Touch detection device, method and electronic equipment

Abstract

The application provides a touch detection device, a method and an electronic equipment. The touch detection device comprises: an analog front-end circuit connected with a touch electrode in a touch display screen, the analog front-end circuit being used for converting a collected capacitance signal of the touch electrode into a voltage signal; a cyclic analog-digital converter connected with an output end of the analog front-end circuit, the cyclic analog-digital converter being used for cyclically performing analog-digital conversion according to an input reference voltage and the voltage signal and outputting a corresponding detection signal; and the cyclic analog-digital converter comprises a control unit, the control unit being used for controlling a cycle number of the analog-digital conversion, so that the cycle number of the analog-digital conversion when the touch display screen is in a screen-off mode is less than the cycle number of the analog-digital conversion when the touch display screen is in a display mode. The application ensures touch detection precision when the touch display screen is in the display mode and reduces power consumption when the touch display screen is in the screen-off mode.

Description

Technical Field

[0001] This application relates to the field of touch display technology, and in particular to a touch detection device, method and electronic device. Background Technology

[0002] With the continuous development of touch technology and screen technology, touch displays are widely used in various electronic devices, such as mobile phones, tablets and computers.

[0003] When detecting whether a user is touching the touchscreen display, the touch detection module performs touch detection on the array of touch electrodes in the display, and determines a touch based on the detection results. When the touchscreen display is in always-on mode, the touch detection module remains operational for extended periods, resulting in significant power consumption. Summary of the Invention

[0004] This application provides a touch detection device, method, and electronic device to solve the problem of high power consumption in touch detection of touch displays in screen-off mode in the prior art, and to reduce the power consumption of touch detection in screen-off mode.

[0005] In a first aspect, a touch detection device is provided, comprising:

[0006] An analog front-end circuit is connected to the touch electrodes in the touch display screen. The analog front-end circuit is used to convert the collected capacitance signal of the touch electrodes into a voltage signal.

[0007] A cyclic analog-to-digital converter is connected to the output of the analog front-end circuit. The cyclic analog-to-digital converter is used to cyclically perform analog-to-digital conversion based on the input reference voltage and the voltage signal, and output a corresponding detection signal.

[0008] The cyclic analog-to-digital converter includes a control unit, which controls the number of cycles of the analog-to-digital conversion, such that the number of cycles of the analog-to-digital conversion when the touch screen is in screen-off mode is less than the number of cycles of the analog-to-digital conversion when the touch screen is in display mode.

[0009] According to the touch detection device provided in this application, when the touch display screen is in screen-off mode, the number of cycles for analog-to-digital conversion is one.

[0010] According to the touch detection device provided in this application, the cyclic analog-to-digital converter further includes:

[0011] Sub-analog-to-digital converter;

[0012] A subtractor is connected to the output of the analog front-end circuit and to the output of the sub-analog-to-digital converter. The subtractor is used to output a residual signal based on the reference voltage and the voltage signal in the first cycle of the analog-to-digital conversion, and to output the residual signal based on the reference voltage and the detection signal obtained by the sub-analog-to-digital converter in the previous cycle of the analog-to-digital conversion in the subsequent cycles of the analog-to-digital conversion.

[0013] A multiplier-to-analog converter is connected to the output of the subtractor, and the multiplier-to-analog converter is used to amplify the residual signal under the drive of the reference voltage;

[0014] The control unit is connected to the input terminal of the multiplication digital-to-analog converter, and the control unit is used to control the multiplication digital-to-analog converter to control the number of cycles of the analog-to-digital conversion;

[0015] The sub-analog-to-digital converter is connected to the output of the multiplication digital-to-analog converter. The sub-analog-to-digital converter is used to convert the amplified residual signal into a digital signal to obtain the detection signal.

[0016] According to the touch detection device provided in this application, the control unit includes:

[0017] A switch is connected to the output terminal of the sub-analog-to-digital converter, and the switch is in the off state when the touch display screen is in screen-off mode.

[0018] A controller, connected to the switch, is configured to not output a control signal when the switch is in the open state, thereby deactivating the enable signal of the multiplication digital-to-analog converter.

[0019] According to the touch detection device provided in this application, the switch is in a closed state when the touch display screen is in display mode;

[0020] The controller is also configured to, when the switch is in the closed state, output the control signal based on the detection signal obtained by the sub-analog-to-digital converter in each cycle, so as to control the switching of the reference voltage.

[0021] According to a touch detection device provided in this application, the controller is specifically used for:

[0022] When the switch is closed, the detection signal obtained by the sub-analog-to-digital converter in each cycle is compared with a preset threshold to obtain a comparison result;

[0023] The control signal is output based on the comparison result to control the switching of the reference voltage.

[0024] According to a touch detection device provided in this application, the preset threshold includes a first preset threshold and a second preset threshold, wherein the first preset threshold is greater than the second preset threshold, and the controller is specifically used for:

[0025] When the switch is closed, the detection signal obtained by the sub-analog-to-digital converter in each cycle is compared with the first preset threshold and the second preset threshold;

[0026] If the detected signal is greater than the first preset threshold, a first control signal is output to control the reference voltage to switch to the first preset value;

[0027] When the detection signal is greater than or equal to the second preset threshold and less than or equal to the first preset threshold, a second control signal is output to control the reference voltage to switch to the second preset value;

[0028] If the detected signal is less than the second preset threshold, a third control signal is output to control the reference voltage to switch to a third preset value;

[0029] The first preset value is greater than the second preset value, and the second preset value is greater than the third preset value.

[0030] According to the touch detection device provided in this application, the cyclic analog-to-digital converter further includes:

[0031] The processing module is connected to the output of the sub-analog-to-digital converter. The processing module is used to perform zero-padding on the detection signal to obtain the detection signal of a preset length.

[0032] Secondly, an electronic device is provided, comprising:

[0033] A touch display screen, including multiple touch electrodes; and

[0034] The touch detection device described above.

[0035] Thirdly, a touch detection method is provided, including:

[0036] The analog front-end circuit converts the capacitance signal of the touch electrode in the touch display screen into a voltage signal; the analog front-end circuit is connected to the touch electrode;

[0037] The cyclic analog-to-digital converter performs analog-to-digital conversion cyclically based on the input reference voltage and the voltage signal, and outputs a corresponding detection signal; the cyclic analog-to-digital converter is connected to the output terminal of the analog front-end circuit;

[0038] The control unit in the cyclic analog-to-digital converter controls the number of cycles of the analog-to-digital conversion, so that the number of cycles of the analog-to-digital conversion when the touch screen is in screen-off mode is less than the number of cycles of the analog-to-digital conversion when the touch screen is in display mode.

[0039] One of the above technical solutions has the following advantages or beneficial effects: by controlling the number of analog-to-digital conversion cycles of the cyclic analog-to-digital converter when the touch screen is in screen-off mode and display mode, the number of analog-to-digital conversion cycles in screen-off mode is less than the number of analog-to-digital conversion cycles in display mode, thereby reducing the number of analog-to-digital conversion cycles in screen-off mode and thus achieving the purpose of reducing power consumption. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of one embodiment of an electronic device provided in this application;

[0042] Figure 2 This is a schematic diagram of the structure of one embodiment of the touch detection device provided in this application;

[0043] Figure 3 This is a schematic diagram of another embodiment of the touch detection device provided in this application;

[0044] Figure 4 This is a schematic diagram of one embodiment of the touch detection device provided in this application;

[0045] Figure 5 This is a schematic diagram of the structure of a cyclic analog-to-digital converter provided by existing technology;

[0046] Figure 6 This is a schematic diagram of the structure of an embodiment of the cyclic analog-to-digital converter in the touch detection device provided in this application;

[0047] Figure 7 This is a schematic diagram of another embodiment of the cyclic analog-to-digital converter in the touch detection device provided in this application;

[0048] Figure 8 This is a flowchart illustrating an embodiment of the touch detection method provided in this application. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0050] Figure 1 This is a schematic diagram illustrating the structure of one embodiment of an electronic device provided in this application. The electronic devices of this application include, but are not limited to, mobile phones, tablets, computers, televisions, in-vehicle devices, and wearable devices. This embodiment uses a mobile phone as an example for explanation.

[0051] like Figure 1 As shown, the electronic device includes multiple arrays of touch electrodes 101 and touch detection devices 102.

[0052] The touch screen of the electronic device can be a capacitive screen, and the touch electrodes 101 can be self-capacitive or mutual-capacitive. Each touch electrode 101 can be connected to the touch detection device 102 via an independent wiring.

[0053] The touch detection device 102 can be installed in the non-display area of ​​the electronic device. The touch detection device 102 converts the capacitance signal of the touch electrode 101 into a voltage signal and outputs a corresponding detection signal to complete the touch detection.

[0054] Figure 2 This is a schematic diagram of the structure of one embodiment of the touch detection device provided in this application. Figure 2 As shown, the touch detection device includes a protection circuit 1021, an analog front end (AFE) circuit 1022, and an analog-to-digital converter (ADC) 1023.

[0055] The protection circuit 1021 provides a reference signal VEX to the analog front-end circuit 1022. The touch electrode 101 is connected to the analog front-end circuit 1022, which converts the capacitance signal of the touch electrode 101 into a voltage signal and sends the voltage signal to the cyclic analog-to-digital converter 1023. The cyclic analog-to-digital converter 1023 converts the voltage signal from an analog signal into a digital signal to obtain a detection signal.

[0056] The cyclic analog-to-digital converter 1023 sends the detection signal to the central controller of the touch detection device, and the central controller determines whether a touch has occurred in the touch display area corresponding to each touch electrode based on the detection signal.

[0057] When the touch screen is touched, a coupling capacitance is generated between the touching object and the touch electrode, causing the capacitance of the touch electrode to increase. The capacitance signal currently collected by the analog front-end circuit 1022 will change compared with the capacitance signal collected previously. The detection signal obtained after the current capacitance signal is processed by the analog front-end circuit 1022 and the cyclic analog-to-digital converter 1023 will also be different from the detection signal obtained previously. Therefore, based on the difference between the detection signals output by the cyclic analog-to-digital converter 1023 multiple times, it is possible to identify whether a touch has occurred in the corresponding area of ​​the touch screen.

[0058] Figure 3 This is a schematic diagram of another embodiment of the touch detection device provided in this application. Figure 3 As shown, the touch detection device provided in this application includes:

[0059] The analog front-end circuit 1022 is connected to the touch electrode 101 in the touch display screen. The analog front-end circuit 1022 is used to convert the collected capacitance signal of the touch electrode 101 into a voltage signal.

[0060] The analog front-end circuit 1022 can correspond one-to-one with the touch electrode 101, and each analog front-end circuit 1022 is connected to the corresponding touch electrode 101, such as... Figure 2 As shown.

[0061] Each analog front-end circuit 1022 acquires the capacitance signal of the corresponding touch electrode 101. The capacitance signal includes the capacitance value of the coupling capacitance between the touch object and the touch electrode 101 when the touch object touches the touch display screen.

[0062] Each analog front-end circuit 1022 converts the capacitance signal of the corresponding touch electrode 101 into a voltage signal. For example, the capacitance signal can first be converted into a corresponding frequency signal through an oscillation circuit, and then the frequency signal can be converted into a voltage value that corresponds linearly to it.

[0063] The cyclic analog-to-digital converter 1023 is connected to the output terminal of the analog front-end circuit 1022. The cyclic analog-to-digital converter 1023 is used to perform analog-to-digital conversion cyclically according to the input reference voltage and voltage signal, and output the corresponding detection signal.

[0064] The cyclic analog-to-digital converter 1023 includes a control unit, which controls the number of cycles of analog-to-digital conversion, such that the number of cycles of analog-to-digital conversion when the touch screen is in screen-off mode is less than the number of cycles of analog-to-digital conversion when the touch screen is in display mode.

[0065] The 1023 cyclic analog-to-digital converter is small in size and moderate in speed, making it suitable for touch detection on touch displays.

[0066] The cyclic analog-to-digital converter 1023 typically performs analog-to-digital conversion based on the externally provided reference voltage and the voltage signal output by the analog front-end circuit 1022 in the first analog-to-digital conversion cycle to obtain a detection signal. In each subsequent analog-to-digital conversion cycle, it performs analog-to-digital conversion based on the reference voltage and the detection signal generated in the previous analog-to-digital conversion cycle to obtain a detection signal. After completing all analog-to-digital conversion cycles, it performs a shift operation on the detection signals generated in all the analog-to-digital conversion cycles and removes the last bit to obtain the final detection signal, which is then output.

[0067] Each analog front-end circuit 1022 and the cyclic analog-to-digital converter 1023 form a channel and output the corresponding detection signal.

[0068] When the touchscreen display is in screen-off mode, the electronic device is in standby mode, and the touch detection device is in LPWG (Low Power Wake Up) mode. When the touchscreen display is in display mode, the electronic device is in normal use.

[0069] The difference between the always-on mode and the always-on mode of the touchscreen display lies in the number of cycles the cyclic analog-to-digital converter 1023 performs analog-to-digital conversion. More cycles result in higher power consumption. However, a higher number of effective bits in the detection signal output by the cyclic analog-to-digital converter 1023 leads to higher touch detection accuracy.

[0070] When the touchscreen is in display mode, the detection signal output by the cyclic analog-to-digital converter 1023 is used to determine whether a touch has occurred on the touchscreen. If a touch is confirmed, the signal is further used to identify the area on the touchscreen where the touch occurred, and the touchscreen displays the corresponding image based on the touched area. Therefore, touch detection needs to maintain high accuracy when the touchscreen is in display mode.

[0071] When the touchscreen display is in always-on mode, the detection signal output by the cyclic analog-to-digital converter 1023 is used to determine whether a touch has occurred on the touchscreen display. If a touch has occurred, the touchscreen display switches to display mode; otherwise, it remains in always-on mode. Therefore, when the touchscreen display is in always-on mode, touch detection does not require high accuracy.

[0072] The number of cycles of analog-to-digital conversion performed by the cyclic analog-to-digital converter 1023 when the touch screen is in display mode can be determined according to the resolution of the cyclic analog-to-digital converter 1023 and the number of bits processed in each cycle, so that the effective number of bits of the detection signal output by the cyclic analog-to-digital converter 1023 reaches the resolution of the cyclic analog-to-digital converter 1023.

[0073] When the touch screen is in display mode, the cyclic analog-to-digital converter 1023 disconnects the cyclic path of analog-to-digital conversion and outputs a detection signal after the number of cycles of analog-to-digital conversion reaches a preset number of cycles. The preset number of cycles is less than the resolution of the cyclic analog-to-digital converter 1023.

[0074] Figure 4 This is a schematic diagram illustrating the principle of one embodiment of the touch detection device provided in this application. Figure 4 As shown, the control unit can be a switch, which controls the number of analog-to-digital converter (ADC) cycles performed by the ADC 1023 when the touchscreen display is in display mode and screen-off mode. When the touchscreen display is in display mode, switch S1 is closed and S2 is open, resulting in a higher number of ADC cycles, such as 4 times. When the touchscreen display is in screen-off mode, switch S1 is open and S2 is closed, resulting in a lower number of ADC cycles, such as 1 time.

[0075] This embodiment controls the number of analog-to-digital conversion cycles of the cyclic analog-to-digital converter (ADC) when the touch screen is in either always-on or display mode. This results in a smaller number of ADC cycles in always-on mode compared to display mode, leading to a higher number of ADC cycles and more effective bits in the output detection signal of the cyclic ADC, thus ensuring touch detection accuracy. In always-on mode, the number of ADC cycles is reduced, thereby lowering power consumption.

[0076] Optionally, the analog-to-digital conversion cycle count is one when the touch display is in screen-off mode.

[0077] When the touch screen is in screen-off mode, after the analog-to-digital converter 1023 cycles once, the analog-to-digital conversion loop path is disconnected, and no further loops are performed, and a detection signal is output.

[0078] When the touchscreen is in always-on mode, high touch detection accuracy is not required. The detection signal output by the cyclic analog-to-digital converter 1023 in one cycle is sufficient to accurately determine whether a touch has occurred on the touchscreen, thus reducing power consumption.

[0079] Figure 5 This is a schematic diagram of the structure of a cyclic analog-to-digital converter 1023 provided by existing technology. For example... Figure 5 As shown, the input to the sample-and-hold circuit in the first analog-to-digital conversion cycle is the voltage signal V. in In subsequent analog-to-digital conversion cycles, the input to the sample-and-hold circuit is the output of the previous cycle.

[0080] For the 12-bit cyclic analog-to-digital converter 1023, a total of 4 analog-to-digital conversion cycles are performed. Each cycle completes a 3.5-bit analog-to-digital conversion operation and amplifies the residual signal output from the subtractor by a factor of 8 before proceeding to the next cycle. Finally, the four 3.5-bit detection signals obtained from the four cycles are added together with a staggered arrangement to obtain a 12-bit detection signal.

[0081] The majority of the power consumption of the cyclic analog-to-digital converter 1023 comes from 2 m The multiplication operation is performed, where m is the multiplication factor. The multiplication operation is typically implemented using a fixed-gain amplifier. A multiplication operation is required for each analog-to-digital conversion cycle.

[0082] If the cyclic analog-to-digital converter 1023 cycles 4 times and outputs a 12-bit detection signal when the touch screen is in display mode, and the average power consumption of the cyclic analog-to-digital converter 1023 is A, then when the touch screen is in screen-off mode, the cyclic analog-to-digital converter 1023 cycles 1 time and outputs a detection signal with an effective number of bits of 3.5, and the power consumption of the cyclic analog-to-digital converter 1023 is A / 4, which reduces the power consumption by 75%.

[0083] This embodiment further reduces power consumption by cyclically cycling the analog-to-digital converter 1023 only once when the touch display is in screen-off mode.

[0084] Figure 6 This is a schematic diagram of one embodiment of the cyclic analog-to-digital converter 1023 in the touch detection device provided in this application. Figure 6 As shown, the cyclic analog-to-digital converter 1023 includes:

[0085] Sub-analog-to-digital converter 10233;

[0086] Subtractor 10231 is connected to the output of analog front-end circuit 1022 and to the output of sub-analog-to-digital converter 10233. Subtractor 10231 is used to output a residual signal based on the reference voltage and voltage signal in the first cycle of analog-to-digital conversion; and to output a residual signal based on the reference voltage and the detection signal obtained by sub-analog-to-digital converter 10233 in the previous cycle of analog-to-digital conversion in the subsequent cycles of analog-to-digital conversion.

[0087] The input terminal of subtractor 10231 is connected to the output terminal of analog front-end circuit 1022. The input terminal of subtractor 10231 receives a voltage signal sent from the output terminal of analog front-end circuit 1022, which is obtained by analog front-end circuit 1022 converting the capacitance signal of touch electrode.

[0088] The input of the subtractor 10231 also receives an externally input reference voltage. In the first cycle of the cyclic analog-to-digital converter 1023 performing model conversion, the reference voltage and the capacitance signal obtained by converting the capacitance signal of the touch electrode are subtracted to obtain the residual signal.

[0089] In each subsequent cycle after the first analog-to-digital conversion cycle, the cyclic analog-to-digital converter 1023 performs analog-to-digital conversion based on the reference voltage and the detection signal generated in the previous analog-to-digital conversion cycle to obtain the detection signal.

[0090] The multiplying digital to analog converter (MDAC) 10232 is connected to the output of the subtractor 10231. The multiplying digital to analog converter 10232 is used to amplify the residual signal under the drive of the reference voltage.

[0091] The input of the multiplier-to-analog converter 10232 is connected to the output of the subtractor 10231. The input of the multiplier-to-analog converter 10232 receives the residual signal sent from the output of the subtractor 10231.

[0092] The multiplier-to-digital converter 10232 can be a fixed-gain amplifier used to amplify the residual signal output by the subtractor 10231.

[0093] The control unit is connected to the input terminal of the multiplication digital-to-analog converter 10232. The control unit is used to control the multiplication digital-to-analog converter 10232 to control the number of analog-to-digital conversion cycles.

[0094] The control unit can control whether the multiplication digital-to-analog converter 10232 outputs and whether the path of the analog-to-digital conversion cycle is disconnected, thereby controlling the number of analog-to-digital conversion cycles.

[0095] The sub-analog-to-digital converter 10233 is connected to the output of the multiplication digital-to-analog converter 10232. The sub-analog-to-digital converter 10233 is used to convert the amplified residual signal into a digital signal to obtain the detection signal.

[0096] The input terminal of the sub-analog-to-digital converter 10233 is connected to the output terminal of the multiplication digital-to-analog converter 10232. The input terminal of the sub-analog-to-digital converter 10233 receives the amplified residual signal output from the output terminal of the multiplication digital-to-analog converter 10232.

[0097] The sub-analog-to-digital converter 10233 is used to convert the amplified residual signal into a detection signal and output the detection signal.

[0098] In this embodiment, the control unit controls the multiplication digital-to-analog converter to control the number of analog-to-digital conversion cycles of the cyclic analog-to-digital converter. This ensures that the number of analog-to-digital conversion cycles in the screen-off mode is less than the number of analog-to-digital conversion cycles in the display mode. As a result, the number of analog-to-digital conversion cycles is greater in the display mode, and the number of effective bits in the output detection signal of the cyclic analog-to-digital converter is greater, thus ensuring touch detection accuracy. In the screen-off mode, the number of analog-to-digital conversion cycles is reduced, thereby reducing power consumption.

[0099] Figure 7 This is a schematic diagram of the structure of an embodiment of the cyclic analog-to-digital converter in the touch detection device provided in this application. Figure 7 As shown, the control unit includes:

[0100] Switch 10234 is connected to the output terminal of sub-analog-to-digital converter 10233. Switch 10234 is in the off state when the touch screen is in screen-off mode.

[0101] Switch 10234 is connected between sub-analog-to-digital converter 10233 and controller 10235. By controlling switch 10234 to the off state, the number of analog-to-digital conversion cycles of cyclic analog-to-digital converter 1023 when the touch screen is in screen-off mode is controlled.

[0102] The controller 10235 is connected to the output terminal of the switch 10234. The controller 10235 is used to not output a control signal when the switch is in the open state, and to trigger the enable signal of the multiplication digital-to-analog converter 10232 to be in an invalid state.

[0103] The enable signal of the multiplication digital-to-analog converter 10232 is used to control whether the entire multiplication digital-to-analog converter 10232 is enabled. When the enable signal is in an invalid state, such as a low level, the multiplication digital-to-analog converter 10232 is not enabled; when the enable signal is in an active state, such as a high level, the multiplication digital-to-analog converter 10232 is enabled. Of course, the invalid state of the enable signal can also be set to a high level, and the active state of the enable signal can be set to a low level.

[0104] When switch 10234 is in the open state, the detection signal output by sub-analog-to-digital converter 10233 in the first analog-to-digital conversion cycle cannot be sent to controller 10235. Controller 10235 has no output, the enable signal that triggers multiplication digital-to-analog converter 10232 is invalid, and multiplication digital-to-analog converter 10232 stops running and cannot perform subsequent analog-to-digital conversion cycles.

[0105] The controller 10235 can trigger the enable signal of the multiplier-to-analog converter 10232 to an invalid state via a pin of the multiplier-to-analog converter 10232. This pin can be an AND gate. One input of the pin is 1, and the other input is connected to the output of the controller 10235. When the controller 10235 has no output, the other input of the pin is 0, and the enable signal output by the AND operation is 1, making the enable signal high and in an active state. When the controller 10235 has an output, the other input is 1, and the enable signal output by the AND operation is 0, making the enable signal low and in an invalid state.

[0106] In this embodiment, the cyclic analog-to-digital converter 1023 performs one analog-to-digital conversion cycle when the touch display is in the screen-off mode. The touch detection process includes: the subtractor 10231 subtracts the reference voltage from the capacitance signal obtained by converting the capacitance signal of the touch electrode 101 to obtain the residual signal; the multiplicative digital-to-analog converter 10232 amplifies the residual signal under the drive of the reference voltage; and the sub-analog-to-digital converter 10233 converts the amplified residual signal into a digital signal to obtain the detection signal.

[0107] This embodiment uses a switch between the controller and the sub-analog-to-digital converter to control whether the controller outputs. When the controller has no output, the enable signal of the multiplication digital-to-analog converter is invalidated, so that when the touch screen is in the screen-off mode, the cyclic analog-to-digital converter cycles once, reducing the power consumption of the cyclic analog-to-digital converter, and the circuit is simple.

[0108] Optionally, switch 10234 is in a closed state when the touch screen is in display mode;

[0109] The controller 10235 is also used to output a control signal based on the detection signal obtained by the sub-analog-to-digital converter 10233 in each cycle when the switch is closed, so as to control the switching of the reference voltage.

[0110] When switch 10234 is closed, controller 10235 can compare the detection signal with a preset threshold and output a corresponding control signal to control the switching of the reference voltage.

[0111] The number of preset thresholds can be determined based on the number of switchable reference voltages. For example, the number of preset thresholds is equal to the number of switchable reference voltages minus 1.

[0112] The detection signal is compared with a preset threshold, and different control signals are output for different comparison results, thereby controlling the switching to different reference voltages.

[0113] For example, if there are two switchable reference voltages, then there is one preset threshold. When the detected signal is greater than the preset threshold, the system switches to one reference voltage; when the detected signal is less than or equal to the preset threshold, the system switches to the other reference voltage.

[0114] The subtractor 10231 is connected to the output of the sub-analog-to-digital converter 10233. The subtractor 10231 is also used to output the residual signal again based on the switched reference voltage and the detection signal.

[0115] The input of subtractor 10231 is also connected to the output of sub-analog-to-digital converter 10233. The input of subtractor 10231 receives the detection signal generated by sub-analog-to-digital converter 10233 in each analog-to-digital conversion cycle.

[0116] Subtractor 10231 acquires the reference voltage and the generated detection signal from the previous analog-to-digital conversion cycle switch, and subtracts the two to obtain the residual signal. Multiplier-to-analog converter 10232, driven by the reference voltage from the previous analog-to-digital conversion cycle switch, amplifies the residual signal output by subtractor 10231.

[0117] In this embodiment, the reference voltage is switched to a different reference voltage based on the magnitude of the detection signal generated in each analog-to-digital conversion cycle, so that the residual signal output by the subtractor can be effectively amplified using the switched reference voltage in the next analog-to-digital conversion cycle.

[0118] Optionally, the preset threshold includes a first preset threshold and a second preset threshold, wherein the first preset threshold is greater than the second preset threshold, and the controller 10235 is specifically used for:

[0119] When the switch is closed, the detection signal obtained by the sub-analog-to-digital converter in each cycle is compared with the first preset threshold and the second preset threshold.

[0120] If the detected signal is greater than the first preset threshold, a first control signal is output to control the reference voltage to switch to the first preset value;

[0121] When the detected signal is greater than or equal to the second preset threshold and less than or equal to the first preset threshold, a second control signal is output to control the reference voltage to switch to the second preset value;

[0122] If the detected signal is less than the second preset threshold, a third control signal is output to control the reference voltage to switch to the third preset value;

[0123] The first preset value is greater than the second preset value, and the second preset value is greater than the third preset value.

[0124] like Figure 7As shown, when the detection signal is greater than the first preset threshold, the controller 10235 outputs a first control signal to control the reference voltage to switch to the preset maximum value VREFP; when the detection signal is greater than or equal to the second preset threshold and less than or equal to the first preset threshold, the controller 10235 outputs a second control signal to control the reference voltage to switch to the preset intermediate value VCM; when the detection signal is less than the second preset threshold, the controller 10235 outputs a third control signal to control the reference voltage to switch to the preset minimum value VREFN.

[0125] like Figure 7 As shown, the multiplier-to-analog converter 10232 may include a capacitor and an amplifier AMP. A reference voltage is input to the capacitor in the multiplier-to-analog converter 10232. The output of the subtractor 10231 is connected to the input of the amplifier AMP, which amplifies the residual signal output by the subtractor 10231.

[0126] The sub-analog-to-digital converter 10233 may include a comparator and a temperature decoder. The input of the comparator is connected to the output of the multiplicative digital-to-analog converter 10232, and the comparator is used to convert the amplified residual signal into a digital signal. The temperature decoder is connected to the comparator and the controller, and the temperature decoder is used to down-divide the digital signal to obtain the detection signal.

[0127] In this embodiment, the reference voltage is switched to a different reference voltage based on the magnitude of the detection signal generated in each analog-to-digital conversion cycle, so that the residual signal output by the subtractor can be effectively amplified using the switched reference voltage in the next analog-to-digital conversion cycle.

[0128] like Figure 7 As shown, the cyclic analog-to-digital converter also includes:

[0129] The processing module 10236 is connected to the output of the sub-analog-to-digital converter 10233. The processing module 10236 is used to perform zero-padding on the detection signal to obtain a detection signal of a preset length.

[0130] In each analog-to-digital converter cycle, the sub-analog-to-digital converter 10233 performs analog-to-digital conversion operations on only a portion of the bits. Finally, it performs a shift operation on all the detection signals generated in the analog-to-digital conversion cycles and removes the last bit to obtain the final detection signal.

[0131] Because the number of analog-to-digital converter cycles of the cyclic analog-to-digital converter 1023 is less in the always-on mode than in the display mode, the final detection signal bit length of the cyclic analog-to-digital converter 1023 is different in always-on mode and display mode.

[0132] To ensure that the final detection signal output by the analog-to-digital converter 10233 has the same number of bits in both the always-on and always-on modes of the touch screen, zero-padding is performed on the detection signal.

[0133] For example, for a 12-bit cyclic analog-to-digital converter (ADC) 1023, each ADC cycle performs a 3.5-bit ADC operation. If the ADC 1023 performs one ADC cycle in the first ADC mode, the detection signal output by the sub-ADC 10233 is 4 bits, with 3.5 effective bits. If the ADC 1023 performs four ADC cycles in the second ADC mode, the detection signal output by the sub-ADC 10233 is 12 bits. The preset length can be set to 12 bits. In the first ADC mode, the processing module 10236 pads the detection signal output by the sub-ADC 10233 with eight zeros to output a 12-bit detection signal.

[0134] In this embodiment, zero-padding is performed on the detection signal to ensure that the final detection signal output by the sub-analog-to-digital converter 10233 has the same number of bits in both the off-screen mode and the display mode, so that the central controller can perform identification processing.

[0135] like Figure 1 As shown, this application also provides an electronic device, including:

[0136] The touch display screen includes a plurality of touch electrodes 101 and a touch detection device 102 of any of the above embodiments.

[0137] This embodiment employs different cyclic modes for the cyclic analog-to-digital converter (ADC) when the touch display is in always-on mode and in display mode. This results in fewer ADC cycles in always-on mode compared to display mode, leading to more ADC cycles in display mode and a larger number of effective bits in the output detection signal, thus ensuring touch detection accuracy. In always-on mode, fewer ADC cycles are used, reducing power consumption.

[0138] The touch detection method provided in this application is described below. The touch detection method described below can be referred to in correspondence with the touch detection device described above.

[0139] Figure 8 This is a flowchart illustrating the touch detection method provided in this application. Figure 8 As shown, the method includes:

[0140] Step 801: The analog front-end circuit converts the capacitance signal of the touch electrode in the acquired touch display screen into a voltage signal; the analog front-end circuit is connected to the touch electrode.

[0141] Step 802: The cyclic analog-to-digital converter performs cyclic analog-to-digital conversion based on the input reference voltage and voltage signal, and outputs the corresponding detection signal; the cyclic analog-to-digital converter is connected to the output terminal of the analog front-end circuit;

[0142] Step 803: The control unit in the cyclic analog-to-digital converter controls the number of cycles of analog-to-digital conversion, so that the number of cycles of analog-to-digital conversion when the touch screen is in screen-off mode is less than the number of cycles of analog-to-digital conversion when the touch screen is in display mode.

[0143] This embodiment controls the number of analog-to-digital conversion cycles of the cyclic analog-to-digital converter (ADC) when the touch screen is in either always-on or display mode. This results in a smaller number of ADC cycles in always-on mode compared to display mode, leading to a higher number of ADC cycles and more effective bits in the output detection signal of the cyclic ADC, thus ensuring touch detection accuracy. In always-on mode, the number of ADC cycles is reduced, thereby lowering power consumption.

[0144] Optionally, the analog-to-digital conversion cycle count is one when the touch display is in screen-off mode.

[0145] Optionally, the cyclic analog-to-digital converter cyclically performs analog-to-digital conversion based on the input reference voltage and voltage signal, and outputs a corresponding detection signal, including:

[0146] In the first cycle of the cyclic analog-to-digital converter (ADC), the subtractor outputs a residual signal based on the reference voltage and the voltage signal. In subsequent cycles of the ADC, it outputs the residual signal based on the reference voltage and the detection signal obtained by the sub-ADC in the previous cycle of the cyclic ADC. The subtractor is connected to the output of the analog front-end circuit and also to the output of the sub-ADC.

[0147] In a cyclic analog-to-digital converter (ADC), the multiplicative ADC amplifies the residual signal under the drive of a reference voltage; the multiplicative ADC is connected to the output of the subtractor.

[0148] The controller is used to control the multiplication digital-to-analog converter to control the number of analog-to-digital conversion cycles; the control unit is connected to the input terminal of the multiplication digital-to-analog converter;

[0149] The sub-analog-to-digital converter converts the amplified residual signal into a digital signal to obtain the detection signal; the sub-analog-to-digital converter is connected to the output of the multiplication digital-to-analog converter.

[0150] Optionally, the control unit includes a switch that is in an open state when the touch screen is in screen-off mode. After the sub-analog-to-digital converter converts the amplified residual signal into a digital signal to obtain the detection signal, it also includes:

[0151] When the switch is in the open state, the controller in the cyclic analog-to-digital converter does not output a control signal, and the enable signal that triggers the multiplication digital-to-analog converter is in an invalid state; the controller is connected to the switch.

[0152] Optionally, the switch is in a closed state when the touch screen is in display mode. After the sub-analog-to-digital converter converts the amplified residual signal into a digital signal to obtain the detection signal, the following steps are also included:

[0153] When the switch is closed, the controller outputs a control signal based on the detection signal obtained by the sub-analog-to-digital converter in each cycle to control the switching of the reference voltage.

[0154] Optionally, when the switch is closed, the controller outputs a control signal based on the detection signal obtained by the sub-analog-to-digital converter in each cycle, including:

[0155] With the switch closed, the detection signal obtained by the sub-analog-to-digital converter in each cycle is compared with a preset threshold to obtain the comparison result;

[0156] The control signal is output based on the comparison result to control the switching of the reference voltage.

[0157] Optionally, the preset threshold includes a first preset threshold and a second preset threshold, where the first preset threshold is greater than the second preset threshold. When the switch is closed, the controller outputs a control signal based on the detection signal obtained by the sub-analog-to-digital converter in each cycle, including:

[0158] When the switch is closed, the detection signal obtained by the sub-analog-to-digital converter in each cycle is compared with the first preset threshold and the second preset threshold.

[0159] If the detected signal is greater than the first preset threshold, a first control signal is output to control the reference voltage to switch to the first preset value;

[0160] When the detected signal is greater than or equal to the second preset threshold and less than or equal to the first preset threshold, a second control signal is output to control the reference voltage to switch to the second preset value;

[0161] If the detected signal is less than the second preset threshold, a third control signal is output to control the reference voltage to switch to the third preset value;

[0162] The first preset value is greater than the second preset value, and the second preset value is greater than the third preset value.

[0163] Optionally, after the sub-analog-to-digital converter converts the amplified residual signal into a digital signal to obtain the detection signal, the method further includes:

[0164] The processing module in the cyclic analog-to-digital converter performs zero-padding on the detection signal to obtain a detection signal of a preset length; the processing module is connected to the output of the sub-analog-to-digital converter.

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A touch detection device, characterized in that, include: An analog front-end circuit is connected to the touch electrodes in the touch display screen. The analog front-end circuit is used to convert the collected capacitance signal of the touch electrodes into a voltage signal. A cyclic analog-to-digital converter is connected to the output of the analog front-end circuit. The cyclic analog-to-digital converter is used to cyclically perform analog-to-digital conversion based on the input reference voltage and the voltage signal, and output a corresponding detection signal. The cyclic analog-to-digital converter includes a control unit, which controls the number of cycles of the analog-to-digital conversion, such that the number of cycles of the analog-to-digital conversion when the touch screen is in screen-off mode is less than the number of cycles of the analog-to-digital conversion when the touch screen is in display mode. The cyclic analog-to-digital converter further includes: Sub-analog-to-digital converter; A subtractor is connected to the output of the analog front-end circuit and to the output of the sub-analog-to-digital converter. The subtractor is used to output a residual signal based on the reference voltage and the voltage signal in the first cycle of the analog-to-digital conversion, and to output the residual signal based on the reference voltage and the detection signal obtained by the sub-analog-to-digital converter in the previous cycle of the analog-to-digital conversion in the subsequent cycles of the analog-to-digital conversion. A multiplier-to-analog converter is connected to the output of the subtractor, and the multiplier-to-analog converter is used to amplify the residual signal under the drive of the reference voltage; The control unit is connected to the input terminal of the multiplication digital-to-analog converter, and the control unit is used to control the multiplication digital-to-analog converter to control the number of cycles of the analog-to-digital conversion; The sub-analog-to-digital converter is connected to the output of the multiplication digital-to-analog converter. The sub-analog-to-digital converter is used to convert the amplified residual signal into a digital signal to obtain the detection signal. The control unit includes: A switch is connected to the output terminal of the sub-analog-to-digital converter, and the switch is in the off state when the touch display screen is in screen-off mode. A controller, connected to the switch, is configured to not output a control signal when the switch is in the open state, thereby triggering the enable signal of the multiplication digital-to-analog converter to be in an invalid state. The switch is in a closed state when the touch screen is in display mode; The controller is also configured to, when the switch is in the closed state, output the control signal based on the detection signal obtained by the sub-analog-to-digital converter in each cycle, so as to control the switching of the reference voltage.

2. The touch detection device according to claim 1, characterized in that, When the touch display screen is in always-on mode, the analog-to-digital conversion cycle is performed once.

3. The touch detection device according to claim 1, characterized in that, The controller is specifically used for: When the switch is closed, the detection signal obtained by the sub-analog-to-digital converter in each cycle is compared with a preset threshold to obtain a comparison result; The control signal is output based on the comparison result to control the switching of the reference voltage.

4. The touch detection device according to claim 3, characterized in that, The preset threshold includes a first preset threshold and a second preset threshold, wherein the first preset threshold is greater than the second preset threshold, and the controller is specifically used for: When the switch is closed, the detection signal obtained by the sub-analog-to-digital converter in each cycle is compared with the first preset threshold and the second preset threshold; If the detected signal is greater than the first preset threshold, a first control signal is output to control the reference voltage to switch to the first preset value; When the detection signal is greater than or equal to the second preset threshold and less than or equal to the first preset threshold, a second control signal is output to control the reference voltage to switch to the second preset value; If the detected signal is less than the second preset threshold, a third control signal is output to control the reference voltage to switch to a third preset value; The first preset value is greater than the second preset value, and the second preset value is greater than the third preset value.

5. The touch detection device according to any one of claims 1-4, characterized in that, The cyclic analog-to-digital converter further includes: The processing module is connected to the output of the sub-analog-to-digital converter. The processing module is used to perform zero-padding on the detection signal to obtain the detection signal of a preset length.

6. An electronic device, characterized in that, include: The touch display screen includes multiple touch electrodes; as well as The touch detection device according to any one of claims 1-5.

7. A touch detection method, characterized in that, The method, applied to the touch detection device according to any one of claims 1-5, comprises: The analog front-end circuit converts the capacitance signal of the touch electrode in the touch display screen into a voltage signal; the analog front-end circuit is connected to the touch electrode; The cyclic analog-to-digital converter performs analog-to-digital conversion cyclically based on the input reference voltage and the voltage signal, and outputs a corresponding detection signal; the cyclic analog-to-digital converter is connected to the output terminal of the analog front-end circuit; The control unit in the cyclic analog-to-digital converter controls the number of cycles of the analog-to-digital conversion, so that the number of cycles of the analog-to-digital conversion when the touch screen is in screen-off mode is less than the number of cycles of the analog-to-digital conversion when the touch screen is in display mode.

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