Capacitance detection method and capacitance detection device

Abstract

The application provides a capacitance detection method, which comprises the following steps: obtaining a first detection value according to a first electrode; obtaining a second detection value according to the first electrode and a second electrode; and adjusting the first detection value according to the second detection value and a coefficient. By using the technical scheme, the capacitance change caused by the environmental change can be corrected, so that the capacitance detection precision is ensured, and misjudgment is avoided. The application further provides a capacitance detection device.

Description

Technical Field

[0001] This application relates to the field of integrated circuit technology, and in particular to a capacitance detection method and a capacitance detection device. Background Technology

[0002] Capacitive sensors are commonly used in products such as Specific Absorption Rate Sensors (SAR Sensors), touch detection, and in-ear detection. To detect only the capacitance caused by human proximity or touch, capacitive sensors must be properly calibrated to offset the influence of the environment on the measured component. Because environmental capacitance changes with factors such as temperature and humidity, calibrating capacitive sensors is very challenging. Typical calibration methods use fixed compensation values ​​or coefficients, but changes in the environment cause variations in capacitance, which in turn affect the calibration results, impacting the detection of human proximity and leading to false triggering.

[0003] Therefore, to address the issue of capacitance detection errors caused by changes in conditions such as temperature and humidity, more accurate capacitance detection and compensation methods are needed to eliminate capacitance value changes caused by environmental variations and avoid misjudgments of human proximity. Summary of the Invention

[0004] Some embodiments of this application provide a capacitance detection method and a capacitance detection device. The following describes this application from multiple aspects, and the embodiments and beneficial effects of the following aspects can be referred to each other.

[0005] In a first aspect, embodiments of this application provide a capacitance detection method, the method comprising: obtaining a first detection value based on a first electrode, obtaining a second detection value based on the first electrode and a second electrode, and adjusting the first detection value based on the second detection value and a coefficient.

[0006] The capacitance detection method provided by the first aspect of this application can correct capacitance changes caused by environmental changes, thereby ensuring capacitance detection accuracy and avoiding misjudgment.

[0007] In some embodiments, the second electrode includes at least one sub-electrode; wherein obtaining a second detection value based on the first electrode and the second electrode includes: obtaining a third detection value corresponding to each sub-electrode based on the first electrode and each sub-electrode respectively; wherein adjusting the first detection value based on the second detection value and a coefficient includes: adjusting the first detection value based on each third detection value and a sub-coefficient corresponding to each third detection value. This compensates for the first detection value based on the capacitance detection values ​​between the first electrode and the multiple sub-electrodes, improving the capacitance detection accuracy of the first detection value.

[0008] In some implementations, the sub-coefficients corresponding to each third detection value can be the same or different. This improves the capacitance detection accuracy of the first detection value.

[0009] In some implementations, when the sub-coefficients are the same, the second detection value includes at least one third detection value. This allows the first detection value to be compensated for by capacitance measurements between the first electrode and multiple sub-electrodes, thereby improving the capacitance detection accuracy of the first detection value.

[0010] In some implementations, the coefficients and sub-coefficients are related to environmental factors, including at least temperature. This allows for correction of capacitance changes caused by temperature variations, improving the accuracy of capacitance detection for the first detection value and preventing misjudgments.

[0011] In some embodiments, obtaining a first detection value based on the first electrode includes: applying a first excitation voltage to the first electrode and detecting the capacitance of the first electrode to ground to obtain the first detection value. This avoids the influence of the self-capacitance of the second electrode on the first electrode and improves the detection accuracy of the self-capacitance value of the first electrode.

[0012] In some embodiments, obtaining a second detection value based on the first electrode and the second electrode includes: applying a second excitation voltage to the second electrode and detecting the capacitance between the first electrode and the second electrode to obtain a second detection value, wherein the second excitation voltage is the same as the first excitation voltage. This allows for the detection of the mutual capacitance between the first electrode and the second electrode, improving the accuracy of the mutual capacitance value detection.

[0013] In some embodiments, adjusting the first detection value based on the second detection value and a coefficient includes: acquiring the difference between second detection values ​​under different environments, and adjusting the first detection value based on the difference and a coefficient. This can correct for capacitance changes caused by environmental variations and improve the detection accuracy of the self-capacitance of the first electrode. In a second aspect, embodiments of this application provide a capacitance detection device, comprising: a first electrode for acquiring a first detection value; and a second electrode, wherein the first electrode is further configured to acquire a second detection value based on the first electrode and the second electrode; wherein the first detection value can be adjusted based on the second detection value and a coefficient.

[0014] The capacitance detection device provided according to the second aspect of this application can correct capacitance changes caused by environmental changes, thereby ensuring capacitance detection accuracy and avoiding misjudgment.

[0015] In some embodiments, the second electrode includes at least one sub-electrode; wherein the second electrode is used to acquire a third detection value corresponding to each sub-electrode based on the first electrode and each sub-electrode; wherein the first detection value can be adjusted based on each third detection value and a sub-coefficient corresponding to each third detection value. This compensates for the first detection value based on the capacitance detection value between the first electrode and the plurality of sub-electrodes, thereby improving the capacitance detection accuracy of the first detection value.

[0016] In some implementations, the sub-coefficients corresponding to each third detection value can be the same or different. This improves the capacitance detection accuracy of the first detection value.

[0017] In some implementations, when the sub-coefficients are the same, the second detection value includes at least one third detection value. This allows the first detection value to be compensated for by capacitance measurements between the first electrode and multiple sub-electrodes, thereby improving the capacitance detection accuracy of the first detection value.

[0018] In some implementations, the coefficients and sub-coefficients are related to environmental factors, including at least temperature. This allows for correction of capacitance changes caused by temperature variations, improving the accuracy of capacitance detection for the first detection value and preventing misjudgments.

[0019] In some embodiments, the first electrode is used to receive a first excitation voltage and detect its capacitance to ground to obtain a first detection value. This avoids the influence of the second electrode on the self-capacitance of the first electrode and improves the detection accuracy of the self-capacitance value of the first electrode.

[0020] In some embodiments, the second electrode is used to receive a second excitation voltage, and the first electrode is used to detect the capacitance between the first and second electrodes to obtain a second detection value; wherein the second excitation voltage is the same as the first excitation voltage. This allows for the detection of the mutual capacitance between the first and second electrodes, improving the accuracy of the mutual capacitance value detection.

[0021] In some implementations, the first detection value is adjusted based on the difference and coefficient between second detection values ​​under different environmental conditions. This allows for correction of capacitance changes caused by environmental variations, improving the accuracy of capacitance value detection for the self-capacitance of the first electrode. Attached Figure Description

[0022] Figure 1 This illustrates application scenarios of the capacitance detection device provided according to some embodiments of this application.

[0023] Figure 2 This illustrates an application scenario for capacitance compensation using a capacitance detection device provided according to some embodiments of this application.

[0024] Figure 3This illustrates application scenarios of the capacitance detection device provided according to some embodiments of this application.

[0025] Figure 4 A flowchart of a capacitance detection method provided according to some embodiments of this application is shown.

[0026] Figure 5 This illustrates an application scenario where a capacitance detection device according to some embodiments of the present application includes multiple driving electrodes.

[0027] Figure 6 A flowchart of a capacitance detection method provided according to some other embodiments of this application is shown.

[0028] Figure 7 This diagram shows a block diagram of a capacitance detection device according to some embodiments of the present application;

[0029] Figure 8 This diagram illustrates a block diagram of a SoC (System on Chip) according to some embodiments of this application. Detailed Implementation

[0030] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0031] Figure 1 The following illustrations show application scenarios of the capacitance detection device provided according to some embodiments of this application. The capacitance detection device is described as an example of a touch sensor.

[0032] like Figure 1 As shown, the capacitance detection device includes: an analog front end (AFE), an analog-to-digital converter (ADC), a digital processing unit, registers, control logic, offset compensation, and detection pins.

[0033] Analog front end, used to output a voltage proportional to the input capacitance.

[0034] Offset compensation is used to counteract the influence of environmental capacitance on human proximity capacitance detection, so that the output voltage of the analog front end is approximately proportional to the human proximity capacitance (i.e., the self-capacitance of the measuring element).

[0035] The analog-to-digital converter unit is used to convert the analog input voltage from the analog front end into digital code and output the digital code to the digital processing unit.

[0036] The digital processing unit is used to process the digital code obtained from the analog-to-digital converter and send the result to the register.

[0037] Registers contain memory-mapped hardware registers used by the CPU to configure capacitive sensors or used by capacitive sensors to report information to the CPU.

[0038] The control logic is used to control the parameter configuration of each module inside the capacitive sensor, and can also control the state of the detection pins of the capacitive sensor.

[0039] The detection pins, i.e., the detection pins of the capacitive sensor, include CHO…CHn, where n=0,1,2,3,…

[0040] Figure 2 This illustrates an application scenario for capacitance compensation using a capacitance detection device provided according to some embodiments of this application.

[0041] like Figure 2 As shown, the capacitance detection device also includes a detection channel CS and a reference channel CR. The capacitance detection value of the parasitic capacitance between the detection channel CS and ground is C. sensor .

[0042] When no human body or conductor is near, the parasitic capacitance C between the reference channel CR and ground. ref The initial value of the capacitance detection is C ref0 C ref Located inside or outside the capacitive sensor. After environmental changes, the parasitic capacitance C... ref The change in the capacitance detection value is ΔC ref .

[0043] Assuming the change in parasitic capacitance of the reference channel CR is proportional to the change in parasitic capacitance of the detection channel CS, let C′ sensor The parasitic capacitance of the detection channel CS after compensation is expressed by the following formula:

[0044] C′ sensor =C sensor +k*ΔC ref

[0045] Where k is a proportionality coefficient between the parasitic capacitance change of the detection channel CS and the parasitic capacitance change of the reference channel CR. This coefficient can be a fixed value or a set of data. For example, if only the effect of temperature is considered, k can be set as a piecewise coefficient that varies with temperature.

[0046] It is understood that the capacitance detection method of this application is applicable to scenarios where a capacitance detection device detects the capacitance of a capacitive sensor.

[0047] As can be understood, as mentioned above, in the prior art, since the physical environment of the external reference channel, such as the PCB trace length, is not completely consistent with the physical environment of the detection channel, the compensation effect for changes in parasitic capacitance caused by environmental changes is limited. In addition, there are problems such as the internal channel not being able to reflect the actual self-capacitance characteristics of the detection channel, which affect the accuracy of capacitance detection and may even cause the capacitance detection device to make a misjudgment.

[0048] To address the aforementioned problems, embodiments of this application provide a capacitance detection device and a capacitance detection method applied to the capacitance detection device. In some embodiments, the capacitance detection method is executed by the capacitance detection device. It is understood that in some embodiments of this application, the capacitance detection device can be implemented as a chip, while in other embodiments, it can be implemented as a circuit. Regardless of the form, as long as capacitance detection is achieved, it is acceptable, and this application does not impose specific limitations on this aspect.

[0049] The capacitance detection method according to an embodiment of this application includes: obtaining a first detection value (i.e., the self-capacitance formed between the first electrode and ground) based on a first electrode (i.e., a detection channel); obtaining a second detection value (i.e., the mutual capacitance formed between the first electrode and the second electrode) based on the first electrode and a second electrode (i.e., a driving electrode); and adjusting the first detection value based on the second detection value and a coefficient. Specifically, a first excitation voltage can be applied to the first electrode and the capacitance between the first electrode and ground can be detected to obtain the first detection value; a second excitation voltage can be applied to the second electrode and the capacitance between the first electrode and the second electrode can be detected to obtain the second detection value; finally, the difference between the second detection values ​​under different environments can be obtained, and the first detection value can be adjusted based on the difference and a coefficient.

[0050] Using the above method, the change in the self-capacitance formed between the first electrode and ground in different environments can be adjusted according to the change in the second detection value between the first electrode and the second electrode in different environments, thereby offsetting the influence of environmental factors on the first detection value and obtaining a more accurate measurement value of the self-capacitance between the first electrode and ground.

[0051] Capacitive sensors can be specifically applied to wearable devices (such as smart bracelets, smartwatches, etc.), mobile phones, tablets, laptops, ultra-mobile personal computers (UMPCs), handheld computers, netbooks, personal digital assistants (PDAs), virtual reality devices, and other electronic devices with touchscreens. This application does not specifically limit the application to capacitive sensors.

[0052] The embodiments of this application will now be described in further detail with reference to the accompanying drawings.

[0053] Figure 3 This is a schematic diagram illustrating an application scenario of the capacitance detection method provided in an embodiment of this application. For example... Figure 3 As shown, the capacitance detection device includes: an analog front-end, an analog-to-digital converter, a digital processing unit, registers, control logic, offset compensation, a detection channel CS, and driving electrodes CD. The functions of the analog front-end, analog-to-digital converter, digital processing unit, registers, control logic, and offset compensation are described above and will not be repeated here. The detection channel is used to detect the capacitance of the component under test using an excitation voltage. The driving electrodes are used to send a voltage signal for capacitance detection.

[0054] There is a parasitic capacitance between the detection channel CS (i.e., the first electrode) and the driving electrode CD (i.e., the second electrode), and there is also a parasitic capacitance between the detection channel CS and ground. The capacitance values ​​of these two parasitic capacitances change with environmental variations. Experiments have shown that there is a certain proportional relationship between the change in mutual capacitance between the detection channel CS and the driving electrode CD and the change in self-capacitance between the detection channel CS and ground. The change in mutual capacitance between the detection channel CS and the driving electrode CD can be used to compensate for the change in self-capacitance between the detection channel CS and ground, thereby correcting the change in self-capacitance of the detection channel CS caused by environmental changes.

[0055] The following is in conjunction with the above. Figure 3 The scene shown and combined Figure 4 This application provides a detailed description of its technical solution. Figure 4 As shown, in some embodiments of this application, the entity executing the capacitance detection method can be a capacitance detection device, and the method may include the following steps:

[0056] Step S1: Obtain the first mutual capacitance measurement value (i.e., the second detection value) between the detection channel (i.e., the first electrode) and the driving electrode (i.e., the second electrode) and the first self-capacitance measurement value (i.e., the first detection value) of the detection channel in the first environmental state.

[0057] Here, the detection channel CS includes traces for connecting the component under test (DUT) to the capacitance detection device. The DUT can be a capacitor or a combination of capacitors that are capacitance detected by the capacitance detection device, for example... Figure 1 Measuring elements, etc. The driving electrode is an electrode used to transmit a voltage signal for capacitance detection.

[0058] The capacitance values ​​of the mutual capacitance between the detection channel and the driving electrode (i.e., the parasitic capacitance between the first and second electrodes) and the self-capacitance of the detection channel (i.e., the capacitance of the first electrode to ground) are affected by the environment. The capacitance measurements obtained during capacitance detection will differ under different environmental conditions. Environmental factors affecting capacitance measurements, i.e., environmental parameters, may include, but are not limited to, temperature, humidity, and air pressure.

[0059] It is understood that when performing capacitance detection on the mutual capacitance between the detection channel and the driving electrode and the self-capacitance of the detection channel, one of the environmental parameters may affect the capacitance measurement value, such as temperature alone or humidity alone, or two or more environmental parameters may affect the capacitance measurement value simultaneously, such as temperature, humidity and air pressure simultaneously. This application does not specifically limit this.

[0060] In some embodiments of this application, capacitance detection is performed on the mutual capacitance between the detection channel CS and the driving electrode CD in a first environmental state. This can be achieved when no human body, such as a finger or conductor, is near the device under test. The driving electrode CD is used as the transmitter, and the detection channel CS as the receiver. An excitation voltage is applied between the driving electrode CD and the detection channel CS to perform capacitance detection, obtaining a first mutual capacitance measurement value. Here, the first mutual capacitance measurement value is denoted as C. m0 .

[0061] In some embodiments of this application, capacitance detection of the self-capacitance of the detection channel CS is performed in a first environmental state. This can be achieved by applying the same excitation voltage to the driving electrode CD as the excitation voltage applied to the detection channel CS, when no human body (such as a finger or conductor) is near the device under test. That is, the waveforms of the excitation voltage signals applied to both are identical, thereby detecting the self-capacitance of the detection channel CS and obtaining a first self-capacitance measurement value. Here, since the excitation voltage signal applied to the driving electrode CD is the same as the excitation voltage signal applied to the detection channel CS, the potential between the driving electrode CD and the detection channel CS is 0. Therefore, when performing capacitance detection on the detection channel CS, the mutual capacitance between the detection channel CS and the driving electrode CD does not affect the capacitance measurement result; the capacitance measurement result only includes the capacitance measurement value of the self-capacitance of the detection channel CS. Here, the first self-capacitance measurement value is denoted as C. sensor0 .

[0062] Step S2: Obtain the second mutual capacitance measurement value between the detection channel and the driving electrode and the second self capacitance measurement value of the detection channel in the second environmental state.

[0063] Here, compared to the first environment, the environmental parameters of the second environment have changed, which causes changes in the capacitance value of the self-capacitance of the detection channel CS and the capacitance value of the mutual capacitance between the detection channel CS and the driving electrode CD.

[0064] It is understood that the change in the second environment relative to the first environment may involve environmental parameters such as temperature, humidity, and air pressure. This change may be due to one parameter, such as temperature, or more parameters, such as temperature and humidity. This application does not impose specific limitations on this.

[0065] Similarly, in the second environmental state, capacitance detection is performed on the mutual capacitance between the detection channel CS and the driving electrode CD. This can be done when no human body, such as a finger or conductor, is near the device under test. The driving electrode CD is used as the transmitter, and the detection channel CS as the receiver. An excitation voltage is applied between the driving electrode CD and the detection channel CS to perform capacitance detection, obtaining a second mutual capacitance measurement value. Here, the second mutual capacitance measurement value is denoted as C. m1 .

[0066] Similarly, in the second environmental state, capacitance detection of the self-capacitance of the detection channel CS can be performed by applying the same excitation voltage to the driving electrode CD as the excitation voltage applied to the detection channel CS, when no human body, such as a finger or conductor, is near the device under test. That is, the waveforms of the excitation voltage signals applied to both are identical, thereby detecting the self-capacitance of the detection channel CS and obtaining a second self-capacitance measurement value. Here, the second self-capacitance measurement value is denoted as C. sensor1 .

[0067] Step S3: Determine the compensation coefficient based on the difference between the second mutual capacitance measurement value and the corresponding first mutual capacitance measurement value, and the difference between the second self capacitance measurement value and the first self capacitance measurement value.

[0068] Here, the self-capacitance of the detection channel CS and the mutual capacitance between the detection channel CS and the driving electrode CD are both affected by environmental factors. Experiments show that, under certain routing and layout conditions, the change in the self-capacitance of the detection channel CS and the change in the mutual capacitance between the detection channel CS and the driving electrode CD are approximately proportional. Therefore, based on this proportional relationship, the change in the self-capacitance of the detection channel CS can be compensated for by the change in the mutual capacitance between the detection channel CS and the driving electrode CD, thus determining the self-capacitance value of the detection channel CS that can resist environmental influences.

[0069] In some embodiments of this application, the first mutual capacitance measurement value obtained in the first environmental state is a capacitance measurement value obtained by capacitance detection of the mutual capacitance between the detection channel CS and the driving electrode CD. The second mutual capacitance measurement value is a capacitance measurement value obtained after the capacitance value of the mutual capacitance between the detection channel CS and the driving electrode CD also changes after the environment changes. It is a change based on the first mutual capacitance measurement value. Therefore, the capacitance measurement change value of the mutual capacitance between the detection channel CS and the driving electrode CD can be determined by calculating the first difference between the second mutual capacitance measurement value and the first mutual capacitance measurement value.

[0070] In some embodiments of this application, the first self-capacitance measurement value obtained in the first environmental state is the capacitance measurement value obtained by capacitance detection of the self-capacitance of the detection channel CS, and the second self-capacitance measurement value is the capacitance measurement value obtained after the capacitance value of the self-capacitance of the detection channel CS also changes after the environment changes. It is a change based on the first self-capacitance measurement value. Therefore, the capacitance measurement change value of the self-capacitance of the detection channel CS can be determined by calculating the second difference between the second self-capacitance measurement value and the first self-capacitance measurement value.

[0071] In some embodiments of this application, a compensation coefficient is determined by calculating the ratio of a second difference between a second self-capacitance measurement and a first self-capacitance measurement, and a first difference between a second mutual capacitance measurement and a first mutual capacitance measurement.

[0072] The compensation coefficient K is determined based on the above ratio, and expressed by the following formula:

[0073]

[0074] Step S4: Compensate the second self-capacitance measurement value according to the compensation coefficient to determine the corrected measurement value of the self-capacitance of the detection channel.

[0075] In some embodiments of this application, the compensation value is determined based on the product of the compensation coefficient K and the measured change in capacitance of the mutual capacitance between the detection channel CS and the driving electrode CD. Here, the product of the measured change in capacitance of the mutual capacitance between the detection channel CS and the driving electrode CD and the compensation coefficient K can be used to describe the change in capacitance of the self-capacitance of the detection channel CS. Compensation value C comp The formula is expressed as follows:

[0076] C comp =K·Δ(C m1 -C m0 )=K·ΔC m (2)

[0077] In some embodiments of this application, the self-capacitance measurement value of the detection channel CS in the current environmental state, i.e., the second self-capacitance measurement value, is compensated according to a compensation value to obtain a corrected measurement value of the self-capacitance of the detection channel CS. Here, the corrected measurement value of the self-capacitance of the detection channel CS is the value of the self-capacitance of the detection channel CS obtained after removing environmental influences.

[0078] Specifically, the difference between the second self-capacitance measurement value and the compensation value is calculated, and the corrected measurement value of the self-capacitance of the detection channel CS is determined based on the obtained difference. It can be understood that the obtained difference can be directly determined as the corrected measurement value of the self-capacitance of the detection channel CS, or the obtained difference can be subjected to certain mathematical transformations, such as linear or polynomial transformations, and the result of the transformation can be determined as the corrected measurement value of the self-capacitance of the detection channel CS. This application embodiment does not specifically limit this approach.

[0079] The difference between the measured value and the compensation value of the second self-capacitance is calculated and expressed by the following formula:

[0080] C′ sensor =C sensor1 -K·(C m1 -C m0 (3)

[0081] Here, the corrected measurement value C′ of the detection channel CS is used. sensor It is the capacitance value after excluding the influence of environmental changes on the self-capacitance of the detection channel CS, and it remains approximately unchanged.

[0082] In other embodiments of this application, the capacitance detection device has multiple driving electrodes CD, and multiple mutual capacitances can be formed between the detection channel CS and the multiple driving electrodes. When performing capacitance detection on the mutual capacitance between the detection channel CS and the multiple driving electrodes, each driving electrode CD can be used as a transmitter in sequence, and the detection channel CS can be used as a receiver. An excitation voltage is applied between each driving electrode CD and the detection channel CS to perform capacitance detection. Each capacitance detection yields a first mutual capacitance measurement value, and finally multiple first mutual capacitance measurement values ​​are obtained.

[0083] Figure 5 The diagram illustrates a structure of a capacitance detection device including multiple driving electrodes in some embodiments of this application. For example... Figure 5 As shown, the capacitance detection device includes two driving electrodes CD1 and CD2. By applying an excitation voltage between the driving electrode CD1 and the detection channel CS in the first environmental state using a method similar to that described above, the first mutual capacitance measurement value C between the driving electrode CD1 and the detection channel CS can be obtained. m1_0 (i.e., the third detection value), here C m1_0 The capacitance measurement can include the parasitic capacitance between the detection channel CS and the driving electrode CD1, or it can include a physical capacitance between the detection channel CS and the driving electrode CD1. By applying an excitation voltage between the driving electrode CD2 and the detection channel CS, the first mutual capacitance measurement value C between the driving electrode CD2 and the detection channel CS can be obtained. m2_0 (i.e., the third detection value), here C m2_0The capacitance measurement can include the parasitic capacitance between the detection channel CS and the driving electrode CD2, or it can include the physical capacitance between the detection channel CS and the driving electrode CD2.

[0084] Similarly, by applying an excitation voltage between the driving electrode CD1 and the detection channel CS in the second environmental state, the second mutual capacitance measurement value C between the driving electrode CD1 and the detection channel CS can be obtained. m1_1 (i.e., the third detection value); by applying an excitation voltage between the driving electrode CD2 and the detection channel CS, the second mutual capacitance measurement value C between the driving electrode CD2 and the detection channel CS can be obtained. m2_1 (i.e., the third detection value).

[0085] Here, C m1_0 and C m1_1 This is the capacitance measurement value between the driving electrode CD1 and the detection channel CS in different environments. The difference between the two values ​​can be used to obtain the change in capacitance ΔC between the driving electrode CD1 and the detection channel CS. m1 C m2_0 and C m2_1 This is the capacitance measurement value between the driving electrode CD2 and the detection channel CS in different environments. The difference between the two values ​​can be used to obtain the change in capacitance ΔC between the driving electrode CD2 and the detection channel CS. m2 .

[0086] It is understood that by applying the same excitation voltage to the driving electrodes CD1 and CD2 as the excitation voltage applied to the detection channel CS, when performing capacitance detection on the detection channel CS, the mutual capacitance between the detection channel CS and the driving electrodes CD1 and CD2 will not affect the capacitance measurement result, and therefore will not affect the first self-capacitance measurement value of the detection channel CS.

[0087] Furthermore, assuming that the change in capacitance between the driving electrodes CD1, CD2 and the detection channel CS is proportional to the change in self-capacitance of the detection channel CS, the capacitance value C′ after compensation is... sensor It can be calculated using the following formula:

[0088] C′ sensor =C sensor -f(C m1 )-f(C m2 (4)

[0089] Where, f(C) m1 ) and f(C m2 ) respectively represent C m1 and C m2 A polynomial with variables.

[0090] Understandable. Figure 5 The driving electrode CD includes two driving electrodes: CD1 and CD2. The number of driving electrodes in the figure is just an example and does not constitute a limitation on the number of driving electrodes CD in the capacitance detection device. The number of driving electrodes CD can be any number, and the embodiments of this application do not make specific limitations on this.

[0091] Figure 6 A flowchart of another capacitance detection method according to some embodiments of this application is shown. Figure 6 As shown, the entity executing this capacitance detection method can be a capacitance detection device, and the method can include the following steps:

[0092] Step S10: Acquire multiple data pairs consisting of mutual capacitance measurements between the detection channel and the driving electrode and self-capacitance measurements of the detection channel in multiple environmental states.

[0093] Here, the detection channel CS includes traces for connecting the component under test (DUT) to the capacitance detection device. The DUT can be a capacitor or a combination of capacitors that are capacitance detected by the capacitance detection device, for example... Figure 1 The measuring elements in the system include... The driving electrode is an electrode used to transmit a voltage signal for capacitance detection. Environmental conditions can include multiple environmental parameters, which differ depending on the environmental condition.

[0094] Environmental changes can cause variations in the self-capacitance of the detection channel CS and the capacitance between the detection channel CS and the driving electrode CD (e.g., ...). Figure 5 The mutual capacitance between CD1 and CD2 shown in the figure changes. However, according to the actual capacitance detection results, the change in the self-capacitance of the detection channel CS and the change in the mutual capacitance between the detection channel CS and the driving electrode CD are not necessarily linearly related. Therefore, another method is needed to fit the relationship between the change in the self-capacitance of the detection channel CS and the change in the mutual capacitance between the detection channel CS and the driving electrode CD to obtain a more accurate compensation coefficient.

[0095] In some embodiments of this application, the mutual capacitance measurement value between the detection channel CS and the driving electrode CD is obtained in multiple environmental states. In multiple environmental states, the driving electrode CD can be used as the transmitting end and the detection channel CS as the receiving end. By applying an excitation voltage, the mutual capacitance between the driving electrode CD and the detection channel CS is detected to obtain the mutual capacitance measurement value between the detection channel CS and the driving electrode CD.

[0096] In some embodiments of this application, the self-capacitance measurement value of the detection channel CS is obtained in multiple environmental states. This can be achieved by applying the same voltage signal as the excitation voltage signal applied to the detection channel CS to the driving electrode CD in multiple environmental states, thereby performing capacitance detection on the self-capacitance of the detection channel CS and obtaining the self-capacitance measurement value of the detection channel CS.

[0097] Specifically, in one environmental state, the mutual capacitance measurement value between the detection channel CS and the driving electrode CD and the self-capacitance measurement value of the detection channel CS can be obtained. The mutual capacitance measurement value and the self-capacitance measurement value are combined into a data pair. Then, by changing the current environmental state to another environmental state, another data pair is obtained. This process is repeated multiple times to obtain multiple data pairs.

[0098] Step S11: Fit multiple data pairs and determine the fitting parameters as compensation coefficients.

[0099] It is understood that various fitting algorithms can be used to fit multiple data pairs, such as linear fitting, curve fitting, piecewise fitting, etc., and the embodiments of this application do not specifically limit this.

[0100] In some embodiments of this application, polynomial fitting is used to fit a data pair consisting of the mutual capacitance measurement between the detection channel CS and the driving electrode CD and the self-capacitance measurement of the detection channel CS, thereby determining the corresponding fitting coefficients. Here, to accelerate the calculation speed of the fitting process, the degree of the terms in the polynomial is limited to less than or equal to 2.

[0101] In some embodiments of this application, a quadratic polynomial is established for the self-capacitance measurement value based on multiple data pairs, and the coefficients of the terms in the obtained quadratic polynomial are determined as compensation coefficients.

[0102] Taking quadratic fitting as an example, using the mutual capacitance measurement value C m Establish the self-capacitance measurement value C as the independent variable. sensor The relationship between the mutual capacitance measurement and the measured value is expressed by the following formula:

[0103]

[0104] Where a is the intercept, b is the coefficient of the linear term, and c is the coefficient of the quadratic term.

[0105] It is understood that either the linear coefficient b or the quadratic coefficient c can be determined as the compensation coefficient, or both the linear coefficient b and the quadratic coefficient c can be determined as the compensation coefficient. This application does not specifically limit this.

[0106] Step S12: Based on the compensation coefficient, compensate for the self-capacitance measurement value in the current environmental state to determine the effective measurement value of the self-capacitance of the detection channel.

[0107] In some embodiments of this application, the compensation value can be determined based on the compensation coefficient and the difference between the mutual capacitance measurement value in the current environmental state and the mutual capacitance measurement value in the initial environmental state. For example, using the above-mentioned first-order coefficient b and second-order coefficient c as compensation coefficients, one way to calculate the compensation value is expressed by the following formula:

[0108] Compensation value = b(C) m -C m0 )+c(C m -C m0 ) 2 +2c·(C m -C m0 )·C m0 (6)

[0109] Among them, C m C represents the measured mutual capacitance value under the current environmental conditions. m0 The values ​​are the mutual capacitance measurements under initial environmental conditions, and b and c are compensation coefficients that can be determined based on experimental results.

[0110] In some embodiments of this application, the self-capacitance measurement value in the current environmental state can be compensated based on a compensation value to determine the corrected measurement value of the self-capacitance of the detection channel. Here, the corrected measurement value of the self-capacitance of the detection channel CS is the compensated value of the self-capacitance of the detection channel CS. The corrected measurement value C′ of the self-capacitance of the detection channel CS. sensor The calculation process is expressed by the following formula:

[0111] C′ sensor =C sensor -b(C m -C m0 )-c(C m -C m0 ) 2 -2c·(C m -C m0 )·C m0 (7)

[0112] Among them, C sensor This is the measured value of the self-capacitance of the detection channel CS under the current environmental conditions.

[0113] In addition to compensating the self-capacitance measurement value of the detection channel CS by polynomial fitting in the above embodiments, this application also provides a method for determining the compensation coefficient according to the temperature range and compensating the self-capacitance measurement value of the detection channel CS.

[0114] Since temperature has the greatest impact on the changes in the self-capacitance of the detection channel CS and the mutual capacitance between the detection channel CS and the driving electrode CD, only the temperature factor can be considered when considering the influence of environmental conditions on the change in capacitance value.

[0115] In some embodiments, multiple temperature ranges can be determined based on the relationship between the self-capacitance measurement of the detection channel CS and the mutual capacitance measurement between the detection channel CS and the driving electrode CD and temperature changes. For example, without the presence or contact of a human body or conductor, a continuous cycle of high and low temperatures can be applied to the capacitance detection device, and the self-capacitance measurement of the detection channel CS and the mutual capacitance measurement between the detection channel CS and the driving electrode CD can be detected at different temperatures. Based on the curves showing the changes in self-capacitance and mutual capacitance measurements with temperature, the entire high and low temperature range can be divided into multiple temperature ranges. Here, to avoid complicating the compensation calculation process by dividing too many temperature ranges, the number of temperature ranges generally does not exceed 10.

[0116] In some embodiments, the data pairs consisting of the self-capacitance measurement value of the detection channel CS and the mutual capacitance measurement value between the detection channel CS and the driving electrode CD are mapped to the corresponding temperature range according to the temperature at the time of detection. Then, the data pairs in each temperature range are linearly fitted to determine the compensation coefficient corresponding to each temperature range.

[0117] In some embodiments, the temperature range corresponding to the current environmental state can be determined, and the corresponding compensation coefficient can be determined based on the temperature range corresponding to the current environmental state. Then, the self-capacitance measurement value in the current environmental state can be compensated based on the compensation coefficient to determine the corrected measurement value of the self-capacitance of the detection channel CS.

[0118] Figure 7 This diagram illustrates a block diagram of a capacitance detection device according to some embodiments of the present application. The capacitance detection device 100 includes: a first detection value acquisition module 110, a second detection value acquisition module 120, and a first detection value adjustment module 130. The first detection value acquisition module 110 is used to acquire a first detection value based on a first electrode.

[0119] The second detection value acquisition module 120 is used to acquire a second detection value based on the first electrode and the second electrode.

[0120] The first detection value adjustment module 130 is used to adjust the first detection value according to the second detection value and the coefficient.

[0121] Figure 8 This diagram illustrates a block diagram of a System-on-Chip (SoC) according to some embodiments of this application. Figure 8In the diagram, similar components share the same reference numerals. Additionally, dashed boxes are an optional feature for more advanced SoCs. Figure 8 In this embodiment, SoC 1500 includes: an interconnect unit 1550 coupled to an application processor 1515; a system proxy unit 1570; a bus controller unit 1580; an integrated memory controller unit 1540; a group or one or more coprocessors 1520, which may include integrated graphics logic, an image processor, an audio processor, and a video processor; a static random access memory (SRAM) unit 1530; and a direct memory access (DMA) unit 1560. In one embodiment, the coprocessor 1520 includes a dedicated processor, such as, for example, a network or communication processor, a compression engine, a GPGPU, a high-throughput MIC processor, or an embedded processor, etc.

[0122] The capacitance detection device, readable storage medium, and program product provided in this application can correct capacitance changes caused by environmental changes, thereby ensuring capacitance detection accuracy and avoiding misjudgment.

[0123] This application may include the following example embodiments: Example 1 may include a capacitance detection method for a capacitance detection device, characterized in that the method includes: acquiring at least one first mutual capacitance measurement value between a detection channel and each of the at least one driving electrodes in a first environmental state, and a first self-capacitance measurement value of the detection channel, wherein the detection channel includes a trace for connecting the device under test to the capacitance detection device, and the at least one driving electrode is used to send a voltage signal for capacitance detection; acquiring at least one second mutual capacitance measurement value between the detection channel and each of the at least one driving electrodes in a second environmental state, and a second self-capacitance measurement value of the detection channel, wherein the environmental parameters of the second environmental state are different from those of the first environmental state; determining at least one compensation coefficient based on the difference between each of the at least one second mutual capacitance measurement values ​​and the corresponding first mutual capacitance measurement values, and the difference between the second self-capacitance measurement value and the first self-capacitance measurement value; and compensating the second self-capacitance measurement value based on the at least one compensation coefficient to determine the corrected measurement value of the self-capacitance of the detection channel.

[0124] Example 2 may include the method as described in Example 1, wherein obtaining at least one first mutual capacitance measurement value between the detection channel and each of the at least one driving electrodes in the first environmental state includes: using each of the at least one driving electrodes as a transmitting end and the detection channel as a receiving end, respectively, performing capacitance detection on the mutual capacitance between each of the at least one driving electrodes and the detection channel by applying an excitation voltage, and obtaining at least one first mutual capacitance measurement value.

[0125] Example 3 may include the method as described in Example 2, wherein obtaining a first self-capacitance measurement value of the detection channel in a first environmental state includes: performing capacitance detection on the self-capacitance of the detection channel by applying a voltage signal identical to the excitation voltage signal applied to the detection channel on each of at least one driving electrode, thereby obtaining a first self-capacitance measurement value.

[0126] Example 4 may include the method as described in Example 1, wherein determining at least one compensation coefficient based on the difference between each of the at least one second mutual capacitance measurements and the corresponding first mutual capacitance measurements, and the difference between the second self-capacitance measurement and the first self-capacitance measurement, includes: obtaining at least one first difference between each of the at least one second mutual capacitance measurements and the corresponding first mutual capacitance measurements; obtaining a second difference between the second self-capacitance measurement and the first self-capacitance measurement; calculating at least one ratio between the second difference and each of the at least one first difference; and determining at least one compensation coefficient based on the at least one ratio.

[0127] Example 5 may include the method as described in Example 4, wherein compensating the second self-capacitance measurement value according to the at least one compensation coefficient to determine a corrected measurement value of the self-capacitance of the detection channel includes: determining a compensation value according to the at least one compensation coefficient and each of the at least one first difference; and compensating the second self-capacitance measurement value according to the compensation value to determine a corrected measurement value of the self-capacitance of the detection channel.

[0128] Example 6 may include the method described in Example 1, wherein the environmental parameters include at least one of the following: temperature, humidity, and air pressure.

[0129] Example 7 may include a capacitance detection method for a capacitance detection device, characterized in that the method includes: acquiring multiple data pairs consisting of mutual capacitance measurements between a detection channel and a driving electrode and self-capacitance measurements of the detection channel in multiple environmental states, wherein the detection channel includes traces for connecting the device under test (DUT) to the capacitance detection device, the driving electrode is used to send a voltage signal for capacitance detection, and the environmental parameters are different in different environmental states; fitting the multiple data pairs and determining the obtained fitting parameters as compensation coefficients; and compensating the self-capacitance measurements in the current environmental state according to the compensation coefficients to determine the corrected self-capacitance measurements of the detection channel.

[0130] Example 8 may include the method described in Example 7, wherein acquiring the mutual capacitance measurement value between the detection channel and the driving electrode in multiple environmental states includes: using the driving electrode as the transmitting end and the detection channel as the receiving end in multiple environmental states, performing capacitance detection on the mutual capacitance between the driving electrode and the detection channel by applying an excitation voltage, and acquiring the mutual capacitance measurement value between the detection channel and the driving electrode.

[0131] Example 9 may include the method as described in Example 7, wherein acquiring the self-capacitance measurement value of the detection channel in multiple environmental states includes: performing capacitance detection on the self-capacitance of the detection channel by applying a voltage signal on the driving electrode that is the same as the excitation voltage signal applied on the detection channel in multiple environmental states, thereby acquiring the self-capacitance measurement value of the detection channel.

[0132] Example 10 may include the method as described in Example 7, wherein fitting the plurality of data pairs includes: performing a polynomial fitting on the plurality of data pairs, wherein the degree of each term in the polynomial is less than or equal to 2.

[0133] Example 11 may include the method as described in Example 10, wherein fitting the plurality of data pairs and determining the resulting fitting parameters as compensation coefficients includes: establishing a quadratic polynomial for the self-capacitance measurement value with respect to the mutual capacitance measurement value based on the plurality of data pairs, and determining the coefficients of the terms in the resulting quadratic polynomial as compensation coefficients.

[0134] Example 12 may include the method as described in Example 11, wherein compensating for the self-capacitance measurement in the current environmental state according to the compensation coefficient to determine the corrected measurement of the self-capacitance of the detection channel includes: determining a compensation value based on the compensation coefficient and the difference between the mutual capacitance measurement in the current environmental state and the mutual capacitance measurement in the initial environmental state; and compensating for the self-capacitance measurement in the current environmental state according to the compensation value to determine the corrected measurement of the self-capacitance of the detection channel.

[0135] Example 13 may include the method as described in Example 7, wherein the environmental parameters include at least temperature.

[0136] Example 14 may include the method described in Example 13, and further includes: determining a plurality of temperature ranges based on the relationship between the self-capacitance measurement and the mutual capacitance measurement and temperature change.

[0137] Example 15 may include the method as described in Example 14, wherein fitting the plurality of data pairs and determining the resulting fitting parameters as compensation coefficients includes: mapping the plurality of data pairs to the temperature ranges; performing linear fitting based on the data pairs in the temperature ranges to determine the compensation coefficients corresponding to each of the temperature ranges.

[0138] Example 16 may include the method as described in Example 15, wherein, according to the compensation coefficient, the self-capacitance measurement value in the current environmental state is compensated to determine the corrected measurement value of the self-capacitance of the detection channel, including: determining a temperature range corresponding to the current environmental state; determining a corresponding compensation coefficient according to the temperature range corresponding to the current environmental state; and compensating the self-capacitance measurement value in the current environmental state according to the compensation coefficient to determine the corrected measurement value of the self-capacitance of the detection channel.

[0139] The various embodiments of the mechanisms disclosed in this application can be implemented in hardware, software, firmware, or a combination of these implementation methods. Embodiments of this application can be implemented as computer programs or program code executable on a programmable system, the programmable system including 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.

[0140] Program code can be applied to input instructions to execute the functions described in this application and generate output information. The output information can be applied to one or more output devices in a known manner. For the purposes of this application, the 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.

[0141] The program code can be implemented using a high-level procedural language or an object-oriented programming language to communicate with the processing system. Assembly language or machine language can also be used when needed. In fact, the mechanisms described in this application are not limited to any particular programming language. In either case, the language can be a compiled language or an interpreted language.

[0142] 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 or stored thereon on one or more temporary or non-temporary 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 through other computer-readable media. Therefore, machine-readable media may include any mechanism for storing or transmitting information in a machine-readable (e.g., computer-readable) form, including but not limited to floppy disks, optical disks, CD-ROMs, magneto-optical disks, read-only memory (ROM), random access memory (RAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic cards or optical cards, flash memory, or tangible machine-readable storage for transmitting information (e.g., carrier waves, infrared signals, digital signals, etc.) using the Internet in the form of electrical, optical, acoustic, or other forms of propagated signals. Therefore, machine-readable media include any type of machine-readable medium suitable for storing or transmitting electronic instructions or information in a machine-readable (e.g., computer-readable) form.

[0143] In the accompanying drawings, some structural or methodological features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. Rather, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular figure does not imply that such features are required in all embodiments, and in some embodiments, these features may be omitted or may be combined with other features.

[0144] It should be noted that all units / modules mentioned in the device embodiments of this application are logical units / modules. Physically, a logical unit / module can be a physical unit / module, a part of a physical unit / module, or a combination of multiple physical units / modules. The physical implementation of these logical units / modules themselves is not the most important factor; the combination of functions implemented by these logical units / modules is the key to solving the technical problems proposed in this application. Furthermore, to highlight the innovative aspects of this application, the above-described device embodiments of this application have not introduced units / modules that are not closely related to solving the technical problems proposed in this application. This does not mean that the above-described device embodiments do not contain other units / modules.

[0145] It should be noted that in the examples and description of this patent, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0146] Although this application has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art should understand that various changes in form and detail may be made thereto without departing from the spirit and scope of this application.

Claims

1. A capacitance detection method, characterized in that, The method includes: A first detection value is obtained based on the first electrode; the first detection value is the measured value of the self-capacitance formed between the first electrode and ground; A second detection value is obtained based on the first electrode and the second electrode; the second detection value is the measured value of the mutual capacitance between the first electrode and the second electrode. The first detection value is adjusted based on the second detection value and the coefficient; The adjustment of the first detection value based on the second detection value and the coefficient includes: The difference between second detection values ​​under different environments is obtained; the different environments include a first environment and a second environment, the environmental parameters of the first environment are different from those of the second environment, and the environmental parameters include at least one of temperature, humidity and air pressure; The first detection value is adjusted based on the difference and the coefficient; the coefficient is determined based on at least two data pairs, each data pair consisting of a mutual capacitance measurement between the first electrode and the second electrode and a self-capacitance measurement of the first electrode obtained based on the same environmental parameter, and different data pairs correspond to different environmental parameters.

2. The method according to claim 1, characterized in that, The second electrode comprises at least one sub-electrode; wherein, The second detection value is obtained based on the first electrode and the second electrode, including: The third detection value corresponding to each of the sub-electrodes is obtained based on the first electrode and each of the sub-electrodes respectively; in, Adjusting the first detection value based on the second detection value and the coefficient includes: The first detection value is adjusted according to each of the third detection values ​​and the sub-coefficients corresponding to each third detection value.

3. The method according to claim 2, characterized in that, The sub-coefficients corresponding to each third detection value can be the same or different.

4. The method according to claim 3, characterized in that, The method also includes: When the sub-coefficients are the same, the second detection value includes at least one third detection value.

5. The method according to claim 3, characterized in that, The coefficients and sub-coefficients are related to environmental factors, which include at least temperature.

6. The method according to claim 1, characterized in that, The first detection value is obtained based on the first electrode, including: A first excitation voltage is applied to the first electrode; The capacitance of the first electrode to ground is detected to obtain the first detection value.

7. The method according to claim 6, characterized in that, The second detection value is obtained based on the first electrode and the second electrode, including: A second excitation voltage is applied to the second electrode; The capacitance between the first electrode and the second electrode is detected to obtain the second detection value; The second excitation voltage is the same as the first excitation voltage.

8. A capacitance detection device, characterized in that, The device includes: A first electrode is used to acquire a first detection value; the first detection value is a measurement of the self-capacitance formed between the first electrode and ground; and The second electrode is used, and the first electrode is further configured to obtain a second detection value based on the first electrode and the second electrode; the second detection value is a measured value of the mutual capacitance between the first electrode and the second electrode; wherein... The first detection value is adjusted based on the second detection value and a coefficient; Wherein, the first detection value is adjusted based on the difference between the second detection values ​​under different environments and the coefficient; the different environments include a first environment and a second environment, the environmental parameters of the first environment are different from those of the second environment, the environmental parameters include at least one of temperature, humidity, and air pressure; the coefficient is determined based on at least two data pairs, each data pair consisting of a mutual capacitance measurement value between the first electrode and the second electrode and a self-capacitance measurement value of the first electrode obtained based on the same environmental parameter, and different data pairs correspond to different environmental parameters.

9. The apparatus according to claim 8, characterized in that, The second electrode comprises at least one sub-electrode; wherein, The second electrode is used to obtain a third detection value corresponding to each of the sub-electrodes based on the first electrode and each of the sub-electrodes respectively; in, The first detection value is adjusted based on each of the third detection values ​​and the sub-coefficients corresponding to each third detection value.

10. The apparatus according to claim 9, characterized in that, The sub-coefficients corresponding to each third detection value can be the same or different.

11. The apparatus according to claim 9, characterized in that, When the sub-coefficients are the same, the second detection value includes at least one third detection value.

12. The apparatus according to claim 10, characterized in that, The coefficients and sub-coefficients are related to environmental factors, which include at least temperature.

13. The apparatus according to claim 8, characterized in that, The first electrode is used to receive the first excitation voltage and detect its capacitance to ground to obtain the first detection value.

14. The apparatus according to claim 13, characterized in that, The second electrode is used to receive the second excitation voltage, and the first electrode is used to detect the capacitance between the first electrode and the second electrode to obtain the second detection value; wherein the second excitation voltage is the same as the first excitation voltage.

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