Driver chip, and linear resonant actuator driving system and method

Abstract

The present application provides a driver chip, and a linear resonant actuator driving system and method. The driver chip is used for driving a linear resonant actuator, and the linear resonant actuator comprises a first coil, a second coil, and a motor vibrator. The driver chip comprises a driving module, a common-mode signal output module, and a signal detection module; the driving module is connected to the two ends of the first coil and applies a driving signal to the first coil so as to drive the motor vibrator to vibrate; the common-mode signal output module is connected to at least one end of the second coil and is used for applying a common-mode signal to the second coil; and the signal detection module is connected to the two ends of the second coil, and performs signal detection on the second coil to obtain the reverse electromotive force of the second coil. In this way, vibration information of the linear resonant actuator can be obtained in real time by applying the driving signal to the first coil of the linear resonant actuator and applying the common-mode signal to the second coil.

Description

Driving chip, linear resonant actuator driving system and method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on March 29, 2024, with application number 202410385879.X and application name “Drive chip, linear resonant actuator drive system and method”. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of linear resonant actuator driving technology, and in particular to a driving chip, a linear resonant actuator driving system and a method. Background Art

[0003] In the field of consumer electronics, especially in mobile electronic products, tactile feedback is developing in the direction of high definition and high experience. The linear resonant actuator, or linear motor, is a key component that provides tactile sensation in the tactile feedback system. How to control the vibration of the vibrator of the linear motor becomes the key to accurately outputting the tactile experience. Ordinary linear motors without Hall sensors can provide better tactile vibration than rotor motors, but they cannot provide real-time information on motor vibration in terms of precise control. For ordinary linear motors without Hall sensors, the drive system usually uses a current-voltage scheme (IV scheme) to estimate the motor vibration information. This information cannot be obtained in real time, so it is difficult for the drive system to accurately control the vibration of the linear motor.

[0004] Summary of the Invention

[0005] In order to solve the problem that the driving system cannot obtain real-time information of the vibration of the linear resonant actuator and thus has difficulty in accurately controlling the vibration of the linear resonant actuator, the present application provides a driving chip, a linear resonant actuator driving system and a method.

[0006] In the first aspect, an embodiment of the present application provides a driving chip for driving a linear resonant actuator, wherein the linear resonant actuator includes a first coil, a second coil and a motor vibrator, the first coil is used to drive the motor vibrator to vibrate, and the second coil is used to detect the reverse electromotive force during the vibration process of the linear resonant actuator; the driving chip includes: a driving module, a common-mode signal output module and a signal detection module; the driving module is connected to both ends of the first coil, and is used to apply a driving signal to the first coil to drive the motor vibrator to vibrate; the common-mode signal output module is connected to at least one end of the second coil, and is used to apply a common-mode signal to the second coil; the signal detection module is connected to both ends of the second coil, and is used to perform signal detection on the second coil to obtain the reverse electromotive force of the second coil.

[0007] In some embodiments of the first aspect above, the common-mode signal output module applies a common-mode signal to the second coil, and when the motor vibrator is in a stationary state, the voltages at both ends of the second coil are equal; or when the motor vibrator is in a vibrating state, there is a voltage difference at both ends of the second coil, and the voltage difference represents the reverse electromotive force of the second coil.

[0008] In some embodiments of the first aspect above, the driving chip further includes a feedback calculation module, which is used to determine the speed of the motor vibrator based on the back electromotive force of the second coil and the magnetic inductance of the second coil.

[0009] In some embodiments of the first aspect above, the linear resonant actuator further includes a thermistor; one end of the thermistor is a first node, which is connected to one end of the second coil; the other end of the thermistor is a second node, which is grounded; the common-mode signal output module is connected to the first node of the thermistor and is further used to apply a common-mode signal to the thermistor; and the signal detection module is connected to both ends of the thermistor and is further used to perform signal detection on the thermistor.

[0010] In some embodiments of the first aspect above, if the common-mode signal is a voltage signal, there is a constant voltage difference across the thermistor, and the signal detection module is used to perform current detection on the thermistor to obtain the current flowing through the thermistor; alternatively, if the common-mode signal is a current signal, the current flowing through the thermistor is a constant current, and the signal detection module is used to perform voltage detection on the thermistor to obtain the voltage difference across the thermistor.

[0011] In some embodiments of the first aspect above, a feedback calculation module is further included, wherein at a first temperature, the resistance of the thermistor is a first impedance, and the first temperature is a preset temperature; the feedback calculation module is used to determine a second impedance of the thermistor based on the constant voltage difference and the current flowing through the thermistor; and the feedback calculation module is further used to determine a second temperature when the resistance of the thermistor is the second impedance based on the second impedance, the first impedance, and a resistance-temperature change relationship of the thermistor.

[0012] In some embodiments of the first aspect above, a feedback calculation module is further included, wherein at a first temperature, the resistance of the thermistor is a first impedance, and the first temperature is a preset temperature; the feedback calculation module is used to determine a second impedance of the thermistor based on a constant current and a voltage difference across the thermistor; and the feedback calculation module is further used to determine a second temperature at which the resistance of the thermistor is the second impedance based on the second impedance, the first impedance, and a resistance-temperature change relationship of the thermistor.

[0013] In some embodiments of the first aspect above, a heat transfer function exists between the temperature of the first coil and the temperature of the thermistor, and the temperature of the first coil is determined according to the second temperature of the thermistor and the heat transfer function.

[0014] In some embodiments of the first aspect above, the thermistor is disposed adjacent to the first coil, and the temperature of the first coil is equal to the second temperature of the thermistor.

[0015] In the second aspect, an embodiment of the present application provides a linear resonant actuator drive system, including a linear resonant actuator and a driving chip according to the first aspect above; the linear resonant actuator includes a first coil, a second coil and a motor vibrator, the first coil is used to drive the motor vibrator to vibrate, and the second coil is used to detect the back electromotive force during the vibration process of the linear resonant actuator.

[0016] In some embodiments of the second aspect above, the linear resonant actuator further includes a shell, and the first coil, the second coil and the motor vibrator are all located inside the shell; the first coil and the second coil are fixed to the first inner surface of the shell.

[0017] In some embodiments of the second aspect above, the first coil and the second coil are arranged on a flexible circuit board and fixed to the first inner surface of the shell; or, the first coil and the second coil are drawn on the flexible circuit board and fixed to the first inner surface of the shell; or, the first coil is directly fixed to the first inner surface of the shell, and the second coil is arranged on the flexible circuit board or drawn on the flexible circuit board and fixed to the first inner surface of the shell; or, the first coil and the second coil are fixed to the first inner surface of the shell, the first inner surface of the shell is a printed circuit board, the first coil and the second coil are drawn on the printed circuit board, and except for the first inner surface of the shell, the other surfaces of the shell are all made of metal; or, the first coil and the second coil are fixed to the first inner surface of the shell, the first inner surface of the shell is a printed circuit board, the first coil is arranged on the printed circuit board, the second coil is drawn on the printed circuit board, and except for the first inner surface of the shell, the other surfaces of the shell are all made of metal.

[0018] In some embodiments of the second aspect above, the linear resonant actuator also includes a shell, and the first coil, the second coil and the motor vibrator are all located inside the shell; the first coil and the second coil are located on both sides of the motor vibrator, the first coil is fixed to the second inner surface of the shell, and the second coil is fixed to the first inner surface of the shell.

[0019] In some embodiments of the second aspect above, the first coil is directly fixed to the second inner surface of the shell, and the second coil is arranged on a flexible circuit board or drawn on a flexible circuit board and fixed to the first inner surface of the shell; or, the first coil is directly fixed to the second inner surface of the shell, the first inner surface of the shell is a printed circuit board, and the second coil is drawn on the printed circuit board. Except for the first inner surface of the shell, the other surfaces of the shell are made of metal.

[0020] In some embodiments of the second aspect above, the linear resonant actuator further includes a thermistor, which is located inside the shell, and the thermistor and the second coil are located on the same side of the motor vibrator; and one end of the thermistor is a first node, which is connected to one end of the second coil; the other end of the thermistor is a second node, which is grounded.

[0021] In some embodiments of the second aspect above, the thermistor and the second coil are arranged on a flexible circuit board and fixed to the first inner surface of the shell; or, the thermistor and the second coil are drawn on the flexible circuit board and fixed to the first inner surface of the shell; or, the thermistor and the second coil are fixed to the first inner surface of the shell, the first inner surface of the shell is a printed circuit board, the thermistor and the second coil are drawn on the printed circuit board, and except for the first inner surface of the shell, the other surfaces of the shell are made of metal; or, the thermistor and the second coil are fixed to the first inner surface of the shell, the first inner surface of the shell is a printed circuit board, the thermistor is arranged on the printed circuit board, the second coil is drawn on the printed circuit board, and except for the first inner surface of the shell, the other surfaces of the shell are made of metal.

[0022] In some embodiments of the second aspect above, the printed circuit board is a multi-layer circuit board, wherein the Nth layer is a shielding layer, the first coil and the second coil are located above the Nth layer, and N is a positive integer greater than or equal to 2; or, the printed circuit board is a multi-layer circuit board, wherein the Nth layer is a shielding layer, the second coil is located above the Nth layer, and N is a positive integer greater than or equal to 2.

[0023] In some embodiments of the second aspect described above, when the driving system is applied to an electronic device, the printed circuit board reuses a bottom printed circuit board of the electronic device.

[0024] On the third aspect, an embodiment of the present application provides a driving method for a driving chip, which is used to drive a linear resonant actuator; the linear resonant actuator includes a first coil, a second coil and a motor vibrator, the first coil is used to drive the motor vibrator to vibrate, and the second coil is used to detect the reverse electromotive force during the vibration process of the linear resonant actuator; the method includes: applying a driving signal to the first coil, the driving signal is used to drive the motor vibrator to vibrate; applying a common mode signal to the second coil; performing signal detection on the second coil to obtain the reverse electromotive force of the second coil.

[0025] In some embodiments of the third aspect above, when the motor vibrator is in a stationary state, the voltages across the second coil are equal; or when the motor vibrator is in a vibrating state, there is a voltage difference between the voltages across the second coil, and the voltage difference represents the reverse electromotive force of the second coil.

[0026] In some embodiments of the third aspect above, the method further includes: determining a speed of the motor vibrator based on a back electromotive force of the second coil and a magnetic inductance of the second coil.

[0027] In some embodiments of the third aspect above, the linear resonant actuator further includes a thermistor; and the method further includes: applying a common-mode signal to the thermistor; and performing signal detection on the thermistor.

[0028] In some embodiments of the third aspect above, the common-mode signal is a voltage signal, and signal detection on the thermistor includes: performing current detection on the thermistor to obtain the current flowing through the thermistor; or the common-mode signal is a current signal, and signal detection on the thermistor includes: performing voltage detection on the thermistor to obtain the voltage difference across the thermistor.

[0029] In some embodiments of the third aspect above, there is a constant voltage difference across the thermistor, at a first temperature, the resistance of the thermistor is a first impedance, and the first temperature is a preset temperature. The method further includes: determining a second impedance of the thermistor based on the constant voltage difference and a current flowing through the thermistor; and determining a second temperature at which the resistance of the thermistor is the second impedance based on the second impedance, the first impedance, and a resistance-temperature change relationship of the thermistor.

[0030] In some embodiments of the third aspect above, the current flowing through the thermistor is a constant current, the resistance of the thermistor is a first impedance at a first temperature, and the first temperature is a preset temperature. The method further includes: determining a second impedance of the thermistor based on the constant current and a voltage difference across the thermistor; and determining a second temperature at which the resistance of the thermistor is the second impedance based on the second impedance, the first impedance, and a resistance-temperature change relationship of the thermistor.

[0031] In some embodiments of the third aspect above, a heat transfer function exists between the temperature of the first coil and the temperature of the thermistor, and the method further includes: determining the temperature of the first coil according to the second temperature of the thermistor and the heat transfer function.

[0032] In some embodiments of the third aspect above, the thermistor is disposed adjacent to the first coil, and the method further includes: a temperature of the first coil being equal to a second temperature of the thermistor.

[0033] The technical solutions provided by the embodiments of this application bring at least the following beneficial effects:

[0034] The driver chip provided in an embodiment of the present application is used to drive a linear resonant actuator, which includes a first coil, a second coil, and a motor vibrator. The driver chip includes: a driver module, a common-mode signal output module, and a signal detection module. The driver module is connected to both ends of the first coil and is used to apply a drive signal to the first coil to drive the motor vibrator to vibrate. The common-mode signal output module is connected to at least one end of the second coil and is used to apply a common-mode signal to the second coil. The signal detection module is connected to both ends of the second coil and is used to detect the signal of the second coil and obtain the reverse electromotive force of the second coil. In this way, by applying a drive signal to the first coil of the linear resonant actuator and a common-mode signal to the second coil, vibration information of the linear resonant actuator can be obtained in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a schematic diagram of an equivalent model of a linear motor provided in an embodiment of the present application;

[0036] FIG2A is a schematic structural diagram of a linear resonant actuator 10 provided in an embodiment of the present application;

[0037] FIG2B is a schematic diagram of a structure of a linear resonant actuator 20 provided in an embodiment of the present application;

[0038] FIG2C is a schematic diagram of a structure of a linear resonant actuator 30 provided in an embodiment of the present application;

[0039] FIG2D is a schematic diagram of a structure of a linear resonant actuator 30 provided in an embodiment of the present application;

[0040] FIG2E is a schematic diagram of the structure of a linear resonant actuator 40 provided in an embodiment of the present application;

[0041] FIG2F is a schematic diagram of the structure of another linear resonant actuator 40 provided in an embodiment of the present application;

[0042] FIG2G is a schematic diagram of a structure of a linear resonant actuator 50 provided in an embodiment of the present application;

[0043] FIG2H is a schematic diagram of the structure of another linear resonant actuator 50 provided in an embodiment of the present application;

[0044] FIG2I is a schematic diagram of the structure of a linear resonant actuator 60 provided in an embodiment of the present application;

[0045] FIG2J is a schematic diagram of the structure of another linear resonant actuator 60 provided in an embodiment of the present application;

[0046] FIG2K is a schematic diagram of a structure of a linear resonant actuator 70 provided in an embodiment of the present application;

[0047] FIG2L is a schematic diagram of the structure of another linear resonant actuator 70 provided in an embodiment of the present application;

[0048] FIG2M is a schematic diagram of a structure of a linear resonant actuator 80 provided in an embodiment of the present application;

[0049] FIG2N is a schematic diagram of the structure of another linear resonant actuator 80 provided in an embodiment of the present application;

[0050] FIG3 is a schematic diagram of a driver chip provided in an embodiment of the present application;

[0051] FIG4 is a schematic diagram of another driver chip provided in an embodiment of the present application;

[0052] FIG5 is a graph showing the voltage across a second coil according to an embodiment of the present application;

[0053] FIG6 is a schematic diagram of another driver chip provided in an embodiment of the present application;

[0054] FIG7 is a graph showing another voltage curve across a second coil according to an embodiment of the present application;

[0055] FIG8 is a schematic diagram of another driver chip provided in an embodiment of the present application;

[0056] FIG9 is a graph showing another voltage curve across a second coil according to an embodiment of the present application. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0058] The illustrative embodiments of the present application include, but are not limited to, a driver chip, a linear resonant actuator driving system, and a method.

[0059] As previously mentioned, conventional Hall-less linear motors cannot provide real-time information about motor vibration, including the speed of the motor's oscillator. Furthermore, these motors only have one set of coils. For these linear motors, the drive system uses an IV scheme to estimate the motor's back electromotive force (BEMF), which reflects the speed of the motor's oscillator.

[0060] Specifically, after the drive system detects the voltage and current of the motor, it estimates the back electromotive force of the motor based on the motor model. The motor model can be referred to in Figure 1. As shown in Figure 1, the motor model can be equivalent to three parts: DC impedance, coil inductance, and back electromotive force. V_LRA is the voltage across the motor, I_LRA is the current passing through the motor, V_R is the voltage consumed by the equivalent DC impedance of the motor coil, and V_L is the voltage consumed by the equivalent inductance of the coil. Since the inductance of most motors is small, V_L can be ignored. As the motor vibrator vibrates, the coil temperature in the linear motor begins to rise, which may cause the resistance value of the equivalent DC impedance R to change. The back electromotive force can be estimated based on the motor model shown in Figure 1. The estimation formula is as follows: V_bemf=V_LRA-I_LRA*R (1)

[0061] Understandably, the IV solution requires detecting the current in the motor coil, which is generally quite large, reaching the ampere level. The sensor resistors used to detect current in the drive system will experience temperature drift under high currents, resulting in inaccurate current detection. The IV solution also requires modeling the motor and calculating the reverse electromotive force of the motor coil based on the voltage and current of the motor coil. This calculation is complex and computationally intensive. Therefore, the drive system cannot obtain motor vibration information in real time, and the accuracy of the motor vibration information obtained is insufficient. Motor vibration information includes information such as the reverse electromotive force during motor vibration and the speed of the motor vibrator.

[0062] To solve the above problems, the present invention provides a driver chip, a linear resonant actuator driving system, and a method. The present invention will be described below with reference to the accompanying drawings.

[0063] A linear resonant actuator provided in an embodiment of the present application can be referred to FIG2A , which shows a structural diagram of a linear resonant actuator 10 . For ease of understanding, the y-direction is defined as the height direction of the linear resonant actuator hereinafter, and the linear resonant actuator includes a bottom and a top along the y-direction.

[0064] In the linear resonant drive system provided in the embodiment of the present application, the linear resonant actuator has one more set of coils than an ordinary linear motor. As shown in Figure 2A, the linear resonant actuator 10 has a shell 11 and a terminal fixing plate 12. The shell 11 includes a first coil 13, a second coil 14 and a motor vibrator 15. In the figure, the solid line coil represents the first coil 13, and the dotted line coil represents the second coil 14. The two ends of the motor vibrator 15 are fixed to the inside of the shell 11 by springs 16.

[0065] The first coil 13 and the second coil 14 are thermally coupled. For example, the first coil 13 and the second coil 14 can be placed closely together and positioned below the motor vibrator 15. The two coil groups are independent of each other (not in a series or parallel connection), and two terminals of each coil group are exposed from within the housing 11, for a total of four terminals for external use. The bottom of the housing 11 is connected to the terminal fixing plate 12, to which the first and second coil terminals are fixed. Heat conduction can occur between the first coil 13 and the second coil 14, and a heat transfer function exists between the temperatures of the first coil 13 and the second coil 14. After measuring the temperature of the second coil 14, the temperature of the first coil 13 can be calculated using the heat transfer function. In particular, when the first coil 13 and the second coil 14 are in close proximity, the heat transfer function can be simplified to an equality relationship, i.e., the temperature of the first coil 13 is equal to the temperature of the second coil 14. The second coil has a magnetic inductance BL2, and the magnetic inductance BL2 is not equal to 0.

[0066] It can be understood that the first coil 13 in the linear resonant actuator 10 can be used as a driving coil, and the second coil 14 can be used as an observation coil. Since the magnetic inductance coefficient BL2 of the second coil 14 is not equal to 0, when the motor vibrator vibrates, a reverse electromotive force will be generated on the second coil 14. Therefore, the vibration information of the linear resonant actuator 10 can be observed on the second coil 14, that is, the linear resonant actuator 10 can provide reverse electromotive force feedback.

[0067] FIG2B shows a structural diagram of a linear resonant actuator 20. As shown in FIG2B , the linear resonant actuator 20 comprises a housing 21 and a terminal fixing plate 22. The housing 21 includes a first coil 23, a second coil 24, and a motor vibrator 25. The motor vibrator 25 is fixed to the housing 21 at both ends by springs 26. The first coil 23 and the second coil 24 are wound independently. The first coil 23 is placed on one side of the motor vibrator 25 (e.g., the side close to the top of the housing 21), and the second coil 24 is placed on the other side of the motor vibrator 25 (e.g., the side close to the bottom of the housing 21). The two terminals of each coil group are exposed from the inside of the housing 21. The bottom of the housing 21 is connected to the terminal fixing plate 22, and the first coil terminal and the second coil terminal are both fixed to the terminal fixing plate 22. The second coil 24 has a magnetic inductance BL2, and the magnetic inductance BL2 is not equal to 0.

[0068] It can be understood that the first coil 23 in the linear resonant actuator 20 can be used as a driving coil, the second coil 24 can be used as an observation coil, and the linear resonant actuator 20 can also provide back electromotive force feedback.

[0069] Figure 2C shows a structural diagram of a linear resonant actuator 30. As shown in Figure 2C, the linear resonant actuator 30 comprises a housing 31 and a terminal fixing plate 32. The housing 31 contains a first coil 33, a second coil 34, a motor vibrator 35, and a flexible printed circuit (FPC) 36. The motor vibrator 35 is secured to the housing 31 at both ends by springs 37. The first coil 33 and the second coil 34 are independently wound. The first coil 33 is placed on one side of the motor vibrator 35 (e.g., near the bottom of the housing 31), and the flexible printed circuit 36 ​​is placed on the other side of the motor vibrator 35 (e.g., near the top of the housing 31). The second coil 34 is placed on the flexible printed circuit 36, with the two terminals of each coil group exposed from the interior of the housing 31. The bottom of the housing 31 is connected to the terminal fixing plate 32, and both the first and second coil terminals are fixed to the terminal fixing plate 32. In some embodiments, as shown in Figure 2D, the first coil 33, the second coil 34, and the flexible printed circuit 36 ​​can also be placed on the same side of the motor vibrator 35 (e.g., near the bottom of the housing 31).

[0070] It can be understood that the flexible circuit board 36 is relatively thin and occupies relatively little space when placed inside the motor housing 35 .

[0071] Figure 2E shows a structural diagram of a linear resonant actuator 40. As shown in Figure 2E, the linear resonant actuator 40 has a shell 41, and the interior of the shell 41 includes a first coil 42, a second coil 43, and a motor vibrator 44. The two ends of the motor vibrator 44 are fixed to the interior of the shell 41 by springs 45. Among them, the first coil 42 is arranged above the motor vibrator 44, for example, fixed to the inner surface of the top of the shell 41 (an example of the second inner surface of the present application). The second coil 43 is arranged below the motor vibrator 44, for example, fixed to the inner surface of the bottom of the shell 41 (an example of the first inner surface of the present application). The first coil terminal and the second coil terminal do not need to be exposed from the inside of the shell 41, but are directly fixed to the bottom of the shell 41.

[0072] In this embodiment, the inner surface of the bottom of the shell 41 is provided with a multilayer printed circuit board (PCB) 411 or a flexible circuit board. The PCB board 411 is taken as an example below, and a flexible circuit board can be used instead in other embodiments. The second coil 43 can be set on the PCB board 411 and then fixed to the bottom of the shell 41. Alternatively, the bottom of the shell 41 is the PCB board 411, and the second coil 43 can be drawn on the PCB board 411. When the bottom of the shell 41 is the PCB board 411, the top and side shells of the shell 41 are made of metal. It should be noted that the coil set on the PCB board refers to a physical coil, and the coil drawn on the circuit board is part of the circuit board, not a separate physical coil.

[0073] The Nth layer of the bottom PCB board 411 may be a shielding layer, where N may be a positive integer greater than or equal to 2. The shielding layers of the top and side shells of the housing 41 and the PCB board 411 may reduce the impact of magnetic field changes inside the housing 41 on the outside world.

[0074] For example, the second coil 43 may be disposed on the Nth layer of the PCB 411. For example, when N is 2 layers, the layer above N may be 1. When N is 3 layers, the layer above N may be 1 or 2.

[0075] In some embodiments, as shown in FIG. 2F , the first coil 42 and the second coil 43 may be wound together and fixed together on the inner surface of the bottom of the housing 41 .

[0076] Furthermore, the first coil 42 and the second coil 43 can both be disposed on the PCB board 411 and then fixed to the bottom of the housing 41. Alternatively, when the bottom of the housing 41 is the PCB board 411, the first coil 42 and the second coil 43 can both be drawn on the PCB board 411, or the first coil 42 can be disposed on the PCB board 411 and the second coil 43 can be drawn on the PCB board 411. Alternatively, the first coil 42 can be directly disposed on the inner surface of the bottom of the housing 41, and the second coil 43 can be disposed on the PCB board 411 and then fixed to the bottom of the housing 41.

[0077] In practical applications of linear resonant actuators, for example, in electronic devices (such as smartphones), the linear resonant actuator can reuse the mainboard PCB of the electronic device (an example of the bottom printed circuit board mentioned in this application) to provide tactile feedback for the electronic device.

[0078] Figure 2G shows a schematic structural diagram of a linear resonant actuator 50. As shown in Figure 2G, the linear resonant actuator 50 reuses the mainboard PCB of the electronic device. The linear resonant actuator 50 has a shell 51 and a terminal fixing plate 52. The interior of the shell 51 includes a first coil 53 and a motor vibrator 54, and the two ends of the motor vibrator 54 are fixed to the interior of the shell 51 by springs 55. The first coil 53 is placed above the motor vibrator 54, for example, fixed to the inner surface of the top of the shell 51 (an example of the second inner surface of the present application). The bottom of the shell 51 is connected to the terminal fixing plate 52, and the two terminals of the first coil 53 are exposed from the inside of the shell 51 and fixed on the terminal fixing plate 52.

[0079] Continuing with reference to FIG2G , the bottom of the linear resonant actuator 50 is in close contact with the main board PCB of the electronic device, and a second coil 56 is provided at a position on the main board PCB corresponding to the bottom of the linear resonant actuator 50 , and the two terminals of the second coil 56 are not covered by the linear resonant actuator 50 .

[0080] The bottom of the shell 51 is made of non-magnetic shielding material, which can pass magnetic signals so that the magnetic lines of force generated by the vibration of the motor vibrator 54 can penetrate the bottom of the shell 51 to the second coil 56. The top and side shells of the shell 51 are made of magnetic shielding material, for example, metal material, to avoid the influence of the magnetic field changes inside the shell 51 on the outside world.

[0081] In addition, the main PCB can be a multi-layer board, wherein the Nth layer is a shielding layer, which can reduce the impact of the magnetic field changes inside the housing 51 on the outside world, and the second coil 56 is placed on the Nth layer. The meaning of "above the Nth layer" can be referred to as described above and will not be repeated here.

[0082] In other embodiments, the mainboard PCB can directly serve as the bottom of the shell 51, and the surface of the mainboard PCB facing the linear resonant actuator 50 is the inner surface of the bottom of the shell 51 (an example of the first inner surface of the present application).

[0083] In some embodiments, as shown in FIG. 2H , the first coil 53 inside the housing of the linear resonant actuator 50 may also be placed below the motor vibrator 54 , for example, fixed to the inner surface of the bottom of the housing 51 .

[0084] It is understood that the surface of the housing 51 of the linear resonant actuator 50 that contacts the mainboard PCB should be made of non-magnetic shielding material to allow the magnetic lines of force generated by the vibration of the motor vibrator 54 to penetrate the housing and reach the second coil 56. Correspondingly, the other housing surfaces should be made of magnetic shielding material to prevent changes in the magnetic field inside the housing 51 from affecting the outside world. That is, when the bottom of the housing 51 contacts the mainboard PCB, the bottom of the housing 51 is made of non-magnetic shielding material, and the top and side shells of the housing 51 are made of magnetic shielding material; when the top of the housing 51 contacts the mainboard PCB, the top of the housing 51 is made of non-magnetic shielding material, and the bottom and side shells of the housing 51 are made of magnetic shielding material.

[0085] Figure 2I shows a structural diagram of a linear resonant actuator 60. As shown in Figure 2I , the linear resonant actuator 60 comprises a housing 61 and a terminal fixing plate 62. Housing 61 houses a first coil 63, a second coil 64, a motor vibrator 65, a flexible printed circuit board 66, and a thermistor 68. Both ends of the motor vibrator 65 are secured to the housing 61 by springs 67.

[0086] The first coil 63 and the second coil 64 are wound independently, with the first coil 63 placed on one side of the motor vibrator 65, for example, fixed to the inner surface of the bottom of the housing 61 (an example of the second inner surface of the present application). A flexible circuit board 66 is placed on the other side of the motor vibrator 65, for example, fixed to the inner surface of the top of the housing 61 (an example of the first inner surface of the present application). The second coil 64 and the thermistor 68 are arranged or drawn on the flexible circuit board 66. One terminal of the thermistor 68 is connected to one terminal of the second coil 64, and the other terminal is exposed from the interior of the housing 61. Both terminals of each set of coils are exposed from the interior of the housing 61.

[0087] The bottom of the housing 61 is connected to the terminal fixing plate 62 , and the first coil terminal, the second coil terminal and the thermistor terminal are all fixed on the terminal fixing plate 62 .

[0088] In some embodiments, as shown in Figure 2J, the first coil 63, the second coil 64, the flexible circuit board 66 and the thermistor 68 can also be placed on the same side of the motor vibrator 65. For example, the first coil 63, the second coil 64, the thermistor 68 are arranged or drawn on the flexible circuit board 66 and then fixed to the inner surface of the bottom of the shell 61.

[0089] Figure 2K shows a structural diagram of a linear resonant actuator 70. As shown in Figure 2K , linear resonant actuator 70 includes a housing 71, which contains a first coil 72, a second coil 73, a motor vibrator 74, and a thermistor 76. Both ends of motor vibrator 74 are fixed to the interior of housing 71 by springs 75.

[0090] A multi-layer PCB board 711 is provided at or directly formed on the bottom of the shell 71. The top and side shells of the shell 71 are made of metal. The Nth layer of the bottom PCB board 711 is a shielding layer. The shielding layers of the top, side shells and PCB board 711 of the shell 71 can reduce the impact of magnetic field changes inside the shell 71 on the outside world.

[0091] First coil 72 is placed above motor vibrator 74, for example, fixed to the inner surface of the top of housing 71 (an example of the second inner surface in the present application). Second coil 73 and thermistor 76 are arranged on PCB 711 and then fixed to the bottom of housing 711 (an example of the first inner surface in the present application), or are directly drawn on PCB 711 and located above layer N. The meaning of "above layer N" can be referred to above and will not be repeated here.

[0092] One terminal of the thermistor 76 is connected to one terminal of the second coil 73 , and the other terminal is fixed to the bottom of the shell 71 . The first coil terminal and the second coil terminal are common and do not need to be exposed from the inside of the shell 71 , but are directly fixed to the bottom of the shell 71 .

[0093] In some embodiments, as shown in Figure 2L, the first coil 72 can also be placed below the motor vibrator 74, and the first coil 72, the second coil 73 and the thermistor 76 are arranged on the PCB board 711 and then fixed to the bottom of the shell 711, or directly drawn on the PCB board 711 and located above the Nth layer.

[0094] Figure 2M shows a schematic diagram of the structure of a linear resonant actuator 80. As shown in Figure 2M, the linear resonant actuator 80 comprises a housing 81 and a terminal fixing plate 82. The housing 81 includes a first coil 83 and a motor vibrator 84, with both ends of the motor vibrator 84 fixed to the housing 81 via springs 85.

[0095] The first coil 83 is placed above the motor vibrator 84, for example, fixed to the inner surface of the top of the shell 84, the two terminals of the first coil 83 are exposed from the inside of the shell 81, the bottom of the shell 81 is connected to the terminal fixing plate 82, and the first coil terminal is fixed on the terminal fixing plate 82.

[0096] In practical applications of the linear resonant actuator 80 , for example, in an electronic device (such as a smart phone), the linear resonant actuator 80 can be disposed on a mainboard PCB of the electronic device to provide tactile feedback for the electronic device.

[0097] Specifically, as shown in Figure 2M, the bottom of the linear resonant actuator 80 is close to the main board PCB of the electronic device, and a second coil 86 and a thermistor 87 are provided at a position on the main board PCB corresponding to the bottom of the linear resonant actuator 80, and the two terminals of the second coil 86 and the terminals of the thermistor are not covered by the linear resonant actuator 80.

[0098] The bottom of the housing 81 is made of non-magnetic shielding material, which allows the magnetic signal to pass through, allowing the magnetic lines of force generated by the vibration of the motor vibrator 84 to penetrate the bottom of the housing 81 and reach the second coil 86. The top and side shells of the housing 81 are made of magnetic shielding material to prevent the magnetic field changes inside the housing 81 from affecting the outside world.

[0099] In addition, the main PCB can be a multi-layer board, wherein the Nth layer is a shielding layer, which can reduce the impact of the magnetic field changes inside the housing 81 on the outside world. The second coil 86 and the thermistor 87 are placed above the Nth layer. The meaning of "above the Nth layer" can be referred to as described above and will not be repeated here.

[0100] In other embodiments, the mainboard PCB can directly serve as the bottom of the housing 81 , and the surface of the mainboard PCB facing the linear resonant actuator 80 is the inner surface of the bottom of the housing 81 .

[0101] In some embodiments, as shown in FIG. 2N , the first coil 83 inside the housing of the linear resonant actuator 80 may also be placed below the motor vibrator 84 , for example, fixed to the inner surface of the bottom of the housing 81 .

[0102] It is understood that the surface of the housing 81 of the linear resonant actuator 80 that contacts the mainboard PCB should be made of non-magnetic shielding material to allow the magnetic lines of force generated by the vibration of the motor vibrator 84 to penetrate the housing and reach the second coil 86. Correspondingly, the other housing surfaces should be made of magnetic shielding material to prevent changes in the magnetic field inside the housing 81 from affecting the outside world. That is, when the bottom of the housing 81 contacts the mainboard PCB, the bottom of the housing 81 is made of non-magnetic shielding material, and the top and side shells of the housing 81 are made of magnetic shielding material; when the top of the housing 81 contacts the mainboard PCB, the top of the housing 81 is made of non-magnetic shielding material, and the bottom and side shells of the housing 81 are made of magnetic shielding material.

[0103] It can be understood that the thermistors in the linear resonant actuators 60, 70 and 80 have a first impedance at a first temperature, which is a preset temperature (eg, room temperature, which may be 25°C), and the first impedance is the impedance measured at the first temperature.

[0104] It should be understood that the linear resonant actuator provided in the embodiment of the present application has no specific restrictions on the placement of the two sets of coils. It only requires that one set of coils be used as a drive coil. Applying an electrical signal (drive signal) to the drive coil can make the motor vibrator vibrate and produce a tactile effect. The other set of coils is used as an induction coil to sense changes in magnetic flux. The expression "first coil" and "second coil" is only to distinguish the two sets of coils, and does not require or imply any actual relationship or order between the two sets of coils. The different shapes of the first coil and the second coil in the accompanying drawings are only to distinguish the two sets of coils. It does not require that the shapes of the two sets of coils are the same or different, and the specific shapes of the two sets of coils are not limited.

[0105] A driving chip provided in an embodiment of the present application may refer to FIG. 3 , wherein the linear resonant actuator may be the linear resonant actuator 10 , the linear resonant actuator 20 , the linear resonant actuator 30 , the linear resonant actuator 40 or the linear resonant actuator 50 .

[0106] As shown in Figure 3, the driving chip includes a driving module 301, a common-mode signal output module 302, a signal detection module 303 and a feedback calculation module 304; the driving module 301 is connected to both ends of the first coil 305, and is used to apply a driving signal to the first coil 305 to drive the motor vibrator to vibrate; the common-mode signal output module 302 is connected to at least one end of the second coil 306, for example, the common-mode signal output module 302 can be connected to one end of the second coil 306 (solid line connection), and the common-mode signal output module 302 can also be connected to the other end of the second coil 306 (dashed line connection) for applying a common-mode signal to the second coil 306, wherein the common-mode signal may include a common-mode voltage signal (V_DC) or a common-mode current signal (I_DC).

[0107] It can be understood that the common-mode signal applied by the common-mode signal output module 302 to the second coil 306 can be a common-mode voltage signal (V_DC), which can raise the voltage across the second coil to near the applied common-mode voltage, that is, the voltages across the second coil are approximately equal to or equal to the common-mode voltage. In addition, the common-mode voltage signal makes the voltages across the second coil 306 equal when the motor vibrator is in a stationary state. Therefore, no current loop is formed on the second coil 306, and the common-mode voltage does not change as the coil temperature rises. When the motor is working, the second coil can sense the change in the magnetic field caused by the movement of the motor vibrator, and the voltage across the second coil will fluctuate around the common-mode voltage.

[0108] Exemplarily, the magnitude of the common-mode voltage signal may be equal to half of the detection range of the signal detection module 303 , or may be determined according to actual needs, which is not limited in this application, wherein the detection range indicates the maximum value of the detectable signal.

[0109] It can be understood that the common-mode signal applied by the common-mode signal output module 302 to the second coil 306 can be a common-mode current signal (I_DC). At this time, one end of the second coil 306 connected to the common-mode signal output module 302 is connected to the thermistor, and the other end of the thermistor is grounded. In this way, the voltage generated by the common-mode current signal (I_DC) output by the common-mode signal output module 302 after passing through the thermistor can be regarded as the common-mode voltage provided by the second coil.

[0110] It should be understood that the magnetic inductance of the second coil is not equal to 0. When the motor vibrator is in a vibrating state, a voltage difference exists across the second coil, which represents the back electromotive force of the second coil. The back electromotive force of the second coil is the back electromotive force during the vibration of the linear resonant actuator.

[0111] The signal detection module 303 is connected to both ends of the second coil 306 and is used to perform signal detection on the second coil 306 to obtain the reverse electromotive force of the second coil.

[0112] Specifically, taking the application of a common-mode voltage signal as an example, a graph of the voltage across the second coil can be seen in FIG5 . It can be understood that when the drive system is in a low-power operating mode, the temperature of the first coil 305 and the second coil 306 does not increase over time (no temperature rise), the magnitude of the common-mode voltage signal remains unchanged, and the magnitude of the back electromotive force of the second coil also remains unchanged. When the drive system is in a high-power operating mode, the temperature of the first coil 305 and the second coil 306 increases over time, but since no current loop is formed on the second coil 306, the magnitude of the common-mode voltage signal remains unchanged, and the magnitude of the back electromotive force of the second coil also remains unchanged.

[0113] In some embodiments, the signal detection module 303 can determine the back electromotive force of the second coil using the following formula (2): V_bemf2=V_DET (2)

[0114] Wherein, V_bemf2 represents the back electromotive force of the second coil, and V_DET represents the voltage difference between both ends of the second coil.

[0115] It can be understood that the back electromotive force generated by the second coil due to the vibration of the motor vibrator is the voltage difference across the second coil. Therefore, the voltage difference detected by the signal detection module 303 is the back electromotive force of the second coil.

[0116] In some embodiments, the feedback calculation module 304 can obtain the vibrator speed based on the back electromotive force generated by the second coil due to the vibration of the motor vibrator. Specifically, the speed of the motor vibrator can be calculated based on the back electromotive force of the second coil combined with the following formula (3): V = V_bemf2 / BL2 (3)

[0117] Here, V represents the speed of the motor vibrator, V_bemf2 represents the back electromotive force of the second coil, and BL2 represents the magnetic inductance of the second coil.

[0118] Another driver chip provided in an embodiment of the present application can be referred to FIG4 . As shown in FIG4 , the driver chip includes a playback control module 401 , an output stage 402 , a common-mode signal output module 403 , a voltage detection module 404 , and a feedback calculation module 405 .

[0119] The playback control module 401 and the output stage 402 are the driver modules mentioned in the embodiments of the present application. The output end of the playback control module 401 is connected to the input end of the output stage 402, and the output end of the output stage 402 is connected to both ends of the first coil 407. The playback control module 401 is used to provide a drive signal to the output stage 402. After receiving the drive signal, the output stage 402 amplifies the power of the drive signal and applies the tactile waveform to the first coil 407.

[0120] The common-mode signal output module 403 is connected to one end of the second coil 408 and is configured to apply a common-mode voltage signal (V_DC) to the second coil 408 .

[0121] Specifically, the common-mode voltage signal applied by the common-mode signal output module 403 to the second coil 408 can raise the voltage across the second coil 408 to near the common-mode voltage. For details, see the common-mode signal output module 302 described in the above embodiment, and for a graph of the voltage across the second coil, see FIG5 . It will be appreciated that because the common-mode voltage signal does not form a current loop in the second coil 408, the back electromotive force of the second coil does not change as the temperature of the second coil 408 increases.

[0122] The voltage detection module 404 may refer to the signal detection module 303 mentioned in the above embodiment. Here, the voltage detection module 404 is used to detect the voltage signal of the second coil 408 to obtain the back electromotive force of the second coil.

[0123] The feedback calculation module 405 may refer to the relevant description of the feedback calculation module 304 mentioned in the above embodiment, and will not be repeated here.

[0124] In an embodiment of the present application, a group of coils is added to an ordinary linear motor, the first coil is used as a driving coil, and the second coil is used as an observation coil, so that the motor vibration information can be obtained in real time. In addition, the drive system does not need to detect current, and the feedback calculation module can directly measure the back electromotive force of the second coil, reducing the complexity of the calculation.

[0125] A driver chip provided in an embodiment of the present application is shown in FIG6 . The linear resonant actuator may be linear resonant actuator 60, linear resonant actuator 70, or linear resonant actuator 80. The following uses linear resonant actuator 60 as an example, and its structure is shown in FIG2I . As shown in FIG6 , the driver chip includes a playback control module 601, an output stage 602, a common-mode signal output module 603, a signal detection module 604, and a feedback calculation module 605.

[0126] The playback control module 601 and the output stage 602 are the driver modules mentioned in the embodiments of the present application. The output end of the playback control module 601 is connected to the input end of the output stage 602, and the output end of the output stage 602 is connected to both ends of the first coil 606. The playback control module 601 is used to provide a drive signal to the output stage 602. After receiving the drive signal, the output stage 602 amplifies the power of the drive signal and applies the tactile waveform to the first coil 606.

[0127] The common-mode signal output module 603 is connected to one end of the second coil 607 and the first node of the thermistor Rsen, respectively, and the second node of the thermistor Rsen is grounded. The common-mode signal output module 603 outputs a constant voltage (V_DC), that is, a common-mode voltage signal, to the first node. In this way, on the one hand, the common-mode voltage signal applied to the second coil 607 can raise the voltage across the second coil 607 to near the common-mode voltage signal, and ensure that the voltages across the second coil 607 are equal when the motor vibrator is in a stationary state, that is, no current loop is formed on the second coil 607. On the other hand, the constant voltage output by the common-mode signal output module 603 to the first node can provide a constant voltage for the thermistor Rsen, so that there is a constant voltage difference across the thermistor Rsen, that is, current flows through the thermistor Rsen.

[0128] The signal detection module 604 is used to detect the voltage signal of the second coil 607 to obtain the back electromotive force (VBEMF) of the second coil, and is also used to detect the current signal of the thermistor Rsen to obtain the current (I_R) flowing through the thermistor Rsen.

[0129] For a specific graph of the voltage across the second coil, see Figure 7. Figure 7 shows the voltage across the second coil over time during motor vibrator vibration. As shown in Figure 7, the first node voltage V_DC, or the common-mode voltage signal, remains constant as the coil temperature increases over time, while thermistor Rsen current I_R increases.

[0130] It is understood that because the common-mode voltage signal does not form a current loop in the second coil 607, the back electromotive force VBEMF of the second coil does not change as the temperature of the second coil 607 increases. Thermistors made of different materials have different temperature characteristics. If the resistance of thermistor Rsen decreases as the temperature increases, the current I_R of thermistor Rsen detected by the signal detection module 604 will gradually increase. If the resistance of thermistor Rsen increases as the temperature increases, the current I_R of thermistor Rsen detected by the signal detection module 604 will gradually decrease.

[0131] The feedback calculation module 605 can calculate the motor vibrator speed according to the back electromotive force of the second coil. The specific calculation method can refer to the relevant description of the feedback calculation module 304 above, which will not be repeated here.

[0132] The feedback calculation module 605 can also determine the second impedance of thermistor Rsen based on the constant voltage difference across thermistor Rsen and the current (I_R) of thermistor Rsen. As previously described, thermistor Rsen has a first impedance at the first temperature. Thus, the feedback calculation module 605 can determine the second temperature at which thermistor Rsen has the second impedance based on the first impedance of thermistor Rsen, the second impedance, and the resistance-temperature relationship of thermistor Rsen (e.g., a resistance-temperature rise formula or a resistance-temperature rise curve).

[0133] Specifically, the feedback calculation module 605 may divide the constant voltage difference (V_DC) across the thermistor Rsen by the current (I_R) of the thermistor Rsen to obtain the resistance of the thermistor Rsen, ie, the second impedance.

[0134] It should be understood that the resistance-temperature rise formula and resistance-temperature rise curve of the thermistor Rsen depend on the metal material type of the thermistor Rsen. The metal material of the thermistor and the related resistance-temperature rise formula are not limited here.

[0135] In an optional embodiment, if the thermistor Rsen is thermally coupled to the first coil, that is, there is a heat transfer function between the temperature of the thermistor Rsen and the temperature of the first coil, the feedback calculation module 605 can determine the temperature of the first coil, that is, the temperature during the motor vibration process, based on the second temperature of the thermistor Rsen and the heat transfer function.

[0136] In some embodiments, the heat transfer function can refer to a mapping relationship between the temperature of the first coil and the temperature of the thermistor. Specifically, once the structure of the drive system is determined, the mapping relationship can be measured in advance in the laboratory, i.e., different temperatures of the first coil correspond to different temperatures of the thermistor. In this way, during operation, the corresponding temperature of the first coil can be directly determined from the mapping relationship based on the temperature of the thermistor using a table lookup method.

[0137] In other embodiments, the heat transfer function can also be obtained through simulation. Specifically, a heat transfer function simulation software, such as finite element simulation software, is used to perform a thermal simulation of the drive system. Parameters such as the position of the first coil, the position of the thermistor, the power of the first coil, and the thermal conductivity of the materials of components in the drive system, such as the motor, are input to ultimately obtain a heat transfer function between the temperature of the first coil and the temperature of the thermistor.

[0138] In particular, when the thermistor Rsen is disposed adjacent to the first coil, ie, the two are in close proximity, the heat transfer function can be simplified to an equality relationship, ie, the second temperature of the thermistor Rsen is equal to the temperature of the first coil.

[0139] It can be understood that when the placement positions of the thermistor Rsen and the first coil are different, whether there is thermal conductive heat dissipation material around them, and the types of thermal conductive heat dissipation materials around them are different, the heat transfer function between the temperature of the thermistor Rsen and the temperature of the first coil is also different. This application does not limit the specific heat transfer function.

[0140] A driver chip provided in an embodiment of the present application is shown in FIG8 . The linear resonant actuator may be linear resonant actuator 60, linear resonant actuator 70, or linear resonant actuator 80. The following uses linear resonant actuator 60 as an example, and its structure is shown in FIG2I . As shown in FIG8 , the driver chip includes a playback control module 701, an output stage 702, a common-mode signal output module 703, a signal detection module 704, and a feedback calculation module 705.

[0141] The playback control module 701 and the output stage 702 are the driver modules mentioned in the embodiments of the present application. The output end of the playback control module 701 is connected to the input end of the output stage 702, and the output end of the output stage 702 is connected to both ends of the first coil 706. The playback control module 701 is used to provide a drive signal to the output stage 702. After receiving the drive signal, the output stage 702 amplifies the power of the drive signal and applies the tactile waveform to the first coil 706.

[0142] Common-mode signal output module 703 is connected to one end of second coil 707 and a first node of thermistor Rsen, respectively. The second node of thermistor Rsen is grounded. Common-mode signal output module 703 outputs a constant current (I_DC), i.e., a common-mode current signal, to the first node. After this current signal flows through thermistor Rsen, a voltage difference is generated across thermistor Rsen, generating a voltage V_R at the first node. This voltage V_R is equivalent to the common-mode voltage signal provided to second coil 707.

[0143] The signal detection module 704 is used to perform voltage signal detection on the second coil 707 and the thermistor Rsen to obtain the back electromotive force of the second coil and the voltage difference between the two ends of the thermistor Rsen.

[0144] Specifically, a graph of the voltage across the second coil can be seen in Figure 9. Figure 9 shows the voltage across the second coil over time during the vibration of the motor vibrator. As shown in Figure 9, the first node voltage V_R is the common-mode voltage signal provided by the second coil. As the operating time increases, the coil temperature gradually increases, and the resistance of thermistor Rsen gradually decreases. Since the current flowing through thermistor Rsen is a constant current I_DC, the first node voltage V_R gradually decreases.

[0145] It is understood that because the common-mode voltage signal does not form a current loop in the second coil 707, the back electromotive force VBEMF of the second coil does not change with increases in the temperature of the second coil 707, nor does it change with changes in the magnitude of the common-mode voltage signal (V_R). Thermistors made of different materials have different temperature characteristics. If the resistance of thermistor Rsen decreases with increasing temperature, the voltage difference across the thermistor Rsen detected by the signal detection module 604 gradually decreases. If the resistance of thermistor Rsen increases with increasing temperature, the voltage difference across the thermistor Rsen detected by the signal detection module 604 gradually increases.

[0146] The feedback calculation module 705 can calculate the motor vibrator speed according to the back electromotive force of the second coil. The specific calculation method can refer to the relevant description of the feedback calculation module 304 above, which will not be repeated here.

[0147] The feedback calculation module 705 can also determine the second impedance of thermistor Rsen based on the constant current flowing through thermistor Rsen and the voltage difference (V_R) across thermistor Rsen. As previously described, thermistor Rsen has a first impedance at the first temperature. Thus, the feedback calculation module 705 can determine the second temperature at which thermistor Rsen has the second impedance based on the first impedance of thermistor Rsen, the second impedance, and the resistance-temperature relationship of thermistor Rsen (e.g., a resistance-temperature rise formula or a resistance-temperature rise curve).

[0148] Specifically, the feedback calculation module 705 may divide the voltage difference (V_R) across the thermistor Rsen by the current (I_DC) of the thermistor Rsen to obtain the resistance of the thermistor Rsen, ie, the second impedance.

[0149] It should be understood that the resistance-temperature rise formula and resistance-temperature rise curve of the thermistor Rsen depend on the metal material type of the thermistor Rsen. The metal material of the thermistor and the related resistance-temperature rise formula are not limited here.

[0150] In an optional embodiment, if the thermistor Rsen is thermally coupled to the first coil, that is, there is a heat transfer function between the temperature of the thermistor Rsen and the temperature of the first coil, the feedback calculation module 705 can determine the temperature of the first coil, that is, the temperature during the motor vibration process, based on the second temperature of the thermistor Rsen and the heat transfer function.

[0151] The heat transfer function, the placement relationship between the thermistor Rsen and the first coil can refer to the relevant description of the above embodiment, which will not be repeated here.

[0152] In this embodiment, a coil and thermistor are added to a conventional linear motor. The first coil serves as the drive coil, and the second coil as the observation coil. This allows real-time acquisition of motor vibration information, including back EMF, motor vibrator velocity, and temperature. Furthermore, this drive system eliminates the need for current detection; the feedback calculation module directly measures the back EMF of the second coil, reducing computational complexity.

[0153] This application also provides a driving method, which is applied to the driver chip of the above embodiment. The driver chip drives the linear resonant actuator by applying a driving signal to the first coil, the driving signal being used to drive the motor vibrator to vibrate; applying a common-mode signal to the second coil, the common-mode signal being used to raise the voltage across the second coil to a level close to the common-mode signal; and performing signal detection on the second coil to obtain the reverse electromotive force of the second coil.

[0154] In an optional embodiment, when the motor vibrator is in a stationary state, the voltages across the second coil are equal.

[0155] It can be understood that the common-mode signal applied to the second coil can raise the voltage across the second coil to near the common-mode signal, ensuring that the voltage across the second coil is equal when the motor vibrator is in a stationary state, that is, no current loop is formed on the second coil.

[0156] In an optional embodiment, when the motor vibrator is in a vibrating state, there is a voltage difference between the two ends of the second coil; the voltage difference represents the back electromotive force of the second coil.

[0157] In an optional embodiment, the speed of the motor vibrator is related to the back electromotive force of the second coil and the magnetic inductance of the second coil. The method further includes determining the speed of the motor vibrator based on the back electromotive force of the second coil and the magnetic inductance of the second coil. The specific method for determining the speed of the motor vibrator and the back electromotive force of the second coil can be referred to in the above embodiment and will not be repeated here.

[0158] In an optional embodiment, the linear resonant actuator further includes a thermistor, wherein at a first temperature, the resistance of the thermistor is a first impedance; wherein the first temperature, as described above, may be a preset temperature (e.g., room temperature, such as 25° C.). The method further includes: applying a common-mode signal to the thermistor, the common-mode signal forming a current loop in the thermistor; and performing signal detection on the thermistor to obtain a voltage difference across the thermistor or a current flowing through the thermistor.

[0159] In an optional embodiment, the common-mode signal is a voltage signal, and signal detection is performed on the thermistor to obtain the voltage difference across the thermistor or the current flowing through the thermistor, including: performing current detection on the thermistor to obtain the current flowing through the thermistor.

[0160] It can be understood that when the common-mode signal applied to the thermistor is a voltage signal, a constant voltage can be provided to the thermistor, so that there is a constant voltage difference across the thermistor, that is, current flows through the thermistor.

[0161] In an optional embodiment, the common-mode signal is a current signal, and signal detection is performed on the thermistor to obtain a voltage difference across the thermistor or a current flowing through the thermistor, including: performing voltage detection on the thermistor to obtain a voltage difference across the thermistor.

[0162] It can be understood that when the common-mode signal applied to the thermistor is a current signal, the current flowing through the thermistor is a constant current. The current signal generates a voltage difference across the thermistor, and the voltage difference can provide a common-mode voltage signal for the second coil.

[0163] In an optional embodiment, there is a constant voltage difference across the thermistor, and the method further includes: determining a second impedance of the thermistor based on the constant voltage difference and a current flowing through the thermistor; and determining a second temperature when the thermistor is at the second impedance based on the second impedance, the first impedance, and a resistance-temperature change relationship of the thermistor.

[0164] Specifically, the second impedance of the thermistor can be obtained by dividing the constant voltage difference across the thermistor by the current flowing through the thermistor. It should be understood that the resistance-temperature-rise formula and resistance-temperature-rise curve of the thermistor Rsen depend on the metal material type of the thermistor Rsen. The metal material of the thermistor and the related resistance-temperature-rise formula are not limited herein.

[0165] In an optional embodiment, the current flowing through the thermistor is a constant current, and the method further includes: determining a second impedance of the thermistor based on the constant current and a voltage difference across the thermistor; and determining a second temperature when the thermistor is at the second impedance based on the second impedance, the first impedance, and a resistance-temperature change relationship of the thermistor.

[0166] Specifically, the second impedance of the thermistor can be obtained by dividing the voltage difference across the thermistor by the constant current.

[0167] In an optional embodiment, the thermistor is thermally coupled to the first coil, and a heat transfer function exists between the temperature of the first coil and the temperature of the thermistor. The method further includes: determining the temperature of the first coil according to the second temperature of the thermistor and the heat transfer function.

[0168] It will be appreciated that when a heat transfer function exists between the temperature of the first coil and the temperature of the thermistor, the temperature of the first coil, i.e., the temperature during motor vibration, can be determined based on the temperature of the thermistor and the heat transfer function. In particular, when the thermistor is in close proximity to the first coil, the heat transfer function can be simplified to an equality relationship, i.e., the second temperature of the thermistor is equal to the temperature of the first coil.

[0169] In this embodiment, a coil is added to a conventional linear motor, with the first coil acting as the drive coil and the second coil acting as the observation coil. Using the driving method provided in this embodiment, the back electromotive force (the back electromotive force of the second coil) and the speed of the motor's oscillator can be determined during motor vibration, providing real-time motor vibration information. By adding a thermistor to a conventional linear motor, the driving method provided in this embodiment can also provide temperature information during motor vibration.

[0170] It will be understood that, as used herein, the term "module" may refer to or include, or be part of, an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and / or memory that executes one or more software or firmware programs, a combinational logic circuit, and / or other appropriate hardware components that provide the described functionality.

[0171] In some cases, the disclosed embodiments may be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried or stored on one or more temporary or non-temporary machine-readable (e.g., computer-readable) storage media, which may be read and executed by one or more processors. For example, the instructions may be distributed over a network or through other computer-readable media. Machine-readable media include any type of machine-readable media suitable for storing or transmitting electronic instructions or information in a form readable by a machine (e.g., a computer).

[0172] In the accompanying drawings, some structural or method features may be shown in a particular arrangement and / or order. However, it should be understood that such a particular arrangement and / or order may not be required. Rather, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. In addition, the inclusion of a structural or method feature in a particular figure does not imply that such feature is required in all embodiments, and in some embodiments, such features may not be included or may be combined with other features.

[0173] It should be noted that, in the examples and description of the present application, relational terms such as first and second, etc., are merely used to distinguish one signal or parameter from another signal or parameter, and do not necessarily require or imply any such actual relationship or order between these signals or parameters. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further restrictions, an element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0174] While the present application has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the present application.

Claims

1. A driver chip, characterized in that: Used to drive a linear resonant actuator, the linear resonant actuator comprising a first coil, a second coil and a motor vibrator, the first coil being used to drive the motor vibrator to vibrate, and the second coil being used to detect a reverse electromotive force during the vibration of the linear resonant actuator; The driver chip includes: a driver module, a common mode signal output module and a signal detection module; The driving module is connected to both ends of the first coil and is used to apply a driving signal to the first coil to drive the motor vibrator to vibrate; The common mode signal output module is connected to at least one end of the second coil and is used to apply a common mode signal to the second coil; The signal detection module is connected to both ends of the second coil and is used to perform signal detection on the second coil to obtain the reverse electromotive force of the second coil.

2. The driver chip according to claim 1, wherein: The common mode signal output module applies the common mode signal to the second coil, When the motor vibrator is in a stationary state, the voltages across the second coil are equal; or When the motor vibrator is in a vibrating state, there is a voltage difference across the second coil, and the voltage difference represents a back electromotive force of the second coil.

3. The driver chip according to claim 1 or 2, characterized in that: The driving chip further includes a feedback calculation module configured to determine a speed of the motor vibrator based on a back electromotive force of the second coil and a magnetic inductance of the second coil.

4. The driver chip according to claim 1, wherein: The linear resonant actuator further includes a thermistor; One end of the thermistor is a first node, and the first node is connected to one end of the second coil; The other end of the thermistor is a second node, and the second node is grounded; The common-mode signal output module is connected to the first node of the thermistor and is further used to apply the common-mode signal to the thermistor; The signal detection module is connected to both ends of the thermistor and is also used to perform signal detection on the thermistor.

5. The driver chip according to claim 4, characterized in that: If the common-mode signal is a voltage signal, there is a constant voltage difference across the thermistor. The signal detection module is used to perform current detection on the thermistor to obtain the current flowing through the thermistor; or, If the common mode signal is a current signal, the current flowing through the thermistor is a constant current. The signal detection module is used to perform voltage detection on the thermistor to obtain a voltage difference between both ends of the thermistor.

6. The driver chip according to claim 5, characterized in that: Also includes feedback calculation module, At a first temperature, the resistance of the thermistor is a first impedance, and the first temperature is a preset temperature; The feedback calculation module is used to determine a second impedance of the thermistor based on the constant voltage difference and the current flowing through the thermistor; The feedback calculation module is further configured to determine a second temperature when the resistance of the thermistor is equal to the second impedance based on the second impedance, the first impedance, and a resistance-temperature variation relationship of the thermistor.

7. The driver chip according to claim 5, characterized in that: Also includes feedback calculation module, At a first temperature, the resistance of the thermistor is a first impedance, and the first temperature is a preset temperature; The feedback calculation module is used to determine the second impedance of the thermistor according to the constant current and the voltage difference between the two ends of the thermistor; The feedback calculation module is further configured to determine a second temperature when the resistance of the thermistor is equal to the second impedance based on the second impedance, the first impedance, and a resistance-temperature variation relationship of the thermistor.

8. The driver chip according to claim 6 or 7, characterized in that: A heat transfer function exists between the temperature of the first coil and the temperature of the thermistor, and the temperature of the first coil is determined according to the second temperature of the thermistor and the heat transfer function.

9. The driver chip according to claim 6 or 7, characterized in that: The thermistor is disposed adjacent to the first coil, and the temperature of the first coil is equal to the second temperature of the thermistor.

10. A linear resonant actuator drive system, characterized in that: comprising a linear resonant actuator and a driving chip according to any one of claims 1 to 9; The linear resonant actuator includes a first coil, a second coil, and a motor vibrator. The first coil is used to drive the motor vibrator to vibrate, and the second coil is used to detect a back electromotive force during the vibration of the linear resonant actuator.

11. The drive system according to claim 10, characterized in that: The linear resonant actuator further includes a housing, wherein the first coil, the second coil, and the motor vibrator are all located inside the housing; The first coil and the second coil are fixed to the first inner surface of the shell.

12. The drive system according to claim 11, characterized in that The first coil and the second coil are provided on a flexible printed circuit board and fixed to the first inner surface of the housing; or, The first coil and the second coil are drawn on a flexible printed circuit board and fixed to the first inner surface of the housing; or, The first coil is directly fixed to the first inner surface of the housing, and the second coil is arranged on a flexible circuit board or drawn on a flexible circuit board and fixed to the first inner surface of the housing; or, The first coil and the second coil are fixed to the first inner surface of the housing. The first inner surface of the housing is a printed circuit board. The first coil and the second coil are drawn on the printed circuit board. Except for the first inner surface of the housing, the other surfaces of the housing are made of metal. or, The first coil and the second coil are fixed to the first inner surface of the shell. The first inner surface of the shell is a printed circuit board. The first coil is arranged on the printed circuit board, and the second coil is drawn on the printed circuit board. Except for the first inner surface of the shell, the other surfaces of the shell are made of metal.

13. The drive system according to claim 10, characterized in that The linear resonant actuator further includes a housing, wherein the first coil, the second coil, and the motor vibrator are all located inside the housing; The first coil and the second coil are located on both sides of the motor vibrator. The first coil is fixed to the second inner surface of the housing, and the second coil is fixed to the first inner surface of the housing.

14. The drive system according to claim 13, wherein: The first coil is directly fixed to the second inner surface of the housing, and the second coil is arranged on a flexible circuit board or drawn on a flexible circuit board and fixed to the first inner surface of the housing; or, The first coil is directly fixed to the second inner surface of the shell. The first inner surface of the shell is a printed circuit board. The second coil is drawn on the printed circuit board. Except for the first inner surface of the shell, the other surfaces of the shell are made of metal.

15. The drive system according to claim 12 or 14, characterized in that: The linear resonant actuator further includes a thermistor, the thermistor being located inside the housing, the thermistor and the second coil being located on the same side of the motor vibrator; and One end of the thermistor is a first node, and the first node is connected to one end of the second coil; The other end of the thermistor is a second node, and the second node is grounded.

16. The drive system according to claim 15, characterized in that The thermistor and the second coil are arranged on a flexible circuit board and fixed to the first inner surface of the housing; or, The thermistor and the second coil are drawn on a flexible circuit board and fixed to the first inner surface of the housing; or, The thermistor and the second coil are fixed to the first inner surface of the housing. The first inner surface of the housing is a printed circuit board. The thermistor and the second coil are drawn on the printed circuit board. Except for the first inner surface of the housing, the other surfaces of the housing are made of metal. or, The thermistor and the second coil are fixed to the first inner surface of the shell. The first inner surface of the shell is a printed circuit board. The thermistor is arranged on the printed circuit board. The second coil is drawn on the printed circuit board. Except for the first inner surface of the shell, the other surfaces of the shell are made of metal.

17. The drive system according to claim 12, 14 or 16, characterized in that The printed circuit board is a multi-layer circuit board, wherein the Nth layer is a shielding layer, the first coil and the second coil are located on the Nth layer, and N is a positive integer greater than or equal to 2; or, The printed circuit board is a multi-layer circuit board, wherein the Nth layer is a shielding layer, and the second coil is located on the Nth layer, where N is a positive integer greater than or equal to 2.

18. The drive system according to claim 17, wherein: When the driving system is applied to an electronic device, the printed circuit board reuses the bottom printed circuit board of the electronic device.

19. A driving method, characterized in that: A drive chip for driving a linear resonant actuator; the linear resonant actuator comprises a first coil, a second coil, and a motor vibrator, the first coil being used to drive the motor vibrator to vibrate, and the second coil being used to detect a reverse electromotive force during the vibration of the linear resonant actuator; The method comprises: applying a driving signal to the first coil, wherein the driving signal is used to drive the motor vibrator to vibrate; applying a common mode signal to the second coil; Signal detection is performed on the second coil to obtain a reverse electromotive force of the second coil.

20. The driving method according to claim 19, wherein: When the motor vibrator is in a stationary state, the voltages across the second coil are equal; or When the motor vibrator is in a vibrating state, there is a voltage difference between the voltages at both ends of the second coil, and the voltage difference represents a back electromotive force of the second coil.

21. The driving method according to claim 19 or 20, characterized in that: The method further comprises: The speed of the motor vibrator is determined based on the back electromotive force of the second coil and the magnetic inductance of the second coil.

22. The driving method according to claim 19, wherein: The linear resonant actuator further includes a thermistor; The method further comprises: applying the common-mode signal to the thermistor; Signal detection is performed on the thermistor.

23. The driving method according to claim 22, wherein: The common mode signal is a voltage signal, The performing signal detection on the thermistor includes: Performing current detection on the thermistor to obtain the current flowing through the thermistor; or The common mode signal is a current signal, The performing signal detection on the thermistor includes: A voltage detection is performed on the thermistor to obtain a voltage difference between both ends of the thermistor.

24. The driving method according to claim 23, wherein: There is a constant voltage difference across the thermistor, and at a first temperature, the resistance of the thermistor is a first impedance. The first temperature is a preset temperature, and the method further includes: determining a second impedance of the thermistor based on the constant voltage difference and the current flowing through the thermistor; A second temperature at which the resistance of the thermistor is equal to the second impedance is determined according to the resistance-temperature variation relationship among the second impedance, the first impedance, and the thermistor.

25. The driving method according to claim 23, wherein: The current flowing through the thermistor is a constant current, the resistance of the thermistor is a first impedance at a first temperature, the first temperature is a preset temperature, and the method further includes: determining a second impedance of the thermistor based on the constant current and a voltage difference across the thermistor; A second temperature at which the resistance of the thermistor is equal to the second impedance is determined according to the resistance-temperature variation relationship among the second impedance, the first impedance, and the thermistor.

26. The driving method according to claim 24 or 25, characterized in that: There is a heat transfer function between the temperature of the first coil and the temperature of the thermistor, and the method further includes: The temperature of the first coil is determined based on the second temperature of the thermistor and the heat transfer function.

27. The driving method according to claim 24 or 25, characterized in that: The thermistor is disposed adjacent to the first coil, and the method further includes: a temperature of the first coil being equal to a second temperature of the thermistor.

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