CN115509396A - Capacitance detection method and capacitance detection device - Google Patents
Capacitance detection method and capacitance detection device Download PDFInfo
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- CN115509396A CN115509396A CN202211321223.9A CN202211321223A CN115509396A CN 115509396 A CN115509396 A CN 115509396A CN 202211321223 A CN202211321223 A CN 202211321223A CN 115509396 A CN115509396 A CN 115509396A
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- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
Abstract
The application provides a capacitance detection method, which is used for a capacitance detection device and comprises the following steps: acquiring a first capacitance measurement value of a detection channel in a first working mode and a second capacitance measurement value of the detection channel in a second working mode in a first environment state; acquiring a third capacitance measurement value of the detection channel in a first working mode and a fourth capacitance measurement value of the detection channel in a second working mode in a second environment state; and determining a capacitance measurement change value of the capacitance between the detection channel and the driving channel and a capacitance measurement change value of the detection channel according to the difference value between the obtained multiple capacitance measurement values, and determining the compensated capacitance measurement value of the detection channel. By adopting the technical scheme, the capacitance change caused by the environmental change can be corrected, so that the capacitance detection precision is ensured, and the occurrence of misjudgment is avoided. The application also provides a capacitance detection device.
Description
Technical Field
The present disclosure relates to the field of touch detection, and in particular, to a capacitance detection method and a capacitance detection apparatus.
Background
The capacitive sensor is a conversion device for converting a physical quantity or a mechanical quantity to be measured into capacitance change, and the capacitive sensor is widely applied to the fields of industrial and consumer electronic products due to the advantages of simple structure, stable performance, high sensitivity and the like, for example: pressure, displacement, acceleration, thickness, level, etc.
Basic working principle of the capacitive sensor: through the capacitance detection circuit, the variation of the capacitance of the sensor can be converted into an electric signal to be output. The magnitude of the electrical signal is measured, and the magnitude of the measured quantity can be judged.
In order to minimize the influence of environmental (temperature, humidity, etc.) changes on the capacitance detection value and reduce the capacitance detection accuracy, particularly, to reduce erroneous determination due to environmental changes, a capacitance detection scheme capable of suppressing the capacitance changes due to environmental changes is required.
Disclosure of Invention
Embodiments of the present application provide a capacitance detection method and a capacitance detection apparatus, which are described below in various aspects, and embodiments and advantageous effects of the following aspects may be mutually referred to.
In a first aspect, an embodiment of the present application provides a capacitance detection method, which is used for a capacitance detection device, and the method includes: acquiring a first capacitance measurement value of a detection channel in a first working mode and a second capacitance measurement value of the detection channel in a second working mode in a first environment state, wherein the first working mode comprises that when the detection channel performs capacitance detection on a capacitance to be detected through an excitation voltage signal, a voltage signal consistent with that of the detection channel is applied to a driving channel; the second working mode comprises that when the capacitance detection is carried out on the capacitance to be detected through the excitation voltage signal by the detection channel, a grounding voltage signal is applied to the driving channel; the detection channel comprises a wire for connecting the capacitor to be detected and the capacitor detection device, one end of the driving channel is connected with the capacitor detection device, and the other end of the driving channel floats; acquiring a third capacitance measurement value of the detection channel in a first working mode and a fourth capacitance measurement value of the detection channel in a second working mode in a second environmental state, wherein the second environmental state is different from the environmental parameters of the first environmental state; determining a capacitance measurement change value of the capacitance between the detection channel and the drive channel according to a difference between the second capacitance measurement value and the first capacitance measurement value and a difference between the fourth capacitance measurement value and the third capacitance measurement value; determining a capacitance measurement change value of the detection channel according to a difference value between the first capacitance measurement value and the third capacitance measurement value; and determining the compensated capacitance measurement value of the detection channel according to the capacitance measurement change value of the detection channel and the capacitance measurement change value of the capacitance between the detection channel and the driving channel.
According to the capacitance detection method provided by the first aspect of the application, the capacitance change caused by the environmental change can be corrected, so that the capacitance detection precision is ensured, and the occurrence of misjudgment is avoided.
In some embodiments, the capacitance between the detection channel and the drive channel includes at least one of: the capacitance that is connected with detection channel and drive channel. The change condition of the measured value of the capacitance existing between the detection channel and the driving channel is fully considered, and the capacitance detection precision is improved.
In some embodiments, determining a capacitance measurement change value for the capacitance between the sense channel and the drive channel based on a difference between the second capacitance measurement and the first capacitance measurement and a difference between the fourth capacitance measurement and the third capacitance measurement comprises: obtaining a first difference between the second capacitance measurement and the first capacitance measurement; obtaining a second difference between the fourth capacitance measurement and the third capacitance measurement; calculating a third difference between the first difference and the second difference; and determining a capacitance measurement change value of the capacitance between the detection channel and the driving channel according to the third difference value. Therefore, the calculation speed can be improved on the basis of ensuring the accuracy of the first capacitance measurement difference value and the second capacitance measurement difference value.
In some embodiments, determining a compensated capacitance measurement value for a sense channel based on a capacitance measurement change value for the sense channel and a capacitance measurement change value for a capacitance between the sense channel and a drive channel comprises: determining a compensation coefficient according to the ratio of the capacitance measurement change value of the detection channel to the capacitance measurement change value of the capacitance between the detection channel and the driving channel; and determining the capacitance measurement value of the compensated detection channel according to the compensation coefficient. Therefore, the calculation speed can be improved on the basis of ensuring the accuracy of the compensation coefficient.
In some embodiments, determining the compensated capacitance measurement for the detection channel based on the compensation factor comprises: and determining the compensated capacitance measurement value of the detection channel according to the product of the compensation coefficient and the capacitance measurement change value of the capacitance between the detection channel and the driving channel. The compensated capacitance measurement value of the detection channel is obtained by compensating the third capacitance measurement value, so that the capacitance change caused by the environmental change can be corrected, the capacitance detection precision is improved, and the occurrence of misjudgment is avoided.
In some embodiments, determining a compensated capacitance measurement value for the sense channel as a function of the compensation factor multiplied by a capacitance measurement change value for the capacitance between the sense channel and the drive channel comprises: and determining the compensated capacitance measurement value of the detection channel according to the difference between the third capacitance measurement value and the product of the compensation coefficient and the capacitance measurement change value of the capacitance between the detection channel and the driving channel. Therefore, the capacitance change caused by the environmental change can be compensated accurately, the capacitance detection precision is improved, and the occurrence of misjudgment is avoided.
In a second aspect, an embodiment of the present application provides a capacitance detection apparatus, including: the detection capacitance sensor is used for acquiring a first capacitance measured value of the detection channel in a first working mode in a first environment state and a third capacitance measured value of the detection channel in the first working mode in a second environment state; the driving capacitance sensor is used for acquiring a second capacitance measured value of the detection channel in a second working mode in the first environment state and a fourth capacitance measured value of the detection channel in the second working mode in the second environment state; and the digital processing unit is used for determining a capacitance measurement change value of the capacitance between the detection channel and the driving channel according to a difference value between the second capacitance measurement value and the first capacitance measurement value and a difference value between the fourth capacitance measurement value and the third capacitance measurement value, determining a capacitance measurement change value of the detection channel according to a difference value between the first capacitance measurement value and the third capacitance measurement value, and determining a compensated capacitance measurement value of the detection channel according to the capacitance measurement change value of the detection channel and the capacitance measurement change value of the capacitance between the detection channel and the driving channel. The capacitance change caused by the environmental change can be corrected, so that the capacitance detection precision is ensured, and the occurrence of misjudgment is avoided.
Drawings
Fig. 1 illustrates an application scenario of a capacitance detection apparatus provided according to some embodiments of the present application.
Fig. 2 illustrates a schematic structural diagram of a capacitance detection device provided according to some embodiments of the present application.
Fig. 3 illustrates a flow diagram of a capacitance detection method provided in accordance with some embodiments of the present application.
Fig. 4 (a) shows a schematic diagram of a capacitance detection device provided according to some embodiments of the present application in a first operating mode.
Fig. 4 (b) shows a schematic diagram of a capacitance detection device provided according to some embodiments of the present application in a second operating mode.
Fig. 5 illustrates a block diagram of a capacitance detection device provided in accordance with some embodiments of the present application.
FIG. 6 illustrates a block diagram of a SoC (System on Chip) provided in accordance with some embodiments of the present application
Detailed Description
Specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.
Fig. 1 illustrates an application scenario of a capacitance detection apparatus provided according to some embodiments of the present application. The capacitance detection device is introduced as an example of the touch sensor.
As shown in fig. 1, the touch sensor has a self-capacitance structure including a touch pad. In other embodiments, the touch sensor may also adopt a mutual capacitance structure, which is not limited herein, and those skilled in the art can select a specific kind of the touch sensor as needed.
A parasitic capacitance C is formed between the touch plate and the reference ground 0 . When a finger approaches the touch pad, a variable capacitance Δ C is formed between the finger and the touch pad. Because the capacitance of the human body is relatively large and the potential of the human body is equivalent to the ground, the capacitance C from the touch plate to the ground is generated in the process that the finger approaches the touch plate x Including parasitic capacitance C 0 And a variable capacitance Δ C, i.e. C x ＝C 0 + Δ C. By detecting the magnitude of the delta C, whether the finger touches or not and the touch position can be judged.
The touch sensor may be applied to wearable devices (e.g., a watch 300 in fig. 1, or a bracelet), a mobile phone 200 (shown in fig. 1), a tablet computer, a notebook computer, an ultra-mobile personal computer (UMPC), a handheld computer, a netbook, a Personal Digital Assistant (PDA), a virtual reality device, and other electronic devices having a touch screen, which is not limited in this application.
It can be understood that the capacitance detection method of the present application is applicable to a scenario where the capacitance detection device detects the capacitance of the capacitive sensor.
It can be understood that, as described above, in the prior art, the capacitance of the detection channel is affected by both the approach of the human body or the conductor and the changes of the environment such as temperature, humidity, and air pressure, and when the environmental change is large, the change of the capacitance measurement value obtained by capacitance detection on the capacitance to be detected is equivalent to the capacitance change caused when the human body or the conductor approaches the capacitance to be detected, so as to affect the capacitance detection accuracy, and even make the capacitance detection device perform erroneous judgment to obtain an erroneous capacitance measurement value.
In order to solve the above problem, embodiments of the present application provide a capacitance detection apparatus and a capacitance detection method applied to the capacitance detection apparatus. In some embodiments, the main body of the capacitance detection method is the capacitance detection device. It is understood that in some embodiments of the present application, the capacitance detection device may implement capacitance detection in the form of a chip, in other embodiments, the capacitance detection device may also implement capacitance detection in the form of a circuit, and no matter what form is, the present application is not limited to this embodiment.
The capacitance detection method according to the embodiment of the application comprises the following steps: respectively acquiring a capacitance measurement value in a first working mode and a capacitance measurement value in a second working mode in two environment states, wherein the first working mode comprises the step of applying a voltage signal consistent with a detection channel on a driving channel when the detection channel performs capacitance detection through an excitation voltage signal; the second mode of operation includes applying a ground voltage signal to the drive channel while the sense channel is capacitively sensed by the stimulus voltage signal. And determining a compensation coefficient according to the capacitance measurement change value of the detection channel obtained in the first working mode and the capacitance measurement change value of the capacitance between the detection channel and the driving channel obtained in the second working mode, and compensating the capacitance measurement value in the first working mode according to the obtained compensation coefficient to obtain the compensated capacitance measurement value of the detection channel.
By the method, the change of the combined capacitor formed by the detection channel and the capacitor to be detected in different environments can be compensated according to the change of the capacitor between the driving channel and the detection channel in different environments, so that the environmental drift of the measured value of the capacitor can be eliminated, and the more accurate measured value of the combined capacitor can be obtained.
The capacitive sensor may be applied to an electronic device with a touch screen, such as a wearable device (e.g., a smart bracelet, a smart watch, etc.), a Mobile phone, a tablet Computer, a notebook Computer, an Ultra-Mobile Personal Computer (UMPC), a handheld Computer, a netbook, a Personal Digital Assistant (PDA), a virtual reality device, and the like, which is not limited in this embodiment of the present application.
Embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
Fig. 2 is a schematic structural diagram of a capacitance detection device according to some embodiments of the present disclosure. As shown in fig. 2, the capacitance detection device 100 includes: the device comprises a detection channel pin CS, a driving channel pin DRV, a capacitance-to-Digital Conversion unit (for example, a capacitance-to-Digital converter, CDC), a driving unit, and a data processing unit. The detection channel pin CS is used for connecting the detection channel wire 1, and the driving channel pin DRV is used for connecting the driving channel wire 2. In some possible embodiments, at least a portion of the driving channel trace 2 is parallel to the detecting channel trace 1, so as to ensure that the peripheral conditions of the driving channel and the detecting channel are as consistent as possible, improve the compensation accuracy, and thus ensure the detection precision of the capacitance detection apparatus 100. In this embodiment, the detection channel trace 1 and the driving channel trace 2 are the same and parallel to eliminate the influence of other variables on the detection result of the detection channel.
And the capacitor digital conversion unit is respectively connected with the detection channel pin CS and the data processing unit and is used for converting the capacitor 400 to be detected into digital quantity and transmitting the digital quantity to the data processing unit. And the data processing unit is used for processing the data output by the capacitance digital conversion unit to obtain a compensated capacitance measured value. And the driving unit is used for outputting a driving voltage signal.
The capacitance detection device 100 is in the form of a chip. In other embodiments, the capacitance detection device 100 may also be in other forms, such as a circuit, which is not limited herein, as long as the function of capacitance detection can be achieved. The capacitance detection device 100 can be used to detect the capacitance value of the capacitor 400 to be detected. In the present embodiment, the capacitance to be detected 400 is a capacitance in a touch sensor (e.g., a SAR touch sensor).
The following describes the technical solution of the present application in detail with reference to the scenarios shown in fig. 1 and fig. 2 and with reference to fig. 3. As shown in fig. 3, the main body of the capacitive detection method in some embodiments of the present application may be a capacitive detection device, and the method may include the following steps:
step S1, a first capacitance measured value of a capacitor to be detected in a first environment state in a first working mode and a second capacitance measured value of the capacitor to be detected in a second working mode are obtained.
It can be understood that the capacitance sensor can cause the change of the self capacitance when a human body such as a finger or a conductor approaches, so that whether the finger touches or not and the touched position can be judged.
Here, the capacitance value of the capacitor to be detected is influenced by the environment, and the capacitance measurement values detected by the capacitor in different environmental states are different. Environmental factors affecting the capacitance measurement, i.e., environmental parameters, may include, but are not limited to: temperature, humidity, air pressure, etc.
It is to be understood that the capacitance to be detected may include a parasitic capacitance between a plate of the capacitive sensor and the ground, a mutual capacitance between a human body or a conductor and a plate of the capacitive sensor, and a combined capacitance formed by the parasitic capacitance between the plate of the capacitive sensor and the ground and the mutual capacitance between the human body or the conductor and the plate of the capacitive sensor, which is not particularly limited in the embodiments of the present application.
It can be understood that, when the capacitance to be detected is measured, one of the environmental parameters may affect the capacitance measurement value, for example, temperature alone or humidity alone, or two or more environmental parameters may simultaneously affect the capacitance measurement value, for example, temperature, humidity and air pressure simultaneously affect the capacitance measurement value, which is not specifically limited in this embodiment of the present application.
In some embodiments of the present application, performing capacitance detection on a capacitance to be detected includes two working modes: the capacitance measuring circuit comprises a first working mode and a second working mode, wherein voltage signals applied to driving channels in the two working modes are different, and detected capacitance can be changed by applying different voltage signals, so that the obtained capacitance measuring value is influenced.
In the first operation mode, when the detection channel performs capacitance detection on the capacitance to be detected through the excitation voltage signal, a voltage signal consistent with the detection channel is applied to the driving channel, as shown in fig. 4 (a). When the capacitance of the capacitor to be detected is detected, the capacitance measurement related to the capacitor to be detected is realized by applying an excitation voltage to a detection channel connected with the capacitor to be detected.
As shown in fig. 4 (a), the detection channel trace is a trace for connecting the capacitor to be detected and the capacitor detection device, the drive channel pin trace is a trace juxtaposed with the detection channel, the juxtaposition here means that the trace of the drive channel is substantially parallel to the trace of the detection channel, that is, most of the traces of the detection channel and the drive channel are parallel, and only a small part of the traces are not parallel. The driving channel and the detection channel are both connected with the capacitance detection device, except that the driving channel is not connected with the capacitance to be detected, namely, the driving channel floats, and the detection channel is connected with the capacitance to be detected.
Here, the value of the self-capacitance of the capacitance to be detected is denoted C x Detection channel walkThe capacitance value of the line is denoted C trace The capacitance measurement value of the capacitor to be detected actually comprises the detection of the capacitor to be detected and the capacitance of the detection channel wiring, and the capacitance measurement value of the capacitor to be detected is represented as C sensor The following formula is given:
C sensor ＝C x +C trace
because the detection channel and the driving channel are both conductors, parasitic capacitance C exists between the detection channel and the driving channel 0 When the capacitance detection is performed by applying an excitation voltage through the detection channel, the parasitic capacitance C 0 The presence of (c) will have an effect on the capacitance measurement.
In some embodiments of the present application, an actual capacitance C may be placed between the sense channel and the drive channel 1 Capacitor C 1 The capacitance, which is in the form of a physical entity, also has an effect on the capacitance measurement after the actual capacitance has been set.
It can be understood that an actual capacitor may be arranged between the detection channel and the driving channel, or the capacitor C may not be arranged, under the condition that the actual capacitor is not arranged 1 The capacitance value of (2) is regarded as 0. This is not particularly limited in the embodiments of the present application.
In the first operation mode, since the voltage signal that is consistent with the detection channel is applied to the driving channel, that is, the waveform of the voltage applied to the driving channel is completely the same as that of the voltage applied to the detection channel, the potentials of the traces of the driving channel and the traces of the detection channel are equal, and the capacitance between the two can be equivalent to 0, that is, the parasitic capacitance and the actual capacitance in fig. 4 (a) are 0.
Therefore, a first capacitance measurement value obtained by detecting the capacitance to be detected in the first working mode comprises the capacitance of the capacitance to be detected and the capacitance of the detection channel wiring, and does not comprise the capacitance between the detection channel and the driving channel, and is expressed by a formula as follows:
C sensor_m1 ＝C x +C trace (1)
wherein, C sensor_m1 The capacitance measurement value is a first capacitance measurement value obtained by capacitance detection of the capacitor to be detected in the first working mode.
In the second operation mode, when the detection channel performs capacitance detection on the capacitance to be detected through the excitation voltage signal, a ground voltage signal is applied to the driving channel, as shown in fig. 4 (b).
In the second operation mode, since the ground voltage signal, i.e., the GND signal, is applied to the driving channel, and a potential difference is formed between the driving channel and the detecting channel, the capacitance measurement value is affected by the parasitic capacitance and the actual capacitance between the driving channel and the detecting channel when the capacitance measurement is performed. Therefore, a second capacitance measurement value obtained by detecting the capacitance to be detected in the second working mode includes the capacitance value of the capacitance to be detected and the capacitance value of the detection channel routing, and also includes the value of the parasitic capacitance between the detection channel and the driving channel and the value of the actual capacitance, and is expressed by a formula as follows:
C sensor_m2 ＝C x +C trace +CP (2)
wherein, C sensor_m2 Representing a second capacitance measurement value obtained by capacitance detection of the capacitance to be detected in a second operating mode, CP being the sum of the value of the parasitic capacitance and the value of the actual capacitance, CP = C 0 +C 1 。
And S2, acquiring a third capacitance measured value of the capacitor to be detected in the second environment state in the first working mode and a fourth capacitance measured value in the second working mode.
Here, compare with first environment, the environmental parameter of second environment has taken place to change for the capacitance value of the self capacitance value of waiting to detect the electric capacity and the capacitance value of detecting the passageway line all have taken place to change.
It is understood that, when the second environment changes relative to the first environment, the environmental parameter such as temperature, humidity, air pressure, etc. may be a change in one parameter such as temperature, or may be a change in more than one parameter such as temperature and humidity, and the embodiment of the present application is not limited thereto.
Similarly, in the second environment, the capacitor to be detected is subjected to capacitor detection in the first working mode to obtain a third capacitor measurement value, the third capacitor measurement value includes a self capacitance value of the changed capacitor to be detected and a capacitance value of the changed detection channel routing, and the third capacitance measurement value is expressed by a formula as follows:
C’ sensor_m1 ＝C x +ΔC x +C trace +ΔC trace (3)
wherein, C' sensor_m1 Represents a third capacitance measurement value, Δ C, obtained by capacitance detection of the capacitance to be detected in the first operating mode x The change of the capacitance value of the capacitor to be detected, Δ C, with the change of the environmental state trace The capacitance value variation of the channel wiring along with the environmental state variation is detected.
Then, the capacitance of the capacitor to be detected is detected in a second working mode to obtain a fourth capacitance measured value, the fourth capacitance measured value not only includes the self capacitance value of the changed capacitor to be detected and the capacitance value of the changed detection channel wiring, but also includes the value of the parasitic capacitance between the changed detection channel and the drive channel and the value of the changed actual capacitance, and the fourth capacitance measured value is expressed as follows by a formula:
C’ sensor_m2 ＝C x +ΔC x +C trace +ΔC trace +CP+ΔCP (4)
wherein, C' sensor_m2 And showing a fourth capacitance measurement value obtained by capacitance detection of the capacitance to be detected in the second working mode, wherein the delta CP is the change amount of the capacitance values of the parasitic capacitance and the actual capacitance along with the change of the environmental state.
And S3, determining a capacitance measurement change value of the capacitance between the detection channel and the driving channel according to a difference value between the second capacitance measurement value and the first capacitance measurement value and a difference value between the fourth capacitance measurement value and the third capacitance measurement value.
In some embodiments of the present application, a capacitance measurement initial value of the parasitic capacitance and the actual capacitance between the detection channel and the driving channel may be obtained by the second capacitance measurement value obtained in the second operation mode and the first capacitance measurement value obtained in the first operation mode in the first environment state, where the capacitance measurement initial value is the first difference. Namely, using formula (2) -formula (1), the following is formulated:
C sensor_m2 －C sensor_m1 ＝CP (5)
in some embodiments of the present application, the capacitance measurement values of the parasitic capacitance and the actual capacitance between the detection channel and the driving channel after the change may be obtained through the fourth capacitance measurement value obtained in the second operating mode in the second environment state and the third capacitance measurement value obtained in the first operating mode, where the capacitance measurement value is the second difference. Namely, using formula (4) -formula (3), the following is formulated:
C’ sensor_m2 －C’ sensor_m1 ＝CP+ΔCP (6)
in some embodiments of the present application, a difference between a capacitance measurement value of the parasitic capacitance and the actual capacitance between the detection channel and the driving channel after the change and a capacitance measurement initial value of the parasitic capacitance and the actual capacitance between the detection channel and the driving channel is calculated, so as to obtain a capacitance measurement change value of the parasitic capacitance and the actual capacitance between the detection channel and the driving channel, where the capacitance measurement change value is a third difference, that is, a formula (6) -a formula (5), and is expressed as follows:
Δ(C’ sensor_m2 －C’ sensor_m1 )＝ΔCP (7)
and S4, determining a capacitance measurement change value of the detection channel according to a difference value between the first capacitance measurement value and the third capacitance measurement value.
In some embodiments of the present application, the first capacitance measurement value and the third capacitance measurement value obtained in the first operating mode are only capacitance measurement values obtained by performing capacitance detection on the to-be-detected capacitance and the detection channel trace, the third capacitance measurement value is a capacitance measurement value obtained after the capacitance values of the to-be-detected capacitance and the detection channel trace are also changed after the environment is changed, and the change is based on the first capacitance measurement value. Namely, using formula (3) -formula (1), the following is formulated:
C’ sensor_m1 －C sensor_m1 ＝ΔC x +ΔC trace (8)
and S5, determining a compensation coefficient according to the capacitance measurement change value of the detection channel and the capacitance measurement change value of the capacitance between the detection channel and the driving channel.
In some embodiments of the present application, a ratio of a capacitance measurement change value of the detection channel to a capacitance measurement change value of a parasitic capacitance and an actual capacitance between the detection channel and the driving channel may be calculated, and the compensation coefficient may be determined according to the ratio.
Here, the self capacitance of the capacitor to be detected, the capacitance of the detection channel routing, the value of the parasitic capacitance between the detection channel and the driving channel, and the value of the actual capacitance all change under the influence of the environment. Through the experiment discovery, under certain line and the overall arrangement condition, treat that the variable quantity of the self capacitance value of the electric capacity and the variable quantity of the capacitance value that the measuring channel walked the line are close to the fixed proportional relation with the value of the parasitic capacitance between measuring channel and drive channel and the variable quantity of the actual capacitance, consequently can treat that the measuring capacity and the capacitance value variable quantity that the measuring channel walked the line are compensated through the parasitic capacitance between measuring channel and drive channel and the variable quantity of the actual capacitance according to this proportional relation, confirm that can restrain the environment drift treat that the electric capacity and the capacitance value that the measuring channel walked the line are waited to detect.
Determining a compensation coefficient K according to the ratio, and formulating as follows:
and S6, compensating the third capacitance measured value according to the compensation coefficient to obtain the compensated capacitance measured value of the detection channel.
In some embodiments of the present application, the determination is based on a product of a compensation factor and a capacitance measurement change value of a capacitance between the sense channel and the drive channelAnd (5) determining a compensation value. Here, the product of the capacitance measurement variation value of the capacitance between the detection channel and the driving channel and the compensation coefficient may be used to describe the capacitance variation of the to-be-detected capacitance and the detection channel routing. Compensation value C comp Is formulated as follows:
C comp ＝K·Δ(C’ sensor_m2 －C’ sensor_m1 )＝K·ΔCP (10)
in some embodiments of the present application, the capacitance measurement value in the first operating mode in the current environment state, that is, the third capacitance measurement value, is compensated according to the compensation value, so as to obtain the compensated capacitance measurement value of the detection channel. Here, the compensated capacitance measurement value of the detection channel is a capacitance value of the to-be-detected capacitor and a capacitance value of the detection channel routing obtained after removing a capacitance value affected by the environmental drift.
Specifically, a difference between the third capacitance measurement value and the compensation value is calculated, and the compensated capacitance measurement value of the detection channel is determined according to the obtained difference. It can be understood that the obtained difference may be directly determined as the compensated capacitance measurement value of the detection channel, or a certain mathematical change, such as a linear change or a polynomial change, may be performed on the obtained difference, and the change result is determined as the compensated capacitance measurement value of the detection channel, which is not specifically limited in this embodiment of the present application.
Calculating a difference between the third capacitance measurement and the compensation value, and formulating as follows:
C”sensor＝C’ sensor_m1 －C comp ＝C x +C trace +ΔC x +ΔC trace －K·ΔCP
＝C x +C trace (11)
in the above formula, Δ C is known from the distortion of the formula (9) x +ΔC trace K · Δ CP, hence Δ C x +ΔC trace －K·ΔCP＝0。
In addition to the method for determining the capacitance measurement value of the compensated detection channel in the above embodiments, the present application also provides a method for determining the capacitance measurement value of the compensated detection channel, and the compensated detectionThe capacitance measurement of the channel is a function of the first capacitance measurement and the second capacitance measurement, i.e. the capacitance measurement of the compensated detection channel = f (C) sensor_m1 ，C sensor_m2 )。
In some possible embodiments, the compensated capacitance measurement of the detection channel satisfies a linear relationship with the first capacitance measurement and the second capacitance measurement, i.e., the compensated capacitance measurement of the detection channel = K 1 ×C sensor_m1 －K 2 ×C sensor_m2 ＝(K 1 -K 2 )×C x +(K 1 -K 2 )×C trace －K 2 ×CP (12)
In the formula (12), K 1 Is a first compensation coefficient; k is 2 Is the second compensation factor.
When the variation of the capacitance of the capacitor 400 to be detected (for example, the capacitance of the touch pad in fig. 1) changing with the environment (for example, temperature) is approximately in a fixed proportional relationship with the capacitance of the detection channel trace 1, the parasitic capacitance between the detection channel trace 1 and the driving channel trace 2, and the variation of the actual capacitance changing with the environment (for example, temperature), the compensated capacitance measurement value of the detection channel can be determined by selecting a suitable first compensation coefficient and a suitable second compensation coefficient.
FIG. 5 illustrates a block diagram of a capacitance detection device provided according to some embodiments of the present application. Capacitance detection device 100, comprising: a detection capacitance sensor 110, a driving capacitance sensor 120, and a digital processing unit 130. The detection capacitance sensor 110 is configured to obtain a first capacitance measurement value of the detection channel in the first operating mode in the first environmental state and a third capacitance measurement value of the detection channel in the first operating mode in the second environmental state.
The capacitive sensor 120 is driven to obtain a second capacitance measurement value of the detection channel in the second operation mode in the first environment state and a fourth capacitance measurement value of the detection channel in the second operation mode in the second environment state.
A digital processing unit 130, configured to determine a capacitance measurement change value of the capacitance between the detection channel and the driving channel according to a difference between the second capacitance measurement value and the first capacitance measurement value and a difference between the fourth capacitance measurement value and the third capacitance measurement value, determine a capacitance measurement change value of the detection channel according to a difference between the first capacitance measurement value and the third capacitance measurement value, and determine a compensated capacitance measurement value of the detection channel according to the capacitance measurement change value of the detection channel and the capacitance measurement change value of the capacitance between the detection channel and the driving channel.
Fig. 6 illustrates a block diagram of a SoC (System on Chip) provided in accordance with some embodiments of the present application. In fig. 6, similar components have the same reference numerals. In addition, the dashed box is an optional feature of more advanced socs. In fig. 6, soC 1500 includes: an interconnect unit 1550 coupled to the application processor 1515; a system agent unit 1570; a bus controller unit 1580; an integrated memory controller unit 1540; a set or one or more coprocessors 1520 which may include integrated graphics logic, an image processor, an audio processor, and a video processor; an Static Random Access Memory (SRAM) unit 1530; a Direct Memory Access (DMA) unit 1560. In one embodiment, the coprocessor 1520 comprises a special-purpose processor, such as, for example, a network or communication processor, compression engine, GPGPU, a high-throughput MIC processor, embedded processor, or the like.
According to the capacitance detection method and the capacitance detection device provided by the application, the capacitance change caused by the environmental change can be corrected, so that the capacitance detection precision is ensured, and the occurrence of misjudgment is avoided.
Embodiments of the mechanisms disclosed herein may be implemented in hardware, software, firmware, or a combination of these implementations. Embodiments of the application may be implemented as computer programs or program code executing on programmable systems comprising at least one processor, a storage system (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device.
Program code may be applied to input instructions to perform the functions described herein and generate output information. The output information may be applied to one or more output devices in a known manner. For purposes of this Application, a processing system includes any system having a Processor such as, for example, a Digital Signal Processor (DSP), a microcontroller, an Application Specific Integrated Circuit (ASIC), or a microprocessor.
The program code may be implemented in a high level procedural or object oriented programming language to communicate with a processing system. The program code can also be implemented in assembly or machine language, if desired. Indeed, the mechanisms described in this application are not limited in scope to any particular programming language. In any case, the language may be a compiled or interpreted language.
In some cases, the disclosed embodiments may be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried by or stored on one or more transitory or non-transitory machine-readable (e.g., computer-readable) storage media, which may be read and executed by one or more processors. For example, the instructions may be distributed via a network or via other computer readable media. Thus, a machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer), including, but not limited to, floppy diskettes, optical disks, read-Only memories (CD-ROMs), magneto-optical disks, read-Only memories (ROMs), random Access Memories (RAMs), erasable Programmable Read-Only memories (EPROMs), electrically Erasable Programmable Read-Only memories (EEPROMs), magnetic or optical cards, flash Memory, or tangible machine-readable memories for transmitting information (e.g., carrier waves, infrared signals, digital signals, etc.) using the Internet to transmit information in an electrical, optical, acoustical or other form of propagated signals. Thus, a machine-readable medium includes any type of machine-readable medium suitable for storing or transmitting electronic instructions or information in a form readable by a machine (e.g., a computer).
In the drawings, some features of the structures or methods may be shown in a particular arrangement and/or order. However, it is to be understood that such specific arrangement and/or ordering may not be required. Rather, in some embodiments, the features may be arranged in a manner and/or order different from that shown in the illustrative figures. In addition, the inclusion of a structural or methodical feature in a particular figure is not meant to imply that such feature is required in all embodiments, and in some embodiments, may not be included or may be combined with other features.
It should be noted that, in the embodiments of the apparatuses in the present application, each unit/module is a logical unit/module, and physically, one logical unit/module may be one physical unit/module, or may be a part of one physical unit/module, and may also be implemented by a combination of multiple physical units/modules, where the physical implementation manner of the logical unit/module itself is not the most important, and the combination of the functions implemented by the logical unit/module is the key to solve the technical problem provided by the present application. Furthermore, in order to highlight the innovative part of the present application, the above-mentioned device embodiments of the present application do not introduce units/modules which are not so closely related to solve the technical problems presented in the present application, which does not indicate that no other units/modules exist in the above-mentioned device embodiments.
It is noted that, in the examples and descriptions of this patent, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, the use of the verb "comprise a" to define an element does not exclude the presence of another, same element in a process, method, article, or apparatus that comprises the element.
While the present application has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present application.
Claims (7)
1. A capacitance detection method for a capacitance detection device, the method comprising:
acquiring a first capacitance measurement value of a detection channel in a first working mode and a second capacitance measurement value of the detection channel in a second working mode in a first environment state, wherein the first working mode comprises that when the detection channel performs capacitance detection on the capacitor to be detected through an excitation voltage signal, a voltage signal consistent with the detection channel is applied to a driving channel; the second working mode comprises that when the capacitance detection is carried out on the capacitor to be detected through the excitation voltage signal by the detection channel, a grounding voltage signal is applied to the driving channel; the detection channel comprises a wire for connecting the capacitor to be detected and the capacitor detection device, one end of the driving channel is connected with the capacitor detection device, and the other end of the driving channel floats;
acquiring a third capacitance measurement value of the detection channel in a first working mode and a fourth capacitance measurement value of the detection channel in a second working mode in a second environmental state, wherein the second environmental state is different from the first environmental state in environmental parameters;
determining a capacitance measurement change value for the capacitance between the detection channel and the drive channel based on a difference between the second capacitance measurement and the first capacitance measurement and a difference between the fourth capacitance measurement and the third capacitance measurement;
determining a capacitance measurement change value of the detection channel according to a difference value between the first capacitance measurement value and the third capacitance measurement value;
and determining the compensated capacitance measurement value of the detection channel according to the capacitance measurement change value of the detection channel and the capacitance measurement change value of the capacitance between the detection channel and the driving channel.
2. The method of claim 1, wherein the capacitance between the detection channel and the drive channel comprises at least one of: the capacitance detection circuit comprises a parasitic capacitance between the detection channel and the driving channel, and a capacitance connected with the detection channel and the driving channel.
3. The method of claim 1, wherein determining a capacitance measurement change value for the capacitance between the sense channel and the drive channel based on a difference between the second capacitance measurement and the first capacitance measurement and a difference between the fourth capacitance measurement and the third capacitance measurement comprises:
obtaining a first difference between the second capacitance measurement and the first capacitance measurement;
obtaining a second difference between the fourth capacitance measurement and the third capacitance measurement;
calculating a third difference between the first difference and the second difference;
and determining a capacitance measurement change value of the capacitance between the detection channel and the driving channel according to the third difference value.
4. The method of claim 1, wherein determining the compensated capacitance measurement value for the detection channel based on the capacitance measurement change value for the detection channel and the capacitance measurement change value for the capacitance between the detection channel and the drive channel comprises:
determining a compensation coefficient according to the ratio of the capacitance measurement change value of the detection channel to the capacitance measurement change value of the capacitance between the detection channel and the driving channel;
and determining the compensated capacitance measurement value of the detection channel according to the compensation coefficient.
5. The method of claim 4, wherein determining the compensated capacitance measurement for the detection channel based on the compensation factor comprises:
and determining the compensated capacitance measurement value of the detection channel according to the product of the compensation coefficient and the capacitance measurement change value of the capacitance between the detection channel and the driving channel.
6. The method of claim 5, wherein determining the compensated capacitance measurement for the sense channel based on the product of the compensation factor and a capacitance measurement change value of the capacitance between the sense channel and the drive channel comprises:
and determining the compensated capacitance measurement value of the detection channel according to the difference value between the third capacitance measurement value and the product of the compensation coefficient and the capacitance measurement change value of the capacitance between the detection channel and the driving channel.
7. A capacitance detection device, comprising:
the detection capacitance sensor is used for acquiring a first capacitance measured value of the detection channel in a first working mode in a first environment state and a third capacitance measured value of the detection channel in the first working mode in a second environment state;
the driving capacitance sensor is used for acquiring a second capacitance measured value of the detection channel in a second working mode in the first environment state and a fourth capacitance measured value of the detection channel in the second working mode in the second environment state;
a digital processing unit, configured to determine a capacitance measurement change value of a capacitance between the detection channel and the driving channel according to a difference between the second capacitance measurement value and the first capacitance measurement value and a difference between the fourth capacitance measurement value and the third capacitance measurement value, determine a capacitance measurement change value of the detection channel according to a difference between the first capacitance measurement value and the third capacitance measurement value, and determine a compensated capacitance measurement value of the detection channel according to the capacitance measurement change value of the detection channel and the capacitance measurement change value of the capacitance between the detection channel and the driving channel.
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| CN117076932A (en) * | 2023-10-13 | 2023-11-17 | 源予半导体南京有限公司 | High-sensitivity capacitance change detection method, system, electronic device and storage medium |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117076932A (en) * | 2023-10-13 | 2023-11-17 | 源予半导体南京有限公司 | High-sensitivity capacitance change detection method, system, electronic device and storage medium |
| CN117076932B (en) * | 2023-10-13 | 2024-01-26 | 源予半导体南京有限公司 | High-sensitivity capacitance change detection method, system, electronic device and storage medium |
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