CN112254846A - Pressure detection device, pressure detection method thereof and electronic equipment - Google Patents
Pressure detection device, pressure detection method thereof and electronic equipment Download PDFInfo
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- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/005—Measuring force or stress, in general by electrical means and not provided for in G01L1/06 - G01L1/22
Abstract
The application discloses pressure detection device and pressure detection method thereof, an electronic equipment, pressure detection device includes: the analog-to-digital conversion module is used for receiving at least one analog pressure sensing signal, and sequentially carrying out analog filtering and analog-to-digital conversion on the analog pressure sensing signal to form a corresponding digital pressure sensing signal; and the digital filtering module is coupled to the analog-to-digital conversion module and used for performing digital filtering processing on the digital pressure-sensitive signal and outputting a digital detection signal. The pressure-sensitive detection device can be used for detecting the signal-to-noise ratio of a signal in a high-digital mode.
Description
Technical Field
The application relates to the technical field of pressure sensing, in particular to a pressure sensing detection device, a pressure detection method thereof and electronic equipment.
Background
The pressure sensor is the most common sensor in industrial practice, is widely applied to the fields of various industrial automatic control environments and consumer electronic automatic control, and relates to a plurality of industrial industries such as water conservancy and hydropower, railway traffic, intelligent buildings, production automatic control, aerospace, military industry, petrifaction and the like, and a plurality of consumer electronic industries such as mobile phones, TWS earphones, wearable devices, household appliances and the like.
The pressure-sensitive key is an important application of a pressure sensor, the principle of the pressure-sensitive key is that the pressure sensor is arranged on the back of a key panel, the pressure sensor can generate corresponding analog signal change according to the stress deformation condition of the key panel, the analog signal is amplified by a Programmable Gain Amplifier (PGA), and different gain amplification factors can be realized through programming configuration to amplify a pressure-sensitive electric signal; the analog-to-digital converter (ADC) converts positive and negative voltage signals output by the PGA into positive voltage digital signals with unchanged waveforms, filters high-frequency components of the positive voltage digital signals and reduces noise interference; the digital signal output by the ADC directly enters a Microcontroller (MCU) for key and gesture recognition algorithm processing, and finally the microcontroller performs algorithm processing to output corresponding key information or sliding gesture information; when the user operates the keys, the deformation of the key panel is large, the analog signal is large, and when the user does not operate the keys, the deformation of the key panel is small, the analog signal is small, so that whether the keys are pressed down or a sliding gesture exists can be identified.
Pressure change signals generated by the pressure sensor due to deformation are very weak, corresponding electric signal changes are in the level of dozens of to hundreds of microvolts (muV), meanwhile, the pressure sensor generally has slow drift of dozens of microvolts (muV), and the sum of the noise of a simulation front end and the pressure sensor is in the level of dozens of to tens of microvolts (muV), so that the real pressure sensing signals are difficult to distinguish in pressure sensing detection, and pressure sensing misjudgment is extremely easy to generate.
At present, pressure detection is widely applied to key and gesture detection of mobile phones, TWS earphones, wearable devices and the like, the requirement on the signal to noise ratio of pressure signals is particularly high, and if the pressure signals cannot be identified from noise, pressure misjudgment is extremely easy to occur. Conventional pressure sensor noise processing generally reduces noise by averaging or other methods, but does not improve signal-to-noise ratio while reducing noise. Under the condition of low signal-to-noise ratio, a good method is not provided for improving the signal-to-noise ratio and reducing pressure-sensitive misjudgment while reducing noise.
Therefore, how to increase the signal-to-noise ratio of the output signal of the pressure-sensitive detection device is an urgent problem to be solved at present.
Disclosure of Invention
In view of this, the present application provides a pressure sensing apparatus, a pressure sensing method thereof and an electronic device to solve the problem of low signal-to-noise ratio of a pressure sensing signal of the existing pressure sensing apparatus.
The application provides a pressure detection device includes: the analog-to-digital conversion module is used for receiving at least one analog pressure sensing signal, and sequentially carrying out analog filtering and analog-to-digital conversion on the analog pressure sensing signal to form a corresponding digital pressure sensing signal; and the digital filtering module is coupled to the analog-to-digital conversion module and used for performing digital filtering processing on the digital pressure-sensitive signal and outputting a digital detection signal.
Optionally, the analog-to-digital conversion module includes: the selection unit is used for gating one analog pressure sensing signal; the programmable gain amplifier is used for performing gain amplification on the analog pressure-sensitive signal; the analog filter is used for filtering high-frequency components in the analog pressure-sensitive signals after gain amplification, and the cut-off frequency of the analog filter is configured according to the frequency characteristics of the analog pressure-sensitive signals; and the analog-to-digital converter is used for performing analog-to-digital conversion on the analog pressure sensing signal filtered by the analog filter to form a digital pressure sensing signal.
Optionally, the analog-to-digital conversion module further includes: and the reference voltage unit is used for providing a reference voltage for the analog-to-digital converter.
Optionally, the method further includes: and the pressure sensing module comprises at least one pressure sensor and is used for sensing pressure and forming a corresponding analog pressure sensing signal.
Optionally, the method further includes: and the power supply unit is used for supplying working voltage to each pressure sensor.
Optionally, the method further includes: and the power supply unit is connected with the at least one pressure sensor in a one-to-one correspondence manner through a switch and used for providing working voltage for each sensor.
Optionally, the digital filtering module includes: a filtering unit and a comparing unit; the filtering unit is connected to the output end of the selection unit and is used for performing digital filtering processing on the digital pressure-sensitive signal output by the selection unit and outputting a digital detection signal; the comparison unit is connected to the filtering unit and used for comparing the digital detection signal output by the filtering unit with a threshold value, and when the digital detection signal is greater than or equal to the threshold value, the digital detection signal is output.
Optionally, the digital filtering process includes: and after the maximum value and the minimum value of the digital pressure sensing signals of the same pressure sensor acquired for multiple times are removed, the average value is calculated and used as the digital detection signals after digital filtering.
Optionally, the analog-to-digital conversion module further includes an analog-to-digital compensation unit, coupled between the analog-to-digital converter and the programmable gain amplifier, for providing a compensation signal to the programmable gain amplifier according to the digital pressure-sensitive signal output by the analog-to-digital converter.
Optionally, the method further includes: and the microprocessor is coupled to the digital filtering module and outputs corresponding pressure operation information after the digital detection signal output by the digital filtering module is subjected to identification algorithm processing.
Embodiments of the present application further provide an electronic device, including: the pressure-sensitive detection device according to any one of the above.
The technical scheme of the application also provides a pressure detection method, which comprises the following steps: acquiring an analog pressure-sensitive signal generated by at least one pressure sensor; sequentially carrying out analog filtering and analog-to-digital conversion on the analog pressure-sensitive signals to generate corresponding digital pressure-sensitive signals; and carrying out digital filtering processing on the digital pressure-sensitive signal and outputting a digital detection signal.
Optionally, providing a reference voltage to an analog-to-digital converter performing the analog-to-digital conversion process; providing an operating voltage to the pressure sensor; the sampling voltage and the working voltage are independent of each other.
Optionally, the signal-to-noise ratio of the digital detection signal is increased by at least one of increasing the operating voltage and decreasing the reference voltage.
Optionally, the method of digital filtering processing includes: and after the maximum value and the minimum value of the digital pressure sensing signals of the same pressure sensor acquired for multiple times are removed, averaging is carried out, and digital detection signals after digital filtering are obtained.
Optionally, the method further includes comparing the digitally filtered digital detection signal with a threshold, and outputting the digitally filtered digital detection signal when the comparison result is greater than or equal to the threshold.
Optionally, the method further includes: and carrying out recognition algorithm processing on the digital detection signal after digital filtering, and outputting corresponding pressure operation information.
The pressure-sensitive detection device comprises a digital filtering module, and digital filtering processing is further carried out on the digital pressure-sensitive signals obtained after analog-digital conversion, so that the signal-to-noise ratio of the digital pressure-sensitive signals can be further improved, and the accuracy of pressure detection is improved.
Furthermore, the pressure-sensitive detection device comprises a power supply unit, which can provide separately configurable working voltage for the pressure sensor, and configure appropriate working voltage according to the characteristics of the pressure sensor, so that the signal-to-noise ratio of the acquired analog pressure-sensitive signal can be improved, and the signal-to-noise ratio of the finally output digital detection signal can be improved.
Furthermore, the analog-to-digital conversion module comprises a reference unit for providing a reference voltage for analog-to-digital conversion, and the signal-to-noise ratio of the digital pressure-sensitive signal after analog-to-digital conversion can be improved by configuring a proper reference voltage, so that the signal-to-noise ratio of the finally output digital detection signal is improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a pressure-sensitive detection device according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a pressure-sensing detecting device according to an embodiment of the present invention;
FIG. 3 is a block diagram of a digital filter module according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a pressure-sensing detecting device according to an embodiment of the present invention;
fig. 5 is a flowchart illustrating a pressure detection method according to an embodiment of the invention.
Detailed Description
As described in the background art, the signal-to-noise ratio of the pressure-sensitive signal obtained in the pressure detection process in the prior art is low, which affects the accuracy of pressure detection. Therefore, the inventor proposes a new scheme, which performs digital filtering again on the digital pressure sensing signal generated after analog-to-digital conversion, so as to further improve the signal-to-noise ratio of the digital pressure sensing signal.
The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. The following embodiments and their technical features may be combined with each other without conflict.
Fig. 1 is a schematic structural diagram of a pressure-sensitive detection device according to an embodiment of the present invention.
In this embodiment, the pressure sensing apparatus includes a pressure detection circuit 100, and the pressure detection circuit 100 includes an analog-to-digital conversion module 120 and a digital filtering module 130. The pressure detection circuit 100 may be formed in the same chip, and the internal parameters may be configured for different pressure sensors or application requirements.
The analog-to-digital conversion module 120 is configured to receive at least one analog pressure sensing signal, perform analog filtering on the analog pressure sensing signal, and convert the analog filtered analog pressure sensing signal into a digital pressure sensing signal. The analog-to-digital conversion module 120 generally needs to perform gain amplification on the analog pressure-sensitive signal, and then perform analog filtering and analog-to-digital conversion processes, so as to improve the accuracy of analog-to-digital conversion.
The digital filtering module 130 is coupled to the analog-to-digital conversion module 120, and configured to further perform digital filtering processing on the digital pressure-sensitive signal, so as to further improve the signal-to-noise ratio of the digital pressure-sensitive signal, thereby improving the accuracy of pressure detection.
The pressure sensing detection device further comprises a pressure sensing module 110, wherein the pressure sensing module 110 comprises at least one pressure sensor for sensing pressure and forming an analog pressure sensing signal. The analog-to-digital conversion module 120 is coupled to the pressure sensing module 110, and is configured to perform pressure detection according to a plurality of analog pressure sensing signals generated by the pressure sensing module 110.
In the embodiment of the present invention, for the division of the functional modules in the device, no limitation is imposed on the physical positions, and each unit in the same module may be disposed on the same chip or may be disposed on different chips. For example, the pressure sensing module 110 and the pressure detection circuit may be formed in the same chip, or may be formed in two chips, respectively, and signal transmission between the chips is performed through a connection line between the chips.
Fig. 2 is a schematic structural diagram of a pressure-sensitive detection device according to an embodiment of the invention.
In this embodiment, the pressure sensing module 110 includes a plurality of pressure sensors, which are respectively pressure sensors 0 to N, to form a pressure sensing array; correspondingly, in this embodiment, the pressure detection circuit 100 further includes a plurality of power supply units, which are respectively power supply units 0 to N, connected to the pressure sensors in a one-to-one correspondence manner, and respectively provide the working voltage VS for the pressure sensors. Each power supply unit and the pressure sensor can be connected through a switch, and the working voltage can be applied to all the pressure sensors at the same time. Preferably, the operating voltage may be applied only to some of the pressure sensors that need to output the analog pressure-sensitive signal, and switches between the other pressure sensors and the power supply unit are turned off, so as to reduce power consumption of the pressure-sensitive detection device.
In other embodiments, the pressure-sensitive detection device may have only one power supply unit, which is connected to each pressure sensor and supplies an operating voltage to each pressure sensor.
In other embodiments, the pressure-sensitive detection device may also have only one pressure sensor, to which the operating voltage is supplied only by one power supply unit.
When the pressure sensor senses the pressure change, the pressure sensor outputs an analog pressure sensing signal. The larger the variation of the analog pressure-sensitive signal is, the larger the signal-to-noise ratio of the output signal is. Meanwhile, the variation of the analog pressure-sensitive signal is in direct proportion to the working voltage VS of the pressure sensor, and the variation of the analog pressure-sensitive signal under the same pressure can be improved by setting a larger VS, so that the signal-to-noise ratio of the analog pressure-sensitive signal generated by the pressure sensor is improved. In the detection process, the operating voltages VS of the pressure sensors 0 to N are preferably the same.
The analog-to-digital conversion module 120 includes: a selection unit 121, a programmable gain amplifier 122, an analog filter 123 and an analog-to-digital converter 124.
The selection unit 121 includes a data selector (MUX) for gating the analog pressure sensing signal generated by one of the pressure sensors. In this embodiment, a time division multiplexing manner is adopted to perform signal transmission, only the output signal of one of the pressure sensors is received in one time period, and the signals output by the respective pressure sensors are sequentially processed in the time period. Accordingly, during the same time period, the operating voltage VS is provided only for the single pressure sensor that is gated on, and the other pressure sensors are not operated, thereby saving power consumption.
The Programmable Gain Amplifier (PGA)122 is coupled to the selection unit 121, and is configured to gain-amplify the analog pressure-sensitive signal. The gain coefficient of the programmable gain amplifier 122 can be programmed, and according to the variation of the analog pressure-sensitive signal output by the pressure sensor, the analog pressure-sensitive signal is amplified by using a proper gain coefficient, so that the level range of the amplified analog pressure-sensitive signal is within the subsequent convertible range of the analog-to-digital converter 124, thereby improving the analog-to-digital conversion precision.
The analog filter 123 is coupled to the programmable gain amplifier 122, and is configured to filter a high-frequency component in the analog pressure-sensitive signal after gain amplification, so as to reduce noise interference. The analog filter 123 includes an RC filter circuit or other filter circuit. In this embodiment, the cut-off frequency of the analog filter 123 is configured according to the frequency characteristics of the analog pressure-sensitive signal, and all high-frequency signals above the cut-off frequency are filtered. For example, the cutoff frequency may be adjusted by adjusting the value of R or C in an RC filter circuit. The cut-off frequency may be set according to a frequency characteristic of the analog pressure-sensitive signal to filter out a noise signal to the maximum extent.
The analog-to-digital converter (ADC)124 is configured to perform analog-to-digital conversion on the analog pressure-sensitive signal filtered by the analog filter 123 to form a digital pressure-sensitive signal. The analog-to-digital converter 124 may be one of a plurality of types of ADCs, such as a successive approximation type ADC, an integral type ADC, a parallel comparison ADC, or a voltage-frequency comparison ADC, and those skilled in the art may select an appropriate type of ADC according to actual requirements, which is not limited herein.
In any type of ADC, a reference voltage VREF is required as a voltage reference for converting an analog voltage value into a digital voltage value. In this embodiment, the analog-to-digital conversion module 120 further includes a reference voltage unit 126 for providing a reference voltage VREF to the analog-to-digital converter 124. For an n-bit ADC, the minimum precision of the digital signal per bit is VREF/2nFor an analog signal with a voltage value Vi, the obtained digital signal quantity is Vi/(VREF/2)n) Inversely proportional to the reference voltage VREF. In this embodiment, a larger amount of digital pressure sensing signals can be obtained by reducing the reference voltage VREF of the analog-to-digital converter 124, so as to obtain a digital pressure sensing signal with a higher signal-to-noise ratio.
In this embodiment, the reference voltage VREF of the analog-to-digital converter 124 is independently provided by the reference voltage unit 126, and is independent of the working voltage VS provided by each of the power supply units 0 to N of the pressure sensing module 110. Since the signal-to-noise ratio of the analog pressure-sensitive signal output by the pressure sensor is proportional to the working voltage VS, and the signal-to-noise ratio of the digital pressure-sensitive signal after analog-to-digital conversion is inversely proportional to the reference voltage VREF, the working voltage VS needs to be increased, and the reference voltage VREF needs to be decreased, so that the signal-to-noise ratio of the finally output digital detection signal is increased. In this embodiment, the signal-to-noise ratio of the finally output digital detection signal may be generally increased by one or both of increasing the working voltage VS and decreasing the reference voltage VREF according to the actual detection scene requirement.
Due to process variations or systematic errors in the pressure sensor, and in the individual devices, the analog-to-digital converter 124 still outputs a digital signal in the absence of pressure. In this embodiment, the analog-to-digital conversion module 120 further includes a digital-to-analog compensation unit 125, where the digital-to-analog compensation unit 125 is coupled between the output terminal of the analog-to-digital converter 124 and the programmable gain amplifier 122, and is configured to receive the digital pressure-sensitive signal output by the analog-to-digital converter 124 and provide an analog compensation signal to the programmable gain amplifier 122 according to the digital pressure-sensitive signal. The compensation signal output by the digital-to-analog compensation unit 125 can be adjusted according to the digital pressure-sensitive signal output by the analog-to-digital converter 124 when the pressure signal is 0, so that the output signal of the analog-to-digital converter 124 is zero in the absence of the pressure signal, thereby improving the accuracy of pressure detection. Through the compensation of the digital-to-analog compensation unit 125, when the pressure sensor receives the pressure signal, the analog filtered signal output by the analog-to-digital converter 124 is only related to the pressure signal.
According to the performance parameters of the pressure sensor in the pressure sensing module 110 and the frequency characteristics of the generated analog pressure-sensitive signal, the working voltage VS generated by the power supply units 0 to N in the pressure detection circuit 100, the reference voltage VREF, the gain multiple of the programmable gain amplifier 122, the cutoff frequency of the analog filter, and the analog compensation signal of the digital-to-analog compensation unit 125 can be configured, so that the signal-to-noise ratio of the digital pressure-sensitive signal finally output in the pressure detection process can be increased.
Fig. 3 is a schematic structural diagram of the digital filtering module 130 according to an embodiment of the invention.
In this embodiment, the digital filtering module 130 includes a filtering unit 131 and a comparing unit 132.
The filtering unit 131 is configured to remove the maximum and minimum values of the digital pressure-sensitive signals of the same pressure sensor obtained multiple times, and then calculate an average value to obtain the digital pressure-sensitive signal after digital filtering.
Specifically, the filtering unit 131 digitally filters the digital pressure-sensitive signal corresponding to the pressure sensor currently gated by the selecting unit 121. The filtering unit 131 sequentially performs digital filtering on the digital pressure-sensitive signals corresponding to the pressure sensors. In one embodiment, the sampling frequency of the analog-to-digital converter 124 is N times per second, and in the digital filtering process, the maximum value and the minimum value of the signal sampled every x times are removed, and then the signal is averaged to obtain the digital pressure-sensitive signal, so that the sampling frequency of the digital pressure-sensitive signal after digital filtering is N/x times per second. When x is too large, the sampling frequency of the filtered digital pressure-sensitive signal is too small, and the change of the pressure cannot be detected in time; x is too small resulting in poor digital filtering. Preferably, x may be generally 8 to 16.
Through the digital filtering processing, the noise can be reduced, and the signal-to-noise ratio of the finally obtained digital pressure-sensitive signal is improved.
For some application scenarios of touch detection, it is also necessary to eliminate the interference of false touch. Since the pressure sensor is also stressed by the false touch, the pressure sensing signal generated by the false touch is not a noise signal and cannot be eliminated by increasing the signal-to-noise ratio of the signal.
In this embodiment, the digital filtering module 130 further includes a comparing unit 132, and the comparing unit 132 is configured to compare the digital pressure-sensitive signal digitally filtered by the digital filtering module 130 or obtained by the analog-to-digital converter 124 with a threshold. Since the pressure of the erroneous touch is usually short, only when the digital pressure-sensitive signal is greater than or equal to the threshold, the comparing unit 132 outputs the digitally filtered digital pressure-sensitive signal as an actual touch signal to perform subsequent processing, thereby reducing the influence of the erroneous operation.
Since the signal-to-noise ratio of the digital pressure-sensitive signal output by the filtering unit 131 is relatively large, the accuracy of eliminating the false touch signal by the comparing unit 132 can be improved.
In other embodiments, the digitally filtered digital pressure sensing signal may also be directly output through the filtering unit 131.
Fig. 4 is a schematic structural diagram of a pressure-sensitive detection device according to an embodiment of the invention.
In this embodiment, the pressure-sensitive detection device further includes a microprocessor 140, and the microprocessor 140 is coupled to the digital filtering module 130, and outputs corresponding pressure operation information after performing recognition algorithm processing on the digital pressure-sensitive signal output by the digital filtering module 130.
The microprocessor 140 performs algorithm recognition according to the characteristics of the digital pressure-sensitive signal to obtain pressure operation information corresponding to the digital pressure-sensitive signal. The pressure operation information includes: single click operation, double click operation, slide operation, and the like.
Since the signal-to-noise ratio of the digital pressure-sensitive signal entering the microprocessor 140 is high, the accuracy of the pressure operation information output after the identification algorithm processing by the microprocessor 140 can be improved, and pressure-sensitive erroneous judgment can be avoided.
An embodiment of the present invention further provides an electronic device, including the pressure-sensitive detection apparatus as described in the above embodiment.
The electronic device can be an electronic device with a touch function, such as a mobile phone, an IPAD, a smart wearable device or a True wireless (True wireless) headset. The pressure detection device can improve the signal-to-noise ratio of the pressure signal, improve the accuracy of touch operation identification and improve user experience.
The invention also provides a pressure detection method.
Fig. 5 is a schematic flow chart of a pressure detection method according to an embodiment of the invention.
The pressure detection method comprises the following steps:
step S501: an analog pressure sensing signal generated by at least one pressure sensor is acquired.
A single pressure sensor may be used to sense pressure and acquire an analog pressure signal generated by the pressure sensor.
In other embodiments, the pressure may be sensed by a pressure sensor array including a plurality of pressure sensors, and the analog pressure sensing signals generated by the respective pressure sensors are sequentially acquired according to the timing control.
When the pressure sensor senses pressure change, the pressure sensor outputs an analog pressure-sensitive signal, and the larger the variation of the analog pressure-sensitive signal is, the larger the signal-to-noise ratio of the output signal is. Meanwhile, the variation of the analog pressure-sensitive signal is in direct proportion to the working voltage VS of the pressure sensor, and the variation of the analog pressure-sensitive signal under the same pressure can be improved by setting the larger VS, so that the signal-to-noise ratio of the analog pressure-sensitive signal is improved. In some embodiments, an independently configurable operating voltage VS may be provided to the pressure sensor, and a larger operating voltage may be set to improve the signal-to-noise ratio of the analog pressure-sensitive signal output by the pressure sensor.
And step S502, sequentially carrying out analog filtering and analog-to-digital conversion on the analog pressure-sensitive signals to generate corresponding digital pressure-sensitive signals.
When a plurality of pressure sensors are used for pressure sensing, signal transmission can be performed in a time division multiplexing mode, only the analog pressure sensing signal of one of the pressure sensors is received in one time period, and analog-to-digital conversion is sequentially performed on the analog pressure sensing signals output by the pressure sensors in the time period.
The analog-to-digital conversion includes: and performing gain amplification on the analog pressure-sensitive signal, and performing analog-to-digital conversion on the signal subjected to gain amplification. The gain times of the gain amplification can be programmed, and the analog pressure-sensitive signals are amplified by adopting a proper gain coefficient according to the variable quantity of the analog pressure-sensitive signals output by the pressure sensor, so that the level range of the amplified analog pressure-sensitive signals is positioned in the convertible range of the subsequent analog-to-digital conversion processing, and the analog-to-digital conversion precision is improved.
In this embodiment, after the signal is gain-amplified, analog filtering processing is further performed to filter out a high-frequency component in the analog pressure-sensitive signal after the gain amplification, so as to reduce noise interference. The cut-off frequency of the analog filtering can be configured according to the frequency characteristics of the analog pressure-sensitive signal, and high-frequency signals above the cut-off frequency are filtered out, so that noise signals are filtered out to the maximum extent.
Analog-to-digital conversion of the analog pressure-sensitive signal after analog filtering may be performed by any one of a plurality of types of ADCs, such as a successive approximation type ADC, an integral type ADC, a parallel comparison ADC, and a pressure-frequency comparison ADC. In the analog-to-digital conversion process, it is necessary to supply a reference voltage VREF as a voltage reference for converting an analog voltage value into a digital voltage value to an analog-to-digital converter that performs analog-to-digital conversion. The signal-to-noise ratio of the digital signal formed by the analog-to-digital conversion is inversely proportional to the reference voltage VREF. The reference voltage VREF and the working voltage VS of the voltage sensor are independent, and the reference voltage VREF can be reduced to obtain a higher signal-to-noise ratio.
Since the signal-to-noise ratio of the analog pressure-sensitive signal output by the pressure sensor is in direct proportion to the working voltage VS, and the signal-to-noise ratio of the digital pressure-sensitive signal after analog-to-digital conversion is in inverse proportion to the reference voltage VREF, the signal-to-noise ratio of the finally output digital detection signal can be improved by at least one of increasing the working voltage VS and decreasing the reference voltage VREF. In some embodiments, the reference voltage VREF and the operating voltage VS may be configured with opposite regulation trends according to performance parameters of a specific pressure sensor and circuit parameters within the analog-to-digital conversion module 120.
And S503, carrying out digital filtering processing on the digital pressure-sensitive signal and outputting a digital detection signal.
The filtering process includes: and after the maximum value and the minimum value of the digital pressure sensing signals of the same pressure sensor acquired for multiple times are removed, averaging is carried out, and digital detection signals after digital filtering are obtained. Through the digital filtering processing, the noise can be further reduced, so that the signal-to-noise ratio of the finally obtained digital detection signal is improved.
In some embodiments, the digitally filtered digital detection signal may be compared with a threshold, and only when the digitally filtered digital pressure-sensitive signal is greater than or equal to the threshold, the digitally filtered digital pressure-sensitive signal is output as an actual touch signal for subsequent processing. By comparing with the threshold, the interference operation caused by the touch with smaller pressure such as error touch can be eliminated, and the accuracy of touch operation detection is improved.
The pressure detection method also comprises the steps of carrying out recognition algorithm processing on the digital detection signals after digital filtering, and outputting corresponding pressure operation information. The pressure operation information includes: single click operation, double click operation, slide operation, and the like. Due to the fact that the signal-to-noise ratio of the digital pressure-sensitive signal acquired by the pressure detection method is high, accuracy of pressure operation information output after processing of the recognition algorithm can be improved, and pressure-sensitive misjudgment is avoided.
According to the pressure detection method, the digital pressure sensing signal obtained by performing analog-to-digital conversion on the analog pressure sensing signal is further subjected to digital filtering processing, so that the signal-to-noise ratio of the digital detection signal can be further improved, and the accuracy of pressure detection is improved.
Furthermore, the signal-to-noise ratio of the acquired analog pressure sensing signal can be improved by independently configuring the working voltage of the pressure sensor, and the signal-to-noise ratio of the digital pressure sensing signal after analog-to-digital conversion is improved by independently configuring the reference voltage of the analog-to-digital conversion, so that the signal-to-noise ratio of the finally output digital detection signal is improved, and the accuracy of pressure detection is improved.
That is, the above description is only an embodiment of the present application, and not intended to limit the scope of the present application, and all equivalent structures or equivalent flow transformations made by using the contents of the specification and the drawings, such as mutual combination of technical features between various embodiments, or direct or indirect application to other related technical fields, are included in the scope of the present application.
Claims (17)
1. A pressure-sensitive detection device, comprising:
the analog-to-digital conversion module is used for receiving at least one analog pressure sensing signal, and sequentially carrying out analog filtering and analog-to-digital conversion on the analog pressure sensing signal to form a corresponding digital pressure sensing signal;
and the digital filtering module is coupled to the analog-to-digital conversion module and used for performing digital filtering processing on the digital pressure-sensitive signal and outputting a digital detection signal.
2. The pressure sensing device of claim 1, wherein the analog-to-digital conversion module comprises:
the selection unit is used for gating one analog pressure sensing signal;
the programmable gain amplifier is used for performing gain amplification on the analog pressure-sensitive signal;
the analog filter is used for filtering high-frequency components in the analog pressure-sensitive signals after gain amplification, and the cut-off frequency of the analog filter is configured according to the frequency characteristics of the analog pressure-sensitive signals;
and the analog-to-digital converter is used for performing analog-to-digital conversion on the analog pressure sensing signal filtered by the analog filter to form a digital pressure sensing signal.
3. The pressure sensing device of claim 2, wherein the analog-to-digital conversion module further comprises: and the reference voltage unit is used for providing a reference voltage for the analog-to-digital converter.
4. The pressure detection apparatus according to claim 1, further comprising: and the pressure sensing module comprises at least one pressure sensor and is used for sensing pressure and forming a corresponding analog pressure sensing signal.
5. The pressure detection apparatus according to claim 4, further comprising: and the power supply unit is used for supplying working voltage to each pressure sensor.
6. The pressure detection apparatus according to claim 5, further comprising: and the power supply unit is connected with the at least one pressure sensor in a one-to-one correspondence manner through a switch and used for providing working voltage for each sensor.
7. The pressure detection device of claim 1, wherein the digital filter module comprises: a filtering unit and a comparing unit; the filtering unit is connected to the output end of the selection unit and is used for performing digital filtering processing on the digital pressure-sensitive signal output by the selection unit and outputting a digital detection signal; the comparison unit is connected to the filtering unit and used for comparing the digital detection signal output by the filtering unit with a threshold value, and when the digital detection signal is greater than or equal to the threshold value, the digital detection signal is output.
8. The pressure sensing device according to claim 7, wherein the digital filtering process includes: and after the maximum value and the minimum value of the digital pressure sensing signals of the same pressure sensor acquired for multiple times are removed, the average value is calculated and used as the digital detection signals after digital filtering.
9. The pressure sensing apparatus of claim 2, wherein the analog-to-digital conversion module further comprises an analog-to-digital compensation unit coupled between the analog-to-digital converter and the programmable gain amplifier for providing a compensation signal to the programmable gain amplifier according to the digital pressure sensing signal outputted from the analog-to-digital converter.
10. The pressure-sensitive detection device according to claim 1, further comprising: and the microprocessor is coupled to the digital filtering module and outputs corresponding pressure operation information after the digital detection signal output by the digital filtering module is subjected to identification algorithm processing.
11. An electronic device, comprising: the pressure-sensitive detection device according to any one of claims 1 to 10.
12. A pressure detection method, comprising:
acquiring an analog pressure-sensitive signal generated by at least one pressure sensor;
sequentially carrying out analog filtering and analog-to-digital conversion on the analog pressure-sensitive signals to generate corresponding digital pressure-sensitive signals;
and carrying out digital filtering processing on the digital pressure-sensitive signal and outputting a digital detection signal.
13. The pressure detection method according to claim 12, wherein a reference voltage is supplied to an analog-to-digital converter that performs the analog-to-digital conversion process; providing an operating voltage to the pressure sensor; the sampling voltage and the working voltage are independent of each other.
14. The method of claim 13, wherein the signal-to-noise ratio of the digital detection signal is increased by at least one of increasing the operating voltage and decreasing the reference voltage.
15. The pressure detection method of claim 12, wherein the digital filtering process comprises: and after the maximum value and the minimum value of the digital pressure sensing signals of the same pressure sensor acquired for multiple times are removed, averaging is carried out, and digital detection signals after digital filtering are obtained.
16. The method of claim 12, further comprising comparing the digitally filtered digital detection signal to a threshold value and outputting the digitally filtered digital detection signal if the comparison result is greater than or equal to the threshold value.
17. The pressure detection method according to claim 12, further comprising: and carrying out recognition algorithm processing on the digital detection signal after digital filtering, and outputting corresponding pressure operation information.
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