WO2018107512A1

WO2018107512A1 - Method for adjusting diaphragm vibration balancing position and speaker

Info

Publication number: WO2018107512A1
Application number: PCT/CN2016/111347
Authority: WO
Inventors: 李芳庆; 张贝; 兰友鎣; 于利刚; 李英明
Original assignee: 华为技术有限公司
Priority date: 2016-12-14
Filing date: 2016-12-21
Publication date: 2018-06-21
Also published as: CN109997372B; CN109997372A

Abstract

Provided in embodiments of the present invention is a method for adjusting a diaphragm balancing position, comprising the following steps: acquiring the displacement by which a diaphragm vibration balancing position of a diaphragm of a speaker deviated from an initial position, where the vibration balancing position serves for the diaphragm as the balancing position for vibrating when the diaphragm is working, and the diaphragm vibrates at a preset maximum amplitude when the initial position serves for the diaphragm as the balancing position for vibrating; inputting a direct current bias current to a voice coil of the speaker on the basis of the displacement so as to calibrate the vibration balancing position of the diaphragm to the initial position, where the voice coil is arranged on one side of the diaphragm and vibrates with the diaphragm. Therefore, the output of an increased sound pressure level by the speaker is ensured, and improved sound output effects are achieved.

Description

Method and speaker for adjusting diaphragm vibration balance position

Technical field

Embodiments of the present invention relate to the field of speaker technologies, and in particular, to a method for dynamically adjusting a vibration balance position of a speaker diaphragm, and a speaker.

Background technique

At present, smart power amplifier (Smart PA) has been widely used in mobile audio. Smart PA can not only exert the acoustic performance of the speaker but also the acoustic performance of the speaker according to the amplitude and temperature characteristics of the speaker (such as the earpiece or speaker). Very good protection for the speakers. In order to protect the normal operation of the speaker, the intelligent power amplifier usually needs to monitor the vibration displacement of the diaphragm in real time. For example, by pre-establishing the model, the real-time displacement of the diaphragm is predicted, and the diaphragm is always working in a safe state. At present, some manufacturers pre-establish the amplitude of the speaker diaphragm (corresponding to the vibration amplitude of the voice coil), the temperature model of the input current and voltage of the speaker, and then predict the real-time amplitude of the diaphragm by monitoring the voltage and current signals during operation to ensure that the real-time amplitude does not exceed The preset maximum amplitude Z_max is used to protect the speaker.

However, there are always some deviations in the physical parameters of the mass-produced speaker products. Under actual working conditions, the up and down displacement of the diaphragm may also be inconsistent, that is, the speaker product cannot guarantee 100% consistency, and the smart power amplifier needs to be Protect the vibrating components with sufficient margin. At this stage, when the diaphragm displacement is predicted by pre-establishing the model, the maximum amplitude of the diaphragm is affected by the detection accuracy and the accuracy of the model, and the original performance of the vibrating component cannot be fully utilized.

Summary of the invention

Embodiments of the present invention provide a method for dynamically adjusting a vibration balance position of a diaphragm, which can ensure that the speaker outputs at a relatively large sound pressure level.

A first aspect of the present invention provides a method for adjusting a vibration balance position of a diaphragm, the method comprising the steps of: acquiring a displacement amount of a vibration balance position of a diaphragm of the speaker from an initial position, wherein the diaphragm is in operation The diaphragm is in an equilibrium position where the vibration balance position is a vibration, When the diaphragm is in the equilibrium position of the vibration of the initial position, the diaphragm can vibrate with a preset maximum amplitude; according to the displacement amount, a DC bias current is input to the voice coil of the speaker to The vibration balance position of the diaphragm is calibrated to the initial position, wherein the voice coil is located on one side of the diaphragm, vibrating with the diaphragm. Therefore, the vibration balance position of the speaker diaphragm can be dynamically adjusted to ensure that the speaker outputs at a large sound pressure level.

According to the first aspect, in the first possible implementation manner of the first aspect, the displacement amount of the vibration balance position of the diaphragm of the speaker is offset from the initial position by: first detecting the front cover and the The capacitance value of the capacitor formed between the diaphragms is calculated; and then the displacement amount is calculated based on the capacitance value.

According to the first possible implementation manner of the first aspect, in the second possible implementation manner of the first aspect, the DC bias current i _offset can be calculated according to the displacement amount d _offset by using the following formula:

Where K _ms is the equivalent stiffness coefficient of the speaker, and Bl is the magnetic force factor of the voice coil and the magnetic circuit component.

According to a first aspect, in a second possible implementation of the first aspect,

According to the first possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, the magnetic induction device in the speaker can be measured by the magnetic induction device by providing a magnetic induction device on the diaphragm Intensity, calculating a vibration displacement of the diaphragm; and calculating a displacement amount of the vibration balance position of the diaphragm from the initial position according to the vibration displacement of the diaphragm.

According to a third possible implementation of the first aspect, in the fourth possible implementation of the first aspect, the magnetic sensing device is a Hall sensor.

In a fifth possible implementation manner of the first aspect, the method further includes: detecting when the speaker is working, according to any one of the possible implementation manners of the first aspect, the fourth possible implementation manner Temperature; determining a DC bias current input to the voice coil of the speaker based on the amount of displacement and the temperature at which the speaker operates. Taking into account the effect of temperature on the bias current, the bias current of the input voice coil is more accurate.

A second aspect of the embodiments of the present invention provides a speaker, which includes, in order from top to bottom, a front cover, a vibration component, and a magnetic circuit component; wherein the vibration component includes a voice coil and a diaphragm, and the voice coil Located on one side of the diaphragm, vibrating with the diaphragm; the speaker further includes a diaphragm amplitude detecting circuit for acquiring a displacement amount of the vibration balance position of the diaphragm from an initial position, wherein When the diaphragm is in operation, the diaphragm is in an equilibrium position of vibration with the vibration balance position, and when the diaphragm is in an equilibrium position of vibration, the diaphragm vibrates at a preset maximum amplitude; Narration The device further includes a diaphragm position control circuit for inputting a DC bias current to the voice coil of the speaker according to the displacement amount detected by the diaphragm detecting circuit to align the vibration balance position of the diaphragm To the initial position. The vibration balance position of the diaphragm of the speaker can be dynamically adjusted to ensure that the speaker is output at a large sound pressure level, and the sound is loud.

According to a second aspect, in a first possible implementation manner of the second aspect, the front cover is made of a metal material, or the front cover is provided with a conductive material layer; the diaphragm is made of a metal material, or the vibration is A layer of conductive material is provided on the film. Thus, a capacitor can be formed between the front cover and the diaphragm. The diaphragm amplitude detecting circuit acquires a displacement amount of a vibration balance position of the diaphragm from the initial position by detecting a capacitance value of a capacitor formed between the front cover and the diaphragm.

According to a second aspect, in a second possible implementation of the second aspect, the diaphragm is provided with a magnetic induction device, and the diaphragm amplitude detecting circuit measures the magnetic induction intensity in the speaker through the magnetic induction device. Obtaining a displacement amount of the vibration balance position of the diaphragm from the initial position.

According to a second possible implementation of the second aspect, in a third possible implementation of the second aspect, the magnetic sensing device is a Hall sensor.

In a fourth possible implementation manner of the first aspect, the speaker includes a temperature compensation circuit, and the temperature compensation circuit is configured according to any one of the first aspect to the third possible implementation manner of the first aspect. And detecting a temperature at which the speaker operates; the diaphragm position control circuit determines a DC bias current input to a voice coil of the speaker according to the displacement amount and a temperature at which the speaker operates.

DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention. Other drawings may also be obtained from those of ordinary skill in the art in view of the drawings.

1 is a schematic exploded view of a speaker according to an embodiment of the present invention;

2(A) is a schematic exploded view of another speaker according to an embodiment of the present invention;

Figure 2 (B) is a schematic exploded view of the speaker core of Figure 2 (A);

3 is a schematic structural diagram of still another speaker according to an embodiment of the present invention;

4(A) is a schematic view showing the vibration of the vibration balance position of the diaphragm provided by the embodiment of the present invention;

4(B) is a schematic view showing the vibration of the diaphragm vibration balance position negatively biased according to the embodiment of the present invention;

4(C) is a schematic view showing the vibration of the vibration balance position of the diaphragm provided by the embodiment of the present invention without bias;

FIG. 5 is a schematic diagram of a capacitance detecting circuit according to an embodiment of the present invention; FIG.

6 is a schematic structural diagram of a capacitor data collector provided by an embodiment of the present invention;

7 is a schematic diagram of a diaphragm amplitude detecting circuit according to an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a PA chip according to an embodiment of the present invention; FIG.

FIG. 9 is a schematic diagram of a method for dynamically adjusting a vibration balance position of a diaphragm according to an embodiment of the present invention.

detailed description

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic exploded view of a speaker according to an embodiment of the present invention.

The speaker in FIG. 1 includes, in order from top to bottom, a front cover 101, a vibration assembly, and a magnetic circuit assembly. The speaker also includes a housing 106 that is coupled together to enclose a cavity for receiving the vibrating assembly and the magnetic circuit assembly.

The front cover 101 is generally made of a metal material, so the front cover is sometimes called a front cover metal plate.

The vibration assembly includes, in order from top to bottom, a diaphragm reinforcing portion (Dome, also called a dome) 102, a diaphragm (Membrane) 103, and a voice coil (Coil) 105, wherein the diaphragm reinforcing portion 102 is fixed to the diaphragm. The center position of the upper surface of the 103, the voice coil 105 is disposed below the diaphragm 103.

In some embodiments, the vibration assembly may further include a Flexible Printed Circuit (FPC) 104 fixed between the diaphragm 103 and the voice coil 105, and the flexible circuit board 104 is coupled to the speaker chip 110. In still other embodiments, the flexible circuit board 104 may also be attached to the upper surface of the diaphragm 103. In some embodiments, the flexible circuit board 104 is not part of a vibrating assembly.

The magnetic circuit assembly includes, in order from top to bottom, a Washer (also called a pole piece) 107, a magnet (Mangnet) 108, and a frame 109. A magnetic gap is formed between the washer 107, the magnet 108 and the basin frame 109, and the voice coil 105 is suspended in the magnetic gap. The vibration assembly including the voice coil 105, the diaphragm 103, and the diaphragm reinforcing portion 102 can vibrate upward or downward by the action of the magnetic field of the magnetic circuit assembly. The magnetic circuit assembly can also be composed of a central huasi, a central magnet, a side huasi, and a side magnet.

FIG. 2(A) is a schematic exploded view of another speaker according to an embodiment of the present invention:

From top to bottom, there are: Damping 121, Lower Cover 122, flexible circuit board 123, Core 124, Plate 125 and Upper Cover 126. The upper cover 126 can also be called a front case. The flexible circuit board 123 is connected to the core 124. Wherein, the lower cover 122 and The upper cover 126 forms a cavity for receiving the inner core 124.

Figure 2 (B) is a schematic exploded view of the core of the speaker of Figure 2 (A):

The vibrating assembly includes, in order from top to bottom, a dome (also called a diaphragm reinforcing portion) 102, a diaphragm 103, and a voice coil 105. The dome 102 is fixed to a central position of the upper surface of the diaphragm 103.

The magnetic circuit assembly includes a basin frame 106, a pole piece 107, a magnet 108, and a yoke 111 in order from top to bottom. A magnetic gap is formed between the pole piece 107, the magnet 108, the yoke 111 and the basin frame 106, and the voice coil 105 is suspended in the magnetic gap. The vibrating assembly can vibrate up or down by the interaction of the magnetic field formed by the magnetic circuit assembly and the voice coil.

The components of the loudspeakers in Figures 1, 2(A) and 2(B) are not required and are merely illustrative. Various components can be deleted according to the needs of the actual product. For example, baffle 114 and/or damping 112 in Figure 2(A) may not be required in other embodiments provided by the present invention.

FIG. 3 is a schematic diagram of a moving coil speaker according to an embodiment of the present invention, wherein:

301-front cover, 302-diaphragm, 303-upper magnetic circuit component, 304-lower magnetic circuit component, 305-folded ring, 306-voice coil, 307-magnet. Wherein, the upper magnetic circuit component may comprise a washer (or a pole piece); the lower magnetic circuit component may comprise a yoke. If the front cover 301 is made of a metal material, the 301 may also be called a front cover metal plate or a metal cover plate.

D1 and d2 are the maximum vibration distances of the diaphragm in the z-direction upward and downward respectively. Generally, d1 is equal to d2, and the initial position of the diaphragm is the center position of the entire vibration distance. The initial position of the diaphragm can also be called the initial position of the voice coil; the vibration of the diaphragm can also be called the vibration of the voice coil. The Smart PA sets the maximum amplitude Z _{max of the} speaker diaphragm in the z-direction and protects the speaker from noise and reliability by limiting the maximum amplitude. If the vibration distance of the diaphragm exceeds Z _max , the diaphragm will touch the metal cover or the upper magnetic circuit assembly, and the speaker will make noise or cause unreliable problems.

Ideally, the diaphragm vibrates with an amplitude of d1 or d2 (d1 = d2 in an ideal state) with the initial position as the equilibrium position of the vibration. In this case, the diaphragm can achieve the maximum effective vibration distance, and the speaker can achieve the best sounding effect.

However, since the speaker is a non-linear device, the following problems occur during operation, and the sound pressure level of the device cannot be fully utilized:

1). The speaker is a mass-produced device, and there will be some deviation during the assembly process. It is difficult to ensure that the initial position of the speaker diaphragm (or voice coil) is exactly the same, the initial position of the diaphragm of some speakers and the vibration of the design. There is a deviation in the center position.

(2) When the speaker is working, the vibration system consisting of voice coil, diaphragm, folding ring, front and rear sound chambers has nonlinear characteristics, which causes the vibration balance position of the diaphragm in the z-direction to be offset from the initial position of the diaphragm. shift.

(3). When the speaker is working, the resonance frequency of the speaker itself will drift due to the temperature effect of the voice coil. When the driving voltage is constant, the maximum amplitude at different resonance frequencies is different, and there is a risk that the vibration amplitude of the diaphragm exceeds the safe range. .

At present, some manufacturers' Smart PAs are implemented in the diaphragm amplitude protection of the speaker by pre-establishing the diaphragm amplitude and temperature of the speaker with respect to the speaker input current and voltage, and then predicting the vibration by monitoring the voltage and current signals during operation. The real-time amplitude of the film ensures that the real-time amplitude does not exceed the preset maximum amplitude Z _max for the purpose of protecting the speaker.

Disadvantages of the above technical solution 1: The speaker is a mass-produced device, and there is a certain deviation in the speaker assembly process. It is difficult to ensure that the initial position of the diaphragm (or voice coil) of the speaker is exactly the same, and the initial position of the speaker diaphragm and the vibration center of the design. There is a deviation in position. Speakers with deviations will more easily reach Z _max when vibrating (if the center position of the diaphragm of a certain speaker is on the initial position of the diaphragm, it will be easier to reach Z _max in the upper part when vibrating). In order to protect these existences in the above technology. The biased speaker needs to reduce the Z _{max to} prevent the diaphragm from coming into contact with the front cover metal plate during vibration to avoid problems such as breakage. However, this solution will lose some of the acoustic performance for a speaker that does not have a diaphragm position deviation.

Disadvantages of the above technical solution 2: After the vibration balance position of the speaker diaphragm is shifted to the initial position, one side will reach the maximum amplitude first, and the Smart PA protection function will be activated at this time, while the other side has not reached the maximum amplitude, which limits the speaker. The output power of its own sound power. The dynamic balance of the diaphragm refers to the equilibrium position of the diaphragm when it is actually working.

The influence on the performance of the speaker when the vibration balance position of the diaphragm deviates from the initial position will be described below with reference to Figs. 4(A) to 4(C).

The vibration balance position of the diaphragm can also be called the vibration balance position of the voice coil. As shown in Fig. 4(C), according to the design, it is desirable that the diaphragm can vibrate between the forward maximum amplitude and the negative maximum amplitude. The initial position of the diaphragm is the intermediate position between the positive maximum amplitude and the negative maximum amplitude. . When the vibration balance position of the diaphragm coincides with the initial position of the diaphragm, the diaphragm can work at the maximum amplitude when it is actually working, and the performance of the speaker can be optimized, and the sound pressure level of the output is large. The maximum amplitude of the diaphragm at this time is the distance between the initial position and the forward maximum amplitude (or between the initial position and the forward maximum amplitude).

When the driving voltage of the speaker is large, the vibration balance position of the speaker diaphragm (also called dynamic vibration center, dynamic balance position) is offset from the initial position. Fig. 4(A) shows that the vibration balance position of the diaphragm is above the initial position (i.e., the z-direction is positive). When the diaphragm vibrates upward, the diaphragm's displacement reaches the maximum amplitude, and the speaker's Smart PA protection function begins to play. The action is to limit the displacement of the diaphragm upward vibration. At this time, the actual vibration amplitude of the diaphragm is the distance between the vibration balance position and the forward maximum amplitude. When the diaphragm works, it oscillates symmetrically upwards and downwards centering on the vibration balance position. Therefore, when the vibration balance position of the diaphragm deviates from the initial position, the distance the diaphragm vibrates downward cannot reach the negative maximum amplitude, so the safe vibration space of the diaphragm downward is not fully utilized, and the sound pressure level of the speaker output is not fully utilized. Smaller; similarly, Figure 4(B) shows the dynamic position of the diaphragm below the initial position (ie, the z-direction is negative). When the amplitude of the downward vibration of the diaphragm reaches the negative maximum amplitude, the speaker's Smart PA When the protection is turned on, the safe vibration space of the diaphragm upward is not fully utilized, and the sound pressure level of the output is small. Figure 4(C) shows that the vibration balance position of the diaphragm is not offset from the initial position. At this time, the amplitudes of the diaphragm up and down reach the maximum amplitude at the same time, and trigger the Smart PA protection function, up and down. The vibration space can be fully utilized and a large sound pressure level can be output.

In order to ensure that the speaker can output at a large sound pressure level, when detecting that the vibration balance position of the speaker diaphragm deviates from the initial position, it is necessary to correct the vibration balance position of the diaphragm, so that the vibration balance position of the diaphragm substantially coincides with the initial position. At this time, the operating state of the diaphragm can reach the state shown in Fig. 4(C).

FIG. 9 is a schematic diagram of a method for adjusting a vibration balance position of a speaker diaphragm according to an embodiment of the present invention:

901: Obtain a displacement amount d _{offset of} a vibration balance position of the speaker diaphragm from an initial position;

When the speaker is working, the diaphragm vibrates up and down with its vibration balance position centered. The initial position of the diaphragm refers to the equilibrium position at which the diaphragm operates at its maximum amplitude. The maximum diaphragm may be a vibration amplitude in which the diaphragm vibrates upward and downward in a safe space (as shown in FIG. 3, the space between the safe spaces 301 and 303), and does not contact other objects. The displacement amount d _offset refers to the displacement amount of the vibration balance position of the diaphragm from the initial value position when the speaker is operated. When the displacement amount d _{offset is} not zero, it is indicated that the vibration balance position of the diaphragm deviates from the initial position, and the vibration balance position of the diaphragm needs to be corrected. It is also possible to set the vibration balance position of the diaphragm to be corrected when the displacement amount d _offset exceeds a preset value. For example, the preset value may be 0.05 mm. A method of how to acquire the displacement amount d _offset will be described below.

902: Input a DC bias current i _offset to the voice coil of the speaker according to the displacement amount d-offset to align the vibration balance position of the speaker diaphragm to the initial position.

After the voice coil of the speaker is supplied with the DC current i _offset , the voice coil generates a magnetic force F _offset , which acts on the diaphragm to cancel the deviation d _offset of the vibration balance position of the diaphragm from the initial position. d _offset , magnetic F _offset and current i _offset have the following relationship:

F _offset =-K _ms *d _offset (1)

Among them, K _ms and Bl are the equivalent stiffness coefficient and magnetic force factor of the speaker respectively, which are known quantities.

Therefore, after the offset d _{offset is} obtained, the magnitude of the bias current i _offset can be calculated.

In some embodiments, it is also possible to further detect the temperature at which the speaker operates, according to which the bias current i _offset can be determined more accurately. For example, according to

steps

901 and 902, the bias current i _offset = 1.0A has been determined. When the temperature of the speaker is detected to be 40 degrees Celsius, the correction bias current is 1.01A; when the temperature of the speaker is 50 degrees Celsius, the bias current is 1.05A.

4(A) is taken as an example to illustrate that the vibration balance position of the diaphragm deviates from the initial position to obtain an offset d _{offset of} about 0.5 mm. A bias current i _{offset is} applied to the voice coil. The size of i _offset can be calculated by the above formulas (1) and (2). After the bias current i _{offset is} applied, the voice coil generates a magnetic force F _offset , and the magnetic force acts on the diaphragm, so that the vibration balance position of the diaphragm moves downward and returns to the initial position. The principle of adjusting the vibration balance position of the diaphragm described in Fig. 4(B) is similar.

A method for acquiring the diaphragm offset d _offset provided by the embodiment of the present invention is described below.

As shown in FIG. 3, a plate capacitor can be formed between the diaphragm 302 of the speaker and the front cover 301. The front cover 101 is generally made of metal. Therefore, the front cover 101 can constitute a fixed plate of the panel capacitor. If the front cover 101 is made of a non-metal material, a conductive material layer may be disposed on the front cover 101, and the conductive material layer may be attached to the lower surface of the front cover 101. It is not necessary for all of the front cover 101 to be made of a metal material, and a part of the front cover 101 is made of a metal material.

If the diaphragm is a plastic diaphragm, such as polypropylene, or the diaphragm is made of synthetic fiber, a layer of conductive material can be placed on the diaphragm. The diaphragm can also be made of metal. Therefore, the diaphragm can constitute a movable plate of the plate capacitor. The fixed plate and the movable plate are opposed to each other to form a capacitor.

In other embodiments provided by the present invention, the flexible circuit board 104 may be fixed on one side of the diaphragm 103, and a conductive material layer is disposed in the middle of the flexible circuit board 104. The flexible circuit board 104 and the front cover 101 are shaped. Into a capacitor.

As shown in Fig. 3, when the speaker is operated, the distance d between the diaphragm and the front cover changes with the vibration of the diaphragm. The corresponding distance change can be calculated from its dynamic capacitance C. Therefore, by monitoring the capacitance in real time, the dynamic position of the diaphragm in the z-direction can be monitored. The offset of the vibration balance position in the z-direction can be calculated by the difference between the upper and lower amplitudes.

In the formula, ε is the dielectric constant, S is the effective area of the parallel plate capacitor, and d is the distance between the plates.

Assuming that the diaphragm vibrates upward, the distance between the plates is calculated to be d _z1 ; when the diaphragm vibrates downward, the distance between the plates is d _z2 . Then there are:

Z _max+ =d1-d _z1 ;Z _max -=d1-d _z2

Therefore, the offset distance d _offset of the vibration balance position of the diaphragm with respect to the initial position is:

In the formula, Z _max+ is the maximum displacement in the z positive direction when the diaphragm is working, and Z _max − is the maximum displacement in the negative z direction when the diaphragm is working.

The embodiment of the invention provides another method for acquiring the diaphragm offset d _offset . A magnetic sensor is attached to the diaphragm, which measures and acquires magnetic induction. The magnetic sensor can be a Hall sensor. Since the magnetic induction intensity is related to the position of the vibration of the diaphragm, the position of the diaphragm during the vibration can be obtained by the magnetic induction.

After obtaining the diaphragm offset d _offset , inputting a DC bias current i _{offset to} the voice coil of the speaker, calibrating the vibration balance position of the speaker diaphragm, and aligning the vibration balance position of the diaphragm to the initial position . When the diaphragm is working, the vibration is balanced with the initial position, and the maximum diaphragm can be achieved by both upward and downward vibration. Therefore, the speaker can perform at its best.

Embodiments of the present invention provide a method of determining the capacitance C of a capacitor formed by a diaphragm and a front cover. The circuit for testing capacitor C is shown in Figure 5. The capacitor formed by the diaphragm and the front cover of the capacitor C. The circuit can be integrated into the chip of the Smart PA or it can be a separate circuit or chip. The ADC in Figure 5 is an analog to digital converter.

The voltage value Uo is proportional to the measured capacitance value C

If jωR _f C _f >>1, then there is

That is, the voltage value U _{0 is} proportional to the measured capacitance value C.

FIG. 6 is a schematic structural diagram of a capacitor data collector provided by an embodiment of the present invention. The capacitance measuring circuit in Figure 6 is shown in Figure 5. Specifically, the voltage U _o is processed by an AC amplifier, a full-wave rectification circuit, a low-pass filter, and an A/D conversion circuit to finally obtain a capacitance C to be measured. The measured capacitance C is represented by C _x in FIG. 6.

A diaphragm amplitude detecting circuit according to an embodiment of the present invention is shown in FIG. After obtaining the measured capacitance C _x through the capacitance data collector, the diaphragm compensation amount d _{offset is} calculated through the diaphragm diaphragm calculation module.

The embodiment of the invention further provides a PA chip 802. As shown in Fig. 8, 801 denotes a capacitor formed by a diaphragm and a front cover, 803 denotes an adder, and 804 denotes an amplifier. The PA chip includes a diaphragm amplitude detecting circuit, a diaphragm position control circuit, a signal and a gain control circuit, and the like. One end of the PA chip is connected to the voice coil, and one end is connected to a capacitor formed by the diaphragm and the front cover. The diaphragm diaphragm detecting circuit detects the amplitude d of the diaphragm and the diaphragm offset d _offset . The amplitude d can also be used to send to the algorithm module, which can determine the bias current i _offset more accurately based on the detected diaphragm d and the operating temperature of the speaker. For example, when the speaker temperature is 40 degrees Celsius, the bias current is 1.0A; when the speaker temperature is 50 degrees Celsius, the bias current is 1.1A. The information sent to the algorithm module may also include or include d _offset at the same time. The diaphragm offset d _offset is sent to the diaphragm position control circuit. The diaphragm position control circuit calculates the bias current i _offset by the method described above. The offset current i _offset and information such as signals and gains are sent to the voice coil, and the vibration balance position of the diaphragm is controlled by the voice coil. The signal can be an audio signal; the gain can change the amplitude of the diaphragm.

Claims

A method for adjusting a vibration balance position of a diaphragm, characterized in that the method comprises:

Acquiring a displacement amount of a vibration balance position of the diaphragm of the speaker from an initial position, wherein the diaphragm is in an equilibrium position of the vibration with the vibration balance position, and the diaphragm is in the initial position When the vibration is in an equilibrium position, the diaphragm vibrates at a preset maximum amplitude;

And inputting a DC bias current to the voice coil of the speaker according to the displacement amount to calibrate a vibration balance position of the diaphragm to the initial position, wherein the voice coil is located at one side of the diaphragm, Vibrate with the diaphragm.
The method according to claim 1, wherein the displacement amount of the vibration balance position of the diaphragm for obtaining the speaker deviates from the initial position is specifically:

Detecting a capacitance value of a capacitor formed between a front cover of the speaker and the diaphragm;

The amount of displacement is calculated based on the capacitance value.
The method according to claim 2, wherein the DC bias current i offset is calculated according to the displacement amount d offset by the following formula:

Where K ms is the equivalent stiffness coefficient of the speaker, and Bl is the magnetic force factor of the voice coil and the magnetic circuit component.
The method according to claim 1, wherein the displacement amount of the vibration balance position of the diaphragm for obtaining the speaker deviates from the initial position is specifically:

Providing a magnetic induction device on the diaphragm, measuring a magnetic induction intensity in the speaker by the magnetic induction device, and calculating a vibration displacement of the diaphragm;

According to the vibration displacement of the diaphragm, the displacement amount of the vibration balance position of the diaphragm from the initial position is calculated.
The method of claim 4 wherein said magnetic sensing device is a Hall sensor.
The method according to any one of claims 1 to 5, wherein the method further comprises:

Detecting the temperature at which the speaker operates;

A DC bias current input to the voice coil of the speaker is determined based on the amount of displacement and the temperature at which the speaker operates.
A speaker, wherein the speaker includes, in order from top to bottom, a front cover, a vibration assembly, and a magnetic circuit assembly; wherein the vibration assembly includes a voice coil and a diaphragm, and the voice coil is located at the vibration One side of the membrane vibrates with the diaphragm;

The speaker further includes a diaphragm amplitude detecting circuit for acquiring a displacement amount of the vibration balance position of the diaphragm from the initial position, wherein the diaphragm is vibrated by the vibration balance position when the diaphragm is in operation An equilibrium position, wherein the diaphragm vibrates at a preset maximum amplitude when the diaphragm is in an equilibrium position of vibration;

The speaker further includes a diaphragm position control circuit for inputting a DC bias current to the voice coil of the speaker according to the displacement amount detected by the diaphragm detecting circuit to balance the vibration of the diaphragm The position is calibrated to the initial position.
A speaker according to claim 7 wherein:

The front cover is made of a metal material, or the front cover is provided with a conductive material layer;

The diaphragm is made of a metal material, or a layer of a conductive material is disposed on the diaphragm;

The diaphragm amplitude detecting circuit acquires a displacement amount of a vibration balance position of the diaphragm from the initial position by detecting a capacitance value of a capacitor formed between the front cover and the diaphragm.
A speaker according to claim 7 wherein:

a magnetic induction device is disposed on the diaphragm;

The diaphragm amplitude detecting circuit measures the magnetic induction intensity in the speaker by the magnetic induction device, and acquires a displacement amount of the vibration balance position of the diaphragm from the initial position.
The speaker according to claim 9, wherein said magnetic sensing device is a Hall sensor.
A speaker according to any one of claims 7 to 10, wherein the speaker comprises a temperature compensation circuit;

The temperature compensation circuit is configured to detect a temperature when the speaker is in operation;

The diaphragm position control circuit determines a DC bias current input to a voice coil of the speaker according to the displacement amount and a temperature at which the speaker operates.