SUMMERY OF THE UTILITY MODEL
An object of the application is to provide a touch detection circuit, aim at solving traditional touch detection circuit and have the unstable problem that causes the life of sensor to be short of detecting.
A first aspect of an embodiment of the present application provides a touch detection circuit for a capacitive sensor, including:
the detection circuit is connected with the capacitive sensor and is configured to receive a first pulse signal and a second pulse signal, output a first voltage to the capacitive sensor according to the first pulse signal and transfer a charging voltage output by the capacitive sensor according to the second pulse signal;
an integration circuit connected to the detection circuit and configured to integrate the charging voltage according to the first pulse signal and the second pulse signal and output a first voltage analog quantity, integrate the charging voltage and the discharging voltage and output the first voltage analog quantity, and integrate the charging voltage, the discharging voltage, and a compensation voltage and output the first voltage analog quantity;
the discharging circuit is connected with the integrating circuit, is configured to receive a third pulse signal and a fourth pulse signal, is charged according to the third pulse signal, and outputs the discharging voltage according to the fourth pulse signal;
a compensation circuit connected to the integration circuit, configured to be charged according to the first pulse signal when a compensation signal is input, and output the compensation voltage according to the second pulse signal; and
a control circuit, respectively connected to the detection circuit, the integration circuit, the discharge circuit, and the compensation circuit, configured to output the first pulse signal and the second pulse signal, and output the third pulse signal, the fourth pulse signal, and the compensation signal according to the first voltage analog quantity;
wherein the first pulse signal and the third pulse signal have the same timing waveform, the second pulse signal and the fourth pulse signal have the same timing waveform, the polarity of the charging voltage is opposite to that of the discharging voltage, and the polarity of the charging voltage is opposite to that of the compensation voltage.
In one embodiment, the capacitive sensor includes N capacitive sensing elements, the charging voltage is an mth charging voltage, and the detection circuit includes N detection elements;
the Mth detection component is connected with the Mth capacitance sensing component and is configured to output the first voltage according to the first pulse signal when the Mth selection signal is input, and transfer the Mth charging voltage output by the Mth capacitance sensing component according to the second pulse signal;
the control circuit is specifically configured to output the mth selection signal, the first pulse signal, and the second pulse signal, and output the third pulse signal, the fourth pulse signal, and the compensation signal according to the first voltage analog quantity;
wherein, N is an integer greater than or equal to 1, M is a positive integer less than or equal to N, and the polarity of the Mth charging voltage is opposite to that of the discharging voltage.
In one embodiment, the integration circuit comprises a first integration component and a second integration component;
the first integration component is configured to integrate the charging voltage and output a second voltage analog quantity, integrate the charging voltage and the discharging voltage and output the second voltage analog quantity, and integrate the charging voltage, the discharging voltage and a compensation voltage and output the second voltage analog quantity; the second integration component is connected with the first integration component and configured to integrate the second voltage analog quantity according to the first pulse signal and the second pulse signal and output the first voltage analog quantity.
In one embodiment, the control circuit comprises a clock component and a digital processing component;
the clock component is configured to output the first pulse signal and the second pulse signal;
the digital processing component is connected with the clock component, configured to output the mth selection signal, and output the third pulse signal and the fourth pulse signal according to the first pulse signal, the second pulse signal and the first voltage analog quantity.
In one embodiment, the mth detection assembly includes an mth first field effect transistor, an mth second field effect transistor, and an mth third field effect transistor;
the drain electrode of the Mth first field effect tube, the source electrode of the Mth second field effect tube and the source electrode of the Mth third field effect tube are connected in common, the source electrode of the Mth first field effect tube is connected to the first voltage output end of the Mth detection assembly, the grid electrode of the Mth first field effect tube is connected to the Mth selection signal input end of the Mth detection assembly, the drain electrode of the Mth second field effect tube is connected with the first reference voltage source, the grid electrode of the Mth second field effect tube is connected to the first pulse signal input end of the Mth detection assembly, the drain electrode of the Mth third field effect tube is connected to the Mth charging voltage output end of the Mth detection assembly, and the grid electrode of the Mth third field effect tube is connected to the second pulse signal input end of the Mth detection assembly.
In one embodiment, the first integration component includes a first capacitor and a first amplifier;
the first end of the first capacitor is connected with the inverting input end of the first amplifier and is connected to the charging voltage input end of the first integrating component, the discharging voltage input end of the first integrating component and the compensation voltage input end of the first integrating component, the second end of the first capacitor is connected with the output end of the first amplifier and is connected to the second voltage analog quantity output end of the first integrating component, and the non-inverting input end of the amplifier is connected with a third reference voltage source.
In one embodiment, the second integration component includes a fourth field effect transistor, a fifth field effect transistor, a sixth field effect transistor, a seventh field effect transistor, a second capacitor, a third capacitor, and a second amplifier;
the drain electrode of the fourth field effect transistor, the drain electrode of the fifth field effect transistor and the first end of the second capacitor are connected in common, the second end of the second capacitor, the drain electrode of the sixth field effect transistor and the source electrode of the seventh field effect transistor are connected in common, the source electrode of the fourth field effect transistor is connected to the second voltage analog quantity input end of the second integration component, the gate electrode of the fourth field effect transistor and the gate electrode of the seventh field effect transistor are both connected to the second pulse signal input end of the second integration component, the gate electrode of the fifth field effect transistor and the gate electrode of the sixth field effect transistor are both connected to the first pulse signal input end of the second integration component, the source electrode of the fifth field effect transistor and the source electrode of the sixth field effect transistor are both connected to a second reference voltage source, and the non-inverting input end of the second amplifier is connected to a fourth reference voltage source, the drain electrode of the seventh field effect transistor, the first end of the third capacitor and the inverting input end of the second amplifier are connected in common, and the second end of the third capacitor is connected with the output end of the second amplifier and connected to the first voltage analog quantity output end of the circuit of the second integrating component.
In one embodiment, the compensation circuit includes an eighth fet, a ninth fet, a tenth fet, an eleventh fet, K twelfth fets, and K compensation capacitors;
the source electrode of an Ltwelfth field effect tube is connected with the first end of an Ltwelfth compensation capacitor, the second end of the Ltwelfth compensation capacitor, the drain electrode of the eighth field effect tube and the drain electrode of the tenth field effect tube are connected in common, the drain electrode of the Ltwelfth field effect tube, the drain electrode of the ninth field effect tube and the source electrode of the eleventh field effect tube are connected in common, the source electrode of the eighth field effect tube is connected with a first reference voltage source, the grid electrode of the eighth field effect tube and the grid electrode of the ninth field effect tube are connected to the first pulse signal input end of the compensation circuit, the grid electrode of the tenth field effect tube and the grid electrode of the eleventh field effect tube are connected to the second pulse signal input end of the compensation circuit, the grid electrode of the Ltwelfth field effect tube is connected to the Lth compensation signal input end of the compensation circuit, and the source electrode of the ninth field effect tube and the source electrode of the tenth field effect tube are connected to a second reference voltage source.
In one embodiment, the discharge circuit includes a thirteenth field effect transistor, a fourteenth field effect transistor, a fifteenth field effect transistor, a sixteenth field effect transistor and a discharge capacitor;
the drain electrode of the sixteenth field effect transistor, the drain electrode of the fourteenth field effect transistor and the first end of the discharge capacitor are connected in common, the second end of the discharge capacitor, the drain electrode of the thirteenth field effect transistor and the source electrode of the fifteenth field effect transistor are connected in common, the source electrode of the sixteenth field effect transistor is connected with a first reference voltage source, the source electrode of the thirteenth field effect transistor and the source electrode of the fourteenth field effect transistor are both connected with a second reference voltage source, the drain electrode of the fifteenth field effect transistor is connected to the discharge voltage output end of the discharge circuit, the grid electrode of the thirteenth field effect transistor and the grid electrode of the sixteenth field effect transistor are both connected to the third pulse signal input end of the discharge circuit, the grid electrode of the fourteenth field effect transistor and the grid electrode of the fifteenth field effect transistor are both connected to a fourth pulse signal input end of the discharge circuit.
A second aspect of embodiments of the present application provides an earphone, including a panel, an elastic support, a circuit board, a capacitive sensor, and the touch detection circuit according to any one of the first aspect;
the capacitive sensor is arranged on the inner face of the panel, the first end of the elastic supporting piece is tightly attached to the capacitive sensor and supports the capacitive sensor, the second end of the elastic supporting piece is fixed on the circuit board, and the touch detection circuit is arranged on the circuit board.
Compared with the prior art, the embodiment of the utility model beneficial effect who exists is: receiving a first pulse signal and a second pulse signal through a detection circuit, outputting a first voltage to a capacitive sensor according to the first pulse signal, and switching a charging voltage output by the capacitive sensor according to the second pulse signal, integrating the charging voltage according to the first pulse signal and the second pulse signal and outputting a first voltage analog quantity, integrating the charging voltage and the discharging voltage and outputting a first voltage analog quantity, integrating the charging voltage, the discharging voltage and a compensation voltage and outputting a first voltage analog quantity, receiving a third pulse signal and a fourth pulse signal by a discharging circuit, charging according to the third pulse signal, and outputting a discharging voltage according to the fourth pulse signal, charging according to the first pulse signal when the compensation signal is input by the compensation circuit, and outputting the compensation voltage according to the second pulse signal by the control circuit, outputting the first pulse signal and the second pulse signal by the control circuit, and the third pulse signal, the fourth pulse signal and the compensation signal are output according to the first voltage analog quantity, so that the capacitive sensor compatible with different relative capacitance values is realized, and when the capacitance sensor has the condition of relative capacitance value change in the using process, the touch state of the capacitive sensor can be continuously identified through compensation, and the service life of the capacitive sensor is prolonged.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Fig. 1 shows a first exemplary schematic block diagram of a touch detection circuit 110 provided in an embodiment of the present application, and for convenience of description, only the parts related to the embodiment are shown, and detailed descriptions are as follows:
the touch detection circuit 110 for the capacitive sensor 200 includes a detection circuit 110, an integration circuit 120, a discharge circuit 140, a compensation circuit 150, and a control circuit 130.
The detection circuit 110 is connected to the N capacitive sensors 200, and configured to receive the first pulse signal ph1 and the second pulse signal ph2, output a first voltage to the capacitive sensor 200 according to the first pulse signal ph1, and switch the charging voltage output by the capacitive sensor 200 according to the second pulse signal ph 2.
And an integration circuit 120 connected to the detection circuit 110, configured to integrate the mth charging voltage according to the first pulse signal ph1 and the second pulse signal ph2 and output a first voltage analog quantity, integrate the charging voltage and the discharging voltage and output a first voltage analog quantity, and integrate the mth charging voltage, the discharging voltage, and the compensation voltage and output a first voltage analog quantity.
And the discharge circuit 140 is connected with the integration circuit 120, is configured to receive the third pulse signal ph3 and the fourth pulse signal ph4, performs charging according to the third pulse signal ph3, and outputs a discharge voltage according to the fourth pulse signal ph 4.
And a compensation circuit 150 connected to the integration circuit 120, configured to be charged according to the first pulse signal ph1 when the compensation signal is input, and output a compensation voltage according to the second pulse signal ph 2.
The control circuit 130 is connected to the detection circuit 110, the integration circuit 120, the discharge circuit 140, and the compensation circuit 150, and configured to output the first pulse signal ph1 and the second pulse signal ph2, and output the third pulse signal ph3, the fourth pulse signal ph4, and the compensation signal according to the first voltage analog quantity.
The first pulse signal ph1 and the third pulse signal ph3 have the same timing waveform, the second pulse signal ph2 and the fourth pulse signal ph4 have the same timing waveform, the polarity of the charging voltage and the polarity of the discharging voltage are opposite, and the polarity of the charging voltage and the polarity of the compensation voltage are opposite.
In this embodiment, when the capacitive sensor 200 is not touched to be in a normal state, the control circuit 130 outputs the first pulse signal ph1 and the second pulse signal ph2, when the first pulse signal ph1 is at a high level and the second pulse signal ph2 is at a low level, the detection circuit 110 outputs a first voltage to the capacitive sensor 200 according to the first pulse signal ph1 at the high level to charge the capacitive sensor 200, when the first pulse signal ph1 is at a low level and the second pulse signal ph2 is at a high level, the detection circuit 110 stops outputting the first voltage and transfers the charging voltage output by the capacitive sensor 200 to the integration circuit 120, the integration circuit 120 integrates according to the charging voltage and outputs the first voltage analog quantity to the control circuit 130, the detection circuit 110 transfers the charging voltage output by the capacitive sensor 200 to the integration circuit 120 once every time the first pulse signal ph1 performs a level shift, so that the integration circuit 120 integrates the charging voltage once and increases the first voltage analog quantity once, when the first voltage analog quantity is smaller than the first preset value, the control circuit 130 outputs a third pulse signal ph3 having the same timing waveform as the first pulse signal ph1 and a fourth pulse signal ph4 having the same timing waveform as the second pulse signal ph2, the control circuit 130 records the number of times that the first voltage analog quantity is increased to be larger than the first preset value as a value T, when the third pulse signal ph3 is at a high level, the discharging circuit 140 charges, when the fourth pulse signal ph4 is at a high level, the discharging circuit 140 outputs a discharging voltage having a polarity opposite to that of the charging voltage, at this time, the integration circuit 120 integrates according to the charging voltage and the discharging voltage, when the first pulse signal ph1 performs a first level transition, the first voltage quantity output by the integration circuit 120 decreases once, and when the first voltage analog quantity is smaller than a second preset value, the control circuit 130 stops outputting the third pulse signal ph3 and the fourth pulse signal ph4, the number of times that the control circuit 130 decreases the first voltage analog quantity to be less than the second preset value is recorded as a Y value, the control circuit 130 determines the state of the capacitance sensor 200 according to the R value (R ═ Y/(T + Y)), and the above-mentioned process is cycled.
When the capacitive sensor 200 is touched, and the charging voltage output after the capacitive sensor 200 is charged when being touched becomes large, the T value becomes small, the Y value becomes large, and the R value becomes large, and the control circuit 130 determines that the capacitive sensor 200 is touched according to the change of the R values of two adjacent times.
When the relative capacitance of the capacitive sensor 200 is relatively large, the difference between the absolute value of the discharge voltage and the absolute value of the charge voltage (for example, the difference is greater than the third reference voltage) is not enough to make the first voltage analog quantity output by the integrating circuit 120 after integrating according to the discharge voltage and the charge voltage not change from increasing to decreasing, at this time, the first voltage analog quantity is always greater than the first preset value, at this time, Y approaches infinity, and R value is infinitely close to 1, at this time, after the capacitive sensor 200 is touched, the difference between the absolute value of the discharge voltage and the absolute value of the charge voltage is also greater than the third reference voltage, and at this time, the R value does not change, so that the control circuit 130 cannot judge the state of the capacitive sensor 200 according to the change of the R value, at this time, the control circuit 130 outputs the compensation signal to the compensation circuit 150 according to the R value with the constant first duration, so that the compensation circuit 150 outputs the compensation voltage with the polarity opposite to the charge voltage to the integrating circuit 120, at this time, the charging voltage is pulled down by the compensation voltage, so that a difference value between an absolute value of the discharging voltage minus an absolute value of the charging voltage and an absolute value of the compensation voltage is greater than a third reference voltage, so that the integration circuit 120 integrates according to the charging voltage, the compensation voltage and the discharging voltage and decrements the output first voltage analog quantity, so that the R value does not tend to 1, and the control circuit 130 can judge that the capacitive sensor 200 is touched through the change of the R value, therefore, the touch detection circuit 110 of the embodiment can be compatible with capacitive sensors 200 with different relative capacitance values, and when the capacitive sensor 200 has a relative capacitance value change during use, the touch state of the capacitive sensor 200 can be continuously identified through compensation, so that the service life of the capacitive sensor 200 is prolonged.
In one embodiment, the first pulse signal ph1 and the second pulse signal ph2 are not at high level at the same time, the falling edge of the first pulse signal ph1 and the rising edge of the second pulse signal ph2 are not overlapped, and the rising edge of the first pulse signal ph1 and the falling edge of the second pulse signal ph2 are not overlapped, so that the first voltage output by the detection circuit 110 and the transfer charging voltage are not generated at the same time.
Referring to fig. 2, in an embodiment, the capacitive sensor 200 includes N capacitive sensing elements (respectively 201 … 20N), the charging voltage is an mth charging voltage, and the detection circuit 110 includes N detection elements (respectively 111 … 11N).
And the Mth detection component is connected with the Mth capacitance sensing component and is configured to output a first voltage according to the first pulse signal ph1 when the Mth selection signal is input, and transfer the Mth charging voltage output by the Mth capacitance sensing component according to the second pulse signal ph 2.
The control circuit 130 is specifically configured to output the mth selection signal, the first pulse signal ph1, and the second pulse signal ph2, and output the third pulse signal ph3, the fourth pulse signal ph4, and the compensation signal according to the first voltage analog quantity.
Wherein N is an integer greater than or equal to 1, M is a positive integer less than or equal to N, and the polarity of the Mth charging voltage and the polarity of the discharging voltage are opposite.
In this embodiment, the N capacitance sensing elements are detected by setting the N detection elements, so that the N capacitance sensing elements can be mutually redundant, and the reliability of the touch detection circuit 110 of the present application is improved.
Referring to fig. 2, in an embodiment, the integrating circuit 120 includes a first integrating element 121 and a second integrating element 122.
And a first integration component 121 configured to integrate according to the mth charging voltage, the discharging voltage, and the compensation voltage and output a second voltage analog quantity.
And the second integration component 122 is connected with the first integration component 121 and configured to integrate the second voltage analog quantity according to the first pulse signal ph1 and the second pulse signal ph2 and output the first voltage analog quantity.
In this embodiment, the first integration component 121 and the second integration component 122 are arranged to perform a second integration on the charging voltage to obtain a first voltage analog quantity, and perform a second integration on the charging voltage and the discharging voltage to obtain a first voltage analog quantity, or perform a second integration on the charging voltage, the discharging voltage and the compensation voltage to obtain a first voltage analog quantity, so that the degree of interference on the process of the first voltage analog quantity is reduced.
Referring to fig. 2, in one embodiment, the control circuit 130 includes a clock component 131 and a digital processing component 132.
The clock module 131 is configured to output a first pulse signal ph1 and a second pulse signal ph 2.
The digital processing module 132 is connected to the clock module 131, and configured to output the mth selection signal, and output the third pulse signal ph3 and the fourth pulse signal ph4 according to the first pulse signal ph1, the second pulse signal ph2, and the first voltage analog quantity.
In the embodiment, the clock module 131 outputs the first pulse signal ph1 and the second pulse signal ph2, the digital processing module 132 outputs the third pulse signal ph3 according to the first pulse signal ph1 and the first voltage modulus and outputs the third pulse signal ph3 according to the second pulse signal ph2 and the first voltage analog quantity, the timing waveforms of the third pulse signal ph3 and the first pulse signal ph1 are the same, and the timing waveforms of the fourth pulse signal ph4 and the second pulse signal ph2 are the same.
Referring to fig. 3, in one embodiment, the mth detection element includes an mth first fet (shown as QD1 … QDn, respectively), an mth second fet (shown as QB1 … QBn, respectively), and an mth third fet (shown as QC1 … QCn, respectively).
The drain electrode of the Mth first field effect transistor, the source electrode of the Mth second field effect transistor and the source electrode of the Mth third field effect transistor are connected in common, the source electrode of the Mth first field effect transistor is connected to the first voltage output end of the Mth detection assembly, the grid electrode of the Mth first field effect transistor is connected to the Mth selection signal input end of the Mth detection assembly, the drain electrode of the Mth second field effect transistor is connected with the first reference voltage source Vx, the grid electrode of the Mth second field effect transistor is connected to the first pulse signal ph1 input end of the Mth detection assembly, the drain electrode of the Mth third field effect transistor is connected to the Mth charging voltage output end of the Mth detection assembly, and the grid electrode of the Mth third field effect transistor is connected to the second pulse signal ph2 input end of the Mth detection assembly.
Referring to fig. 3, in one embodiment, the first integrating element 121 includes a first capacitor C1 and a first amplifier U1.
A first terminal of the first capacitor C1 is connected to the inverting input terminal of the first amplifier U1 and to the charging voltage input terminal of the first integrating element 121, the discharging voltage input terminal of the first integrating element 121, and the compensation voltage input terminal of the first integrating element 121, a second terminal of the first capacitor C1 is connected to the output terminal of the first amplifier U1 and to the second voltage analog output terminal of the first integrating element 121, and the non-inverting input terminal of the amplifier is connected to the third reference voltage source Vz 1.
Referring to fig. 3, in an embodiment, the second integration element 122 includes a fourth fet Q4, a fifth fet Q5, a sixth fet Q6, a seventh fet Q7, a second capacitor C2, a third capacitor C3, and a second amplifier U2.
The drain of the fourth fet Q4, the drain of the fifth fet Q5, and the first end of the second capacitor C2 are connected in common, the second end of the second capacitor C2, the drain of the sixth fet Q6, and the source of the seventh fet Q7 are connected in common, the source of the fourth fet Q4 is connected to the second voltage analog input terminal of the second integrating component 122, the gate of the fourth fet Q4 and the gate of the seventh fet Q7 are connected to the second pulse signal ph2 input terminal of the second integrating component 122, the gate of the fifth fet Q5 and the gate of the sixth fet Q6 are connected to the first pulse signal ph1 input terminal of the second integrating component 122, the source of the fifth fet Q5 and the source of the sixth fet Q6 are connected to the second reference voltage source Vy, the input terminal of the second non-phase amplifier U2 is connected to the source of the fourth reference voltage Vz2, and the drain of the seventh fet Q7 is connected to the drain of the second reference voltage source Vz2, The first terminal of the third capacitor C3 and the inverting input terminal of the second amplifier U2 are connected together, and the second terminal of the third capacitor C3 is connected to the output terminal of the second amplifier U2 and to the first voltage analog output terminal of the circuit of the second integrating component 122.
Referring to fig. 3, in an embodiment, the compensation circuit 150 includes an eighth fet Q8, a ninth fet Q9, a tenth fet Q10, an eleventh fet Q11, K twelfth fets (shown as QA1 … QAk, respectively) and K compensation capacitors (shown as Coff1 … Coffk, respectively).
The source electrode of the Ltwelfth field effect transistor is connected with the first end of the Ltwelfth compensation capacitor, the second end of the Ltwelfth compensation capacitor, the drain electrode of the eighth field effect transistor Q8 and the drain electrode of the tenth field effect transistor Q10 are connected in common, the drain electrode of the Ltwelfth field effect transistor, the drain of the ninth field-effect transistor Q9 and the source of the eleventh field-effect transistor Q11 are connected in common, the source of the eighth field-effect transistor Q8 is connected with the first reference voltage source Vx, the gate of the eighth field-effect transistor Q8 and the gate of the ninth field-effect transistor Q9 are both connected to the first pulse signal ph1 input terminal of the compensation circuit 150, the gate of the tenth field-effect transistor Q10 and the gate of the eleventh field-effect transistor Q11 are both connected to the second pulse signal ph2 input terminal of the compensation circuit 150, the gate of the lth field-effect transistor Q9 is connected to the lth compensation signal input terminal of the compensation circuit 150, and the source of the ninth field-effect transistor Q9 and the source of the tenth field-effect transistor Q10 are both connected to the second reference voltage source Vy.
Referring to fig. 3, in an embodiment, the discharge circuit 140 includes a thirteenth fet Q13, a fourteenth fet Q14, a fifteenth fet Q15, a sixteenth fet Q16, and a discharge capacitor Cref.
The drain of the sixteenth fet Q16, the drain of the fourteenth fet Q14 and the first end of the discharge capacitor Cref are connected in common, the second end of the discharge capacitor Cref, the drain of the thirteenth fet Q13 and the source of the fifteenth fet Q15 are connected in common, the source of the sixteenth fet Q16 is connected to the first reference voltage source Vx, the source of the thirteenth fet Q13 and the source of the fourteenth fet Q14 are both connected to the second reference voltage source Vy, the drain of the fifteenth fet Q15 is connected to the discharge voltage output terminal of the discharge circuit 140, the gate of the thirteenth fet Q13 and the gate of the fourteenth fet Q16 are both connected to the third pulse signal ph3 input terminal of the discharge circuit 140, and the gate of the fourteenth fet Q14 and the gate of the fifteenth fet Q15 are both connected to the fourth pulse signal ph4 input terminal of the discharge circuit 140.
Referring to fig. 3, in an embodiment, the clock module 131 includes a clock chip U4, a first clock terminal CLK3 of the clock chip U4 is connected to an output terminal of a first pulse signal ph1 of the clock module 131, and a second clock terminal CLK4 of the clock chip U4 is connected to an output terminal of a second pulse signal ph2 of the clock module 131.
Referring to fig. 3, in an embodiment, the digital processing component 132 includes an analog-to-digital processing chip U3, a first clock terminal CLK1 of the analog-to-digital processing chip U3 is connected to a first pulse signal ph1 input terminal of the digital processing component 132, a second clock terminal CLK2 of the analog-to-digital processing chip U3 is connected to a second pulse signal ph2 input terminal of the digital processing component 132, an mth first general input/output terminal (PA 1 … Pan in the figure) of the analog-to-digital processing chip U3 is connected to an mth selection signal output terminal of the digital processing component 132, a first pulse output terminal PWM1 of the analog-to-digital processing chip U3 is connected to a third pulse signal ph3 output terminal of the digital processing component 132, a second pulse output terminal PWM2 of the digital-to-digital processing chip is connected to a fourth pulse signal ph4 output terminal of the digital processing component 132, an analog signal input terminal a/D of the analog-to-digital processing chip U3 is connected to a first voltage analog input terminal of the digital processing component 132, the Lth second general input/output terminal (PB 1 … PBk in the figure) of the analog-to-digital processing chip U3 is connected to the Lth compensation signal output terminal of the digital processing component 132.
To explain the touch detection circuit 110 of fig. 3 with reference to the working principle, the mth first general input/output terminal of the analog-to-digital processing chip U3 outputs a high level (mth selection signal) to the gate of the mth first fet to turn on the mth first fet, when the mth capacitive sensing element is not touched, the first clock terminal CLK3 of the clock chip U4 outputs a first pulse signal ph1 to the gate of the mth second fet, the gate of the fifth fet Q5 and the gate of the sixth fet Q6, the second clock terminal CLK4 of the clock chip U4 outputs a first pulse signal ph1 to the gate of the mth third fet, the gate of the fourth fet Q4 and the gate of the seventh fet Q7, when the first pulse signal ph1 is a high level and the second pulse signal ph2 is a low level, the mth second fet is turned on and the mth third fet is turned off, at this time, the first reference voltage source Vx charges the mth capacitance sensing element through the mth second field effect transistor and the mth first field effect transistor, when the first pulse signal ph1 jumps to a low level and the second pulse signal ph2 jumps to a high level, the mth second field effect transistor is turned off and the mth third field effect transistor is turned on, the mth capacitance sensing element outputs the mth charging voltage to the inverting input terminal of the first amplifier U1 and the first capacitor C1 through the mth first field effect transistor and the mth second field effect transistor, the mth charging voltage is greater than the third reference voltage at this time, the first amplifier U1 and the first capacitor C1 inversely integrate the mth charging voltage and output a second voltage analog quantity, the second voltage analog quantity is decreased, the second capacitor C2 is charged by the second voltage analog quantity, the second capacitor C2 outputs a voltage to the inverting input terminal of the second amplifier U2 and the third capacitor C3, and the output voltage of the second capacitor C2 is less than the fourth reference voltage Vz2, the second amplifier U2 and the third capacitor C3 integrate the output voltage of the second capacitor C2 in the forward direction and output the first voltage analog quantity to the analog signal input terminal U3 of the analog-to-digital processing chip U3, at this time, the first voltage analog quantity is increased, the analog-to-digital processing chip U3 performs analog-to-digital conversion and digital filtering on the first voltage analog quantity, when the level of the first pulse signal ph1 is inverted once, the first voltage analog quantity is increased once, when the first voltage analog quantity is increased to be greater than the first preset value, the number of times that the first voltage analog quantity is increased to be greater than the first preset value by the analog-to-digital processing chip U3 is recorded as a T value, and the first pulse output terminal PWM1 of the analog-to-digital processing chip U3 outputs the third pulse signal ph3 to the gate of the thirteenth fet Q13 and the sixteenth fet 16 having the same timing waveform as the first pulse signal ph1, and the second pulse output end PWM2 of the analog-digital processing chip U3 outputs the fourth pulse signal ph4 to the gate of the fourteenth field-effect tube Q14 and the gate of the fifteenth field-effect tube Q15 with the same time sequence waveform as the second pulse signal ph2, when the third pulse signal ph3 is at high level and the fourth pulse signal ph4 is at low level, the thirteenth field-effect tube Q13 and the sixteenth field-effect tube Q16 are both turned on, the first reference voltage source Vx charges the discharge capacitor Cref through the sixteenth field-effect tube Q16, when the third pulse signal ph3 is at high level and the fourth pulse signal ph4 is at low level, the fourteenth field-effect tube Q14 and the fifteenth field-effect tube Q15 are both turned on, the discharge capacitor Cref outputs the discharge voltage to the inverting input end of the first amplifier U1 and the first capacitor C1 through the fifteenth field-effect tube Q15, the difference between the absolute value of the discharge voltage and the absolute value of the M charge voltage is smaller than the third reference voltage, the first amplifier U1 and the first capacitor C1 perform forward integration, the second voltage analog quantity is increased progressively, the second amplifier U2 and the third capacitor C3 perform backward integration, the first voltage analog quantity is decreased progressively, when the level of the first pulse signal ph1 is inverted once, the first voltage analog quantity is decreased once, when the first voltage analog quantity is smaller than the second preset value, the analog-to-digital processing chip U3 stops outputting the third pulse signal ph3 and the fourth pulse signal ph4, the number of times that the analog-to-digital processing chip U3 decreases the first voltage analog quantity to be smaller than the second preset value is recorded as a Y value, and the analog-to-digital processing chip U3 records an R value (R Y/(T + Y)), and the above process is cycled.
When the mth capacitance sensing assembly is touched, the charging voltage output after the mth capacitance sensing assembly is charged when the mth capacitance sensing assembly is touched is increased, so that the value T is decreased, the value Y is increased, and the value R is increased, and then the analog-to-digital processing chip U3 judges that the capacitance sensing assembly is touched according to the change of the value R of two adjacent times.
When the relative capacitance value of the mth capacitance sensing assembly is relatively large, the difference between the absolute value of the discharge voltage and the absolute value of the charge voltage is larger than the third reference voltage, at this time, the first amplifier U1 and the first capacitor C1 cannot perform conversion from forward integration to reverse integration according to the discharge voltage and the mth charge voltage, so the first voltage analog quantity is not converted into descending, the Y value at this time is close to the R value, the R value tends to 1, at this time, after the mth capacitance sensing assembly is touched, the difference between the absolute value of the discharge voltage and the absolute value of the charge voltage is also larger than the third reference voltage, the R value is unchanged, so the analog-to-digital processing chip U3 cannot judge the state of the mth capacitance sensing assembly according to the change of the R value, when the R value is continuously unchanged for a first time period, the first and second general input/output end of the analog-to-digital processing chip U3 outputs a first compensation signal to the first twelfth fet to turn on the first twelfth fet, when the first pulse signal ph1 is at a high level and the second pulse signal ph2 is at a low level, the eighth fet Q8 and the ninth fet Q9 are both turned on, the first reference voltage charges the first compensation capacitor through the eighth fet Q8, and when the first pulse signal ph1 is at a low level and the second pulse signal ph2 is at a high level, the first compensation capacitor outputs the first compensation voltage to the inverting input terminal of the first amplifier U1 and the first capacitor C1 through the first twelfth fet Q11, so that when the third pulse signal ph3 is at a high level and the fourth pulse signal ph4 is at a low level, the first amplifier U1 and the first capacitor C1 integrate according to the first compensation voltage, the charging voltage, and the discharging voltage, if the difference between the absolute value of the discharging voltage and the absolute value of the charging voltage is subtracted from the absolute value of the compensation voltage, is greater than the third reference voltage, the first voltage analog quantity is decreased, the R value does not tend to 1, and when the mth sensing element is touched, the value of R becomes larger, the analog-to-digital processing chip U3 can determine that the mth capacitive sensing element is touched according to the larger value of R, if the difference between the absolute value of the discharge voltage minus the absolute value of the charge voltage and the absolute value of the compensation voltage is smaller than the third reference voltage, the second general-purpose input/output terminal of the analog-to-digital processing chip U3 outputs a second compensation signal to the second twelfth fet to turn on the second twelfth fet, so that the first compensation capacitor and the second compensation capacitor output the compensation voltage at the same time to increase the absolute value of the compensation voltage, then the subsequent process is the same as above, until the difference between the absolute value of the discharging voltage minus the absolute value of the charging voltage and the absolute value of the compensation voltage is larger than the third reference voltage or all the compensation capacitors output the compensation voltage. In one embodiment, the touch detection circuit 110 of the present application is integrated on a circuit board.
In an embodiment, the touch detection circuit 110 of the present application is integrated in a chip, and at this time, the clock chip U4 should be understood as all electronic components including thyristors, which can implement the corresponding functions of the clock chip U4 described in the present application, rather than being limited to the clock chip U4 as an independent chip, and at this time, the analog-to-digital processing chip U3 should be understood as all electronic components including thyristors, which can implement the corresponding functions of the analog-to-digital processing chip U3 described in the present application, rather than being limited to the analog-to-digital processing chip U3 as an independent chip.
The present embodiment further provides an earphone, which includes the capacitive sensor 200 and the touch detection circuit 110 according to any of the above embodiments, because the earphone of the present embodiment includes the touch detection circuit 110 according to any of the above embodiments, the earphone of the present embodiment at least includes the corresponding advantages of the touch detection circuit 110 according to any of the above embodiments.
Referring to fig. 4, in an embodiment, the earphone further includes a panel 300, an elastic supporting member 400 and a circuit board 500, the capacitive sensor 200 is mounted on an inner surface of the panel 300, a first end of the elastic supporting member 400 is attached to the capacitive sensor 200 and supports the capacitive sensor 200, a second end of the elastic supporting member 400 is fixed on the circuit board 500, and the touch detection circuit is disposed on the circuit board 500.
In this embodiment, the elastic support 400 supports the capacitive sensor 200 mounted on the inner surface of the panel 300, so that the yield of mass production of the capacitive sensor 200 can be improved.
The elastic supporting member 400 may be a conductive spring or a silicone layer, and when the elastic supporting member 400 is a conductive spring, the capacitive sensor 200 may be electrically connected to the touch detection circuit on the circuit board through the conductive spring.
In one embodiment, the earphone is a wireless earphone.
In one embodiment, the headset is a bluetooth wireless headset.
The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.