CN115656640A - Capacitance detection method and capacitance detection device - Google Patents
Capacitance detection method and capacitance detection device Download PDFInfo
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- CN115656640A CN115656640A CN202211320893.9A CN202211320893A CN115656640A CN 115656640 A CN115656640 A CN 115656640A CN 202211320893 A CN202211320893 A CN 202211320893A CN 115656640 A CN115656640 A CN 115656640A
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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 in a first environment state and a second capacitance measurement value of the detection channel in a second working mode in the first environment state; acquiring a third capacitance measurement value of the detection channel in a first working mode in a second environment state and a fourth capacitance measurement value of the detection channel in a second working mode in the second environment state; and determining the capacitance measurement change value of the bypass channel and the capacitance measurement change value of the detection channel according to the acquired capacitance measurement value, and determining the compensated capacitance measurement value of the detection channel. By adopting the technical scheme, the parasitic capacitance change caused by the environmental change can be corrected, so that the detection precision of the touch capacitance detection 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 electronics due to the advantages of simple structure, stable performance, high sensitivity and the like, for example: pressure, displacement, acceleration, thickness, level, etc.
The basic working principle of the capacitive sensor is as follows: 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.
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 for a capacitance detection device, where the method includes: acquiring a first capacitance measured value of the detection channel in a first working mode in a first environment state and a second capacitance measured value of the detection channel in a second working mode in the first environment state, wherein the first working mode is that the detection channel and the bypass channel are in a disconnected state; the second working mode is that the detection channel and the bypass channel are in a connection state; the detection channel comprises a detection channel wire, one end of the detection channel wire is connected with the capacitance detection device, the other end of the detection channel wire is connected with the capacitance to be detected, the bypass channel comprises a bypass channel wire, one end of the bypass channel wire is connected with the capacitance detection device, and the other end of the bypass channel wire floats; acquiring a third capacitance measurement value of the detection channel in a first working mode in a second environment state and a fourth capacitance measurement value of the detection channel in a second working mode in the second environment state, wherein the second environment state is different from the first environment state in environmental parameters; determining a capacitance measurement change value of the bypass channel based on 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 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 bypass 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, determining a capacitance measurement change value for the bypass 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: determining a first capacitance measurement difference value as a difference between the second capacitance measurement value and the first capacitance measurement value, and determining a second capacitance measurement difference value as a difference between the fourth capacitance measurement value and the third capacitance measurement value; and determining a capacitance measurement change value of the bypass channel according to the first capacitance measurement difference value and the second capacitance measurement 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 capacitance measurement change value for the bypass channel based on the first capacitance measurement difference and the second capacitance measurement difference comprises: and determining a capacitance measurement change value of the bypass channel according to the difference value between the second capacitance measurement difference value and the first capacitance measurement difference value. Therefore, the calculation speed can be improved on the basis of ensuring the accuracy of the capacitance measurement change value of the bypass channel.
In some embodiments, determining a capacitance measurement change value for the detection channel based on the first capacitance measurement and the third capacitance measurement comprises: and determining a capacitance measurement change value of the detection channel according to a difference value between the third capacitance measurement value and the first capacitance measurement value. Therefore, the calculation speed can be improved on the basis of ensuring the accuracy of the capacitance measurement change value of the detection channel.
In some embodiments, determining a compensated capacitance measurement for the detection channel based on the capacitance measurement change value for the detection channel and the capacitance measurement change value for the bypass 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 bypass channel; 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 bypass channel. Therefore, 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 the compensated capacitance measurement for the detection channel as a function of the product of the compensation factor and the capacitance measurement change value for the bypass 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. 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 bypass 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 bypass 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 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 bypass channel. The capacitance change caused by the environmental change can be corrected, so that the capacitance detection precision is ensured, and the 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 (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. 2 (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. 3 illustrates a flow diagram of a capacitance detection method provided in accordance with some embodiments of the present application.
FIG. 4 illustrates a flow chart for determining a value of a change in a capacitance measurement of a bypass channel provided in accordance with some embodiments of the present application.
FIG. 5 illustrates a flow chart for determining a compensated capacitance measurement for a detection channel provided in accordance with some embodiments of the present application.
FIG. 6 illustrates a block diagram of a capacitance detection device provided in accordance with some embodiments of the present application;
fig. 7 illustrates a block diagram of a SoC (System on Chip) provided in accordance with some embodiments of the present application.
Detailed Description
The following detailed description of specific embodiments of the present application will be described in conjunction with 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 polar 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 touched 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.
Fig. 2 (a) shows a schematic diagram of a capacitance detection device provided according to some embodiments of the present application in a first operating mode. As shown in fig. 2 (a), 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 particularly 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).
As shown in fig. 2 (a), the touch sensor has a self-capacitance structure including a touch pad. 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 ac, that is,
C x ＝C 0 +ΔC (1)
however, when the capacitance C of the touch pad of the capacitance detection apparatus 100 is adopted x When the detection is performed, the wires inevitably need to be arranged, as shown in fig. 2 (a), the detection channel includes a detection channel wire 1, one end of the detection channel wire 1 is connected with the capacitance detection device 100, and the other end of the detection channel wire 1 is connected with the capacitance 400 to be detected. Thus, the capacitance C of the channel is actually detected senor Capacitance C comprising a touch pad x And a capacitor C for detecting the channel wiring 1 trace1 The two parts, namely,
C sensor ＝C x +C trace1 (2)
as can be seen from the above equations (1) and (2), the capacitance C of the detection channel senor May be affected by the proximity of an object (e.g., a human body or a conductor) (i.e., the influence of the variable capacitance ac). However, at the same time, it is also susceptible to environmental changes such as temperature and humidity (i.e., the parasitic capacitance C between the touch pad and the reference ground caused by environmental changes 0 And a capacitor C for detecting the channel wiring 1 trace1 Variations of (d). Parasitic capacitance caused by environmental changeC 0 And a capacitor C for detecting the channel wiring 1 trace1 When the change of (a) is equivalent to the change of the variable capacitance Δ C caused by the object (a human body or a conductor) approaching the touch pad, a false determination may be made (for example, a finger does not touch the screen, but is mistakenly determined as being touched, and then a screen-on action occurs).
Therefore, in order to minimize the influence of environmental (temperature, humidity, etc.) changes on the capacitance detection value of the detection channel to ensure the capacitance detection accuracy, and particularly to avoid erroneous determination due to environmental changes, the present application proposes a capacitance detection apparatus 100 and a capacitance detection method applied to the capacitance detection apparatus 100, which can suppress the capacitance changes due to environmental changes. In other words, according to the capacitance detection device 100 and the capacitance detection method of the present application, it is possible to correct a change in capacitance due to a change in environment.
As shown in fig. 2 (a), the capacitance detection device 100 includes: the device comprises a detection channel pin CS, a bypass channel pin CP of the detection channel, a connection channel (for example, a connection line for connecting the detection channel pin CS and the bypass channel pin CP) which is used for connecting the detection channel and the bypass channel and can be controlled to be connected or disconnected, a capacitance Digital Conversion unit (for example, a capacitance Digital converter, CDC) and a data processing unit. The detection channel pin CS is used for connecting the detection channel trace 1, and the bypass channel pin CP is used for connecting the bypass channel trace 2. In some possible embodiments, at least a portion of the bypass trace 2 is parallel to the detection trace 1, so as to ensure that the peripheral conditions of the bypass trace and the detection trace are as consistent as possible, improve the compensation accuracy, and ensure the detection accuracy of the capacitance detection apparatus 100. In this embodiment, the detection channel trace 1 and the bypass channel trace 2 are the same and are arranged in parallel, so as to eliminate the influence of other variables on the detection result of the bypass channel.
And the capacitor digital conversion unit is respectively connected with the detection channel pin CS and the data processing unit, and the bypass channel pin CP can be also connected with the detection channel pin CS through a connecting channel 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.
The bypass channel and the detection channel are in a disconnected state and a connected state by controlling the disconnection and the connection of the connection channel. In some embodiments, a switch SW is provided on the connection channel, and the opening and closing of the switch SW is controlled by a signal sent by a control unit (not shown in the figure, for example, the control unit may be a control unit provided in the capacitance-to-digital conversion unit) to open and close the connection channel, so that the bypass channel and the detection channel are in the open state and the connection state. The switch SW may be implemented using a circuit including a transistor.
As shown in fig. 2 (a), when the switch SW is turned off, the bypass channel and the detection channel are in an off state, that is, in the first operation mode, the detection channel is connected to the capacitance-to-digital conversion unit, and the bypass channel is not connected to the capacitance-to-digital conversion unit.
Fig. 2 (b) shows a schematic diagram of a capacitance detection device provided according to some embodiments of the present application in a second operating mode. As shown in fig. 2 (b), when the switch SW is closed, the detection channel and the bypass channel are in a connection state, that is, in the second operation mode, both the detection channel and the bypass channel are connected to the capacitance-to-digital conversion unit, and the detection channel pin CS and the bypass channel pin CP are short-circuited.
As described above, the switch SW is located outside the capacitance-to-digital conversion unit, and it is understood that in some embodiments, the switch SW or its equivalent may be located inside the capacitance-to-digital conversion unit, and the connection channel of the detection channel and the bypass channel is also located inside the capacitance-to-digital conversion unit.
By controlling the disconnection and connection of the connection channel, the detection mode is switched between the first working mode and the second working mode, so that the capacitance measurement values of the detection channel corresponding to different working modes in different environmental states can be obtained, the capacitance measurement change value of the detection channel and the capacitance measurement change value of the bypass channel are determined, the compensation coefficient is further determined, the capacitance value measured after environmental change is compensated, and the detection precision of the capacitance detection device 100 is improved.
For example, in a first environment state, a first capacitance measurement value of the detection channel in a first working mode and a second capacitance measurement value of the detection channel in a second working mode are obtained; and in a second environment state, acquiring a third capacitance measurement value of the detection channel in the first working mode and a fourth capacitance measurement value of the detection channel in the second working mode, wherein the first environment state and the second environment state have different environment parameters, such as at least one of temperature, humidity and air pressure changes. Further, determining a capacitance measurement change value of the bypass channel according to the first capacitance measurement value, the second capacitance measurement value, the third capacitance measurement value and the fourth capacitance measurement value; and determining a capacitance measurement change value of the detection channel according to the first capacitance measurement value and the third capacitance measurement value. And then, 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 bypass channel. Therefore, the change of the capacitance measurement value of the detection channel due to the environmental change can be compensated, so that the accuracy of the capacitance detection device 100 can be improved, and the occurrence of misjudgment can be avoided.
Fig. 3 illustrates a flow diagram of a capacitance detection method provided in accordance with some embodiments of the present application. The capacitance detection method using the capacitance detection device of the present application will be described in detail with reference to fig. 3.
The application provides a capacitance detection method, which comprises the following steps:
step S1, a first capacitance measured value of the detection channel in a first working mode in a first environment state and a second capacitance measured value after the first working mode is switched into a second working mode are obtained. As described above, referring to fig. 1 and 2, in the first operation mode, the detection channel and the bypass channel are in a disconnected state; in the second working mode, the detection channel and the bypass channel are in a connection state. The detection channel includes a detection channel trace 1, one end of the detection channel trace 1 is connected to a capacitance detection device (for example, a detection channel pin CS in fig. 1 and 2), and the other end of the detection channel trace 1 is connected to a capacitance 400 to be detected (for example, a touch pad in fig. 1). The bypass channel is juxtaposed to the detection channel, the bypass channel includes a bypass channel trace 2, one end of the bypass channel trace 2 is connected to the capacitance detection device (for example, a bypass channel pin CP in fig. 1 and 2), and the other end of the bypass channel trace floats.
For example, in a first environmental state, referring to fig. 1, the switch SW is turned off, the detection channel performs detection, and a first capacitance measurement value in the first working mode is obtained, at this time, the detection channel is connected to the capacitance digital conversion unit of the capacitance detection device 100, and the bypass channel is not connected to the capacitance digital conversion unit of the capacitance detection device 100, so that the first capacitance measurement value is equal to the sum of the capacitance of the to-be-detected capacitor 400 and the capacitance of the detection channel trace 1, that is, the first capacitance measurement value is equal to the sum of the capacitance measurement value and the capacitance measurement value
C sensor-E1-M1 ＝C x-E1 +C trace1-E1 (3)
In the formula (3), C sensor-E1-M1 Detecting a first capacitance measurement value of the channel in a first operating mode M1 in a first environmental state E1; c x-E1 Is the capacitance of the capacitance 400 to be detected in the first environmental state E1; c trace1-E1 To detect the capacitance of the channel trace 1 in the first environmental state E1.
Referring to fig. 2, the switch SW is closed, the first operating mode is switched to the second operating mode, the detection channel performs detection to obtain a second capacitance measurement value in the second operating mode, at this time, the detection channel and the bypass channel are both connected to the capacitance digital conversion unit of the capacitance detection device 100, and the detection channel pin CS is short-circuited with the bypass channel pin CP, so that the second capacitance measurement value is equal to the sum of the capacitance of the to-be-detected capacitor 400, the capacitance of the detection channel trace 1 and the capacitance of the bypass channel trace 2, that is, the sum is the sum of the capacitance of the to-be-detected capacitor 400, the capacitance of the detection channel trace 1 and the capacitance of the bypass channel trace 2
C sensor-E1-M2 ＝C x-E1 +C trace1-E1 +C trace2-E1 (4)
In the formula (4), C sensor-E1-M2 Detecting a second capacitance measurement of the channel in a second operating mode M2 in the first environmental state E1; c x-E1 Is the capacitance of the capacitance 400 to be detected in the first environmental state E1; c trace1-E1 Detecting the capacitance of the channel trace 1 in the first environmental state E1; c trace2-E1 The capacitance of the bypass path 2 in the first ambient state E1 is routed.
And S2, acquiring a third capacitance measured value of the detection channel in a first working mode in a second environment state and a fourth capacitance measured value after the first working mode is switched into a second working mode. Wherein the second environmental state is different from the environmental parameter of the first environmental state. The "environmental parameter" is understood to be a physical quantity that reflects an environmental state, such as temperature, humidity, air pressure, and the like, so that a change in capacitance due to at least one of temperature, humidity, and air pressure can be corrected to improve the capacitance detection accuracy.
For example, in the second environment state (for example, the temperature in the second environment state is 25 ℃, the temperature in the first environment state is 15 ℃, and other environment parameters are not changed), referring to fig. 1, the switch SW is turned off, the detection channel performs detection to obtain the third capacitance measurement value in the first operating mode, at this time, the detection channel is connected to the capacitance digital conversion unit of the capacitance detection device 100, and the bypass channel is not connected to the capacitance digital conversion unit of the capacitance detection device 100, so that the third capacitance measurement value is equal to the sum of the capacitance to be detected and the capacitance of the detection channel routing 1, that is, the third capacitance measurement value is equal to the sum of the capacitance to be detected and the capacitance of the detection channel routing 1
C sensor-E2-M1 ＝C x-E2 +C trace1-E2 (5)
In the formula (5), C sensor-E2-M1 Detecting a third capacitance measurement of the channel in the first operating mode M1 in the second environmental state E2; c x-E2 The capacitance of the capacitor 400 to be detected in the second environmental state E2; c trace1-E2 To detect the capacitance of the channel trace 1 in the second ambient state E2.
Referring to fig. 2, when the switch SW is closed, the first operating mode is switched to the second operating mode, the detection channel performs detection to obtain a fourth capacitance measurement value in the second operating mode, at this time, the detection channel and the bypass channel are both connected to the capacitance-to-digital conversion unit of the capacitance detection apparatus 100, and the detection channel pin CS and the bypass channel pin CP are shorted, so that the fourth capacitance measurement value C is obtained sensor-E2-M2 Equal to the sum of the capacitance of the capacitor to be detected, the capacitance of the detection channel wire 1 and the capacitance of the bypass channel wire 2, i.e. the sum
C sensor-E2-M2＝ C x-E2 +C trace1-E2 +C trace2-E2 (6)
In the formula (6), C sensor-E1-M2 A fourth capacitance measurement in the second operating mode M2 of the detection channel in the second environmental state E2; c x-E2 The capacitance of the capacitor 400 to be detected in the second environmental state E2; c trace1-E2 Detecting the capacitance of the channel wire 1 in the second environment state E2; c trace2-E2 The capacitance of the bypass path 2 in the second ambient state E2 is routed.
And S3, determining a capacitance measurement change value of the bypass 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.
FIG. 4 illustrates a flow chart for determining a value of a change in a capacitance measurement of a bypass channel provided in accordance with some embodiments of the present application. The steps for determining the value of the change in the capacitance measurement of the bypass path are described in detail below with reference to fig. 4.
It should be noted that the capacitance measurement variation value of the bypass channel can be understood as the capacitance measurement variation value of the bypass channel trace 2. The first environmental state is taken as an initial environmental state as an example.
Step S31 determines a first capacitance measurement difference value as a difference between the second capacitance measurement value and the first capacitance measurement value, and determines a second capacitance measurement difference value as a difference between the fourth capacitance measurement value and the third capacitance measurement 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.
As can be seen from equations (4) - (3), the first capacitance measurement difference = the second capacitance measurement value — the first capacitance measurement value = C sensor-E1-M2 -C sensor-E1-M1 ＝(C x-E1 +C trace1-E1 +C trace2-E1 )-(C x-E1 +C trace1-E1 )＝C trace2-E1 (7)
As can be seen from equations (6) - (5), the second capacitance measurement difference = fourth capacitance measurement value — third capacitance measurement value = C sensor-E2-M2 -C sensor-E2-M1 ＝(C x-E2 +C trace1-E2 +C trace2-E2 )-(C x-E2 +C trace1-E2 )＝C trace2-E2 (8)
And step S32, determining a capacitance measurement change value of the bypass channel according to the first capacitance measurement difference value and the second capacitance measurement difference value. Therefore, the calculation speed can be improved on the basis of ensuring the accuracy of the capacitance measurement change value of the bypass channel.
In some possible embodiments, the capacitance measurement change value of the bypass channel may be determined from a difference of the second capacitance measurement difference and the first capacitance measurement difference.
From the formulas (7) and (8), the measured capacitance change value of the bypass channel, i.e. the measured capacitance change value Δ C of the bypass channel trace trace2-E1-E2 = second capacitance measurement difference-first capacitance measurement difference = C trace2-E2 -C trace2-E1 ＝(C sensor-E2-M2 -C sensor-E2-M1 )-C sensor-E1-M2 -C sensor-E1-M1 (9)，
In the formula (9), Δ C trace2-E1-E2 The capacitance measurement change value of the bypass channel trace 2, i.e. the capacitance measurement change value of the bypass channel trace, which is changed from the first environmental state E1 to the second environmental state E2.
And S4, determining a capacitance measurement change value of the detection channel according to the third capacitance measurement value and the first capacitance measurement value. Therefore, the calculation speed can be improved on the basis of ensuring the accuracy of the capacitance measurement change value of the detection channel.
In some possible embodiments, the capacitance measurement change value of the detection channel may be determined based on a difference between the third capacitance measurement value and the first capacitance measurement value.
As can be seen from the equations (3) and (5), the capacitance measurement variation value Δ C of the detection channel sensor-E1-E2 = third capacitance measurement-first capacitance measurement = C sensor-E2 -C sensor-E1 ＝(C x-E2 +C trace1-E2 )-(C x-E1 +C trace1-E1 )＝(C x-E2 -C x-E1 )+(C trace1-E2 -C trace1-E1 )＝ΔC x-E1-E2 +ΔC trace1-E1-E2 (10)
In the formula (10), Δ C x-E1-E2 Measuring a change value for a capacitance of a capacitance to be detected 400 (e.g., a touch pad in FIG. 1) that changes from a first environmental state E1 to a second environmental state E2; delta C trace1-E1-E2 The capacitance measurement variation value of the detection channel trace 1 is changed from the first environmental state E1 to the second environmental state E2.
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 bypass channel. Therefore, the calculation speed can be improved on the basis of ensuring the accuracy of the compensation coefficient.
In some possible embodiments, the compensation factor may be determined from a ratio of a measured change in capacitance of the detection channel to a measured change in capacitance of the bypass channel.
Compensation factor K = capacitance measurement change value of detection channel/capacitance measurement change value of bypass channel = Δ C sensor-E1-E2 /ΔC trace2-E1-E2 (11)
And S6, compensating the third capacitance measured value according to the compensation coefficient and the capacitance detection change value of the bypass channel to determine the compensated capacitance measured value of the detection channel. By compensating the third capacitance measured value, the capacitance change caused by the environmental change can be corrected, the capacitance detection precision is improved, and the occurrence of misjudgment is avoided.
FIG. 5 illustrates a flow chart provided in accordance with some embodiments of the present application for determining a compensated capacitance measurement for a detection channel. The steps for determining the compensated capacitance measurements for the detection channels are described in detail below with reference to fig. 5.
And S61, determining a compensation value according to the product of the compensation coefficient and the capacitance measurement change value of the bypass channel.
I.e. the compensation value C comp = compensation factor × capacitance measurement variation value of bypass channel = K × Δ C trace2-E1-E2 (12)
And S62, compensating the third capacitance measurement value according to the compensation value to determine the compensated capacitance measurement value of the detection channel. Therefore, the capacitance change caused by the environmental change can be compensated more accurately, the capacitance detection precision is improved, and the occurrence of misjudgment is avoided.
In some possible embodiments, the compensated capacitance measurement for the detection channel may be determined by a difference between the third capacitance measurement and the compensation value.
As can be seen from equations (11) and (12), the capacitance measurement value = third capacitance measurement value — compensation value = C of the compensated detection channel sensor-E2-M1 -C comp ＝C sensor-E2-M1 -K×ΔC trace2-E1-E2 ＝C sensor-E2-M1 -ΔC sensor-E1-E2 /ΔC trace2-E1-E2 ×ΔC trace2-E1-E2 ＝C sensor-E2-M1 -ΔC sensor-E1-E2 ＝C sensor-E1-M1
It can be derived from the above formula that the third capacitance measurement value is equal to the first capacitance measurement value after compensation of the compensation value, so that the change of the parasitic capacitance caused by the environmental change can be corrected, the accuracy of the touch capacitance measurement value is improved, the capacitance detection accuracy is ensured, and misjudgment is avoided.
In addition to the method of determining a capacitance measurement value for a compensated sense channel in the above embodiments, the present application also provides a method of determining a capacitance measurement value for a compensated sense channel as a function of a first capacitance measurement value and a second capacitance measurement value, i.e., a capacitance measurement value = f (C) for a compensated sense channel sensor-E1-M1 ，C sensor-E1-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-E1-M1 -K 2 ×C sensor-E1-M2 ＝(K 1 -K 2 )×C x-E1-M1 +(K 1 -K 2 )×C trace1-E1-M1 -K 2 ×C trace2-E1-M1 (13)
In the formula (13), K 1 Is a first compensation coefficient; k 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 variation of the capacitance of the detection channel trace 1 and the capacitance of the bypass channel trace 2 changing with the environment (for example, temperature), the compensated capacitance measurement value of the detection channel can be determined by selecting a proper first compensation coefficient and a proper second compensation coefficient.
Fig. 6 illustrates a block diagram of a capacitance detection device provided in accordance with some embodiments of the present application. Capacitance detection device 100, comprising: a detection capacitance sensor 110, a bypass 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 bypass capacitive sensor 120 is configured to obtain a second capacitance measurement of the detection channel in the second operating mode in the first environmental condition and a fourth capacitance measurement of the detection channel in the second operating mode in the second environmental condition.
The digital processing unit 130 is configured to determine a capacitance measurement change value of the bypass 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 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 bypass channel.
Fig. 7 illustrates a block diagram of a SoC (System on Chip) provided in accordance with some embodiments of the present application. In fig. 7, similar components have the same reference numerals. In addition, the dashed box is an optional feature of more advanced socs. In fig. 7, 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. Program code may 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 a tangible machine-readable memory for transmitting information (e.g., carrier waves, infrared digital signals, etc.) using the internet in an electrical, optical, acoustical or other form of propagated signal. 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 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 each device embodiment of the present application, each unit/module is a logical unit/module, and physically, one logical unit/module may be one physical unit/module, or 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 solving 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 description of the present 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.
The method embodiments of the present application may be implemented in software, magnetic, firmware, etc.
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. Program code may also be implemented in assembly or machine language, if desired. Indeed, the mechanisms described herein are not limited in scope to any particular programming language. In any case, the language may be a compiled or interpreted language.
One or more aspects of at least one embodiment may be implemented by representative instructions stored on a computer-readable storage medium which represent various logic within a processor, which when read by a machine causes the machine to fabricate logic to perform the techniques described herein. These representations, known as "IP cores" (IP cores), may be stored on a tangible computer-readable storage medium and provided to a number of customers or production facilities to load into the manufacturing machines that actually make the logic or processor.
In some cases, an instruction converter may be used to convert instructions from a source instruction set to a target instruction set. For example, the instruction converter may transform (e.g., using static binary transformations, dynamic binary transformations including dynamic compilation), morph, emulate, or otherwise convert an instruction into one or more other instructions to be processed by the IP core. The instruction converter may be implemented in software, hardware, firmware, or a combination thereof. The instruction converter may be on the processor, off-processor, or partially on and partially off-processor.
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 measured value of a detection channel in a first working mode in a first environment state and a second capacitance measured value of the detection channel in a second working mode in the first environment state, wherein the first working mode is that the detection channel and a bypass channel are in a disconnected state; the second working mode is that the detection channel and the bypass channel are in a connection state; the detection channel comprises a detection channel wire, one end of the detection channel wire is connected with the capacitance detection device, the other end of the detection channel wire is connected with the capacitance to be detected, the bypass channel comprises a bypass channel wire, one end of the bypass channel wire is connected with the capacitance detection device, and the other end of the bypass channel wire floats;
acquiring a third capacitance measurement value of the detection channel in a first working mode in a second environment state and a fourth capacitance measurement value of the detection channel in a second working mode in the second environment state, wherein the second environment state is different from the first environment state in environmental parameters;
determining a capacitance measurement change value for the bypass 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 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 bypass channel.
2. The method of claim 1, wherein determining a capacitance measurement change value for the bypass 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:
determining a first capacitance measurement difference value as a difference between the second capacitance measurement value and the first capacitance measurement value, and determining a second capacitance measurement difference value as a difference between the fourth capacitance measurement value and the third capacitance measurement value;
and determining a capacitance measurement change value of the bypass channel according to the first capacitance measurement difference value and the second capacitance measurement difference value.
3. The method of claim 2, wherein determining a capacitance measurement change value for the bypass channel based on the first capacitance measurement difference and the second capacitance measurement difference comprises:
and determining a capacitance measurement change value of the bypass channel according to the difference value of the second capacitance measurement difference value and the first capacitance measurement difference value.
4. The method of claim 1, wherein determining a capacitance measurement change value for the detection channel based on the first capacitance measurement value and the third capacitance measurement value comprises:
determining a capacitance measurement change value for the detection channel based on a difference between the third capacitance measurement value and the first capacitance measurement value.
5. The method of claim 1, wherein determining the compensated capacitance measurement for the detection channel based on the capacitance measurement change value for the detection channel and the capacitance measurement change value for the bypass channel comprises:
determining the compensation coefficient according to the ratio of the capacitance measurement change value of the detection channel to the capacitance measurement change value of the bypass channel;
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 bypass channel.
6. The method of claim 5, wherein determining the compensated capacitance measurement for the detection channel based on a product of the compensation factor and the capacitance measurement change value for the bypass 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.
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 bypass 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 the bypass 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 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 bypass channel.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116880717A (en) * | 2023-09-07 | 2023-10-13 | 上海海栎创科技股份有限公司 | Capacitance detection device, and method and device for improving detection precision of capacitive touch screen |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116880717A (en) * | 2023-09-07 | 2023-10-13 | 上海海栎创科技股份有限公司 | Capacitance detection device, and method and device for improving detection precision of capacitive touch screen |
| CN116880717B (en) * | 2023-09-07 | 2023-12-12 | 上海海栎创科技股份有限公司 | Capacitance detection device, and method and device for improving detection precision of capacitive touch screen |
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