Frequency-adjustable integrated circuit for treating xerophthalmia

Abstract

The invention discloses a frequency-adjustable integrated circuit for treating xerophthalmia, and belongs to the technical field of electronic circuits. According to the circuit, a battery charging module controls a charging current to a safe range through a current-limiting resistor and a temperature-limiting resistor, and stabilizes an input voltage through a filter capacitor; the voltage stabilizing module outputs 3.3 V voltage and supplies power to the control module, the driving module and the communication module through a capacitor; the communication module is connected with the control module through a serial port resistor and receives an external instruction; the control module adjusts the duty ratio of an input signal of the driving module based on the PWM technology, dynamically adjusts the current output of the vibration motor load module, and achieves the precise control of the vibration frequency. Through the real-time feedback and frequency adjustment functions, the problem that an existing single-frequency device is poor in adaptability is solved, personalized treatment requirements can be met, curative effect decline caused by nerve adaptability is avoided, meanwhile, the system state is fed back in real time through the indicator lamp module, and the safety and scientificity of treatment are improved.

Description

Technical Field

[0001] The present invention belongs to the field of electronic circuit design, and particularly relates to an adjustable frequency integrated circuit applied to the treatment of dry eye disease. Background Art

[0002] So far, the massage devices for treating dry eye disease on the market have a single frequency or intensity. On the one hand, the massage instrument with a single vibration frequency cannot meet the individualized needs and cannot adjust the stimulation frequency according to the personal needs of users to improve the treatment effect. For example, some patients may need low-frequency vibration to avoid excessive stimulation, while other patients may need high-frequency vibration to effectively promote tear secretion; the single fixed frequency cannot be dynamically adjusted according to the real-time feedback of patients (such as the amount of tear secretion, comfort), which may lead to insufficient or excessive stimulation and affect the treatment effect. On the other hand, long-term use of vibration stimulation with a single frequency may lead to the adaptability of the nervous system, making patients gradually numb to the stimulation of this frequency, thus reducing the promotion effect on tear secretion. The device with adjustable frequency can avoid nerve adaptability and maintain the treatment effect by changing the frequency. By adjusting the vibration frequency, the situation of excessive or insufficient stimulation is avoided, making the treatment process more scientific and effective. At the same time, the use of frequency adjustment technology can reduce the discomfort of patients, lower the treatment cost, and has good prospects for popularization and application. Summary of the Invention

[0003] The present invention provides an adjustable frequency integrated circuit applied to the treatment of dry eye disease to solve the problems existing in the above-mentioned prior art.

[0004] To achieve the above object, the present invention provides an adjustable frequency integrated circuit applied to the treatment of dry eye disease, including:

[0005] A communication module, configured to receive an instruction signal from an external device and transmit it to the control module;

[0006] A control module, configured to generate an adjustment signal according to the instruction signal of the external device;

[0007] A driving module, configured to adjust the current and power of the vibration motor load module according to the adjustment signal;

[0008] A vibration motor load module, configured to generate a vibration stimulus corresponding to the adjusted current and power;

[0009] A battery charging module, configured to provide a power input for the circuit;

[0010] A voltage stabilizing module, configured to stabilize the input voltage and supply power to the communication module, control module and driving module;

[0011] A clock oscillation module, configured to provide a clock signal for the circuit.

[0012] Preferably, the circuit further includes an indicator load module and a charging port. The indicator load module is used to provide real-time feedback on the operating status of the device, and the charging port is used to provide an input interface for an external power supply.

[0013] Preferably, the communication module includes:

[0014] A communication power input terminal, connected to the output terminal of the voltage regulation module, for receiving power input;

[0015] A serial port transmission terminal, connected to the control module through a sixth resistor, for sending instructions;

[0016] A serial port reception terminal, connected to the control module through a seventh resistor, for receiving instructions;

[0017] An operating status output terminal, connected to the detection input terminal of the control module, for providing feedback on the communication connection status.

[0018] Preferably, the control module includes:

[0019] A control power input terminal, connected to the output terminal of the voltage regulation module, for receiving power;

[0020] A detection input terminal, connected to the charging status output terminal of the battery charging module and the operating status output terminal of the communication module, for detecting the charging status and communication connection status in real time;

[0021] A PWM output terminal, connected to the pulse width modulation input terminal of the drive module, for sending a PWM signal for adjusting the vibration frequency;

[0022] A logic control pin, connected to the enable terminal of the drive module, for controlling the operating status of the drive module;

[0023] A status output terminal, connected to the positive pole of the indicator load module, for controlling the lighting and extinguishing of the indicator lamp and providing real-time feedback on the operating status of the device;

[0024] An external clock input terminal and an output terminal, connected to an external clock system, for synchronizing the timing;

[0025] The serial debug clock line and the serial debug data line of the control chip of the control module are respectively connected to one end of a fourth resistor and a fifth resistor, and the other ends of the fourth resistor and the fifth resistor are respectively connected to ground and power supply.

[0026] Preferably, the drive module includes:

[0027] A drive power input terminal, connected to the output terminal of the voltage regulation module, for receiving power;

[0028] The logic power input terminal is connected to the output terminal of the voltage regulation module through the ninth filter capacitor and the tenth filter capacitor to provide motor power for the drive chip;

[0029] The pulse width modulation input terminal is connected to the PWM output terminal of the control module to receive the PWM signal;

[0030] The enable terminal is connected to the logic control pin of the control module to control the working state of the drive chip;

[0031] The output terminal is connected to the vibration motor load module to drive the vibration motor to work.

[0032] Preferably, the vibration motor load module includes:

[0033] The vibration motor is connected to the output terminal of the drive module to generate vibration stimulation according to the received current and power;

[0034] The filter capacitor is connected in parallel with the power supply terminal of the vibration motor to suppress the voltage fluctuation generated when the motor works.

[0035] Preferably, the battery charging module includes:

[0036] The external power input terminal is connected to an external power supply to provide power input for the entire circuit;

[0037] The first resistor has one end connected to the power input terminal and the other end connected to the power supply terminal of the battery charging chip for current limiting;

[0038] The second resistor has one end connected to the first resistor and the other end connected to the CE terminal of the battery charging chip for temperature limiting;

[0039] The third resistor has one end connected to the PROG pin of the battery charging chip and the other end grounded to set the charging current of the battery charging chip;

[0040] The first filter capacitor has one end connected to the BAT pin of the battery charging chip and the other end grounded to smooth the charging current

[0041] The fourth filter capacitor has one end connected to the output terminal of the battery charging chip and the other end connected to ground to filter out high-frequency noise;

[0042] The charging state output terminal is connected to the detection input terminal of the control module to feedback the charging state.

[0043] Preferably, the voltage regulation module includes:

[0044] The voltage regulation chip input terminal is connected to the charging output terminal of the battery charging module to receive the input voltage;

[0045] The output terminal of the voltage regulator chip is connected to the power input terminals of the control module, the drive module, and the communication module, and is used to output voltage.

[0046] The second filter capacitor and the third filter capacitor are connected in parallel between the input voltage source and the ground, and are used to stabilize the input voltage.

[0047] Preferably, the clock oscillation module includes:

[0048] A crystal oscillator, which is used to generate a clock signal;

[0049] The seventh filter capacitor and the eighth filter capacitor are respectively connected to both ends of the crystal oscillator and grounded, and are used to stabilize the oscillation frequency.

[0050] Preferably, the working process of the circuit for adjusting the vibration frequency includes:

[0051] The communication module receives a message from an external transmitter and forwards it to the control module. The control module uses pulse width modulation technology to adjust the duty cycle of the input signal; by adjusting the duty cycle, the periodic fluctuation of the signal is changed, so as to adjust the vibration frequency within different frequency ranges;

[0052] The control module inputs the adjusted control signal into the drive module. The drive module adjusts the vibration frequency of the vibration motor load module according to the control signal; the drive module controls the vibration speed of the motor by adjusting the magnitude and frequency of the motor current, so as to obtain the required vibration frequency.

[0053] Compared with the prior art, the present invention has the following advantages and technical effects:

[0054] In the present invention, the vibration frequency is dynamically adjusted through pulse width modulation (PWM) technology, and low-frequency or high-frequency stimulation is provided according to the actual needs of the patient, avoiding insufficient or excessive stimulation caused by a single frequency, realizing precise and controllable personalized treatment, and the components used in the circuit are less, reducing costs and reducing the occurrence of failures at the same time.

[0055] In the present invention, by combining the communication module to receive external instructions and the real-time detection function of the control module, the vibration parameters can be dynamically adjusted according to the real-time feedback of the patient, enhancing the scientificity and flexibility of the treatment. Description of the Drawings

[0056] The drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation of this application. In the drawings:

[0057] Figure 1 It is the overall circuit structure diagram of the embodiment of the present invention;

[0058] Figure 2This is the circuit sub-module structure diagram of the embodiment of the present invention. Detailed implementation manners

[0059] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0060] It should be noted that the steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from that here.

[0061] Embodiment 1

[0062] As Figure 1 - Figure 2 shown, in this embodiment, an adjustable frequency integrated circuit applied to the treatment of dry eye is provided, including:

[0063] A communication module, configured to receive an instruction signal from an external device and transmit it to the control module;

[0064] A control module, configured to generate an adjustment signal according to the instruction signal from the external device;

[0065] A drive module, configured to adjust the current and power of the vibration motor load module according to the adjustment signal;

[0066] A vibration motor load module, configured to generate a vibration stimulus corresponding to the adjusted current and power;

[0067] A battery charging module, configured to provide a power input for the circuit;

[0068] A voltage stabilization module, configured to stabilize the input voltage and supply power to the communication module, the control module and the drive module;

[0069] A clock oscillation module, configured to provide a clock signal for the circuit;

[0070] An indicator light load module and a charging port, the indicator light load module is configured to feedback the working state of the device in real time, and the charging port is configured to provide an input interface for an external power supply.

[0071] Further, the communication module includes:

[0072] A communication power input terminal, connected to the output terminal of the voltage stabilization module, configured to receive a power input;

[0073] A serial port sending end, connected to the control module through a sixth resistor R6, configured to send an instruction;

[0074] A serial port receiving end, connected to the control module through a seventh resistor R7, configured to receive an instruction;

[0075] The working state output terminal is connected to the detection input terminal of the control module and is used to feedback the communication connection state.

[0076] Among them, the serial port transmitter TX and receiver RX of the communication chip in the communication module are respectively connected to the corresponding pins of the control module through the sixth resistor R6 and the seventh resistor R7 to realize instruction transmission. The working state output terminal PA1 is connected to the detection input terminal of the control module and is used to feedback the communication connection state (such as waiting to connect / connection successful).

[0077] The communication module also communicates with Bluetooth. When the user does not connect to Bluetooth within 10s, the system enters the sleep state to reduce the system power consumption;

[0078] When the Bluetooth is disconnected, it will flash for 10s, and when the Bluetooth is connected, it will be on constantly for 5s;

[0079] The system also includes a touch switch, which is connected to the PA0 terminal of the STM32 main control chip, and only needs to be pressed once to turn on the machine.

[0080] Furthermore, the control module includes:

[0081] The control power input terminal is connected to the output terminal of the voltage stabilization module and is used to receive power;

[0082] The detection input terminal is connected to the charging state output terminal of the battery charging module and the working state output terminal of the communication module, and is used to detect the charging state and the communication connection state in real time;

[0083] The PWM output terminal is connected to the pulse width modulation input terminal of the drive module and is used to send a PWM signal for adjusting the vibration frequency;

[0084] The logic control pin is connected to the enable terminal of the drive module and is used to control the working state of the drive module;

[0085] The state output terminal is connected to the positive pole of the indicator load module and is used to control the lighting and extinguishing of the indicator lamp and feedback the working state of the device in real time;

[0086] The external clock input terminal and output terminal are connected to the external clock system and are used to synchronize the timing;

[0087] The serial debug clock line and serial debug data line of the control chip of the control module are respectively connected to one end of the fourth resistor R4 and the fifth resistor R5, and the other ends of the fourth resistor R4 and the fifth resistor R5 are respectively connected to the ground and the power supply.

[0088] Specifically, the control module is connected to the communication module through serial communication technology, and the timing is synchronized through an external clock system. The positive pole of LED1 of the indicator load module is connected to the status output terminal of the control module to indicate the operating status of each module of the circuit system to the user. The user sends the target vibration frequency instruction through the mobile phone software. After the communication module receives the instruction, it transmits the data to the control module through the serial port. After the control chip parses the instruction, it calls the preset PWM algorithm to adjust the duty cycle of the output signal. When the vibration frequency needs to be increased, the duty cycle of the PWM signal is increased; otherwise, the duty cycle is reduced. The control module inputs the generated PWM signal into the drive module, and the drive chip adjusts the current and voltage output to the vibration motor according to the signal duty cycle. When the duty cycle increases, the voltage of the motor power supply terminal VM1 increases, the motor speed increases, and the vibration frequency increases accordingly; when the duty cycle decreases, the speed decreases and the frequency decreases. By real-time monitoring of the feedback signal of the motor (such as the current value), the control module can dynamically adjust the duty cycle to ensure that the frequency is accurately controllable.

[0089] Furthermore, the driving module includes:

[0090] A driving power input terminal is connected to the output terminal of the voltage stabilizing module and is used to receive power;

[0091] The logic power input terminal is connected to the output terminal of the voltage regulator module through the ninth filter capacitor C9 and the tenth filter capacitor C10 to provide motor power for the driver chip;

[0092] A pulse width modulation input terminal is connected to the PWM output terminal of the control module to receive a PWM signal;

[0093] The enable terminal is connected to the logic control pin of the control module and is used to control the working state of the driver chip;

[0094] The output end is connected to the vibration motor load module and is used to drive the vibration motor to work.

[0095] Among them, the pulse width modulation input terminals PWMA and PWMB of the driver chip in the driver module are connected to the PWM output terminals of the control module, and the enable terminals AIN1 and AIN2 and BIN1 and BIN2 are respectively connected to the logic control pins of the control module. The output terminals AO1 and AO2 and BO1 and BO2 are respectively connected to the vibration motor load modules 1 and 2 to drive the vibration motor to work.

[0096] Further, in this embodiment, the vibration motor load module includes a vibration motor load module 1 and a vibration motor load module 2, wherein the vibration motor load module includes:

[0097] A vibration motor connected to the output terminal of the driving module, and used to generate vibration stimulation according to the received current and power;

[0098] The filtering capacitor is connected in parallel with the power supply terminal of the vibration motor and is used to suppress the voltage fluctuation generated when the motor operates. Two vibration motor load modules respectively suppress the voltage fluctuation generated when the motor operates through the fifth filtering capacitor C5 and the sixth filtering capacitor C6.

[0099] Further, the battery charging module includes:

[0100] An external power input terminal, connected to an external power supply, is used to provide power input for the entire circuit;

[0101] The first resistor R1, with one end connected to the power input terminal and the other end connected to the power supply terminal of the battery charging chip, is used for current limiting to prevent the surge current from impacting the chip;

[0102] The second resistor R2, with one end connected to the first resistor R1 and the other end connected to the CE terminal of the battery charging chip, is used for temperature limiting;

[0103] The third resistor R3, with one end connected to the PROG pin of the battery charging chip and the other end grounded, is used to set the charging current of the battery charging chip;

[0104] The first filtering capacitor C1, with one end connected to the BAT pin of the battery charging chip and the other end grounded, is used to smooth the charging current

[0105] The fourth filtering capacitor C4, with one end connected to the output terminal of the battery charging chip and the other end connected to the ground, is used to filter out high-frequency noise;

[0106] The charging status output terminal, connected to the detection input terminal of the control module, is used to feedback the charging status.

[0107] Among them, one end of the first resistor R1 in the battery charging module is connected to the power input terminal, and the other end is connected to the power supply terminal of the battery charging chip and the first end of the second resistor R2; the other end of the second resistor R2 is connected to the CE terminal of the battery charging chip; the fourth filtering capacitor C4 is electrically connected to the battery and is connected to one end of the second filtering capacitor C2 in the voltage stabilizing module; the working status output terminal CHRG is connected in series with the detection working status input terminal of the control chip in the control module. To ensure the safety and stability during the battery charging process, the charging current I BAT is limited to 400 mA, and the resistance value of the current limiting resistor R3 can be calculated by the following formula:

[0108]

[0109] It is calculated that the resistance value of the current limiting resistor R3 is 3 kΩ.

[0110] Further, the voltage stabilizing module includes:

[0111] The voltage stabilizing chip input terminal, connected to the charging output terminal of the battery charging module, is used to receive the input voltage;

[0112] The output terminal of the voltage regulator chip is connected to the power input terminals of the control module, the drive module, and the communication module, and is used to output voltage.

[0113] The second filter capacitor C2 and the third filter capacitor C3 are connected in parallel between the input voltage source and the ground, and are used to stabilize the input voltage.

[0114] The following is an explanation with reference to the drawings: The output terminal VOUT of the voltage regulator chip of the voltage regulator module is respectively connected to the power input terminals (VBAT, NRST, VDDA, VDD_1 to VDD_3) of the control chip of the control module and one end of the fifth resistor R5 (pull-up resistor) of the serial wire debug input / output SWDIO; it is connected to the logic power input terminal VCC of the drive chip of the drive module and is connected to the motor power input terminals VM1 to VM3 of the drive chip of the drive module through the ninth filter capacitor C9 and the tenth filter capacitor C10; it is connected to the power input terminal VBAT1 of the communication chip of the communication module. The voltage regulator module provides a stable 3.3V voltage for other modules.

[0115] Furthermore, the clock oscillation module includes:

[0116] A crystal oscillator, which is used to generate a clock signal;

[0117] The seventh filter capacitor C7 and the eighth filter capacitor C8 are respectively connected to both ends of the crystal oscillator and are grounded, and are used to stabilize the oscillation frequency.

[0118] Furthermore, the working process of the circuit for adjusting the vibration frequency includes:

[0119] The communication module receives a message from an external transmitter and forwards it to the control module. The control module uses pulse width modulation technology to adjust the duty cycle of the input signal; by adjusting the duty cycle, the periodic fluctuation of the signal is changed, so as to adjust the vibration frequency within different frequency ranges;

[0120] The control module inputs the adjusted control signal into the drive module. The drive module adjusts the vibration frequency of the vibration motor load module according to the control signal; the drive module controls the vibration speed of the motor by adjusting the magnitude and frequency of the motor current, so as to obtain the required vibration frequency.

[0121] Specifically, it includes the following two stages:

[0122] The first stage: The communication module receives a message from an external transmitter and forwards it to the control module. The control chip of the control module uses pulse width modulation (PWM) technology according to the pre-programmed code, so as to adjust the duty cycle of the input signal. By adjusting the duty cycle, the control chip can accurately change the periodic fluctuation of the signal, and then adjust the vibration frequency within different frequency ranges.

[0123] Second stage: The control module inputs the adjusted control signal into the drive module, and the drive module adjusts the vibration frequency of the vibration motor load module according to this control signal. Specifically, the drive module precisely controls the vibration speed of the motor by adjusting the magnitude and frequency of the motor current, thereby achieving the required vibration frequency. This process can be adjusted through real-time feedback signals to ensure precise control of the vibration frequency.

[0124] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An adjustable frequency integrated circuit for treating dry eye, characterized in that: include: A communication module, used for receiving command signals from external devices and transmitting them to the control module; A control module, used for generating a regulation signal according to a command signal of the external device; A driving module, used for adjusting the current and power of the vibration motor load module according to the adjustment signal; A vibration motor load module, used to generate vibration stimulation corresponding to the regulated current and power; A battery charging module, used to provide power input for the circuit; A voltage stabilizing module, used to stabilize the input voltage and provide power to the communication module, the control module and the drive module; The clock oscillator module is used to provide a clock signal for the circuit.

2. The circuit according to claim 1, characterized in that The circuit also includes an indicator light load module and a charging port. The indicator light load module is used to provide real-time feedback on the working status of the device, and the charging port is used to provide an input interface for an external power source.

3. The circuit according to claim 1, characterized in that The communication module comprises: A communication power input terminal, connected to the output terminal of the voltage stabilizing module, for receiving power input; The serial port sending end is connected to the control module through the sixth resistor and is used to send instructions; The serial port receiving end is connected to the control module through the seventh resistor and is used to receive instructions; The working status output terminal is connected to the detection input terminal of the control module and is used to feedback the communication connection status.

4. The circuit according to claim 1, characterized in that The control module comprises: A control power input terminal connected to the output terminal of the voltage stabilizing module for receiving power; A detection input terminal connected to the charging status output terminal of the battery charging module and the working status output terminal of the communication module, and used for real-time detection of the charging status and the communication connection status; A PWM output terminal connected to a pulse width modulation input terminal of the driving module, and used to send a PWM signal for adjusting the vibration frequency; A logic control pin, connected to the enable terminal of the driving module, and used to control the working state of the driving module; The status output terminal is connected to the positive pole of the indicator light load module to control the on and off of the indicator light and provide real-time feedback on the working status of the device; External clock input and output terminals, connected to an external clock system for timing synchronization; The control chip serial debugging clock line and the serial debugging data line of the control module are respectively connected to one end of the fourth resistor and the fifth resistor, and the other ends of the fourth resistor and the fifth resistor are respectively connected to the ground and the power supply.

5. The circuit according to claim 1, characterized in that The driving module comprises: A driving power input terminal connected to the output terminal of the voltage stabilizing module for receiving power; The logic power input terminal is connected to the output terminal of the voltage regulator module through the ninth filter capacitor and the tenth filter capacitor to provide motor power for the driver chip; A pulse width modulation input terminal is connected to the PWM output terminal of the control module to receive a PWM signal; An enable terminal, connected to the logic control pin of the control module, for controlling the working state of the driver chip; The output end is connected to the vibration motor load module and is used to drive the vibration motor to work.

6. The circuit according to claim 1, characterized in that The vibration motor load module comprises: A vibration motor connected to the output end of the driving module, and used to generate vibration stimulation according to the received current and power; The filter capacitor is connected in parallel with the power supply terminal of the vibration motor to suppress the voltage fluctuation generated when the motor is working.

7. The circuit according to claim 1, characterized in that The battery charging module comprises: An external power input terminal, connected to an external power source, for providing power input for the entire circuit; A first resistor, one end of which is connected to the power input terminal and the other end of which is connected to the power terminal of the battery charging chip, for current limiting; A second resistor, one end of which is connected to the first resistor, and the other end of which is connected to the CE terminal of the battery charging chip, for temperature limiting; A third resistor, one end of which is connected to the PROG pin of the battery charging chip and the other end is grounded, and is used to set the charging current of the battery charging chip; The first filter capacitor has one end connected to the BAT pin of the battery charging chip and the other end connected to ground, which is used to smooth the charging current. A fourth filter capacitor, one end of which is connected to the output end of the battery charging chip and the other end of which is connected to the ground, and is used to filter out high-frequency noise; The charging status output terminal is connected to the detection input terminal of the control module and is used to feedback the charging status.

8. The circuit according to claim 1, characterized in that The voltage stabilizing module comprises: The voltage stabilizing chip input terminal is connected to the charging output terminal of the battery charging module and is used to receive an input voltage; The output end of the voltage regulator chip is connected to the power input end of the control module, the drive module and the communication module, and is used to output voltage; The second filter capacitor and the third filter capacitor are connected in parallel between the input voltage source and the ground to stabilize the input voltage.

9. The circuit according to claim 1, characterized in that The clock oscillation module comprises: A crystal oscillator for generating a clock signal; The seventh filter capacitor and the eighth filter capacitor are respectively connected to the two ends of the crystal oscillator and grounded for stabilizing the oscillation frequency.

10. The circuit according to claim 1, characterized in that The workflow of the circuit to adjust the vibration frequency includes: The communication module receives messages from the external transmitter and forwards them to the control module, which uses pulse width modulation technology to adjust the duty cycle of the input signal; by adjusting the duty cycle, the periodic fluctuation of the signal is changed, thereby adjusting the vibration frequency within different frequency ranges; The control module inputs the adjusted control signal to the drive module, and the drive module adjusts the vibration frequency of the vibration motor load module according to the control signal; the drive module controls the vibration speed of the motor by adjusting the magnitude and frequency of the motor current, thereby obtaining the required vibration frequency.

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