Driving circuit, electronic device and driving method of vibration device

Abstract

The invention provides a drive circuit capable of driving a vibration device with high efficiency, an electronic device, and a driving method of the vibration device. The drive circuit is provided with: a signal generation unit that generates a drive signal at a drive frequency and transmits the generated drive signal to a vibration device that vibrates in accordance with the drive signal; a detection unit that detects, from the vibrating device, vibration information relating to vibration of the vibrating device; and a control unit that determines a drive frequency on the basis of the vibration information detected by the detection unit, and transmits the determined drive frequency to the signal generation unit.

Description

Technical Field

[0001] This invention relates to drive circuits, electronic devices, and driving methods for vibration equipment. Background Technology

[0002] Previously, there were known electronic devices that included drive circuits for driving vibrating devices such as tactile devices.

[0003] In this regard, Patent Document 1 discloses an electronic pen that has a vibration device and reproduces various virtual writing surface resistances by vibration of the vibration device.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: U.S. Patent Application Publication No. 2013 / 0307829 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The power consumption efficiency of a vibrating device is highest when the driving frequency used to drive the vibrating device matches the resonant frequency of the vibrating device. However, in the technology described in Patent Document 1, the electronic device drives the vibrating device using a fixed driving frequency, thus the power consumption efficiency decreases due to deviations in the resonant frequency caused by manufacturing errors, different environments in which the vibrating device is installed, etc.

[0009] The present invention was made in view of such a problem, and its object is to provide a drive circuit and electronic device capable of driving a vibrating device with high efficiency.

[0010] Methods for solving problems

[0011] To address the aforementioned issues, the first invention relates to a drive circuit that drives a vibration device that vibrates according to a drive signal. The drive circuit comprises: a signal generation unit that generates the drive signal in a manner having a drive frequency and sends the generated drive signal to the vibration device; a detection unit that detects vibration information related to the vibration of the vibration device from the vibration device; and a control unit that determines the drive frequency based on the vibration information detected by the detection unit and sends the determined drive frequency to the signal generation unit.

[0012] Furthermore, in the drive circuit of the second invention, the vibration information is the vibration frequency of the vibration device.

[0013] Furthermore, in the drive circuit of the third invention, the control unit determines the drive frequency in such a way that the drive frequency is close to the vibration frequency.

[0014] Furthermore, in the drive circuit of the fourth invention, the detection unit detects the vibration information from the vibration device after the signal generation unit stops sending the drive signal to the vibration device.

[0015] Furthermore, in the drive circuit of the fifth invention, the vibration information is the phase difference between the vibration signal generated by the vibration of the vibration device and the drive signal.

[0016] Furthermore, in the drive circuit of the sixth invention, the control unit determines the drive frequency in a manner that brings the phase difference close to a predetermined value.

[0017] Furthermore, in the drive circuit of the seventh invention, the vibration information is the amplitude of the vibration signal generated by the vibration of the vibration device.

[0018] Furthermore, in the drive circuit of the eighth invention, the control unit determines the drive frequency in a manner that increases the amplitude.

[0019] Furthermore, the electronic device of the Ninth Invention includes: a vibration device that vibrates according to a drive signal; and a drive circuit having a signal generation unit, a detection unit, and a control unit, wherein the signal generation unit generates the drive signal in a manner having a drive frequency and sends the generated drive signal to the vibration device, the detection unit detects vibration information related to the vibration of the vibration device from the vibration device, and the control unit determines the drive frequency based on the vibration information detected by the detection unit and sends the determined drive frequency to the signal generation unit.

[0020] In addition, the electronic device involved in the tenth invention functions as an electronic pen.

[0021] Furthermore, the eleventh invention relates to a method for driving a vibration device that vibrates according to a driving signal, comprising: generating the driving signal in a manner having a driving frequency; sending the generated driving signal to the vibration device; detecting vibration information related to the vibration of the vibration device from the vibration device; and determining the driving frequency based on the detected vibration information.

[0022] Invention Effects

[0023] According to the present invention, the drive circuit and electronic equipment can drive the vibration device with high efficiency. Attached Figure Description

[0024] Figure 1 This is a diagram showing the first example of a drive circuit.

[0025] Figure 2 This is a flowchart illustrating a series of actions of the drive circuit in the first example.

[0026] Figure 3 This is a diagram showing a second example of a drive circuit.

[0027] Figure 4A It is a graph showing the relationship between the ratio of the driving frequency to the vibration frequency and the phase difference when the vibrating device is vibrating.

[0028] Figure 4B It is a graph showing the relationship between the ratio of the driving frequency to the vibration frequency and the amplitude ratio when the vibrating device is vibrating.

[0029] Figure 5 This is a flowchart illustrating a series of actions of the drive circuit in the second example.

[0030] Figure 6 This is a diagram illustrating an example of an electronic device equipped with a drive circuit. Detailed Implementation

[0031] The following is a reference to the appendix. Figure 1 The following description pertains to embodiments of the present invention (hereinafter referred to as "first embodiments" or "second embodiments"). To facilitate understanding, the same reference numerals will be used as much as possible to label the same constituent elements and steps in the accompanying drawings, and repeated descriptions will be omitted.

[0032] ―――First Implementation―――

[0033] First, the first embodiment will be described.

[0034] <Structure>

[0035] Figure 1 This diagram shows a first example of a drive circuit. The drive circuit 10A drives a vibration device 20, such as a tactile device. Furthermore, when driving the vibration device 20, the drive circuit 10A detects vibration information related to the vibration of the vibration device 20 and reflects the detected vibration information to the control of driving the vibration device 20. The drive circuit 10A is configured, for example, to include a signal generation unit 11, a detection unit 12A, a control unit 13A, and an output circuit 14A. The drive circuit 10A is, for example, mounted on an electronic device that uses the vibration device 20.

[0036] It should be noted that electronic devices equipped with the drive circuit 10A include, for example, a portable electronic pen, a user interface device installed in a car, a controller for a game device, a mobile phone, a smartphone, a tablet, a buzzer, a massager, and a toy with a vibration function. Additionally, electronic pens equipped with the drive circuit 10A include, for example, a stylus for a tablet and a pen-type device for VR (Virtual Reality).

[0037] The vibration device 20 is a tactile device such as an LRA (Linear Resonant Actuator) or an eccentric motor, which vibrates according to the drive control of the drive circuit 10A. When the short-circuit control elements SW1 and SW2 of the output circuit 14A are short-circuited, if a drive signal dr, whose signal is amplified via the output circuit 14A, is applied to both ends of the vibration device 20, the vibration device 20 vibrates according to the application. Conversely, when the short-circuit control elements SW1 and SW2 of the output circuit 14A are disconnected, the detection unit 12A detects vibration information related to the vibration of the vibration device 20 based on the change in the potential difference between the two ends of the vibration device 20 caused by its vibration. Furthermore, one end of the vibration device 20 is connected to one end of the short-circuit control element SW1 and one of the two input terminals of the detection unit 12A, and the other end of the vibration device 20 is connected to one end of the short-circuit control element SW2 and the other of the two input terminals of the detection unit 12A.

[0038] The signal generation unit 11 generates a drive signal dr with a drive frequency fdr and sends the generated drive signal dr to the vibration device 20. Specifically, the signal generation unit 11 generates the drive signal dr with a drive frequency fdr represented by the feedback signal fb sent from the control unit 13A, and sends the generated drive signal dr to the vibration device 20 via the output circuit 14A. It should be noted that the drive signal dr sent from the signal generation unit 11 is input to the logic NOT circuits INV1 and INV3 of the output circuit 14A.

[0039] The output circuit 14A converts the drive signal dr sent from the signal generation unit 11 into a differential signal that alternates in opposite phases, further amplifies the signal, and then outputs it to the vibration device 20. The output circuit 14A is configured, for example, to include logic NOT circuits INV1 to INV3 and short-circuit control elements SW1 and SW2.

[0040] The NOT circuits INV1 to INV3 are, for example, configured as inverter circuits containing transistors. The NOT circuit INV1 performs a NOT operation on the drive signal dr sent from the signal generation unit 11 and outputs the signal after the operation to the NOT circuit INV2.

[0041] The NOT circuit INV2 performs a NOT operation on the signal output from the NOT circuit INV1, and outputs the signal after the operation to one end of the vibration device 20 via the short-circuit control element SW1. Furthermore, the NOT circuit INV2 is configured to include transistors TR1 and TR2.

[0042] The NOT circuit INV3 performs a NOT operation on the drive signal dr sent from the signal generation unit 11, and outputs the signal after the operation to the other end of the vibration device 20 via the short-circuit control element SW2. Furthermore, the NOT circuit INV3 is configured to include transistors TR3 and TR4.

[0043] Transistors TR1 and TR3 are, for example, P-type MOS-FETs. Transistors TR1 and TR3 supply or deactivate the potential supplied to the source terminal to the drain terminal according to the signal input to the gate terminal. Specifically, when the signal input to the gate terminal is low, transistors TR1 and TR3 supply the potential supplied to the source terminal to the drain terminal; conversely, when the signal input to the gate terminal is high, they deactivate the potential supply.

[0044] Transistors TR2 and TR4 are, for example, N-type MOS-FETs. Transistors TR2 and TR4 extract charge from the drain terminal towards the source terminal or stop extracting charge according to the signal input to the gate terminal. Specifically, when the signal input to the gate terminal is in a high state, transistors TR2 and TR4 extract charge from the drain terminal towards the source terminal; on the other hand, when the signal input to the gate terminal is in a low state, they stop extracting charge.

[0045] The gate terminal of transistor TR1 is connected to the output terminal of the logic NOT circuit INV1 and the gate terminal of transistor TR2, supplying a power supply potential VDD to the source terminal of transistor TR1. The drain terminal of transistor TR1 is connected to the drain terminal of transistor TR2 and one end of the short-circuit control element SW1.

[0046] The gate terminal of transistor TR2 is connected to the output terminal of the logic NOT circuit INV1, and the source terminal of transistor TR2 is supplied with ground potential GND. The drain terminal of transistor TR2 is connected to the drain terminal of transistor TR1 and one end of the short-circuit control element SW1.

[0047] The gate terminal of transistor TR3 is connected to the output terminal of signal generation unit 11, the input terminal of logic NOT circuit INV1, and the gate terminal of transistor TR4. The power supply potential VDD is supplied to the source terminal of transistor TR3. The drain terminal of transistor TR3 is connected to the drain terminal of transistor TR4 and the other end of short-circuit control element SW2.

[0048] The gate terminal of transistor TR4 is connected to the output terminal of signal generation unit 11, the input terminal of logic NOT circuit INV1, and the gate terminal of transistor TR3. Ground potential GND is supplied to the source terminal of transistor TR4. The drain terminal of transistor TR4 is connected to the drain terminal of transistor TR3 and the other end of short-circuit control element SW2.

[0049] The short-circuit control elements SW1 and SW2 are, for example, switching elements or transistors. Under the control of the control unit 13A, they output an amplified drive signal dr from the output circuit 14A or stop the output. Specifically, one end of the short-circuit control element SW1 is connected to the drain terminals of transistors TR1 and TR2, and the other end is connected to one end of the vibration device 20 and one of the two input terminals of the detection unit 12A. The short-circuit control element SW1 short-circuits or disconnects its two ends under the control of the control unit 13A. Similarly, one end of the short-circuit control element SW2 is connected to the other end of the vibration device 20 and the other of the two input terminals of the detection unit 12A, and the other end is connected to the drain terminals of transistors TR3 and TR4. The short-circuit control element SW2 short-circuits or disconnects its two ends under the control of the control unit 13A.

[0050] The detection unit 12A detects vibration information related to the vibration of the vibration device 20 from the vibration device 20. Specifically, after the signal generation unit 11 stops sending the drive signal dr to the vibration device 20, the detection unit 12A acquires the time shift of the potential difference between the two ends of the vibration device 20 as a vibration signal, and detects the frequency, amplitude, etc. of the acquired signal as vibration information. It should be noted that the frequency of the signal acquired by the detection unit 12A represents the vibration frequency fres of the vibration device 20. The detection unit 12A outputs a detection signal res containing the detected vibration information to the control unit 13A.

[0051] The control unit 13A determines the drive frequency fdr based on vibration information such as vibration frequency fres and amplitude detected by the detection unit 12A, and sends the determined drive frequency fdr as a feedback signal fb to the signal generation unit 11. Specifically, the control unit 13A determines the drive frequency fdr in a manner that makes the drive frequency fdr close to the vibration frequency fres. In addition, the control unit 13A determines the drive frequency fdr in a manner that increases the amplitude represented by the vibration information. Furthermore, the control unit 13A controls the transmission and cessation of the drive signal dr performed by the signal generation unit 11, the short-circuiting and opening of the short-circuit control elements SW1 and SW2, and the detection and cessation of vibration information from the vibration device 20 performed by the detection unit 12A.

[0052] Next, an example of an electronic device equipped with the drive circuit 10A according to the first embodiment will be described. Figure 6 This is a diagram showing an example of an electronic device 1 equipped with a drive circuit 10A. Figure 6 The electronic device 1 shown is, for example, a stylus for a tablet or a pen-type device for VR. Electronic device 1 is configured to include, for example, a drive circuit 10A, a vibration device 20, an input circuit 30, a transceiver circuit 40, and a control circuit 50. The structure and operation of the drive circuit 10A and the vibration device 20 are as described above, therefore their description is omitted.

[0053] The input circuit 30 is a circuit used to convert the received operation into a signal when the operator of the electronic device 1 receives the operation through the input interface. The input circuit 30 converts the operation received from the operator into a signal containing information related to the operation content, and sends the converted signal to the control circuit 50.

[0054] The transceiver circuit 40 is used for communication between the electronic device 1 and devices other than the electronic device 1. For example, the transceiver circuit 40 transmits and receives signals indicating the position of a pen, the degree of pressure applied by the pen to the tablet, etc., with tablets, VR devices, etc. Additionally, the transceiver circuit 40 receives signals for transmission from the control circuit 50 and outputs the received signals to the control circuit 50.

[0055] The control circuit 50 is a circuit used to control the operation of the electronic device 1. The control circuit 50 generates a transmission signal based on the signal sent from the input circuit 30 and the signal received from the transceiver circuit 40, and outputs the generated signal to the transceiver circuit 40. Furthermore, the control circuit 50 outputs commands related to the vibration operation of the vibration device 20 to the drive circuit 10A based on the signals sent from the input circuit 30 and received from the transceiver circuit 40. In addition, the control circuit 50 performs various other controls necessary for the electronic device 1 to function as an electronic pen.

[0056] When the electronic device 1 configured as described above starts up, resumes from a sleep mode for battery saving, or so on, the drive circuit 10A performs a process to correct the drive frequency fdr so that it is close to the vibration frequency fres. Furthermore, after the drive frequency fdr correction process is completed, the electronic device 1 performs processing according to the operator's commands or commands from other devices with which it is transmitting and receiving data.

[0057] Furthermore, when the electronic device 1 functions as an electronic pen, when the operator places the electronic device 1 in contact with the tablet to indicate a position, the drive circuit 10A is driven in such a way that the degree of vibration of the vibration device 20 is changed according to the pressure applied to the tablet. Thus, the electronic device 1 can reproduce the writing and drawing feel of an analog pen while functioning as a digital pen.

[0058] Furthermore, when the electronic device 1 functions as a VR pen, the drive circuit 10A is activated by the operator pointing the electronic device 1 at a virtual plane positioned in space, thereby changing the degree of vibration of the vibration device 20 according to the moving speed and acceleration relative to the virtual plane. Thus, the electronic device 1 can reproduce the writing and drawing sensations of a simulated pen while functioning as a VR pen.

[0059] <The flow of a series of actions>

[0060] The above describes the various components of the drive circuit 10A and electronic device 1, as well as the vibration device 20, according to the first embodiment. Next, the flow of a series of operations of the drive circuit 10A according to the first embodiment will be described. Figure 2 This is a flowchart illustrating a series of operations of the drive circuit 10A in the first example.

[0061] (Step SP10)

[0062] The drive circuit 10A uses the control unit 13A to control the two ends of the short-circuit control elements SW1 and SW2 to be in a short-circuit state respectively. Then, it processes the shift step SP12.

[0063] (Step SP12)

[0064] The drive circuit 10A, using the control unit 13A, causes the signal generation unit 11 to generate a drive signal dr, which is then applied to the vibration device 20 for a predetermined time via the output circuit 14A. It should be noted that the signal generation unit 11 generates the drive signal dr with a drive frequency fdr having an initial value determined or predetermined by the control unit 13A. Then, the process moves to step SP14.

[0065] (Step SP14)

[0066] The drive circuit 10A uses the control unit 13A to stop the generation and application of the drive signal dr performed by the signal generation unit 11. Next, the drive circuit 10A uses the control unit 13A to control the two ends of the short-circuit control elements SW1 and SW2 to be in an open state respectively. Then, the process of moving to step SP16 is processed.

[0067] (Step SP16)

[0068] The drive circuit 10A uses the control unit 13A to cause the detection unit 12A to acquire the time shift of the potential difference between the two ends of the vibration device 20 as a vibration signal, and detects the frequency of the acquired vibration signal as the vibration frequency fres of the vibration device 20. Then, the process moves to step SP18.

[0069] (Step SP18)

[0070] The drive circuit 10A, using the control unit 13A, calculates the difference between the drive frequency fdr and the vibration frequency fres, and determines whether the calculated difference is within a specified range. The specified range may be, for example, a range between a predetermined upper and lower limit relative to the calculated difference, or a range between a predetermined upper and lower limit relative to the ratio of the calculated difference to the drive frequency fdr (e.g., ±1% relative to the drive frequency fdr). If the determination is negative, the drive circuit 10A determines that the drive frequency fdr is inappropriate relative to the vibration device 20 and proceeds to step SP20. Conversely, if the determination is positive, the drive circuit 10A determines that the drive frequency fdr is appropriate relative to the vibration device 20. Figure 2 The series of processes shown has ended.

[0071] (Step SP20)

[0072] The drive circuit 10A uses the control unit 13A to determine whether the drive frequency fdr is lower than the vibration frequency fres. If the determination is positive, the process proceeds to step SP22. Conversely, if the determination is negative, the process proceeds to step SP24.

[0073] (Step SP22)

[0074] The drive circuit 10A, using the control unit 13A, increases the drive frequency fdr compared to its current value. When increasing the drive frequency fdr, the control unit 13A can increase it by a predetermined value, by a predetermined percentage, or by increasing it to the same value as the vibration frequency fres. Then, the process returns to step SP10.

[0075] (Step SP24)

[0076] The drive circuit 10A, using the control unit 13A, reduces the drive frequency fdr compared to its current value. When reducing the drive frequency fdr, the control unit 13A can reduce it by a predetermined value, a predetermined percentage, or reduce it to the same value as the vibration frequency fres. Then, the process returns to step SP10.

[0077] <Effect>

[0078] In the first embodiment described above, the drive circuit 10A is a drive circuit 10A that drives the vibration device 20 that vibrates according to the drive signal dr. It includes: a signal generation unit 11 that generates the drive signal dr with a drive frequency fdr and sends the generated drive signal dr to the vibration device 20; a detection unit 12A that detects vibration information related to the vibration of the vibration device 20 from the vibration device 20; and a control unit 13A that determines the drive frequency fdr based on the vibration information detected by the detection unit 12A and sends the determined drive frequency fdr to the signal generation unit 11.

[0079] According to this structure, the drive circuit 10A determines the drive frequency fdr based on the vibration information of the vibration device 20, thus enabling the vibration device 20 to be driven with high efficiency.

[0080] In addition, in the first embodiment, the vibration information is the vibration frequency fres of the vibration device 20.

[0081] According to this structure, the drive circuit 10A determines the drive frequency fdr based on the vibration frequency fres of the vibration device 20, thus enabling the vibration device 20 to be driven with high efficiency.

[0082] In addition, in the first embodiment, the control unit 13A determines the drive frequency fdr in such a way that the drive frequency fdr is close to the vibration frequency fres.

[0083] According to this structure, the drive circuit 10A makes the drive frequency fdr close to the vibration frequency fres of the vibration device 20, thus enabling the vibration device 20 to be driven with high efficiency.

[0084] In addition, in the first embodiment, the vibration information is the amplitude of the vibration signal generated by the vibration of the vibration device 20.

[0085] According to this structure, the drive circuit 10A determines the drive frequency fdr based on the amplitude of the vibration signal, thus enabling it to drive the vibration device 20 with high efficiency.

[0086] In addition, in the first embodiment, the control unit 13A determines the driving frequency fdr in a manner that increases the amplitude of the vibration signal.

[0087] According to this structure, the drive circuit 10A determines the drive frequency fdr in a way that increases the amplitude of the vibration signal, thus enabling the vibration device 20 to be driven with high efficiency.

[0088] In addition, in the first embodiment, the electronic device 1 includes: a vibration device 20 that vibrates according to a drive signal dr; and a drive circuit 10A having a signal generation unit 11, a detection unit 12A, and a control unit 13A. The signal generation unit 11 generates a drive signal dr with a drive frequency fdr and sends the generated drive signal dr to the vibration device 20. The detection unit 12A detects vibration information related to the vibration of the vibration device 20 from the vibration device 20. The control unit 13A determines the drive frequency fdr based on the vibration information detected by the detection unit 12A and sends the determined drive frequency fdr to the signal generation unit 11.

[0089] According to this structure, the electronic device 1 determines the driving frequency fdr based on the vibration information of the vibration device 20, thus enabling it to drive the vibration device 20 with high efficiency.

[0090] In addition, in the first embodiment, the electronic device 1 functions as an electronic pen.

[0091] According to this structure, when the electronic pen containing the vibration device 20 is used, the electronic device 1 determines the driving frequency fdr based on the vibration information, and thus can drive the vibration device 20 of the electronic pen with high efficiency.

[0092] In addition, in the first embodiment, the driving method of the vibration device 20 is a driving method for driving the vibration device 20 that vibrates according to the driving signal dr, which includes: generating the driving signal dr in a manner having a driving frequency fdr; sending the generated driving signal dr to the vibration device 20; detecting vibration information related to the vibration of the vibration device 20 from the vibration device 20; and determining the driving frequency fdr based on the detected vibration information.

[0093] According to this method, the driving method of the vibration device 20 determines the driving frequency fdr based on the vibration information of the vibration device 20, thus enabling the vibration device 20 to be driven with high efficiency.

[0094] ―――Second Implementation―――

[0095] Next, the second embodiment will be described.

[0096] <Structure>

[0097] Figure 3This diagram shows a second example of the drive circuit. The drive circuit 10B is configured, for example, by replacing the output circuit 14A with the drive circuit 10A, providing the detection unit 12B with the detection unit 12A, and providing the control unit 13B with the control unit 13A. It should be noted that the signal generation unit 11 is the same as in the first embodiment, except that it sends the generated drive signal dr not only to the output circuit 14A but also to the detection unit 12B; therefore, its description is omitted.

[0098] The vibration device 20 is the same as in the first embodiment, vibrating according to the drive control of the drive circuit 10A. If a drive signal dr, whose signal is amplified via the output circuit 14B, is applied to both ends of the vibration device 20, the vibration device 20 vibrates accordingly. Furthermore, one end of the vibration device 20 is connected to the drain terminals of transistors TR1 and TR2 in the output circuit 14B, and the other end of the vibration device 20 is connected to the drain terminals of transistors TR3 and TR4 in the output circuit 14B and the input terminal of the detection unit 12B.

[0099] Output circuit 14B is configured by eliminating short-circuit control elements SW1 and SW2 relative to output circuit 14A. The NOT circuit INV2 in output circuit 14B performs a NOT operation on the signal output from NOT circuit INV1, and outputs the signal after this operation to one end of the vibration device 20. Furthermore, the NOT circuit INV3 in output circuit 14B performs a NOT operation on the drive signal dr sent from signal generation unit 11, and outputs the signal after this operation to the other end of the vibration device 20.

[0100] The detection unit 12B detects vibration information related to the vibration of the vibration device 20. Specifically, the detection unit 12B begins detecting vibration information of the vibration device 20 based on the drive signal dr sent from the signal generation unit 11 to the output circuit 14B and the detection unit 12B. Here, the detection unit 12B detects the time shift between the drive signal dr and the potential at the other end of the vibration device 20, i.e., the phase difference θ of the vibration signal, the amplitude of the vibration signal, etc., as vibration information. In addition, the detection unit 12B outputs a detection signal res containing the detected vibration information to the control unit 13B.

[0101] It should be noted that when detecting the phase difference θ between the drive signal dr and the vibration signal, the detection unit 12B uses a phase synchronization circuit such as a PLL (phase-locked loop) for detection. Additionally, the detection unit 12B measures, for example, the time from the rise time of the potential of the drive signal dr to the rise time of the potential of the vibration signal. The detection unit 12B can also divide the measured time by the period of the drive signal dr or the vibration signal, and calculate the phase difference θ by converting the division result into a phase difference.

[0102] The control unit 13A determines the drive frequency fdr based on vibration information such as phase difference θ and amplitude detected by the detection unit 12B, and sends the determined drive frequency fdr to the signal generation unit 11. Specifically, the control unit 13B determines the drive frequency fdr such that the absolute value of the phase difference θ is close to, for example, π / 2. Furthermore, the control unit 13B determines the drive frequency fdr such that the amplitude represented by the vibration information increases. In addition, the control unit 13B controls the transmission and cessation of the drive signal dr performed by the signal generation unit 11, and the detection and cessation of vibration information from the vibration device 20 performed by the detection unit 12B.

[0103] While referring to Figure 4A and Figure 4B The relationship between the ratio of the driving frequency fdr to the vibration frequency fres, the phase difference θ, and the amplitude ratio when the vibrating device 20 is vibrating is explained. Figure 4A This is a graph showing the relationship between the ratio of the driving frequency fdr to the vibration frequency fres and the phase difference θ when the vibrating device 20 is vibrating. Additionally, Figure 4B It is a graph showing the relationship between the ratio of the driving frequency fdr to the vibration frequency fres and the amplitude multiple when the vibrating device 20 is vibrating.

[0104] like Figure 4A As shown, the ratio of the driving frequency fdr to the vibration frequency fres is 1.0 regardless of whether the vibration attenuation ratio of the vibrating device 20 is 0, 0.2, 0.5, or 1.0, when the phase difference θ is π / 2. That is, the driving frequency fdr is approximately equal to the vibration frequency fres when the phase difference θ is π / 2.

[0105] In addition, such as Figure 4B As shown, regardless of whether the damping ratio of the vibration of the vibrating device 20 is 0, 0.2, 0.5, or 1.0, the amplitude ratio increases as the ratio of the driving frequency fdr to the vibration frequency fres approaches 1.0. It should be noted that the amplitude ratio is roughly at its maximum when the driving frequency fdr is slightly larger than the vibration frequency fres.

[0106] <The flow of a series of actions>

[0107] The components of the drive circuit 10B and the vibration device 20 according to the second embodiment have been described above. Next, the flow of a series of operations of the drive circuit 10B according to the second embodiment will be described. Figure 5 This is a flowchart illustrating a series of operations of the drive circuit 10B in the second example.

[0108] (Step SP50)

[0109] The drive circuit 10B, using the control unit 13B, causes the signal generation unit 11 to generate a drive signal dr, which is then applied to the vibration device 20 for a predetermined time via the output circuit 14B. It should be noted that the signal generation unit 11 generates the drive signal dr with a drive frequency fdr having an initial value determined or predetermined by the control unit 13B. Then, the process moves to step SP52.

[0110] (Step SP52)

[0111] The drive circuit 10B uses the control unit 13B to cause the detection unit 12B to acquire the time shift of the potential at the other end of the vibration device 20 as a vibration signal, and detects the phase difference θ between the acquired vibration signal and the drive signal dr. Then, the process of shifting to step SP54 is processed.

[0112] (Step SP54)

[0113] The drive circuit 10B, using the control unit 13B, determines whether the phase difference θ is within a specified range. The specified range is, for example, the range between an upper and lower limit value predetermined based on π / 2. The upper and lower limits are, for example, π / 2 ± 1%. Furthermore, if the determination is negative, the drive circuit 10B determines that the drive frequency fdr is inappropriate for the vibration device 20 and proceeds to step SP56. Conversely, if the determination is positive, the drive circuit 10B determines that the drive frequency fdr is appropriate for the vibration device 20. Figure 5 The series of processes shown has ended.

[0114] (Step SP56)

[0115] The drive circuit 10B uses the control unit 13B to determine whether the phase difference θ is a value greater than 0 and less than π / 2. If the determination is positive, the process proceeds to step SP58. Conversely, if the determination is negative, the process proceeds to step SP60.

[0116] (Step SP58)

[0117] The drive circuit 10B, using the control unit 13B, increases the drive frequency fdr compared to its current value. When increasing the drive frequency fdr, the control unit 13B can increase it by a predetermined value or by a predetermined percentage. Then, the process returns to step SP52.

[0118] (Step SP60)

[0119] The drive circuit 10B, using the control unit 13B, reduces the drive frequency fdr compared to its current value. When reducing the drive frequency fdr, the control unit 13B can reduce it by a predetermined value or by a predetermined percentage. Then, the process returns to step SP52.

[0120] <Effect>

[0121] In the second embodiment, the vibration information is the phase difference θ between the vibration signal generated by the vibration of the vibration device 20 and the drive signal dr.

[0122] According to this structure, the drive circuit 10B determines the drive frequency fdr based on the phase difference θ between the vibration signal and the drive signal dr, thus enabling high-efficiency driving of the vibration device 20. Furthermore, the drive frequency fdr can be determined even when the drive signal dr is applied.

[0123] In addition, in the second embodiment, the control unit 13B determines the driving frequency fdr in such a way that the phase difference θ is close to a predetermined value (e.g., π / 2).

[0124] According to this structure, the drive circuit 10B determines the drive frequency fdr in a manner that brings the phase difference θ close to a predetermined value, thus enabling high-efficiency driving of the vibration device 20. Furthermore, the drive frequency fdr can be determined even when a drive signal dr is applied.

[0125] In addition, in the second embodiment, the vibration information is the amplitude of the vibration signal generated by the vibration of the vibration device 20.

[0126] According to this structure, the drive circuit 10B determines the drive frequency fdr based on the amplitude of the vibration signal, thus enabling high-efficiency driving of the vibration device 20. Furthermore, the drive frequency fdr can be determined while the drive signal dr is applied.

[0127] In addition, in the second embodiment, the control unit 13B determines the driving frequency fdr in a manner that increases the amplitude of the vibration signal.

[0128] According to this structure, the drive circuit 10B determines the drive frequency fdr in a way that increases the amplitude of the vibration signal, thus enabling high-efficiency driving of the vibration device 20. Furthermore, the drive frequency fdr can be determined while the drive signal dr is applied.

[0129] ―――Variations―――

[0130] It should be noted that the present invention is not limited to the embodiments described above. That is, any technology obtained by those skilled in the art through appropriate design modifications to the above embodiments is also included within the scope of the present invention, as long as it possesses the features of the present invention. Furthermore, the elements of the above embodiments and the variations described below can be combined within a technically feasible range, and any technology formed by combining them is also included within the scope of the present invention, as long as it contains the features of the present invention.

[0131] For example, in the first embodiment, the detection unit 12A obtains the time shift of the potential difference between the two ends of the vibration device 20 as a vibration signal, but it is not limited to this. The detection unit 12A may also obtain the time shift of the potential at one of the two ends of the vibration device 20 as a vibration signal.

[0132] According to this structure, the drive circuit 10A references the potential of one of the two ends of the vibration device 20, thus reducing the need for components used for differential signal processing, and enabling the vibration device 20 to be driven at low cost and high efficiency.

[0133] In addition, in the second embodiment, the detection unit 12B obtains the time shift of the potential at the other end of the vibration device 20 as a vibration signal, but is not limited to this. The detection unit 12B may also obtain the time shift of the potential difference between the two ends of the vibration device 20 as a vibration signal.

[0134] According to this structure, the drive circuit 10A references the potential difference between the two ends of the vibration device 20, thus enabling the vibration device 20 to be driven with high precision and high efficiency.

[0135] Furthermore, in the first embodiment, the electronic device 1 increases or decreases the drive frequency fdr in the process of correcting the drive frequency fdr to be close to the vibration frequency fres, but is not limited to this. The electronic device 1 may also increase or decrease the drive frequency fdr in a manner close to the vibration frequency fres during the stages after the drive frequency fdr correction process has been performed at startup timing and sleep mode release timing, and during the stages after receiving operator commands or commands from other electronic devices.

[0136] Specifically, electronic device 1 uses drive circuit 10A to control short-circuit control elements SW1 and SW2 to a short-circuit state. Next, electronic device 1 uses drive circuit 10A to obtain the vibration signal by measuring the time shift of the potential difference across the two ends of the vibration device 20, and detects and stores the amplitude of the obtained vibration signal. Electronic device 1 refers to the most recent shift of the calculated amplitude difference and the history of increases and decreases in the drive frequency fdr.

[0137] Electronic device 1 uses drive circuit 10A to determine whether the amplitude obtained this time has increased compared to the amplitude obtained last time. If the determination is positive, electronic device 1 uses drive circuit 10A to increase the drive frequency fdr if it increased last time, and decrease the drive frequency fdr if it decreased last time. Conversely, if the determination is negative, electronic device 1 uses drive circuit 10A to decrease the drive frequency fdr if it increased last time, and increase the drive frequency fdr if it decreased last time. It should be noted that immediately after electronic device 1 begins receiving commands from the operator or other electronic devices, it can also increase or decrease the drive frequency fdr by a predetermined value to confirm the shift in the amplitude of the potential difference across the vibrating device 20.

[0138] According to this structure, the electronic device 1 is also determined in such a way that the driving frequency fdr is close to the vibration frequency fres during the operation of the electronic device 1 by the operator, so that the vibration device 20 can be driven with high efficiency during the operation of the operator.

[0139] Furthermore, in the stages where the electronic device 1 equipped with the drive circuit 10A according to the first embodiment performs drive frequency fdr correction processing at the startup timing and the sleep mode release timing, and then receives operator operations or commands from other electronic devices, the drive frequency fdr is increased or decreased in a manner close to the vibration frequency fres. However, when equipped with the drive circuit 10B according to the second embodiment, the same processing can also be performed. It should be noted that the electronic device 1 equipped with the drive circuit 10B performs the same processing as the electronic device 1 equipped with the drive circuit 10A, except for the short-circuit and open-circuit control elements SW1 and SW2, so its description is omitted.

[0140] According to this structure, the electronic device 1 is also determined in such a way that the driving frequency fdr is close to the vibration frequency fres during the operation of the electronic device 1 by the operator, so that the vibration device 20 can be driven with high efficiency during the operation of the operator.

[0141] Explanation of reference numerals in the attached figures

[0142] 1…electronic device, 10A…drive circuit, 10B…drive circuit, 11…signal generation unit, 12A…detection unit, 12B…detection unit, 13A…control unit, 13B…control unit, 20…vibration device.

Claims

1. A driving circuit is a driving circuit for driving a vibration device that vibrates according to a driving signal, wherein: have: a signal generating unit, generating the driving signal in a manner having a driving frequency, and sending the generated driving signal to the vibration device; a detection unit that detects vibration information related to the vibration of the vibration device from the vibration device; and The control unit determines the driving frequency based on the vibration information detected by the detection unit, and transmits the determined driving frequency to the signal generation unit.

2. The driving circuit according to claim 1, The vibration information is the vibration frequency of the vibration device.

3. The driving circuit according to claim 2, The control unit determines the driving frequency so that the driving frequency approaches the vibration frequency.

4. The driving circuit according to any one of claims 1 to 3, The detection unit detects the vibration information from the vibration device after the signal generation unit stops transmitting the drive signal to the vibration device.

5. The driving circuit according to claim 1, The vibration information is a phase difference between a vibration signal generated by the vibration of the vibration device and the drive signal.

6. The driving circuit according to claim 5, The control unit determines the driving frequency so that the phase difference approaches a predetermined value.

7. The driving circuit according to claim 1, The vibration information is the amplitude of a vibration signal generated due to the vibration of the vibration device.

8. The driving circuit according to claim 7, The control unit determines the driving frequency so as to increase the amplitude.

9. An electronic device comprising: a vibration device that vibrates in response to a drive signal; and The driving circuit includes a signal generating unit, a detecting unit and a controlling unit. The signal generating unit generates the driving signal in a manner having a driving frequency and sends the generated driving signal to the vibration device. The detecting unit detects vibration information related to the vibration of the vibration device from the vibration device. The controlling unit determines the driving frequency based on the vibration information detected by the detecting unit and sends the determined driving frequency to the signal generating unit.

10. The electronic device according to claim 9, Functions as an electronic pen.

11. A method for driving a vibration device, which is a method for driving a vibration device that vibrates according to a driving signal, wherein: include: generating the driving signal in a manner having a driving frequency; sending the generated driving signal to the vibration device; detecting, from the vibration device, vibration information associated with the vibration of the vibration device; and The driving frequency is determined based on the detected vibration information.

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