-analog converter is electrically connected with the output end of the analog-to-digital converter, and the output end of the digital-to-analog converter is electrically connected with the second end of the compensation capacitor and used for generating the common-mode voltage according to the digital voltage signal output by the analog-to-digital converter.
3. The MEMS sensor system of claim 2,
the digital signal processor is further configured to generate a digital sequence for canceling the dc offset signal, and output the digital sequence to the digital-to-analog converter.
4. The MEMS sensor system of claim 1, wherein the pulse generator is further configured to control the upper plate to be connected to a reference voltage or the lower plate to be connected to a reference voltage according to the pulse signal, wherein the lower plate is connected to a ground or a 0V voltage when the upper plate is connected to the reference voltage, and the upper plate is connected to a ground or a 0V voltage when the lower plate is connected to the reference voltage.
5. The MEMS sensor system of claim 4, wherein the digital signal processor is further configured to subtract the first digital voltage signal and the second digital voltage signal output by the analog-to-digital converter and output a varying pulse signal; the first digital voltage signal is a signal output by the analog-to-digital converter when the upper plate is connected with the reference voltage, and the second digital voltage signal is a signal output by the analog-to-digital converter when the lower plate is connected with the reference voltage.
6. The MEMS sensor system of claim 1, wherein the pulse signal is a fixed width pulse signal or a pulse signal whose width is adjusted as the timing signal varies.
7. The MEMS sensor system of claim 1, wherein the pulse generator further comprises a clock jitter filter for reducing clock jitter noise.
8. A method of using a MEMS sensor system, the MEMS sensor system being a sensor system according to any one of claims 1 to 7, the method comprising:
converting the electric charge output by the MEMS sensor into an analog voltage signal through a preamplifier and outputting the analog voltage signal;
storing a portion of the charge of the MEM sensor via a compensation capacitor;
converting the analog voltage signal into a digital voltage signal through an analog-to-digital converter and outputting the digital voltage signal;
carrying out noise suppression processing on the digital voltage signal output by the analog-to-digital converter through a digital signal processor, generating a time sequence signal according to the digital voltage signal after the noise suppression processing, and outputting the time sequence signal;
and generating a pulse signal by a pulse generator according to the timing signal so as to drive the MEMS sensor to work.
9. The method of using a MEMS sensor system according to claim 8, further comprising:
and generating the common-mode voltage according to the digital voltage signal output by the analog-to-digital converter through a digital-to-analog converter.
10. The method of using a MEMS sensor system according to claim 8, wherein the pulse signal is a fixed width pulse signal or a pulse signal with an adjusted width as the timing signal varies.
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| CN206876724U (en) * | 2017-07-17 | 2018-01-12 | 四川知微传感技术有限公司 | A kind of charge modulation device accelerometer capacitance detecting device |
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