Pressure feedback and touchpad

Abstract

The present application provides a pressure feedback device and a touch panel, the pressure feedback device includes: a detection circuit for detecting a pressure signal output by a piezoelectric ceramic; a drive circuit including a differential amplifier for outputting a drive signal to the piezoelectric ceramic according to the pressure signal, the drive signal being a sinusoidal differential signal; a first switch circuit connected between the first output end of the differential amplifier and the first end of the piezoelectric ceramic, the second output end of the differential amplifier connected to the second end of the piezoelectric ceramic, the first switch circuit including a first switch tube and a second switch tube, the collector of the first switch tube being connected to the emitter set of the second switch tube, the emitter set of the first switch tube being connected to the collector of the second switch tube; a control circuit for controlling the first switch tube and the second switch tube to be disconnected when the detection circuit detects a pressure signal, and controlling the first switch tube and the second switch tube to be turned on when the drive circuit outputs a drive signal. The pressure feedback device can realize pressure detection and tactile feedback functions.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of touch control, and more specifically, to a pressure feedback device and a touch panel. Background Art

[0002] The touchpad senses the position and movement of the user's finger through the touch sensor and controls the movement of the pointer on the display interface. Traditional touchpads detect the user's pressing action through physical buttons to perform functions such as confirmation or calling up menus. However, the user's pressing action can only be performed in the area below 1 / 2 of the touchpad, and cannot be performed in any area of ​​the entire panel.

[0003] In order to continue the user's usage habits of traditional touchpads, pressure touchpads generally use tactile feedback devices to simulate the feeling of pressing and bouncing physical buttons, solving the problem that traditional touchpads can only press locally. Pressure touchpads can adjust the response strength and vibration feedback intensity to user pressing actions according to user usage habits. The quality of user experience depends largely on the design of the pressure feedback device in the pressure touchpad, which can realize the pressure detection and tactile feedback functions of the touchpad. Therefore, how to improve the performance of the pressure feedback device in the pressure touchpad has become a problem that needs to be solved. Summary of the invention

[0004] The embodiments of the present application provide a pressure feedback device and a touch panel with better performance.

[0005] In a first aspect, a pressure feedback device is provided, which is applied to a touch panel, wherein the touch panel includes a plurality of piezoelectric ceramics, and the pressure feedback device includes:

[0006] A detection circuit connected to the piezoelectric ceramic and used to detect a pressure signal output by the piezoelectric ceramic when a user presses the touch panel;

[0007] A driving circuit, comprising a differential amplifier, for outputting a differential driving signal to the piezoelectric ceramic according to the pressure signal, so as to drive the piezoelectric ceramic to vibrate, wherein the driving signal is generated based on a sinusoidal signal;

[0008] A first switch circuit is connected between the first output end of the differential amplifier and the first end of the piezoelectric ceramic, the second output end of the differential amplifier is connected to the second end of the piezoelectric ceramic, the first switch circuit comprises a first switch tube and a second switch tube, the first switch tube and the second switch tube are connected in parallel, the collector of the first switch tube is connected to the emitter of the second switch tube, and the emitter of the first switch tube is connected to the collector of the second switch tube;

[0009] The control circuit is used to control the first switch tube and the second switch tube to be disconnected when the detection circuit detects the pressure signal, and to control the first switch tube and the second switch tube to be turned on when the drive circuit outputs the drive signal to transmit the drive signal.

[0010] Based on this technical solution, the pressure feedback device includes a detection circuit, a drive circuit, a first switch circuit connected between the detection circuit and the drive circuit, and a control circuit for controlling the conduction and disconnection of the first switch circuit. When the detection circuit detects the pressure signal output by the piezoelectric ceramic, the first switch circuit is disconnected, and when the drive circuit is required to output a drive signal to the piezoelectric ceramic, the first switch circuit is turned on to connect the drive circuit and the piezoelectric ceramic. In this way, the control of the pressure detection process and the tactile feedback process is realized through the first switch circuit. The drive signal output by the drive circuit can be generated based on a sinusoidal signal. Compared with the pulse signal, its frequency component is concentrated in 200-300Hz, which can improve the vibration intensity of the piezoelectric ceramic, and the noise generated by the vibration of the piezoelectric ceramic is lower. And because a differential amplifier is used to output a differential drive signal, the vibration effect of the piezoelectric ceramic can be improved, and the performance of the drive circuit is improved, so that the output drive signal can obtain a larger voltage peak-to-peak value. Accordingly, the first switch circuit includes a first switch tube and a second switch tube connected in parallel, wherein the collector of the first switch tube is connected to the emitter of the second switch tube, and the emitter of the first switch tube is connected to the collector of the second switch tube, so that bidirectional transmission of current can be realized, so as to facilitate the transmission of differential sinusoidal signals, so that the drive signal can be transmitted to the piezoelectric ceramic. Therefore, the pressure feedback device can realize the functions of pressure detection and tactile feedback of the touch panel, and has better performance.

[0011] In one implementation, when the voltage at the first output end of the differential amplifier is greater than the voltage corresponding to the first end of the piezoelectric ceramic, the first switch tube is turned on; when the voltage at the first output end of the differential amplifier is less than the voltage corresponding to the first end of the piezoelectric ceramic, the second switch tube is turned on.

[0012] In this embodiment, when the driving circuit outputs a driving signal to the piezoelectric ceramic, the current can be transmitted alternately between the first switch tube and the second switch tube based on the difference in voltage between the driving circuit and the piezoelectric ceramic. In this way, the first switch circuit realizes bidirectional transmission of current, so that the differential sinusoidal signal output by the driving circuit can be transmitted to the piezoelectric ceramic.

[0013] In one implementation, the first switch circuit further includes a third switch tube and a fourth switch tube. The base of the first switch tube is connected to the collector of the third switch tube, the emitter of the third switch tube is grounded, and the base of the third switch tube is connected to the control circuit; the base of the second switch tube is connected to the collector of the fourth switch tube, the emitter of the fourth switch tube is grounded, and the base of the fourth switch tube is connected to the control circuit.

[0014] In one implementation, the control circuit is specifically used to: when the detection circuit detects the pressure signal, input a low level to the base of the third switch tube and the base of the fourth switch tube to disconnect the first switch tube and the second switch tube; when the drive circuit outputs the drive signal, input a high level to the base of the third switch tube and the base of the fourth switch tube to turn on the first switch tube and the second switch tube.

[0015] In this embodiment, the control circuit inputs low-level and high-level signals to the base of the third switch tube and the base of the fourth switch tube in the first switch circuit to control the disconnection and conduction of the first switch tube and the second switch tube in the first switch circuit, thereby realizing control of the pressure detection process and the tactile feedback process.

[0016] In one implementation, the first switch circuit further includes a third switch tube, the base of the first switch tube and the base of the second switch tube are both connected to the collector of the third switch tube, the emitter of the third switch tube is grounded, and the base of the third switch tube is connected to the control circuit.

[0017] In one implementation, the control circuit is specifically used to: when the detection circuit detects the pressure signal, input a low level to the base of the third switch tube to disconnect the first switch tube and the second switch tube; when the drive circuit outputs the drive signal, input a high level to the base of the third switch tube to turn on the first switch tube and the second switch tube.

[0018] In this embodiment, only the third switch tube is used, and low-level and high-level signals are input to the base of the third switch tube to control the disconnection and conduction of the first switch tube and the second switch tube in the first switch circuit, thereby realizing the control of the pressure detection process and the tactile feedback process.

[0019] In one implementation, the pressure feedback device also includes: a second switch circuit connected between the piezoelectric ceramic and the first switch circuit, the second switch circuit includes a fifth switch tube and a sixth switch tube, and the fifth switch tube and the sixth switch tube are respectively connected to both ends of the piezoelectric ceramic.

[0020] In this embodiment, the piezoelectric ceramic assembly includes a plurality of piezoelectric ceramics, and one or more piezoelectric ceramics that are currently required to generate vibration can be selected based on the user's pressing position on the touch panel. At this time, the fifth switch tube and the sixth switch tube in the second switch circuit connected to the selected piezoelectric ceramic are turned on, so that the driving signals output by the two output ends of the driving circuit are transmitted to the piezoelectric ceramic through the fifth switch tube and the sixth switch tube.

[0021] In one implementation, the second switch circuit further includes a seventh switch tube and an eighth switch tube. The base of the fifth switch tube is connected to the collector of the seventh switch tube, the emitter of the seventh switch tube is grounded, and the base of the seventh switch tube is connected to the control circuit; the base of the sixth switch tube is connected to the collector of the eighth switch tube, the emitter of the eighth switch tube is grounded, and the base of the eighth switch tube is connected to the control circuit.

[0022] In this embodiment, the control circuit controls the disconnection and conduction of the fifth switch tube and the sixth switch tube in the first switch circuit by inputting low-level and high-level signals to the base of the seventh switch tube and the base of the eighth switch tube in the second switch circuit, thereby realizing selective driving of multiple piezoelectric ceramics.

[0023] In one implementation, the control circuit is specifically used to: if the piezoelectric ceramic is a piezoelectric ceramic selected to be driven among the multiple piezoelectric ceramics, when the drive circuit outputs the drive signal, input a high level to the bases of the seventh switch tube and the eighth switch tube to turn on the fifth switch tube and the sixth switch tube; if the piezoelectric ceramic is a piezoelectric ceramic that is not selected to be driven among the multiple piezoelectric ceramics, input a low level to the bases of the seventh switch tube and the eighth switch tube to turn off the fifth switch tube and the sixth switch tube.

[0024] In one implementation, freewheeling diodes are connected in parallel to both ends of the fifth switch tube and both ends of the sixth switch tube.

[0025] In this embodiment, when the driving circuit is required to output a driving signal to one or more selected piezoelectric ceramics, the control circuit controls the fifth switch tube and the sixth switch tube in the second switch circuit connected to the piezoelectric ceramic to be turned on, so that the driving signal is transmitted to the piezoelectric ceramic through the fifth switch tube and the sixth switch tube, and for other unselected piezoelectric ceramics, the control circuit controls the fifth switch tube and the sixth switch tube in the second switch circuit connected to these piezoelectric ceramics to be turned off, so that the driving signal cannot be transmitted to these piezoelectric ceramics. In this way, selective driving of multiple piezoelectric ceramics is achieved.

[0026] In one implementation, the first switch unit also includes an eleventh switch tube and a twelfth switch tube, the eleventh switch tube and the twelfth switch tube are connected in parallel, the collector of the eleventh switch tube is connected to the emitter set of the twelfth switch tube, and the emitter set of the eleventh switch tube is connected to the collector of the twelfth switch tube; the control circuit is also used to control the eleventh switch tube and the twelfth switch tube to be turned on to transmit the drive signal when the drive circuit outputs the drive signal.

[0027] In one implementation, the first switch unit further includes a thirteenth switch tube. The base of the eleventh switch tube and the base of the twelfth switch tube are both connected to the collector of the thirteenth switch tube, the emitter of the thirteenth switch tube is grounded, and the base of the thirteenth switch tube is connected to the control circuit.

[0028] In one implementation, the control circuit is specifically configured to: when the drive circuit outputs the drive signal, input a high level to the base of the thirteenth switch tube to turn on the eleventh switch tube and the twelfth switch tube.

[0029] In one implementation, the detection circuit includes a first resistor, a second resistor and a third resistor, one end of the first resistor and one end of the second resistor are respectively connected to the first end and the second end of the piezoelectric ceramic, the other end of the first resistor is connected to one end of the third resistor and the processing circuit, and the other end of the second resistor is connected to the other end of the third resistor and the reference voltage.

[0030] The first resistor and the third resistor can act as a voltage divider, so that the pressure signal output by the piezoelectric ceramic reaches the processing circuit after being divided by the first resistor and the third resistor, thereby preventing the pressure signal from being too large and exceeding the dynamic voltage range of the processing circuit.

[0031] In one implementation, the pressure feedback device also includes: a discharge circuit, including a ninth switch tube and a tenth switch tube, the ninth switch tube is connected between the first end of the piezoelectric ceramic and the ground, and the tenth switch tube is connected between the second end of the piezoelectric ceramic and the ground, and the discharge circuit is used to release the electricity stored in the piezoelectric ceramic before the detection circuit detects the pressure signal.

[0032] In this embodiment, when switching between the pressure detection process and the tactile feedback process, it is necessary to release the excess electricity in the piezoelectric ceramic. When the driving circuit outputs a driving signal to the piezoelectric ceramic and causes the piezoelectric ceramic to vibrate, there may be residual electricity in the piezoelectric ceramic, and the residual electricity is quickly released through the discharge circuit, thereby avoiding the influence of the residual electricity on the pressure detection and improving the accuracy of the pressure detection.

[0033] In one implementation, both ends of the ninth switch tube and both ends of the tenth switch tube are connected in parallel with freewheeling diodes. The collector of the ninth switch tube is connected to the first end of the piezoelectric ceramic, the emitter of the ninth switch tube is grounded, and the base of the ninth switch tube is connected to the control unit; the collector of the tenth switch tube is connected to the second end of the piezoelectric ceramic, the emitter of the tenth switch tube is grounded, and the base of the tenth switch tube is connected to the control unit.

[0034] In one implementation, the pressure feedback device further includes: a processing circuit, including an analog-to-digital converter ADC, wherein the ADC is connected to the detection circuit and is used to process the pressure signal output by the piezoelectric ceramic.

[0035] In a second aspect, a touch panel is provided, comprising: a capacitance detection array; a touch chip connected to the capacitance detection array and used to detect touch information of a user on the touch panel; a piezoelectric ceramic component; and a pressure feedback device in the first aspect or any implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the frequency spectrum of the noise generated by the vibration of piezoelectric ceramics when two driving signals are used.

[0037] Figure 2 It is a schematic block diagram of a touch panel according to an embodiment of the present application.

[0038] Figure 3 It is a schematic block diagram of a pressure feedback device according to an embodiment of the present application.

[0039] Figure 4 is a schematic block diagram of a driving circuit according to an embodiment of the present application.

[0040] Figure 5 It is a schematic block diagram of a first switching circuit according to an embodiment of the present application.

[0041] Figure 6 It is a schematic block diagram of a first switch circuit according to another embodiment of the present application.

[0042] Figure 7 It is a schematic block diagram of the second switch circuit of an embodiment of the present application.

[0043] Figure 8 It is a schematic block diagram of a first switch circuit according to another embodiment of the present application.

[0044] Fig. 9 It is a schematic block diagram of a discharge circuit of an embodiment of the present application.

[0045] Fig.10 It is a schematic diagram of the timing of various signals in an embodiment of the present application.

[0046] Fig.11 It is a schematic diagram of a waveform of a driving signal according to an embodiment of the present application. DETAILED DESCRIPTION

[0047] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0048] The piezoelectric effect of piezoelectric ceramics is usually used in pressure touch panels to simulate the feeling of pressing and popping up physical buttons in traditional touch panels. Piezoelectric ceramics are provided in the pressure touch panel. When the user presses on the pressure touch panel, the piezoelectric ceramics in the pressure touch panel are deformed, and a current signal is generated based on the positive piezoelectric effect of the piezoelectric ceramics. Based on the current signal, the user's pressing force on the pressure touch panel can be detected. Based on the pressing force, a driving signal can be output to the piezoelectric ceramics. Based on the inverse piezoelectric effect of the piezoelectric ceramics, the piezoelectric ceramics generate an electric field in the polarization direction thereof, thereby causing mechanical deformation and achieving a vibration effect.

[0049] Here, the direct piezoelectric effect and the inverse piezoelectric effect are collectively referred to as the piezoelectric effect. When pressure or tension is applied to certain materials along a certain direction, as deformation occurs, charges of opposite signs will be generated on two opposite surfaces. When the external force is removed and the deformation disappears, it returns to a state of no charge. This phenomenon is called the direct piezoelectric effect. Conversely, applying an electric field in the polarization direction of these materials will cause mechanical deformation. When the electric field is removed, the deformation disappears. This phenomenon is called the inverse piezoelectric effect. We call materials with piezoelectric effect piezoelectric materials, and piezoelectric ceramics are a type of piezoelectric material.

[0050] Usually, a pulse signal can be used to drive piezoelectric ceramics to generate vibrations, but the pulse signal has more high-frequency components, resulting in lower vibration intensity of the piezoelectric ceramics and high-frequency harsh noise during the vibration process. Using a sine signal can achieve a stronger vibration and less noise. Figure 1 The figure shows the spectrum distribution of the noise caused by the vibration of the piezoelectric ceramic when the driving signal is a sine wave and a square wave, where the horizontal axis indicates the frequency and the vertical axis indicates the spectrum component. Curve A is the spectrum distribution of the noise signal corresponding to the driving signal being a sine wave, and curve B is the spectrum distribution of the noise signal corresponding to the driving signal being a square wave. Usually, a microphone can be used to collect the noise when the piezoelectric ceramic vibrates, and the spectrum analysis of the noise can be performed to obtain Figure 1 The results are shown. Figure 1 It can be seen that using a sine wave as the driving signal of the piezoelectric ceramic causes less high-frequency noise and can provide better tactile feedback to the user.

[0051] The embodiment of the present application generates a driving signal based on a sinusoidal signal to drive the piezoelectric ceramic to generate vibration. In addition, in order to improve the vibration effect of the piezoelectric ceramic and enhance the performance of the driving circuit, the present application adopts a differential driving signal. To this end, the present application implements an adaptive improvement to the circuit structure in the pressure feedback device in the pressure touch panel so that it can meet the transmission requirements of the differential sinusoidal wave signal.

[0052] Figure 2 is a schematic block diagram of a touch panel according to an embodiment of the present application. Figure 2 As shown, the touch panel 10 includes a pressure feedback device 100, a piezoelectric ceramic component 200, a touch chip 300 and a capacitance detection array 400. It can be understood that the touch panel involved in the present application is a pressure touch panel, hereinafter referred to as a touch panel.

[0053] The touch chip 300 is connected to the capacitance detection array 400 to detect the touch information of the user on the touch panel 10 , such as the coordinates of the touch position.

[0054] The pressure feedback device 100 is connected to the piezoelectric ceramic component 200 and is used to detect the pressing force of the user on the touch panel 10 and drive the piezoelectric ceramic component 200 to output vibration corresponding to the pressing force to the user.

[0055] The pressure feedback device 100 includes a first 2 C interface and the second I 2 C interface, the pressure feedback device 100 passes through the first I 2 C interface is connected to the touch chip 300 and is connected to the touch chip 300 through the second I 2 The pressure feedback device 100 detects the pressure signal output by the piezoelectric ceramic component 200, and outputs a driving signal to the piezoelectric ceramic component 200 when the pressure signal reaches a threshold value, so that the piezoelectric ceramic component 200 vibrates. The pressure feedback device 100 can also be connected to the main control of the electronic device such as the CPU through the first I 2 The I2C interface obtains the user's touch information from the touch chip 300, processes the touch information and collects pressure signals, and reports the touch time, pressure information and key events to the main control through the second I2C interface.

[0056] Figure 3 FIG. 1 is a schematic block diagram of a pressure feedback device 100 according to an embodiment of the present application. The pressure feedback device 100 can be applied to the above-mentioned touch panel 10, which includes a piezoelectric ceramic component 200, and the piezoelectric ceramic component 200 includes a plurality of piezoelectric ceramics. Hereinafter, a piezoelectric ceramic 210 among the plurality of piezoelectric ceramics is taken as an example. Figure 3As shown, the pressure feedback device 100 includes a detection circuit 110, a drive circuit 120, a first switch circuit 130 and a control circuit 140. The control circuit 140 may be, for example, a single chip microcomputer MCU.

[0057] The detection circuit 110 is connected to the piezoelectric ceramic 210 and is used to detect the pressure signal output by the piezoelectric ceramic 210 when the user presses the touch panel 10. The pressure signal can be, for example, a current signal or a voltage signal generated by the deformation of the piezoelectric ceramic 210 caused by the user's pressing. The pressure signal is associated with the degree of deformation of the piezoelectric ceramic 210.

[0058] The driving circuit 120 includes a differential amplifier 121, which is used to output a differential driving signal to the piezoelectric ceramic 210 according to the pressure signal, so as to drive the piezoelectric ceramic 210 to vibrate. Figure 4 As shown, the differential amplifier 121 can be a high voltage programmable gain amplifier (PGA), which can output a differential signal. The drive signal is generated based on a sinusoidal signal. For example, the drive signal can be a sinusoidal signal, a cosine signal, or a composite signal of a sinusoidal signal and a cosine signal.

[0059] The first switch circuit 130 is connected between the first output terminal of the differential amplifier 121 and the first terminal of the piezoelectric ceramic 210, and the second output terminal of the differential amplifier 121 is connected to the second terminal of the piezoelectric ceramic 210. Figure 5 As shown, the first switch circuit 130 includes a first switch tube Q1 and a second switch tube Q2, the first switch tube Q1 and the second switch tube Q2 are connected in parallel, wherein the collector of the first switch tube Q1 is connected to the emitter of the second switch tube Q2, and the emitter of the first switch tube Q1 is connected to the collector of the second switch tube Q2.

[0060] The control circuit 140 is used to control the first switch tube Q1 and the second switch tube Q2 to be disconnected when the detection circuit 110 detects the pressure signal, and to control the first switch tube Q1 and the second switch tube Q2 to be turned on when the drive circuit 120 outputs a drive signal to transmit the drive signal, which is a differential sinusoidal signal.

[0061] It can be seen that in the embodiment of the present application, the pressure feedback device 100 includes a detection circuit 110, a drive circuit 120, a first switch circuit 130 connected between the detection circuit 110 and the drive circuit 120, and a control circuit 140 for controlling the on and off of the first switch circuit 130. Among them, when the detection circuit 110 detects the pressure signal output by the piezoelectric ceramic 210, the first switch circuit 130 is disconnected, and when the drive circuit 120 is required to output a drive signal to the piezoelectric ceramic 210, the first switch circuit 130 is turned on to connect the drive circuit 120 and the piezoelectric ceramic 210. In this way, the control of the pressure detection process and the tactile feedback process is realized through the first switch circuit 130. The drive signal output by the drive circuit 120 can be generated based on a sinusoidal signal. Compared with a pulse signal, its frequency component is concentrated in 200-300Hz, which can improve the vibration intensity of the piezoelectric ceramic 210, and the noise generated by the vibration of the piezoelectric ceramic 210 is lower. And because the differential amplifier 121 is used to output the differential driving signal, the vibration effect of the piezoelectric ceramic 210 can be enhanced, and the performance of the driving circuit is improved, so that the output driving signal can obtain a larger voltage peak-to-peak value. Accordingly, the first switch circuit 130 includes a first switch tube Q1 and a second switch tube Q2 in parallel, wherein the collector of the first switch tube Q1 is connected to the emitter set of the second switch tube Q2, and the emitter set of the first switch tube Q1 is connected to the collector of the second switch tube Q2, which can realize bidirectional transmission of current, so as to facilitate the transmission of the differential sinusoidal signal output by the differential amplifier, so that the driving signal can be transmitted to the piezoelectric ceramic 210. Therefore, the pressure feedback device 100 can realize the functions of pressure detection and tactile feedback of the touch panel 10, and has better performance.

[0062] In the embodiment of the present application, the voltage at the first output terminal of the differential amplifier 121 is OUT+, and the voltage at the second output terminal of the differential amplifier 121 is OUTN. The voltage corresponding to the first terminal of the piezoelectric ceramic 210 is OUTP, and the voltage corresponding to the second terminal of the piezoelectric ceramic 210 is OUTN.

[0063] like Figure 4 As shown, one input terminal of the differential amplifier 121 is used to input a signal Vin, which is a low voltage analog signal output by the control circuit 140. The other input terminal of the differential amplifier 121 is a DC common mode input terminal, where VCM is a reference signal output by a voltage regulator. The gain of the differential amplifier 121 can be adjusted by the resistor R f Feedback regulation is performed. The differential amplifier 121 outputs a double-ended differential signal OUT+ and OUTN. Generally, the peak-to-peak value of the differential signal output after amplification by the differential amplifier 121 can be, for example, 210 Vpp.

[0064] Furthermore, in one implementation, Figure 5 As shown, the first switch circuit 130 also includes a third switch tube Q3 and a fourth switch tube Q4. The base of the first switch tube Q1 is connected to the collector of the third switch tube Q3, the emitter of the third switch tube Q3 is grounded, and the base of the third switch tube Q3 is connected to the control circuit 140; the base of the second switch tube Q2 is connected to the collector of the fourth switch tube Q4, the emitter of the fourth switch tube Q4 is grounded, and the base of the fourth switch tube Q4 is connected to the control circuit 140.

[0065] At this time, the control circuit 140 is used to:

[0066] When the detection circuit 110 detects the pressure signal, a low level is input to the base of the third switch tube Q3 and the base of the fourth switch tube Q4, so that the first switch tube Q1 and the second switch tube Q2 are disconnected;

[0067] When the driving circuit 120 outputs the driving signal, a high level is input to the base of the third switch tube Q3 and the base of the fourth switch tube Q4 to turn on the first switch tube Q1 and the second switch tube Q2.

[0068] In this way, the control circuit 140 controls the disconnection and conduction of the first switch tube Q1 and the second switch tube Q2 in the first switch circuit 130 by inputting low-level and high-level signals to the base of the third switch tube Q3 and the base of the fourth switch tube Q4 in the first switch circuit 130, thereby realizing the control of the pressure detection process and the tactile feedback process.

[0069] Among them, when the voltage OUT+ of the first output end of the differential amplifier 121 is greater than the voltage OUTP corresponding to the first end of the piezoelectric ceramic 210, the current that drives the piezoelectric ceramic 210 to vibrate flows from the collector to the emitter of the first switch tube Q1; when the voltage OUT+ of the first output end of the differential amplifier 121 is less than the voltage OUTP corresponding to the first end of the piezoelectric ceramic 210, the current that drives the piezoelectric ceramic 210 to vibrate flows from the collector to the emitter of the second switch tube Q2.

[0070] For example, Figure 5 As shown, the first switch circuit 130 includes four switch tubes, namely the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4, which can be high-voltage triodes. When the detection circuit 110 detects the pressure signal output by the piezoelectric ceramic 210, the control circuit 140 controls Power_EN to be low level, the third switch tube Q3 and the fourth switch tube Q4 are disconnected, and accordingly, the first switch tube Q1 and the second switch tube Q2 cannot be turned on either. Then, Figure 5As shown, the OUT+ terminal and the OUTP terminal are completely cut off; when the driving circuit 120 needs to output a driving signal to the piezoelectric ceramic 210, the control circuit 140 controls Power_EN to be high level, such as 3.3V, the third switch tube Q3 and the fourth switch tube Q4 are turned on, the base of the first switch tube Q1 and the base of the second switch tube Q2 are equivalent to grounding, the first switch tube Q1 and the second switch tube Q2 are turned on, then, Figure 5 As shown, bidirectional current transmission can be achieved between the OUT+ terminal and the OUTP terminal.

[0071] Since the present application adopts a differential sinusoidal signal as a driving signal, based on the characteristics of the driving signal, the amplitude of the sinusoidal signal is alternating between positive and negative. In order to transmit the sinusoidal signal in a differential manner, the direction of the current output by the driving circuit 210 to the piezoelectric ceramic 210 will change, so it is necessary to use the first switch circuit 130 to achieve bidirectional transmission of current. The first switch circuit 130 adopts a first switch tube Q1 and a second switch tube Q2 connected in parallel and with opposite current transmission directions, so as to achieve bidirectional transmission of current, and can be transmitted to the piezoelectric ceramic 210 when the driving signal is a differential sinusoidal signal or a composite signal of a differential sinusoidal signal and a cosine signal.

[0072] Each switch tube in the embodiment of the present application is a triode. For example, the first switch tube and the second switch tube in the first switch circuit are both triodes. Of course, one of the switch tubes in the first switch circuit 130 can also be replaced by a freewheeling diode, but considering that when the detection circuit 110 detects the pressure signal output by the electric ceramic 210, the pressure signal cannot output leakage current to the drive circuit 120 to prevent inaccurate pressure detection, it is better to use a triode whose on and off can be controlled.

[0073] Specifically, when the voltage at the OUT+ terminal is greater than the voltage at the OUTP terminal, that is, OUT+>OUTP, and the first switch tube Q1 is turned on, the current signal at the OUT+ terminal is transmitted to the OUTP terminal through the first switch tube Q1; when the voltage at the OUT+ terminal is less than the voltage at the OUTP terminal, that is, OUT+<OUTP, the second switch tube Q2 is turned on, and the current signal at the OUTP terminal is transmitted to the OUT+ terminal through the second switch tube Q2.

[0074] It can be seen that when the driving circuit 120 is required to output a driving signal to the piezoelectric ceramic, based on the difference in voltage between the driving circuit 120 and the piezoelectric ceramic 210, the current can be alternately transmitted between the first switch tube Q1 and the second switch tube Q2. When the voltage OUT+ of the driving signal output from the first output terminal of the differential amplifier 121 is greater than the voltage OUTP corresponding to the first end of the piezoelectric ceramic 210, the current driving the piezoelectric ceramic 210 to vibrate flows from the collector of the first switch tube Q1 to the emitter; and when the voltage OUT+ of the driving signal output from the first output terminal of the differential amplifier 121 is less than the voltage OUTP corresponding to the first end of the piezoelectric ceramic 210, the current driving the piezoelectric ceramic to vibrate flows from the collector of the second switch tube Q2 to the emitter. In this way, the first switch circuit 130 realizes bidirectional transmission of current, so that the differential sinusoidal signal output by the driving circuit 120 can be transmitted to the piezoelectric ceramic 210.

[0075] In one implementation, Figure 6 As shown, the first switch circuit 130 further includes a third switch tube Q3. The base of the first switch tube Q1 and the base of the second switch tube Q2 are both connected to the collector of the third switch tube Q3, the emitter of the third switch tube Q3 is grounded, and the base of the third switch tube Q3 is connected to the control circuit.

[0076] At this time, the control circuit 140 is used to: when the detection circuit 110 detects the pressure signal, input a low level to the base of the third switch tube Q3 to disconnect the first switch tube Q1 and the second switch tube Q2; when the drive circuit 120 outputs the drive signal, input a high level to the base of the third switch tube Q3 to turn on the first switch tube Q1 and the second switch tube Q2.

[0077] It can be seen that only the third switch tube Q3 can be used. By inputting low-level and high-level signals to the base of the third switch tube Q3, the disconnection and conduction of the first switch tube Q1 and the second switch tube Q2 in the first switch circuit 130 can be controlled, thereby realizing the control of the pressure detection process and the tactile feedback process.

[0078] In one implementation, Figure 3 As shown, the pressure feedback device 100 further includes a second switch circuit 150. The second switch circuit 150 is connected between the piezoelectric ceramic 210 and the first switch circuit 130. Figure 7 As shown, the second switch circuit 150 may include, for example, a fifth switch tube Q5 and a sixth switch tube Q6 , and the fifth switch tube Q5 and the sixth switch tube Q6 are connected to two ends of the piezoelectric ceramic 210 , respectively.

[0079] In this embodiment, the piezoelectric ceramic assembly 200 includes a plurality of piezoelectric ceramics, and one or more piezoelectric ceramics that are currently required to generate vibration can be selected based on the user's pressing position on the touch panel. At this time, the fifth switch tube Q5 and the sixth switch tube Q6 in the second switch circuit 150 connected to the selected piezoelectric ceramic are turned on, so that the driving signals output from the two output ends of the driving circuit 120 are transmitted to the two ends of the piezoelectric ceramic 210 through the fifth switch tube Q5 and the sixth switch tube Q6.

[0080] Furthermore, for example Figure 7 As shown, the second switch circuit 150 may further include a seventh switch tube Q7 and an eighth switch tube Q8. The base of the fifth switch tube Q5 is connected to the collector of the seventh switch tube Q7, the emitter of the seventh switch tube Q7 is grounded, and the base of the seventh switch tube Q7 is connected to the control circuit 140; the base of the sixth switch tube Q6 is connected to the collector of the eighth switch tube Q8, the emitter of the eighth switch tube Q8 is grounded, and the base of the eighth switch tube Q8 is connected to the control circuit 140.

[0081] In addition, freewheeling diodes may be connected in parallel at both ends of the fifth switch tube Q5 and the sixth switch tube Q6. Figure 7 As shown, two ends of the fifth switch tube Q5 are connected in parallel with a freewheeling diode D5 , and two ends of the sixth switch tube Q6 are connected in parallel with a freewheeling diode D6 .

[0082] At this time, the control circuit 140 is used to:

[0083] If the piezoelectric ceramic 210 is a piezoelectric ceramic selected to be driven among the multiple piezoelectric ceramics, when the driving circuit 120 outputs the driving signal, a high level is input to the bases of the seventh switch tube Q7 and the eighth switch tube Q8 to turn on the fifth switch tube Q5 and the sixth switch tube Q6, so that the differential signal output by the differential amplifier 121 is transmitted to the piezoelectric ceramic 210 through the fifth switch tube Q5 and the sixth switch tube Q6;

[0084] If the piezoelectric ceramic 210 is a piezoelectric ceramic that is not selected for driving among the plurality of piezoelectric ceramics, a low level is input to the base of the seventh switch tube Q7 and the base of the eighth switch tube Q8 to disconnect the fifth switch tube Q5 and the sixth switch tube Q6.

[0085] In this way, the control circuit 140 controls the disconnection and conduction of the fifth switch tube Q5 and the sixth switch tube Q6 in the second switch circuit 150 by inputting low-level and high-level signals to the bases of the seventh switch tube Q7 and the eighth switch tube Q8 in the second switch circuit 150, thereby realizing selective driving of multiple piezoelectric ceramics.

[0086] For example, Figure 7As shown, the second switch circuit 150 includes four switch tubes, namely, the fifth switch tube Q5, the sixth switch tube Q6, the seventh switch tube Q7 and the eighth switch tube Q8. The piezoelectric ceramic assembly 200 includes a plurality of piezoelectric ceramics. It should be understood that in the embodiment of the present application, not all of the piezoelectric ceramics in the plurality of piezoelectric ceramics are driven at the same time, but some of the piezoelectric ceramics can be selected to be driven based on the user's pressing position, so as to generate local vibration on the touch panel 10.

[0087] If the piezoelectric ceramic 210 is a piezoelectric ceramic selected to be driven among multiple piezoelectric ceramics, the control circuit 140 inputs a high level to IO1, the bases of the seventh switch tube Q7 and the eighth switch tube Q8 are at a high level, so the fifth switch tube Q5 and the sixth switch tube Q6 are turned on, and the differential signal output by the first output end of the first switch circuit 130 and the second output end of the differential amplifier 121 is transmitted to the piezoelectric ceramic 210; if the piezoelectric ceramic 210 is a piezoelectric ceramic that is not selected to be driven among multiple piezoelectric ceramics, the control circuit 140 inputs a low level to IO1, the bases of the seventh switch tube Q7 and the eighth switch tube Q8 are at a low level, the fifth switch tube Q5 and the sixth switch tube Q6 are turned off, and the piezoelectric ceramic 210 is disconnected from the driving circuit 120.

[0088] It can be seen that when the driving circuit 120 is required to output a driving signal to one or more selected piezoelectric ceramics, the control circuit 140 controls the fifth switch tube Q5 and the sixth switch tube Q6 in the second switch circuit 150 connected to these piezoelectric ceramics to be turned on, so that the driving signal is transmitted to these piezoelectric ceramics through the fifth switch tube Q5 and the sixth switch tube Q6, and for other unselected piezoelectric ceramics, the control circuit 140 controls the fifth switch tube Q5 and the sixth switch tube Q6 in the second switch circuit 150 connected to these piezoelectric ceramics to be turned off, so that the driving signal cannot be transmitted to these piezoelectric ceramics. In this way, selective driving of multiple piezoelectric ceramics is achieved. Here, the role of the second switch tube 150 is equivalent to a multiplexer, which is used to select the piezoelectric ceramics.

[0089] In one implementation, the pressure feedback device 100 in the embodiment of the present application may not include the second switch circuit 150. In this case, the first switch unit 130 also includes the eleventh switch tube Q11 and the twelfth switch tube Q12, the eleventh switch tube Q11 and the twelfth switch tube Q12 are connected in parallel, the collector of the eleventh switch tube Q11 is connected to the emitter of the twelfth switch tube Q12, and the emitter of the eleventh switch tube Q11 is connected to the collector of the twelfth switch tube Q12. Accordingly, the control circuit 140 is also used to control the eleventh switch tube Q11 and the twelfth switch tube Q1 to conduct when the drive circuit 120 outputs a drive signal, so as to transmit the drive signal, and the drive signal is a differential sinusoidal signal.

[0090] For example, Figure 8As shown, the first switch circuit 130 includes two groups of switch tubes, wherein the first group of switch tubes includes a first switch tube Q1, a second switch tube Q2 and a third switch tube Q3. The collector of the first switch tube Q1 is connected to the emitter of the second switch tube Q2, the emitter of the first switch tube Q1 is connected to the collector of the second switch tube Q2, the base of the first switch tube Q1 and the base of the second switch tube Q2 are both connected to the collector of the third switch tube Q3, the emitter of the third switch tube Q3 is grounded, and the base of the third switch tube Q3 is connected to the control circuit 140.

[0091] The second group of switch tubes includes an eleventh switch tube Q11, a twelfth switch tube Q12, and a thirteenth switch tube Q13. The collector of the eleventh switch tube Q11 is connected to the emitter of the twelfth switch tube Q12, the emitter of the eleventh switch tube Q11 is connected to the collector of the twelfth switch tube Q12, the base of the eleventh switch tube Q11 and the base of the twelfth switch tube Q12 are both connected to the collector of the thirteenth switch tube Q13, the emitter of the thirteenth switch tube Q13 is grounded, and the base of the thirteenth switch tube Q13 is connected to the control circuit 140.

[0092] At this time, the control circuit 140 is used to:

[0093] When the detection circuit 110 detects a pressure signal, a low level is input to the base of the third switch tube Q3 and / or a low level is input to the base of the thirteenth switch tube Q13 to disconnect the first switch tube Q1 and the second switch tube Q2; when the drive circuit 120 outputs a drive signal, a high level is input to the base of the third switch tube Q3 to turn on the first switch tube Q1 and the second switch tube Q2, and a high level is input to the base of the thirteenth switch tube Q13 to turn on the eleventh switch tube Q11 and the twelfth switch tube Q12.

[0094] It can be understood that when the first switch circuit 130 includes two sets of switch tubes, the two sets of switch tubes are respectively connected to the two ends of the piezoelectric ceramic 210. Figure 8 The first switch circuit 130 shown is compared to Figure 6 The first switch circuit shown in FIG. 1 adds one more set of switch tubes, which is equivalent to Figure 6 The first switch circuit 130 and Figure 7 The combination of the functions of the second switch circuit 150 shown eliminates the need for the second switch circuit 150 , thereby reducing the complexity of the circuit structure.

[0095] Another way of understanding it can also be seen as Figure 7 The flyback diode D5 of the second switch tube 150 is replaced by a triode with a transmission direction opposite to that of the fifth switch tube Q5, and the flyback diode D6 is replaced by a triode with a transmission direction opposite to that of the sixth switch tube Q6, which is also equivalent to Figure 6 The first switch circuit 130 and Figure 7 The combination of the functions of the second switch circuit 150 shown eliminates the need for the first switch circuit 130 , thereby reducing the complexity of the circuit structure.

[0096] It should be understood that when the first switch circuit 130 and the second switch circuit 150 exist at the same time, the first end of the piezoelectric ceramic 210 is an end connected to the second switch circuit 150, and the voltage corresponding to the first end of the piezoelectric ceramic 210 can be the voltage OUTP of the input end of the second switch circuit 150, that is, the voltage OUTP of the output end of the first switch circuit 130; the second end of the piezoelectric ceramic 210 is an end connected to the second output end of the differential amplifier 121, and the voltage corresponding to the second end of the piezoelectric ceramic 210 can be the voltage OUTN of the second output end of the differential amplifier 121.

[0097] In the case where only the first switch circuit 130 exists, the first end of the piezoelectric ceramic 210 is connected to one end of the first group of switch tubes in the first switch circuit 130, and the voltage corresponding to the first end of the piezoelectric ceramic 210 can be the voltage OUTP of the input end of the first group of switch tubes, that is, the voltage OUTP of the first output end of the differential amplifier 121; the second end of the piezoelectric ceramic 210 is connected to one end of the second group of switch tubes in the first switch circuit 130, and the voltage corresponding to the second end of the piezoelectric ceramic 210 can be the voltage OUTN of the input end of the second group of switch tubes, that is, the voltage OUTN of the first output end of the differential amplifier 121. At this time, Figure 4 The OUT+ in the figure can be changed to OUTN. For the sake of brevity, it is not shown separately here.

[0098] In one implementation, for example Figure 7 and Figure 8 As shown, the detection circuit 110 includes a first resistor R7, a second resistor R8 and a third resistor R9, one end of the first resistor R7 and one end of the second resistor R8 are respectively connected to the first end and the second end of the piezoelectric ceramic, the other end of the first resistor R7 is connected to one end of the third resistor R9 and the processing circuit 160, and the other end of the second resistor R8 is connected to the other end of the third resistor R9 and the reference voltage REF.

[0099] like Figure 7 and Figure 8 As shown, the first resistor R7 and the third resistor R9 can act as a voltage divider, so that the pressure signal output by the piezoelectric ceramic 210 reaches the processing circuit 160 after being divided by the first resistor R7 and the third resistor R9, thereby preventing the voltage of the piezoelectric ceramic from being too large and exceeding the dynamic voltage range of the processing circuit 160. REF is a DC voltage signal of a reference source, which provides a DC bias for the pressure detection of the piezoelectric ceramic 210.

[0100] In one implementation, the pressure feedback device 100 further includes a processing circuit 160 for processing the pressure signal output by the piezoelectric ceramic 210. For example, the processing circuit 160 includes an analog-to-digital converter ADC connected to the detection circuit 110 for processing the pressure signal output by the piezoelectric ceramic.

[0101] In one implementation, the pressure feedback device 100 further includes a discharge circuit 170. The discharge circuit 170 includes a ninth switch tube Q9 and a tenth switch tube Q10, the ninth switch tube Q9 is connected between the first end of the piezoelectric ceramic 210 and the ground, the tenth switch tube Q10 is connected between the second end of the piezoelectric ceramic 210 and the ground, and the discharge circuit 170 is used to release the electricity stored in the piezoelectric ceramic 210 before the detection circuit 110 detects the pressure signal.

[0102] When switching between the pressure detection process and the tactile feedback process, it is necessary to release the excess electricity in the piezoelectric ceramic 210. When the driving circuit 120 outputs a driving signal to the piezoelectric ceramic 210 and causes the piezoelectric ceramic 210 to vibrate, there may be residual electricity in the piezoelectric ceramic 210. The residual electricity is quickly released through the discharge circuit 170, which can avoid the influence of the residual electricity on the pressure detection and improve the accuracy of the pressure detection.

[0103] In one implementation, Fig. 9 As shown, the collector of the ninth switch tube Q9 is connected to the first end of the piezoelectric ceramic 210, the emitter of the ninth switch tube Q9 is grounded, and the base of the ninth switch tube Q9 is connected to the control unit 140; the collector of the tenth switch tube Q10 is connected to the second end of the piezoelectric ceramic 210, the emitter of the tenth switch tube Q10 is grounded, and the base of the tenth switch tube Q10 is connected to the control unit 140.

[0104] In addition, both ends of the ninth switch tube Q9 and both ends of the tenth switch tube Q10 are connected in parallel with freewheeling diodes. Fig. 9 As shown, two ends of the ninth switch tube Q9 are connected in parallel with a freewheeling diode D9 , and two ends of the tenth switch tube Q10 are connected in parallel with a freewheeling diode D10 .

[0105] Of course, the first resistor R7, the second resistor R8 and the third resistor R9 in the detection circuit 110 can also be used to absorb the excess electricity in the piezoelectric ceramic 210, but the first resistor R7, the second resistor R8 and the third resistor R9 are usually at the MΩ level, which makes the discharge speed of the piezoelectric ceramic 210 too slow, thereby affecting the efficiency of pressure detection. Therefore, the discharge circuit 170 is provided to enable the piezoelectric ceramic 210 to discharge quickly, and also enable the first switch circuit 130 and the second switch circuit 150 to discharge quickly.

[0106] like Fig. 9As shown, when the piezoelectric ceramic 210 needs to be discharged quickly, the control circuit 140 inputs a high level to IO_DIS, and the ninth switch tube Q9 and the tenth switch tube Q10 are turned on, thereby providing a fast discharge path for the high-voltage drive signal after the piezoelectric ceramic vibrates.

[0107] Fig.10 The timing of the output signal OUT of the driving circuit 120 (including OUT+ represented by a solid line and OUTN represented by a dotted line), the Power_EN signal of the control end of the first switch circuit 130, the signal of the IO1 port of the second switch circuit 150, and the signal of the IO_IDS port of the discharge circuit 170 is shown. Among them, at the time T0, the Power_EN signal is enabled, and the first switch tube Q1 and the second switch tube Q2 in the switch unit 130 can realize the bidirectional conduction of the current between the OUT+ terminal and the OUTP terminal. Between T0 and T1 is the process of the driving circuit 120 driving the piezoelectric ceramic 210 to generate vibration. The waveform of the driving signal output by the driving circuit 120 can be a sine signal or a waveform of its synthetic signal, and it is a differential signal. At the time T2, the discharge circuit 170 causes the piezoelectric ceramic 210, the first switch circuit 130 and the second switch circuit 150 to start rapid discharge. Between T2 and T5 is the dead zone control period of the piezoelectric ceramic 210, wherein T3 is the end time of the signal of the IO1 port, at which time the switch tube in the second switch circuit 150 is disconnected from both ends of the piezoelectric ceramic 210, T4 is the end time of the Power_EN signal, and T5 is the end time of the signal of the IO_IDS port.

[0108] As an example, Fig.10 The waveform of the output signal OUT of the driving circuit 120 is a sine waveform. In practical applications, the waveform of the output signal OUT of the driving circuit 120 may also be a composite waveform of a sine and cosine signal, for example Fig.11 As shown, the solid line represents OUT+ and the dotted line represents OUTN.

[0109] It should be noted that, under the premise of no conflict, the various embodiments described in this application and / or the technical features in each embodiment can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the protection scope of this application.

[0110] The systems, devices and methods disclosed in the embodiments of the present application may be implemented in other ways. For example, some features of the method embodiments described above may be ignored or not performed. The device embodiments described above are merely schematic, and the division of units is merely a logical function division. There may be other division methods in actual implementation, and multiple units or components may be combined or integrated into another system. In addition, the coupling between the units or the coupling between the components may be direct coupling or indirect coupling, and the coupling may include electrical, mechanical or other forms of connection.

[0111] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described devices and equipment and the technical effects produced can refer to the corresponding processes and technical effects in the aforementioned method embodiments, and will not be repeated here.

[0112] It should be understood that the specific examples in the embodiments of the present application are only to help those skilled in the art to better understand the embodiments of the present application, rather than to limit the scope of the embodiments of the present application. Those skilled in the art can make various improvements and modifications based on the above embodiments, and these improvements or modifications all fall within the scope of protection of the present application.

[0113] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A pressure feedback device, characterized in that: Applied to a touch panel, the touch panel includes a plurality of piezoelectric ceramics, and the pressure feedback device includes: A detection circuit connected to the piezoelectric ceramic and used to detect a pressure signal output by the piezoelectric ceramic when a user presses the touch panel; A driving circuit, comprising a differential amplifier, for outputting a differential driving signal to the piezoelectric ceramic according to the pressure signal, so as to drive the piezoelectric ceramic to vibrate, wherein the driving signal is generated based on a sinusoidal signal, and the frequency of the driving signal is 200-300 Hz; A first switch circuit is connected between the first output end of the differential amplifier and the first end of the piezoelectric ceramic, the second output end of the differential amplifier is connected to the second end of the piezoelectric ceramic, the first switch circuit comprises a first switch tube and a second switch tube, the first switch tube and the second switch tube are connected in parallel, the collector of the first switch tube is connected to the emitter of the second switch tube, and the emitter of the first switch tube is connected to the collector of the second switch tube; a control circuit, configured to control the first switch tube and the second switch tube to be disconnected when the detection circuit detects the pressure signal, and control the first switch tube and the second switch tube to be turned on when the drive circuit outputs the drive signal, so as to transmit the drive signal; a second switch circuit connected between the piezoelectric ceramic and the first switch circuit, the second switch circuit comprising a fifth switch tube and a sixth switch tube, the fifth switch tube and the sixth switch tube being connected to two ends of the piezoelectric ceramic respectively; The second switch circuit further includes a seventh switch tube and an eighth switch tube; The base of the fifth switch tube is connected to the collector of the seventh switch tube, the emitter of the seventh switch tube is grounded, and the base of the seventh switch tube is connected to the control circuit; The base of the sixth switch tube is connected to the collector of the eighth switch tube, the emitter of the eighth switch tube is grounded, and the base of the eighth switch tube is connected to the control circuit.

2. The pressure feedback device according to claim 1, characterized in that: When the voltage at the first output terminal of the differential amplifier is greater than the voltage corresponding to the first terminal of the piezoelectric ceramic, the first switch tube is turned on; When the voltage at the first output terminal of the differential amplifier is less than the voltage corresponding to the first terminal of the piezoelectric ceramic, the second switch tube is turned on.

3. The pressure feedback device according to claim 1 or 2, characterized in that: The first switch circuit further includes a third switch tube and a fourth switch tube. The base of the first switch tube is connected to the collector of the third switch tube, the emitter of the third switch tube is grounded, and the base of the third switch tube is connected to the control circuit; The base of the second switch tube is connected to the collector of the fourth switch tube, the emitter of the fourth switch tube is grounded, and the base of the fourth switch tube is connected to the control circuit.

4. The pressure feedback device according to claim 3, characterized in that: The control circuit is specifically used for: When the detection circuit detects the pressure signal, a low level is input to the base of the third switch tube and the base of the fourth switch tube, so that the first switch tube and the second switch tube are disconnected; When the driving circuit outputs the driving signal, a high level is input to the base of the third switch tube and the base of the fourth switch tube, so that the first switch tube and the second switch tube are turned on.

5. The pressure feedback device according to claim 1 or 2, characterized in that: The first switch circuit further includes a third switch tube, The base of the first switch tube and the base of the second switch tube are both connected to the collector of the third switch tube, the emitter of the third switch tube is grounded, and the base of the third switch tube is connected to the control circuit.

6. The pressure feedback device according to claim 5, characterized in that: The control circuit is specifically used for: When the detection circuit detects the pressure signal, a low level is input to the base of the third switch tube, so that the first switch tube and the second switch tube are disconnected; When the driving circuit outputs the driving signal, a high level is input to the base of the third switch tube to turn on the first switch tube and the second switch tube.

7. The pressure feedback device according to claim 1, characterized in that: The control circuit is specifically used for: If the piezoelectric ceramic is the piezoelectric ceramic selected to be driven among the plurality of piezoelectric ceramics, when the driving circuit outputs the driving signal, a high level is input to the bases of the seventh switch tube and the eighth switch tube to turn on the fifth switch tube and the sixth switch tube; If the piezoelectric ceramic is a piezoelectric ceramic that is not selected for driving among the plurality of piezoelectric ceramics, a low level is input to the base of the seventh switch tube and the base of the eighth switch tube to disconnect the fifth switch tube and the sixth switch tube.

8. The pressure feedback device according to claim 7, characterized in that: Both ends of the fifth switch tube and both ends of the sixth switch tube are connected in parallel with freewheeling diodes.

9. The pressure feedback device according to claim 1 or 2, characterized in that: The detection circuit includes a first resistor, a second resistor and a third resistor, one end of the first resistor and one end of the second resistor are respectively connected to the first end and the second end of the piezoelectric ceramic, the other end of the first resistor is connected to one end of the third resistor and the processing circuit, and the other end of the second resistor is connected to the other end of the third resistor and the reference voltage.

10. The pressure feedback device according to claim 1 or 2, characterized in that: The pressure feedback device also includes: The discharge circuit includes a ninth switch tube and a tenth switch tube, wherein the ninth switch tube is connected between the first end of the piezoelectric ceramic and the ground, and the tenth switch tube is connected between the second end of the piezoelectric ceramic and the ground. The discharge circuit is used to release the electricity stored in the piezoelectric ceramic before the detection circuit detects the pressure signal.

11. The pressure feedback device according to claim 10, characterized in that: Both ends of the ninth switch tube and both ends of the tenth switch tube are connected in parallel with freewheeling diodes. The collector of the ninth switch tube is connected to the first end of the piezoelectric ceramic, the emitter of the ninth switch tube is grounded, and the base of the ninth switch tube is connected to the control unit; The collector of the tenth switch tube is connected to the second end of the piezoelectric ceramic, the emitter of the tenth switch tube is grounded, and the base of the tenth switch tube is connected to the control unit.

12. The pressure feedback device according to claim 1 or 2, characterized in that: The pressure feedback device also includes: The processing circuit includes an analog-to-digital converter ADC, which is connected to the detection circuit and is used to process the pressure signal output by the piezoelectric ceramic.

13. A touch panel, characterized in that: include: Capacitive detection array; A touch chip connected to the capacitive detection array and used to detect touch information of a user on the touch panel; Piezoelectric ceramic components; as well as, A pressure feedback device according to any one of claims 1 to 12.

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