Piezoelectric tactile feedback wake-up circuit, piezoelectric driving chip and electronic equipment

Abstract

The invention provides a piezoelectric tactile feedback wake-up circuit, a piezoelectric driving chip and electronic equipment, and relates to the technical field of power management chips, the circuit comprises a switch logic circuit, a wake-up circuit, a high-voltage driving circuit, a sampling circuit, a folding inverter circuit and a main control circuit; the main control circuit pre-configures a wake-up threshold value of the wake-up circuit and an enable signal of the switch logic circuit; the switch logic circuit transmits the first voltage and the second voltage to the wake-up circuit according to the enable signal, so that the wake-up circuit calculates a difference value between the first voltage and the second voltage to obtain a differential voltage, and compares the differential voltage with a wake-up threshold to obtain a wake-up result; and the main control circuit or the high-voltage driving circuit is also used for controlling the sampling circuit to sample the differential voltage according to the wake-up result to obtain a sampling voltage, and controlling the high-voltage driving circuit to generate a driving signal according to the sampling voltage so as to drive the piezoelectric actuator to generate corresponding tactile feedback. The adjustment of the wake-up threshold voltage and the detection direction is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power management chips, in particular to a piezoelectric haptic feedback wake-up circuit, a piezoelectric driving chip and an electronic device. BACKGROUND

[0002] The piezoelectric actuator works based on the principle of piezoelectric effect, and the piezoelectric effect is a reversible process. When an external force is applied to the piezoelectric material, the piezoelectric material will generate an electric charge based on the piezoelectric effect, and the electric charge can be a voltage or a current. The specific value of the voltage or the current can be detected through a corresponding detection circuit. For the opposite process, when an electric charge is applied to the piezoelectric material, the piezoelectric material will produce mechanical deformation based on the inverse piezoelectric effect.

[0003] An example application scenario is: when an external force is applied to the piezoelectric material, for example, when a user presses on a button including piezoelectric material, a voltage or a current is generated, which can be detected by an electronic device. The electronic device informs the system that the user presses on the button. When a voltage or a current is applied to the piezoelectric material, for example, when the electronic device is vibrating, it is used to provide sensory feedback to the user. The electronic device applies a voltage waveform to the piezoelectric actuator to produce the desired feeling. For systems that need to sense and actuate, piezoelectric actuators are attractive because they can be used as both sensors and actuators. For example, in virtual reality device applications, piezoelectric actuators can enhance the user's interactive experience.

[0004] When the piezoelectric actuator is used as a force sensor, a detection circuit is usually needed to detect the voltage or current generated by the piezoelectric material. The working current of the detection circuit can reach the order of milliamperes. For electronic devices such as mobile phones and laptops, a larger working current will result in larger power consumption, which will in turn affect the endurance time of the electronic device. Therefore, low-power detection is of great significance for the application of piezoelectric actuators in electronic devices.

[0005] Reference Figure 1 , Figure 1 A schematic diagram of a low-power piezoelectric circuit provided by the related art is shown in FIG. 1. As shown in FIG. 1, the low-power piezoelectric circuit includes a piezoelectric material 101, a resistor 102, a capacitor 103, and a detection circuit 104. When an external force is applied to the piezoelectric material 101, the piezoelectric material 101 generates a voltage or a current, which is detected by the detection circuit 104. The resistor 102 and the capacitor 103 are connected in series to the piezoelectric material 101, and the detection circuit 104 is connected to the resistor 102 and the capacitor 103. Figure 1As shown, the circuit is based on the switch tube M1 to realize low-power detection, and the voltage generated by the piezoelectric actuator is transmitted to the switch tube M1 through the capacitor C1. When the piezoelectric actuator is pressed, and the voltage generated by the piezoelectric actuator is higher than the opening threshold voltage Vth of the switch tube M1 (for example, the opening threshold voltage Vth is about 0.7V), the switch tube M1 is turned on, and the output voltage VOUT of the switch tube M1 is switched from high level to low level, prompting the control circuit to generate an external pressing action, and the detection circuit is detected; when the piezoelectric actuator is not pressed or the voltage generated by the piezoelectric actuator is lower than the opening threshold voltage Vth of the switch tube M1, the switch tube M1 is cut off, and the output voltage VOUT of the switch tube M1 is kept at high level due to the pull-up resistor R0, prompting the control circuit that no external pressing action is generated, and keeping the detection circuit in a dormant state, which is used to realize low-power detection.

[0006] The threshold voltage of the wake-up detection circuit of the low-power piezoelectric circuit provided by the related technology completely depends on the opening threshold voltage Vth of the switch tube M1. After the circuit is fixed, the wake-up threshold voltage is a fixed value and cannot be adjusted. The voltage generated by the piezoelectric actuator during pressing and releasing is different, and the corresponding difference has positive and negative values. However, the low-power piezoelectric circuit provided by the related technology can only detect one direction after the circuit is fixed, for example, the difference is positive, and the detection direction is fixed, and the flexible adjustment of the circuit cannot be realized. SUMMARY

[0007] The present application provides a piezoelectric tactile feedback wake-up circuit, a piezoelectric drive chip and an electronic device to realize the adjustment of the wake-up threshold voltage and the detection direction, and further realize the flexible adjustment of the circuit.

[0008] In a first aspect, the present application provides a piezoelectric tactile feedback wake-up circuit, which comprises: a switch logic circuit, a wake-up circuit, a high-voltage drive circuit, a sampling circuit, a folding inversion circuit and a master control circuit. The first input end of the switch logic circuit is used to access the first voltage, the second input end of the switch logic circuit is used to access the second voltage, the first output end of the switch logic circuit is electrically connected with the first input end of the wake-up circuit, and the second output end of the switch logic circuit is electrically connected with the second input end of the wake-up circuit; the switch logic circuit is also electrically connected with the high-voltage drive circuit and the master control circuit; the wake-up circuit is also electrically connected with the high-voltage drive circuit and the master control circuit; the high-voltage drive circuit is electrically connected with the sampling circuit, the folding inversion circuit and the master control circuit respectively; and the sampling circuit is electrically connected with the folding inversion circuit and the master control circuit respectively. The master control circuit is configured to pre-configure a wake-up threshold of the wake-up circuit and an enable signal of the switch logic circuit; the enable signal is configured to control channel switching of the switch logic circuit, so that the first output end of the switch logic circuit outputs the first voltage or the second voltage, and so that the second output end of the switch logic circuit outputs the second voltage or the first voltage correspondingly. The switch logic circuit is configured to transmit the first voltage and the second voltage to the wake-up circuit according to the enable signal. The wake-up circuit is configured to calculate a difference between the first voltage and the second voltage to obtain a differential voltage, compare the differential voltage with the wake-up threshold to obtain a wake-up result, and transmit the wake-up result to the master control circuit and the high-voltage driving circuit, so that the master control circuit controls the sampling circuit to sample the differential voltage to obtain a sampling voltage according to the wake-up result, and controls the high-voltage driving circuit to generate a driving signal according to the sampling voltage; or so that the high-voltage driving circuit controls the sampling circuit to sample the differential voltage to obtain the sampling voltage according to the wake-up result, and controls itself to generate the driving signal according to the sampling voltage. The foldback inverter circuit is configured to transform the driving signal, and transmit the transformed driving signal to the piezoelectric actuator to drive the piezoelectric actuator to generate a haptic feedback corresponding to the driving signal.

[0009] The master control circuit is further configured to control the sampling circuit to sample the differential voltage to obtain a sampling voltage when the wake-up result is switched from a first level to a second level, and control the high-voltage driving circuit to generate a driving signal when the sampling voltage meets a first feedback condition, and transmit the driving signal to the piezoelectric actuator through the foldback inverter circuit to drive the piezoelectric actuator to generate a haptic feedback corresponding to the driving signal.

[0010] In a possible design, the wake-up circuit includes a subtraction circuit and a comparison circuit. The subtraction circuit is configured to calculate a difference between the first voltage and the second voltage to obtain a differential voltage. The comparison circuit is configured to compare the differential voltage with the wake-up threshold to obtain a wake-up result.

[0011] In a possible design, the subtraction circuit includes a first current source, a second current source, a first transistor, a second transistor, a third transistor, a fourth transistor, a first resistor, and a second resistor; and the comparison circuit includes a comparator. The output end of the first current source is electrically connected with the first end of the first transistor and the first end of the second transistor respectively, and the output end of the second current source is electrically connected with the first end of the third transistor and the first end of the fourth transistor respectively. The control end of the first transistor is used as the reverse input end of the subtraction circuit and the second input end of the wake-up circuit; the control end of the second transistor is used as the forward input end of the subtraction circuit and the first input end of the wake-up circuit; the control end of the third transistor is used as the third input end of the wake-up circuit, and the third input end of the wake-up circuit is electrically connected with the main control circuit, so that the main control circuit configures the wake-up threshold through the third input end of the wake-up circuit. The second end of the first transistor is electrically connected with the second end of the third transistor, the positive input end of the comparator and the first end of the first resistor respectively. The second end of the second transistor is electrically connected with the second end of the fourth transistor, the reverse input end of the comparator and the first end of the second resistor respectively. The output end of the comparator is used as the output end of the wake-up circuit and is used for outputting the wake-up result. The second end of the first resistor, the second end of the second resistor and the control end of the fourth transistor are grounded.

[0012] In a possible design, the main control circuit is further configured to control the sampling circuit to sample the differential voltage to obtain the sampling voltage when the wake-up result is switched from the first level to the second level, and control the high-voltage driving circuit to generate the driving signal when the sampling voltage meets the first feedback condition.

[0013] In a possible design, the main control circuit is further configured to control the high-voltage driving circuit, the sampling circuit and the fold-back inverter circuit to be in the off state when the wake-up result is the first level.

[0014] In a possible design, the high-voltage driving circuit is configured to control the sampling circuit to sample to obtain the sampling voltage when the wake-up result is switched from the first level to the second level, and control itself to generate the driving signal when the sampling voltage meets the second feedback condition.

[0015] In a possible design, the high-voltage driving circuit is further configured to control the switching logic circuit to be in the off state when the high-voltage driving circuit generates the driving signal.

[0016] In a possible design, the master control circuit is configured to control the high-voltage driving circuit to generate a driving signal when the sampled voltage is greater than or equal to a first haptic feedback trigger threshold, and control the high-voltage driving circuit to be in an off state when the sampled voltage is less than the first haptic feedback trigger threshold.

[0017] In a possible design, the high-voltage driving circuit is configured to control itself to generate a driving signal when the sampled voltage is greater than or equal to a second haptic feedback trigger threshold, and control itself to be in an off state when the sampled voltage is less than the second haptic feedback trigger threshold.

[0018] In a possible design, the first transistor, the second transistor, the third transistor, and the fourth transistor are all P-type MOS transistors. In a second aspect, the present application provides a piezoelectric driving chip, which comprises the switching logic circuit, the wake-up circuit, the high-voltage driving circuit, the sampling circuit, and the folding inversion circuit as described in the first aspect.

[0019] In a third aspect, the present application provides an electronic device, which comprises the piezoelectric driving chip as described in the second aspect, and further comprises the master control circuit, the piezoelectric actuator as described in the first aspect.

[0020] The present application has the following beneficial effects: In this embodiment, the piezoelectric tactile feedback wake-up circuit includes a switching logic circuit, a wake-up circuit, a high-voltage drive circuit, a sampling circuit, a folding inverter circuit, and a main control circuit. The main control circuit pre-configures the wake-up threshold of the wake-up circuit, enabling flexible adjustment of the wake-up threshold voltage. The main control circuit also pre-configures an enable signal for the switching logic circuit, which controls channel switching to provide different detection directions and adjust the detection direction. The switching logic circuit transmits a first voltage and a second voltage to the wake-up circuit, allowing the wake-up circuit to calculate the difference between the first and second voltages, obtain a differential voltage, and compare the differential voltage with the wake-up threshold to obtain a wake-up result. The main control circuit controls the sampling circuit to sample the differential voltage based on the wake-up result, obtaining a sampled voltage, and controls the high-voltage drive circuit to generate a drive signal based on the sampled voltage. Alternatively, the high-voltage drive circuit controls the sampling circuit to sample the differential voltage based on the wake-up result, obtaining a sampled voltage, and controls itself to generate a drive signal based on the sampled voltage. Finally, the folding inverter circuit transforms the drive signal and transmits it to the piezoelectric actuator to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal. This allows the piezoelectric tactile feedback wake-up circuit in this application to not only drive and detect the piezoelectric actuator, but also to flexibly adjust the wake-up threshold voltage and detection direction, making the circuit adaptable to different loads and detection scenarios. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0022] Figure 1 A schematic diagram of a low-power piezoelectric circuit provided for related technologies; Figure 2 This is a schematic diagram of the structure of a piezoelectric tactile feedback wake-up circuit provided in an embodiment of this application; Figure 3 This is a schematic diagram of a wake-up circuit provided in an embodiment of this application; Figure 4 A circuit diagram of a wake-up circuit provided in an embodiment of this application; Figure 5 A first timing diagram of a piezoelectric actuator during pressing, provided in an embodiment of this application; Figure 6 A second timing diagram of a piezoelectric actuator during pressing, provided in an embodiment of this application; Figure 7A timing diagram of a piezoelectric actuator during release, provided as an embodiment of this application; Figure 8 This is a schematic diagram of an electronic device structure provided in an embodiment of this application. Detailed Implementation

[0023] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c alone can mean: a alone, b alone, c alone, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] The terms “center,” “longitudinal,” “lateral,” “up,” “down,” “left,” “right,” “front,” and “rear,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] The terms "connected" and "connected" should be interpreted broadly. For example, in circuit structures, "connected" or "connected" can refer not only to physical connections but also to electrical or signal connections. This could be a direct connection (physical connection) or an indirect connection via at least one intermediate component, as long as the circuit is connected. It could also refer to the internal connection between two components. Similarly, a signal connection can refer to a connection via a circuit or a medium, such as radio waves. Those skilled in the art will understand the specific meaning of these terms in this application based on the specific circumstances.

[0026] To address the inflexible adjustment of the wake-up threshold voltage and detection direction in related technologies, this application provides a piezoelectric tactile feedback wake-up circuit, see [link to relevant documentation]. Figure 2 , Figure 2 This is a schematic diagram of the structure of a piezoelectric tactile feedback wake-up circuit provided in an embodiment of this application, as shown below. Figure 2As shown, the piezoelectric tactile feedback wake-up circuit 1000 may include: a switching logic circuit, a wake-up circuit, a high-voltage drive circuit, a sampling circuit ADC, a folding inverter circuit, and a main control circuit MCU.

[0027] The first input terminal IN1 of the switching logic circuit is used to connect to the first voltage OUTP, and the second input terminal IN2 of the switching logic circuit is used to connect to the second voltage OUTN. The first output terminal OUT1 of the switching logic circuit is electrically connected to the first input terminal P1 of the wake-up circuit, and the second output terminal OUT2 of the switching logic circuit is electrically connected to the second input terminal P2 of the wake-up circuit. The switching logic circuit is also electrically connected to the high-voltage drive circuit and the main control circuit MCU. The wake-up circuit is electrically connected to the high-voltage drive circuit and the main control circuit MCU. The high-voltage drive circuit is electrically connected to the sampling circuit ADC, the folding inverter circuit, and the main control circuit MCU. The sampling circuit ADC is electrically connected to the folding inverter circuit and the main control circuit MCU.

[0028] The main control circuit MCU is used to pre-configure the wake-up threshold of the wake-up circuit and the enable signal EN of the switching logic circuit. The enable signal EN is used to control the channel switching of the switching logic circuit so that the first output terminal OUT1 of the switching logic circuit outputs the first voltage OUTP or the second voltage OUTN, so that the second output terminal OUT2 of the switching logic circuit outputs the second voltage OUTN or the first voltage OUTP.

[0029] A switching logic circuit is used to transmit the first voltage OUTP and the second voltage OUTN to the wake-up circuit according to the enable signal EN.

[0030] The wake-up circuit calculates the difference between the first voltage OUTP and the second voltage OUTN to obtain a differential voltage. It then compares this differential voltage with a wake-up threshold to obtain a wake-up result. This wake-up result is transmitted to the main control circuit and the high-voltage drive circuit. The main control circuit then controls the sampling circuit to sample the differential voltage based on the wake-up result, obtaining a sampled voltage. Based on this sampled voltage, the main control circuit controls the high-voltage drive circuit to generate a drive signal. Alternatively, the high-voltage drive circuit controls the sampling circuit to sample the differential voltage based on the wake-up result, obtaining a sampled voltage. Based on this sampled voltage, the high-voltage drive circuit generates its own drive signal.

[0031] The folded inverter circuit is used to transmit the drive signal to the piezoelectric actuator to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal.

[0032] In this application, the piezoelectric tactile feedback wake-up circuit 1000 is used to drive and detect the piezoelectric actuator PZT. The application scenario for the piezoelectric tactile feedback wake-up circuit 1000 to detect the piezoelectric actuator PZT is as follows: when a user presses the piezoelectric actuator PZT, the piezoelectric material generates voltage or current, which is detected by the piezoelectric tactile feedback wake-up circuit. The application scenario for the piezoelectric tactile feedback wake-up circuit 1000 to drive the piezoelectric actuator PZT is as follows: the piezoelectric tactile feedback wake-up circuit 1000 generates a driving signal and applies it to the piezoelectric actuator to produce corresponding tactile feedback. For example, the tactile feedback can be vibration, and different driving signals produce different vibrations. When the piezoelectric actuator PZT is pressed by an external force, it outputs a first voltage OUTP and a second voltage OUTN.

[0033] In practical project applications, piezoelectric actuators (PZTs) are typically driven and monitored using a piezoelectric driver chip. In one possible embodiment, the piezoelectric driver chip includes a switching logic circuit, a wake-up circuit, a high-voltage drive circuit, a sampling ADC circuit, and a folding inverter circuit. The driving and monitoring functions of the piezoelectric actuator (PZT) are achieved through the electrical connections between the piezoelectric driver chip, the piezoelectric actuator (PZT), and the main control circuit MCU.

[0034] During the operation of the piezoelectric haptic feedback wake-up circuit in this application, the wake-up threshold of the wake-up circuit needs to be pre-configured through the main control circuit. This can be achieved by using the communication method between the main control circuit MCU and the piezoelectric driver chip, and configuring the pre-determined wake-up threshold into the wake-up circuit through the third input terminal P3 of the wake-up circuit. Alternatively, the pre-determined wake-up threshold can be configured into the wake-up circuit through the third input terminal P3 of the wake-up circuit via a host computer. Since the wake-up threshold of the wake-up circuit in this application is configured through the main control circuit MCU, the value of the wake-up threshold is not fixed and can be changed according to the user's needs. Compared with the related technologies where the threshold voltage depends entirely on the turn-on threshold voltage of the switching transistor, this allows for flexible adjustment of the wake-up threshold voltage. The size of the wake-up threshold can be set by the user according to their design requirements.

[0035] In addition, the main control circuit MCU can pre-configure the enable signal EN of the switching logic circuit. The enable signal EN can turn on the switching logic circuit and is also used to control the channel switching of the switching logic circuit. For example, the switching logic circuit may include a multi-channel switch. The channel switching of the multi-channel switch is controlled by the enable signal. For example, when the enable signal is high, the first output terminal OUT1 of the switching logic circuit outputs a first voltage OUTP, and the second output terminal OUT2 of the switching logic circuit outputs a second voltage OUTN; when the enable signal is low, the first output terminal OUT1 of the switching logic circuit outputs a second voltage OUTN, and the second output terminal OUT2 of the switching logic circuit outputs a first voltage OUTP.

[0036] It should be noted that the first voltage OUTP and the second voltage OUTN output by the piezoelectric actuator PZT are different during the pressing and releasing processes. For example, during the pressing process, the first voltage OUTP is greater than the second voltage OUTN, and the difference between the two voltages is positive. During the releasing process, the first voltage OUTP is less than or equal to the second voltage OUTN, and the difference between the two voltages is zero or negative. Therefore, for the pressing and releasing processes of the piezoelectric actuator PZT, it is necessary to provide detection of both positive and negative voltage directions.

[0037] To achieve accurate detection of the piezoelectric actuator (PZT) during the pressing and releasing processes, this application pre-configures an enable signal EN for the switching logic circuit via the main control circuit (MCU). The enable signal EN controls the channel switching of the switching logic circuit, causing the first output terminal OUT1 of the switching logic circuit to output either a first voltage OUTP or a second voltage OUTN, and the second output terminal OUT2 to output either a second voltage OUTN or a first voltage OUTP. This allows the wake-up circuit to calculate the difference between the first voltage OUTP and the second voltage OUTN, or vice versa, providing different detection directions and enabling adjustment of the detection direction.

[0038] Based on the pre-configured wake-up threshold of the wake-up circuit and the enable signal of the switching logic circuit, the switching logic circuit transmits a first voltage OUTP and a second voltage OUTN to the wake-up circuit according to the enable signal. The wake-up circuit calculates the difference between the first voltage OUTP and the second voltage OUTN to obtain a differential voltage, and compares the differential voltage with the wake-up threshold to obtain a wake-up result. The wake-up result indicates whether the differential voltage is higher than the wake-up threshold. For example, a low wake-up result indicates that the differential voltage is lower than the wake-up threshold; a high wake-up result indicates that the differential voltage is higher than the wake-up threshold.

[0039] This application transmits the wake-up result to the main control circuit and the high-voltage drive circuit, and provides two methods for controlling the sampling circuit to sample and controlling the high-voltage drive circuit to generate a drive signal. The first method involves the main control circuit controlling the sampling circuit to sample the differential voltage based on the wake-up result, obtaining a sampled voltage, and then controlling the high-voltage drive circuit to generate a drive signal based on the sampled voltage. The second method involves the high-voltage drive circuit controlling the sampling circuit to sample the differential voltage based on the wake-up result, obtaining a sampled voltage, and then controlling itself to generate a drive signal based on the sampled voltage. In other words, the sampling circuit and the high-voltage drive circuit can be controlled separately by the main control circuit and the high-voltage drive circuit.

[0040] The folded inverter circuit transforms the drive signal and transmits the transformed signal to the piezoelectric actuator, which then drives the actuator to generate tactile feedback corresponding to the drive signal. For example, when the drive signal is a half-sine wave, the folded inverter circuit can be a circuit including four MOS (Metal-Oxide-Semiconductor Field-Effect Transistors). The half-sine wave drive signal is converted into a sine wave after passing through the folded inverter circuit and transmitted to the piezoelectric actuator. Different drive signals will produce different tactile feedback.

[0041] In this embodiment, the piezoelectric tactile feedback wake-up circuit includes a switching logic circuit, a wake-up circuit, a high-voltage drive circuit, a sampling circuit, a folding inverter circuit, and a main control circuit. The main control circuit pre-configures the wake-up threshold of the wake-up circuit, enabling flexible adjustment of the wake-up threshold voltage. The main control circuit also pre-configures an enable signal for the switching logic circuit, which controls channel switching to provide different detection directions and adjust the detection direction. The switching logic circuit transmits a first voltage and a second voltage to the wake-up circuit, allowing the wake-up circuit to calculate the difference between the first and second voltages, obtain a differential voltage, and compare the differential voltage with the wake-up threshold to obtain a wake-up result. The main control circuit controls the sampling circuit to sample the differential voltage based on the wake-up result, obtaining a sampled voltage, and controls the high-voltage drive circuit to generate a drive signal based on the sampled voltage. Alternatively, the high-voltage drive circuit controls the sampling circuit to sample the differential voltage based on the wake-up result, obtaining a sampled voltage, and controls itself to generate a drive signal based on the sampled voltage. Finally, the folding inverter circuit transforms the drive signal and transmits it to the piezoelectric actuator to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal. This allows the piezoelectric tactile feedback wake-up circuit in this application to not only drive and detect the piezoelectric actuator, but also to flexibly adjust the wake-up threshold voltage and detection direction, making the circuit adaptable to different loads and detection scenarios.

[0042] In one possible embodiment, see Figure 3 , Figure 3 This is a schematic diagram of a wake-up circuit provided in an embodiment of this application, as shown below. Figure 3 As shown, the wake-up circuit 100 includes a subtraction circuit and a comparison circuit.

[0043] The subtraction circuit is used to calculate the difference between the first voltage OUTP and the second voltage OUTN to obtain the differential voltage.

[0044] The comparator circuit is used to compare the differential voltage with the wake-up threshold to obtain the wake-up result.

[0045] The wake-up threshold of the wake-up circuit 100 is configured by the main control circuit MCU through the third input terminal P3 of the wake-up circuit 100, and is used as a comparison voltage of the comparison circuit.

[0046] The subtraction circuit can calculate the difference between the first voltage OUTP and the second voltage OUTN to obtain the differential voltage. Due to the different enable signals of the switching logic circuit, the first output terminal OUT1 of the switching logic circuit outputs either the first voltage OUTP or the second voltage OUTN; the second output terminal OUT2 of the switching logic circuit outputs either the second voltage OUTN or the first voltage OUTP. Therefore, the subtraction circuit can calculate the difference between the first voltage OUTP and the second voltage OUTN to obtain the differential voltage OUTP-OUTN, or it can calculate the difference between the second voltage OUTN and the first voltage OUTP to obtain the differential voltage OUTN-OUTP.

[0047] The comparator circuit compares the differential voltage with a wake-up threshold to obtain a wake-up result. When the differential voltage is greater than the wake-up threshold, the wake-up result is high; when the differential voltage is less than the wake-up threshold, the wake-up result is low. This allows the main control circuit (MCU) and the high-voltage drive circuit to determine whether the sampling circuit (ADC) needs to sample the differential voltage based on the wake-up result.

[0048] In one possible embodiment, see Figure 4 , Figure 4 A circuit diagram of a wake-up circuit provided in an embodiment of this application is shown below. Figure 4 As shown, the subtraction circuit includes: a first current source SS1, a second current source SS2, a first transistor MP1, a second transistor MP2, a third transistor MP3, a fourth transistor MP4, a first resistor R1, and a second resistor R2; the comparison circuit includes: a comparator CMP.

[0049] The output terminal of the first current source SS1 is electrically connected to the first terminal of the first transistor MP1 and the first terminal of the second transistor MP2, respectively. The output terminal of the second current source SS2 is electrically connected to the first terminal of the third transistor MP3 and the first terminal of the fourth transistor MP4, respectively.

[0050] The control terminal of the first transistor MP1 serves as the inverting input terminal INN of the subtraction circuit and as the second input terminal P2 of the wake-up circuit 100; the control terminal of the second transistor MP2 serves as the non-inverting input terminal INP of the subtraction circuit and as the first input terminal P1 of the wake-up circuit 100; the control terminal of the third transistor MP3 serves as the third input terminal P3 of the wake-up circuit 100, and the third input terminal P3 of the wake-up circuit 100 is electrically connected to the main control circuit MCU so that the main control circuit MCU can configure the wake-up threshold Vbias through the third input terminal P3 of the wake-up circuit 100.

[0051] The second terminal of the first transistor MP1 is electrically connected to the second terminal of the third transistor MP3, the positive input terminal of the comparator CMP, and the first terminal of the first resistor R1.

[0052] The second terminal of the second transistor MP2 is electrically connected to the second terminal of the fourth transistor MP4, the inverting input terminal of the comparator CMP, and the first terminal of the second resistor R2.

[0053] The output of comparator CMP is used as the output of the wake-up circuit to output the wake-up result Vout.

[0054] The second terminal of the first resistor R1, the second terminal of the second resistor R2, and the control terminal of the fourth transistor MP4 are all grounded.

[0055] In this application, the first transistor MP1, the second transistor MP2, the third transistor MP3, and the fourth transistor MP4 can be bipolar transistors or field-effect transistors (FETs). For example, when the first transistor MP1, the second transistor MP2, the third transistor MP3, and the fourth transistor MP4 are bipolar transistors, their control terminal refers to the base of the bipolar transistor, and the first terminal can be the collector or emitter of the bipolar transistor, while the corresponding second terminal can be the emitter or collector of the bipolar transistor. When the first transistor MP1, the second transistor MP2, the third transistor MP3, and the fourth transistor MP4 are field-effect transistors (FETs), their control terminal refers to the gate of the field-effect transistor, and the first terminal can be the drain or source of the field-effect transistor, while the corresponding second terminal can be the source or drain of the field-effect transistor.

[0056] When the first transistor MP1, the second transistor MP2, the third transistor MP3, and the fourth transistor MP4 are all P-type MOS transistors, the control terminal of the first transistor MP1, the second transistor MP2, the third transistor MP3, and the fourth transistor MP4 refers to the gate of the P-type MOS transistor, the first terminal of the first transistor MP1, the second transistor MP2, the third transistor MP3, and the fourth transistor MP4 is the source of the P-type MOS transistor, and the corresponding second terminal of the first transistor MP1, the second transistor MP2, the third transistor MP3, and the fourth transistor MP4 is the drain of the P-type MOS transistor.

[0057] See Figure 4The subtraction circuit's positive input terminal INP and negative input terminal INN can accept different signals depending on the enable signal of the switching logic circuit. The wake-up threshold Vbias is a pre-set wake-up threshold. The subtraction circuit consists of four voltage-controlled current sources: a first current source SS1, a second current source SS2, a first transistor MP1, a second transistor MP2, a third transistor MP3, and a fourth transistor MP4. The voltage signals connected to the positive input terminal INP and the negative input terminal INN, along with the wake-up threshold Vbias, are converted into current signals flowing through the first resistor R1 and the second resistor R2 based on the control of the gates of the first transistor MP1, the second transistor MP2, the third transistor MP3, and the fourth transistor MP4. These current signals are then converted back into voltage signals at the first terminals of the first resistor R1 and the second resistor R2, and transmitted to the positive and negative input terminals of the comparator CMP.

[0058] See Figure 4 Since the first transistor MP1, the second transistor MP2, the third transistor MP3, and the fourth transistor MP4 are all P-type MOSFETs, for P-type MOSFETs, the higher the gate voltage, the smaller the current flowing through the P-type MOSFET. When the voltage at the positive input terminal INP of the subtraction circuit is higher than the voltage at the negative input terminal INN, and the difference between the voltage at the positive input terminal INP and the voltage at the negative input terminal INN is greater than the wake-up threshold Vbias, the current flowing through the second transistor MP2 is less than the current flowing through the first transistor MP1. Therefore, the voltage at the first end of the second resistor R2 is lower than the voltage at the first end of the first resistor R1. That is, the voltage at the positive input terminal of the comparator is higher than the voltage at the negative input terminal, and the output of the comparator flips, changing from a low level to a high level, thus realizing the comparison function between the differential voltage and the wake-up threshold.

[0059] For the subtraction circuit in the embodiments of this application, the larger of the first voltage OUTP and the second voltage OUTN generated by the piezoelectric actuator PZT is typically connected to the positive input terminal INP of the subtraction circuit. For example, when pressed, since the first voltage OUTP generated by the piezoelectric actuator PZT is higher than the second voltage OUTN, the first voltage OUTP can be connected to the positive input terminal INP of the subtraction circuit, and the second voltage OUTN can be connected to the inverting input terminal INP of the subtraction circuit. When released, since the first voltage OUTP generated by the piezoelectric actuator PZT is lower than the second voltage OUTN, the second voltage OUTN can be connected to the positive input terminal INP of the subtraction circuit, and the first voltage OUTP can be connected to the inverting input terminal INP of the subtraction circuit.

[0060] In this application, the order of signals accessed in the subtraction circuit during pressing and releasing can be controlled by setting the enable signal. For the release process, the negative differential voltage can be converted into a positive differential voltage before detection. Compared with directly detecting the negative differential voltage, the piezoelectric haptic feedback wake-up circuit in this application makes the detection of the release process more convenient, and also expands the voltage detection range of the negative differential voltage.

[0061] See Figure 4 In one example, the working principle of the wake-up circuit is illustrated by detecting the pressing of a piezoelectric actuator PZT: When pressed, the enable signal of the switching logic circuit is configured by the main control circuit MCU, so that the positive input terminal INP of the subtraction circuit is connected to the first voltage OUTP, and the negative input terminal INN of the subtraction circuit is connected to the second voltage OUTN. In the initial state before the piezoelectric actuator PZT is pressed, the first voltage OUTP and the second voltage OUTN are equal. Due to the existence of the wake-up threshold Vbias, the voltage at the negative input terminal of the comparator CMP is higher than the voltage at the positive input terminal, and the voltage at the output terminal of the comparator CMP is low. When the pressing action occurs, the first voltage OUTP is higher than the second voltage OUTN, and the voltage at the negative input terminal of the comparator CMP is lower than the voltage at the positive input terminal. The comparator CMP flips, and the output terminal of the comparator CMP switches from low to high, realizing the comparison function of the differential voltage OUTP-OUTN and the wake-up threshold Vbias.

[0062] Unlike related technologies, this application uses a wake-up circuit composed of a subtraction circuit and a comparison circuit to replace the switching transistor structure in related technologies, realizing the function of comparing the output signal of the piezoelectric actuator PZT with the wake-up threshold. Furthermore, the wake-up threshold can be flexibly configured through the main control circuit, the order of the input signals to the subtraction circuit can be controlled by configuring the enable signal of the switching logic circuit, and bidirectional detection of the pressing and releasing processes can be achieved by setting the voltage detection direction of the first voltage OUTP and the second voltage OUTN.

[0063] In one possible embodiment, the main control circuit MCU is further configured to control the sampling circuit ADC to sample the differential voltage when the wake-up result switches from the first level to the second level, and obtain the sampled voltage. When the sampled voltage meets the first feedback condition, the high-voltage drive circuit is controlled to generate a drive signal to drive the piezoelectric actuator PZT to generate tactile feedback corresponding to the drive signal.

[0064] When the wake-up result switches from the first level to the second level, for example, when the wake-up result switches from the low level to the high level, it indicates that the voltage generated by the piezoelectric actuator PZT is higher than the wake-up threshold. At this time, the sampling circuit can be controlled by the main control circuit to sample the differential voltage and obtain the sampled voltage. The sampled voltage at this time is the voltage generated by the piezoelectric actuator PZT that is accurately acquired. When the sampled voltage meets the first feedback condition, the high voltage drive circuit is controlled to generate a drive signal. The drive signal is transmitted to the piezoelectric actuator through the folded inverter circuit to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal.

[0065] When the wake-up result is at the first level, it indicates that the differential voltage is lower than the wake-up threshold. There is no need to control the sampling circuit to perform sampling, thus enabling the piezoelectric tactile feedback wake-up circuit to perform low-power detection of the piezoelectric actuator.

[0066] In one possible embodiment, see Figure 3 The main control circuit is also used to control the high-voltage drive circuit, sampling circuit, and folding inverter circuit to be in the off state when the wake-up result is the first level.

[0067] Since the piezoelectric driver chip is used to drive and detect the piezoelectric actuator (PZT), it can include a switching logic circuit, a wake-up circuit, a high-voltage drive circuit, a sampling circuit (ADC), and a folding inverter circuit. During operation, the main control circuit communicates with the chip to pre-configure the wake-up threshold for the wake-up circuit and the enable signal for the switching logic circuit. After configuration, the main control circuit puts the chip into a low-power detection mode. In this mode, the switching logic circuit transmits the first voltage OUTP and the second voltage OUTN output by the PZT to the subtraction circuit in the wake-up circuit to obtain a differential voltage, while simultaneously turning off the sampling circuit (ADC). At this time, only the switching logic circuit and the wake-up circuit are operating in the piezoelectric driver chip, requiring very low operating current, down to the microamp level, for example, 15µA. By reducing the operating current in the piezoelectric driver chip, low-power detection is achieved, effectively improving the battery life of electronic devices.

[0068] When the wake-up result is at the first level, for example, when the wake-up result is at a low level, it indicates that the piezoelectric actuator PZT has not been pressed or the differential voltage generated after pressing is lower than the wake-up threshold. At this time, there is no need for the wake-up sampling circuit to sample, nor is it necessary to control the high-voltage drive circuit to generate a drive signal based on the sampling voltage, or to transmit the drive signal to the piezoelectric actuator through the folded inverter circuit to control the piezoelectric drive chip to be in a low-power detection mode. Therefore, when the wake-up result is at the first level, the main control circuit needs to control the high-voltage drive circuit, sampling circuit, and folded inverter circuit to be in a closed state to reduce the operating current in the piezoelectric drive chip and achieve low-power detection.

[0069] In one possible embodiment, see Figure 3 The high-voltage drive circuit is used to control the sampling circuit to sample when the wake-up result switches from the first level to the second level, and obtain the sampling voltage. When the sampling voltage meets the second feedback condition, it controls itself to generate a drive signal to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal.

[0070] In the above embodiment, when the piezoelectric actuator PZT is pressed, and the differential voltage generated by the piezoelectric actuator PZT after pressing is higher than the preset wake-up threshold, the wake-up result output by the comparison circuit switches from the first level to the second level, for example, from low level to high level. This signal is transmitted to the main control circuit MCU through the interrupt line to prompt the main control circuit MCU that a pressing event has occurred. At this time, the main control circuit MCU controls the sampling circuit ADC to sample the differential voltage to obtain the accurate voltage value generated by the piezoelectric actuator PZT. The sampled voltage is obtained to determine whether the sampled voltage meets the first feedback condition. When the sampled voltage meets the first feedback condition, the high-voltage drive circuit is controlled to generate a corresponding drive signal. The drive signal is converted by the folding inverter circuit and transmitted to the piezoelectric actuator to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal.

[0071] Based on this, this application also provides a possible embodiment in which the wake-up result is directly transmitted to the high-voltage drive circuit. The high-voltage drive circuit controls the sampling circuit to sample and obtain the accurate voltage value generated by the piezoelectric actuator PZT. Specifically, when the wake-up result switches from a first level to a second level, for example, from a low level to a high level, the high-voltage drive circuit controls the sampling circuit to sample to obtain the accurate voltage value generated by the piezoelectric actuator PZT, thus obtaining the sampled voltage. When the sampled voltage meets the second feedback condition, the circuit controls itself to generate a drive signal, and the drive signal is transformed by the folding inverter circuit and transmitted to the piezoelectric actuator to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal.

[0072] The main control circuit (MCU) controls the sampling circuit (ADC) to sample the differential voltage, obtaining a sampled voltage. When the sampled voltage meets a first feedback condition, the high-voltage drive circuit generates a corresponding drive signal. The first feedback condition is typically set in an internal register of the MCU. The high-voltage drive circuit then controls the sampling circuit to sample the voltage, obtaining a sampled voltage. When the sampled voltage meets a second feedback condition, the drive circuit generates its own drive signal. This second feedback condition is typically set in an internal register of the piezoelectric drive chip.

[0073] In one possible embodiment, the high-voltage drive circuit is also used to control the switch logic circuit to be in a closed state when it generates a drive signal.

[0074] Typically, pressing a piezoelectric actuator (PZT) generates a differential voltage of less than 10V, while the voltage required to drive the PZT to produce good tactile feedback can be as high as 80V or 200V, a significant difference. Therefore, when the high-voltage drive circuit generates a drive signal, the switching logic circuit can be automatically controlled to be in the off state to avoid damage caused by the drive signal. In practical project applications, for the switching logic circuit, high-voltage devices that match the drive signal are usually selected to prevent irreversible damage caused by the drive signal.

[0075] In one possible embodiment, the main control circuit is configured to control the high-voltage drive circuit to generate a drive signal when the sampling voltage is greater than or equal to the first tactile feedback trigger threshold, and to control the high-voltage drive circuit to be in a closed state when the sampling voltage is less than the first tactile feedback trigger threshold.

[0076] For the main control circuit, the piezoelectric haptic feedback wake-up circuit provided in this application requires two judgments during low-power detection. The first judgment compares the differential voltage with a wake-up threshold, and determines whether the sampling circuit needs to be controlled to sample the differential voltage based on the wake-up result. Before the second judgment, the sampling circuit needs to be controlled to sample the differential voltage in advance to improve the detection accuracy. The second judgment compares the sampled voltage with a first haptic feedback trigger threshold to determine whether the high-voltage drive circuit needs to be controlled to generate a drive signal. The first haptic feedback trigger threshold is usually set in the internal register of the main control circuit MCU.

[0077] Specifically, when the sampling voltage is less than the first tactile feedback trigger threshold, it indicates that the differential voltage generated by the piezoelectric actuator PZT is higher than the wake-up threshold, but the first feedback condition is not met, and the high-voltage drive circuit is controlled to be in the off state; when the sampling voltage is greater than or equal to the first tactile feedback trigger threshold, the first feedback condition is met, and the high-voltage drive circuit is controlled to generate a drive signal.

[0078] In one possible embodiment, the high-voltage drive circuit is configured to control itself to generate a drive signal when the sampling voltage is greater than or equal to the second tactile feedback trigger threshold, and to control itself to be in a closed state when the sampling voltage is less than the second tactile feedback trigger threshold.

[0079] Based on the same principle as the above embodiments, for high-voltage drive circuits, the piezoelectric tactile feedback wake-up circuit provided in this application also requires two judgments during low-power detection. The first judgment compares the differential voltage with the wake-up threshold, and determines whether the sampling circuit needs to be controlled to sample the differential voltage based on the wake-up result. Before the second judgment, the sampling circuit needs to be controlled to sample the differential voltage in advance to improve the detection accuracy. The second judgment compares the sampled voltage with the second tactile feedback trigger threshold to determine whether it needs to be controlled to generate a drive signal. The second tactile feedback trigger threshold is usually set in the internal register of the piezoelectric drive chip.

[0080] Specifically, when the sampling voltage is less than the second tactile feedback trigger threshold, it indicates that the differential voltage generated by the piezoelectric actuator PZT is higher than the wake-up threshold, but the second feedback condition is not met, and the control itself is in the off state; when the sampling voltage is greater than or equal to the second tactile feedback trigger threshold, the second feedback condition is met, and the high-voltage drive circuit is controlled to generate a drive signal.

[0081] Based on all the above embodiments, this application provides a detailed description of the operation of the piezoelectric tactile feedback wake-up circuit. See also... Figure 3 First, the wake-up threshold of the wake-up circuit, the enable signal of the switching logic circuit, and the haptic feedback trigger threshold need to be pre-configured. The haptic feedback trigger threshold can be controlled by the main control circuit or the high-voltage drive circuit based on the wake-up result, correspondingly selecting either a first or second haptic feedback trigger threshold. When configuring the wake-up threshold and the enable signal of the switching logic circuit, the specific voltage value of the wake-up threshold and the corresponding level of the enable signal need to be configured. When configuring the haptic feedback trigger threshold, the waveform data of the haptic feedback trigger threshold needs to be configured, such as the waveform period and amplitude, and whether the waveform is a sine wave or a square wave, etc.

[0082] After configuration, the high-voltage drive circuit, sampling circuit, and folding inverter circuit are turned off, meaning the piezoelectric drive chip enters a low-power detection mode and sleeps. In this mode, only the switching logic circuit and the wake-up circuit are working. The first voltage OUTP and the second voltage OUTN output by the piezoelectric actuator PZT are transmitted to the subtraction circuit in the wake-up circuit through the switching logic circuit. The wake-up result is generated by the comparison circuit and transmitted to the main control circuit MCU and the high-voltage drive circuit. Then, the sampling circuit is controlled by the main control circuit MCU or the high-voltage drive circuit to sample the differential voltage and determine whether a drive signal needs to be generated based on the sampling result.

[0083] Specifically, the explanation will be based on two different scenarios: the detection of the pressing action and the release action. See [link / reference] Figure 3During the detection of the pressing action, the enable signal of the switch logic circuit is configured through the main control circuit MCU, the first voltage OUTP is connected to the positive input terminal of the subtraction circuit, the second voltage OUTN is connected to the inverted input terminal of the subtraction circuit, and the piezoelectric drive chip is controlled to enter the sleep state.

[0084] When the piezoelectric actuator PZT is pressed, the first voltage OUTP output by the piezoelectric actuator PZT is higher than the second voltage OUTN. The first voltage OUTP and the second voltage OUTN are passed through the switching logic circuit and then enter the subtraction circuit for subtraction. The output differential voltage is a positive voltage. When the differential voltage is higher than the wake-up threshold, the wake-up result output by the comparison circuit switches from low level to high level and is transmitted to the high voltage drive circuit and the main control circuit. Both the high voltage drive circuit and the main control circuit can wake up the piezoelectric drive chip, so that the sampling circuit samples the differential voltage generated by the piezoelectric actuator PZT.

[0085] If the main control circuit wakes up the piezoelectric drive chip, causing the sampling circuit to sample the differential voltage generated by the piezoelectric actuator PZT, the main control circuit can obtain the sampling voltage detected by the sampling circuit ADC through a preset communication bus. For example, the preset communication bus is the I2C (Inter-Integrated Circuit) bus protocol, or the preset communication bus can be the I3C (Improved-Inter-Integrated Circuit) bus protocol. Based on the sampling voltage and the first feedback condition, the main control circuit controls the high-voltage drive circuit to generate a drive signal to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal.

[0086] If the high-voltage drive circuit wakes up the piezoelectric drive chip, the sampling circuit samples the differential voltage generated by the piezoelectric actuator PZT. Based on the sampled voltage detected by the ADC of the sampling circuit, when the sampled voltage meets the second feedback condition, it controls itself to generate a drive signal. The drive signal is then transformed by the folded inverter circuit and transmitted to the piezoelectric actuator to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal. The switch logic circuit is automatically controlled to be in the off state. When the waveform corresponding to the drive signal finishes playing, the piezoelectric drive chip automatically enters the sleep state, reduces the operating current, turns on the low-power detection mode, and enters the next detection cycle.

[0087] See Figure 5 , Figure 5 A first timing diagram of a piezoelectric actuator during pressing, provided in an embodiment of this application, is shown below. Figure 5 As shown: During the t0~t1 phase, starting from time t0, the piezoelectric actuator is pressed, and the differential voltage between the first voltage OUTP and the second voltage OUTN begins to rise.

[0088] During the t1~t2 phase, at time t1, the differential voltage output by the subtraction circuit reaches the wake-up threshold, the wake-up result output by the comparator switches from low level to high level, the piezoelectric drive chip is woken up, and the control sampling circuit starts sampling.

[0089] During the t2~t3 phase, after time t2, when the sampling voltage reaches the tactile feedback trigger threshold, the high-voltage drive circuit generates a drive signal and automatically controls the switching logic circuit to the off state. During the process of driving the piezoelectric actuator via the drive signal, the voltage at the piezoelectric actuator output changes following the waveform of the drive signal.

[0090] At time t3, the drive signal playback ends, the piezoelectric drive chip automatically enters sleep mode, reduces operating current to start low-power detection mode, and enters the next detection cycle.

[0091] When the piezoelectric actuator PZT is pressed, if the differential voltage output by the subtraction circuit is higher than the wake-up threshold, but the sampling voltage detected by the sampling circuit ADC is lower than the haptic feedback trigger threshold, the high-voltage drive circuit will not generate a drive signal. When the differential voltage is lower than the wake-up threshold again, the piezoelectric drive chip will re-enter the sleep state, reduce the operating current, enable the low-power detection mode, and enter the next detection cycle.

[0092] See Figure 6 , Figure 6 A second timing diagram of a piezoelectric actuator during pressing, as provided in an embodiment of this application, is shown below. Figure 6 As shown: During the t0~t1 phase, starting from time t0, the piezoelectric actuator is pressed, and the differential voltage between the first voltage OUTP and the second voltage OUTN begins to rise.

[0093] During the t1~t2 phase, at time t1, the differential voltage output by the subtraction circuit reaches the wake-up threshold, the wake-up result output by the comparator switches from low level to high level, the piezoelectric drive chip is woken up, and the control sampling circuit starts sampling.

[0094] During the t2~t3 phase, after time t2, when the sampling voltage has not reached the tactile feedback trigger threshold, the high-voltage drive circuit does not operate and does not generate a drive signal, and the voltage at the output of the piezoelectric actuator changes freely.

[0095] During the t3~t4 phase, at time t3, the differential voltage falls below the wake-up threshold again. The wake-up result output by the comparator circuit switches from high level to low level, and the piezoelectric drive chip automatically enters sleep mode, reducing operating current and enabling low-power detection mode to enter the next detection cycle.

[0096] See Figure 3During the release process, the enable signal of the switch logic circuit is configured through the main control circuit MCU, the second voltage OUTN is connected to the positive input terminal of the subtraction circuit, the first voltage OUTP is connected to the inverting input terminal of the subtraction circuit, and the piezoelectric drive chip is controlled to enter the sleep state.

[0097] When the piezoelectric actuator PZT is pressed, the first voltage OUTP output by the piezoelectric actuator PZT is higher than the second voltage OUTN. The first voltage OUTP and the second voltage OUTN are fed into the subtraction circuit through the switching logic circuit for subtraction. The output differential voltage is a negative voltage or a zero voltage. When this differential voltage is definitely lower than the wake-up threshold, the wake-up result output by the comparator circuit is a low level, and the piezoelectric driver chip will not be woken up. The sampling circuit will also not perform sampling.

[0098] When the piezoelectric actuator PZT is released, the second voltage OUTN output by the piezoelectric actuator PZT is higher than the first voltage OUTP. After the subtraction circuit performs the subtraction operation, the output differential voltage is a positive voltage. The subsequent working process is consistent with the detection pressing process in the above embodiment. That is, when the differential voltage is higher than the wake-up threshold, the wake-up result output by the comparison circuit switches from low level to high level and is transmitted to the high voltage drive circuit and the main control circuit. Both the high voltage drive circuit and the main control circuit can wake up the piezoelectric drive chip, so that the sampling circuit samples the differential voltage generated by the piezoelectric actuator PZT.

[0099] If the main control circuit wakes up the piezoelectric drive chip, causing the sampling circuit to sample the differential voltage generated by the piezoelectric actuator PZT, the main control circuit can obtain the sampling voltage detected by the sampling circuit ADC through the preset communication bus, and control the high voltage drive circuit to generate a drive signal based on the first feedback condition according to the sampling voltage, so as to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal.

[0100] If the high-voltage drive circuit wakes up the piezoelectric drive chip, the sampling circuit samples the differential voltage generated by the piezoelectric actuator PZT. Based on the sampled voltage detected by the ADC of the sampling circuit, when the sampled voltage meets the second feedback condition, it controls itself to generate a drive signal and transmits the drive signal to the piezoelectric actuator through the folded inverter circuit to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal, and automatically controls the switching logic circuit to be in the off state. When the waveform corresponding to the drive signal finishes playing, the piezoelectric drive chip automatically enters the sleep state, reduces the operating current, turns on the low-power detection mode, and enters the next detection cycle.

[0101] See Figure 7 , Figure 7 A timing diagram of a piezoelectric actuator during release, provided for an embodiment of this application, is shown below. Figure 7 As shown: During the t0~t1 phase, at time t0, the piezoelectric actuator is pressed, and the differential voltage between the first voltage OUTP and the second voltage OUTN begins to rise.

[0102] During the t1~t2 phase, at time t1, the piezoelectric actuator begins to release, the differential voltage between the first voltage OUTP and the second voltage OUTN begins to decrease, and the differential voltage output by the subtraction circuit begins to increase.

[0103] During the t2~t3 phase, at time t2, the differential voltage output by the subtraction circuit reaches the wake-up threshold, the wake-up result output by the comparator switches from low level to high level, the piezoelectric drive chip is woken up, and the control sampling circuit starts sampling.

[0104] During the t3~t4 phase, at time t3, when the sampling voltage reaches the tactile feedback trigger threshold, the high-voltage drive circuit generates a drive signal and automatically controls the switching logic circuit to the off state. During the process of driving the piezoelectric actuator via the drive signal, the voltage at the piezoelectric actuator output changes in accordance with the waveform of the drive signal.

[0105] At time t4, the drive signal playback ends, the piezoelectric drive chip automatically enters sleep mode, and enables the switch logic circuit to reduce operating current and start low-power detection mode to enter the next detection cycle.

[0106] Based on all the above embodiments, it can be seen that the piezoelectric tactile feedback wake-up circuit provided in this application can achieve flexible adjustment of the wake-up threshold voltage by pre-configuring the wake-up threshold voltage through the main control circuit or the host computer; the enable signal of the switching logic circuit is pre-configured through the main control circuit, and the enable signal is used to control the channel switching of the switching logic circuit, providing different detection directions and realizing the adjustment of the detection direction. Then, the difference between the first voltage OUTP and the second voltage OUTN is calculated by the subtraction circuit to obtain the differential voltage. The comparison circuit compares the differential voltage with the wake-up threshold to obtain the wake-up result; based on the wake-up result, the wake-up sampling circuit realizes the function of sampling the differential voltage. In this application, the sampling circuit can be woken up by the main control circuit or the high-voltage drive circuit to sample the differential voltage, and the sampled voltage is compared with the tactile feedback trigger threshold to determine whether a drive signal is generated. The drive signal is used to drive the piezoelectric actuator so that the piezoelectric actuator generates tactile feedback corresponding to the drive signal.

[0107] This application also provides a piezoelectric drive chip, including: the switching logic circuit, wake-up circuit, high voltage drive circuit, sampling circuit, and folding inverter circuit as described above.

[0108] Piezoelectric drive chips are used to drive piezoelectric actuators to generate tactile feedback corresponding to the drive signal.

[0109] This application also provides an electronic device, see [link to relevant documentation] Figure 8 , Figure 8 This application provides a schematic diagram of an electronic device structure, such as... Figure 8 As shown, the electronic device may include: a piezoelectric drive chip, a main control circuit, and a piezoelectric actuator.

[0110] The electronic device may include, but is not limited to, mobile phones, laptops, VR (Virtual Reality) display devices, etc.

[0111] Among them, the piezoelectric drive chip is used to detect the signal generated by the piezoelectric actuator, and also to drive the piezoelectric actuator to generate tactile feedback corresponding to the drive signal through the drive signal.

[0112] The main control circuit is used to configure the wake-up threshold and enable signal of the piezoelectric drive chip. It can also wake up the piezoelectric drive chip to perform sampling based on the wake-up result, and control the piezoelectric drive chip to generate a drive signal based on the sampled voltage.

[0113] Finally, it should be noted that the above embodiments are merely specific implementations of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A piezoelectric tactile feedback wake-up circuit, wherein the piezoelectric tactile feedback wake-up circuit is used to drive and detect a piezoelectric actuator, characterized in that, The circuit includes: a switching logic circuit, a wake-up circuit, a high-voltage drive circuit, a sampling circuit, a folding inverter circuit, and a main control circuit. The first input terminal of the switching logic circuit is used to connect to a first voltage, and the second input terminal of the switching logic circuit is used to connect to a second voltage. The first output terminal of the switching logic circuit is electrically connected to the first input terminal of the wake-up circuit, and the second output terminal of the switching logic circuit is electrically connected to the second input terminal of the wake-up circuit. The switching logic circuit is also electrically connected to the high-voltage drive circuit and the main control circuit. The wake-up circuit is electrically connected to both the high-voltage drive circuit and the main control circuit. The high-voltage drive circuit is electrically connected to the sampling circuit, the folding inverter circuit, and the main control circuit. The sampling circuit is electrically connected to both the folding inverter circuit and the main control circuit. The main control circuit is used to pre-configure the wake-up threshold of the wake-up circuit and the enable signal of the switching logic circuit; the enable signal is used to control the channel switching of the switching logic circuit so that the first output terminal of the switching logic circuit outputs the first voltage or the second voltage, so that the second output terminal of the switching logic circuit outputs the second voltage or the first voltage accordingly. The switching logic circuit is used to transmit the first voltage and the second voltage to the wake-up circuit according to the enable signal; The wake-up circuit is configured to calculate the difference between the first voltage and the second voltage to obtain a differential voltage, compare the differential voltage with the wake-up threshold to obtain a wake-up result, and transmit the wake-up result to the main control circuit and the high-voltage drive circuit. The main control circuit controls the sampling circuit to sample the differential voltage based on the wake-up result to obtain a sampled voltage, and controls the high-voltage drive circuit to generate a drive signal based on the sampled voltage. Alternatively, the high-voltage drive circuit controls the sampling circuit to sample the differential voltage based on the wake-up result to obtain the sampled voltage, and controls itself to generate the drive signal based on the sampled voltage. The folded inverter circuit is used to transform the driving signal and transmit the transformed driving signal to the piezoelectric actuator to drive the piezoelectric actuator to generate tactile feedback corresponding to the driving signal.

2. The piezoelectric tactile feedback wake-up circuit according to claim 1, characterized in that, The wake-up circuit includes a subtraction circuit and a comparison circuit; The subtraction circuit is used to calculate the difference between the first voltage and the second voltage to obtain the differential voltage; The comparison circuit is used to compare the differential voltage with the wake-up threshold to obtain a wake-up result.

3. The piezoelectric tactile feedback wake-up circuit according to claim 2, characterized in that, The subtraction circuit includes: a first current source, a second current source, a first transistor, a second transistor, a third transistor, a fourth transistor, a first resistor, and a second resistor; the comparison circuit includes: a comparator; The output terminal of the first current source is electrically connected to the first terminal of the first transistor and the first terminal of the second transistor, respectively; the output terminal of the second current source is electrically connected to the first terminal of the third transistor and the first terminal of the fourth transistor, respectively. The control terminal of the first transistor serves as the inverting input terminal of the subtraction circuit and as the second input terminal of the wake-up circuit; the control terminal of the second transistor serves as the positive input terminal of the subtraction circuit and as the first input terminal of the wake-up circuit; the control terminal of the third transistor serves as the third input terminal of the wake-up circuit, and the third input terminal of the wake-up circuit is electrically connected to the main control circuit so that the main control circuit configures the wake-up threshold through the third input terminal of the wake-up circuit. The second terminal of the first transistor is electrically connected to the second terminal of the third transistor, the positive input terminal of the comparator, and the first terminal of the first resistor, respectively. The second terminal of the second transistor is electrically connected to the second terminal of the fourth transistor, the inverting input terminal of the comparator, and the first terminal of the second resistor, respectively. The output terminal of the comparator serves as the output terminal of the wake-up circuit, used to output the wake-up result; The second end of the first resistor, the second end of the second resistor, and the control terminal of the fourth transistor are all grounded.

4. The piezoelectric tactile feedback wake-up circuit according to claim 1, characterized in that, The main control circuit is further configured to control the sampling circuit to sample the differential voltage when the wake-up result switches from the first level to the second level, thereby obtaining the sampled voltage, and to control the high-voltage drive circuit to generate the drive signal when the sampled voltage satisfies the first feedback condition.

5. The piezoelectric tactile feedback wake-up circuit according to claim 1, characterized in that, The main control circuit is also used to control the high-voltage drive circuit, the sampling circuit, and the folding inverter circuit to be in a closed state when the wake-up result is at the first level.

6. The piezoelectric tactile feedback wake-up circuit according to claim 1, characterized in that, The high-voltage driving circuit is used to control the sampling circuit to sample when the wake-up result switches from the first level to the second level, to obtain the sampling voltage, and to control itself to generate the driving signal when the sampling voltage meets the second feedback condition.

7. The piezoelectric tactile feedback wake-up circuit according to claim 1 or 6, characterized in that, The high-voltage drive circuit is also used to control the switching logic circuit to be in a closed state when it generates a drive signal.

8. The piezoelectric tactile feedback wake-up circuit according to claim 4, characterized in that, The main control circuit is used to control the high-voltage drive circuit to generate a drive signal when the sampling voltage is greater than or equal to the first tactile feedback trigger threshold; and to control the high-voltage drive circuit to be in a closed state when the sampling voltage is less than the first tactile feedback trigger threshold.

9. The piezoelectric tactile feedback wake-up circuit according to claim 6, characterized in that, The high-voltage drive circuit is used to control itself to generate a drive signal when the sampling voltage is greater than or equal to the second tactile feedback trigger threshold, and to control itself to be in a closed state when the sampling voltage is less than the second tactile feedback trigger threshold.

10. The piezoelectric tactile feedback wake-up circuit according to claim 3, characterized in that, The first transistor, the second transistor, the third transistor, and the fourth transistor are all P-type MOS transistors.

11. A piezoelectric drive chip, characterized in that, include: The switching logic circuit, the wake-up circuit, the high-voltage drive circuit, the sampling circuit, and the folding inverter circuit as described in any one of claims 1-10.

12. An electronic device, characterized in that, include: The piezoelectric drive chip as described in claim 11 further includes the main control circuit and the piezoelectric actuator as described in any one of claims 1-10.

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