CN113965851B - Loudspeaker diaphragm displacement control circuit and control method and electronic equipment - Google Patents
Loudspeaker diaphragm displacement control circuit and control method and electronic equipment Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2499/00—Aspects covered by H04R or H04S not otherwise provided for in their subgroups
- H04R2499/10—General applications
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Abstract
The application provides a loudspeaker diaphragm control circuit and a control method, wherein the loudspeaker diaphragm control circuit comprises a displacement prediction module, a displacement dynamic range control module, a temperature calculation module and a multiplier; the real-time temperature calculation module of the loudspeaker is added, and the temperature calculation module is connected with the displacement prediction module, namely, the real-time temperature of the environment where the loudspeaker is located can be obtained through the temperature calculation module, the real-time temperature is fed back to the displacement prediction module, and the displacement prediction result is corrected, so that the obtained predicted displacement value is related to the real-time temperature, the control accuracy of the displacement of the loudspeaker diaphragm is improved, the problem that the loudspeaker is damaged due to the fact that the temperature influences the loudspeaker diaphragm to exceed the specified maximum displacement value is avoided, and the loudspeaker is protected.
Description
Technical Field
The present invention relates to the field of control technologies, and in particular, to a loudspeaker diaphragm displacement control circuit, a loudspeaker diaphragm displacement control method, and an electronic device.
Background
In the market of mobile terminals, the requirements of customers on the audio texture of mobile phones are increasing. In order to improve the loudness and tone quality of a speaker (also called a loudspeaker) of a mobile terminal, an audio power amplifier chip must reasonably control the speaker so that the speaker plays the very role as much as possible, but does not damage the speaker.
The loudspeaker emits sound by vibrating the diaphragm. The larger the amplitude of the vibration, the higher the loudness of the sound for the same frequency point. In the digital audio power amplification chip, the maximum loudness of the loudspeaker is exerted, and meanwhile, the vibration displacement of the loudspeaker diaphragm is ensured not to exceed the specified maximum displacement, so that the loudspeaker is prevented from being damaged. Therefore, modeling and displacement prediction are required for the displacement of the speaker, and when the predicted displacement exceeds a prescribed maximum displacement, the actual maximum displacement of the speaker is ensured to be just or slightly smaller than the prescribed maximum displacement value by reducing the amplitude of the input voltage.
However, the diaphragm displacement prediction accuracy of the speaker in the prior art is low, and the risk of damage to the speaker is high.
Disclosure of Invention
In view of the above, the invention provides a loudspeaker diaphragm displacement control circuit, a control method and an electronic device, so as to solve the problems of low diaphragm displacement prediction precision and high risk of damage to a loudspeaker in the prior art.
In order to achieve the above purpose, the present invention provides the following technical solutions:
a loudspeaker diaphragm control circuit, comprising:
the device comprises a displacement prediction module, a displacement dynamic range control module, a temperature calculation module and a multiplier;
the temperature calculation module is used for calculating the real-time temperature of the loudspeaker;
the displacement prediction module is connected with the output end of the temperature calculation module and is used for receiving a voltage input signal and calculating a predicted displacement value according to the voltage input signal and the real-time temperature;
the displacement dynamic range control module is used for receiving the predicted displacement value output by the displacement prediction module and calculating to obtain a gain value according to the received predicted displacement value;
the multiplier is used for multiplying the voltage input signal with the gain value output by the displacement dynamic range control module to obtain a voltage output signal;
the output end of the multiplier is connected with the input end of the loudspeaker and is used for driving the loudspeaker to emit sound.
Preferably, the temperature calculation module includes:
the device comprises a loudspeaker input end voltage sampling circuit, a resistor connected with the loudspeaker in series, a voltage sampling circuit at two ends of the resistor and a temperature calculation sub-module;
the loudspeaker input end voltage sampling circuit is used for acquiring the input end voltage of the loudspeaker;
the temperature calculation sub-module is used for calculating and obtaining the real-time current of the input end of the loudspeaker according to the resistance value of the resistor and the voltages at the two ends of the resistor;
the direct current impedance of the loudspeaker is calculated according to the input end voltage of the loudspeaker and the input end real-time current;
and the real-time temperature of the loudspeaker corresponding to the direct current impedance is obtained through calculation according to the direct current impedance.
Preferably, the displacement dynamic range control module comprises:
a gain generation module;
the gain generation module is used for receiving the predicted displacement value, calculating to obtain a gain value of the displacement dynamic range control module, wherein the gain value of the displacement dynamic range control module is a correlation function of a control threshold, a gain curve smooth transition parameter and a pressing slope of the gain curve.
Preferably, a delay is also included;
the input end of the delay device is used for receiving a voltage input signal;
the delayer is used for carrying out delay processing on the voltage input signal, and outputting the delayed voltage input signal to one input end of the multiplier so as to multiply the gain value output by the displacement dynamic range control module.
Preferably, the dynamic range control module further comprises:
a gain smoothing module;
the input end of the gain smoothing module is connected with the output end of the gain generating module, the output end of the gain smoothing module is connected with the other input end of the multiplier, and the gain value output by the displacement dynamic range control module is output;
the gain smoothing module is used for modulating the pressing time and the releasing time of the gain value output by the gain generating module, and the pressing time is bound with the delay time of the delayer.
The invention also provides a loudspeaker diaphragm control method based on the loudspeaker diaphragm control circuit, which comprises the following steps:
acquiring a voltage input signal and a real-time temperature of the loudspeaker;
calculating to obtain a predicted displacement value according to the voltage input signal and the real-time temperature;
calculating according to the predicted displacement value to obtain a gain value;
and multiplying the voltage input signal with the gain value, outputting a voltage output signal, and controlling the loudspeaker to sound.
Preferably, before multiplying the voltage input signal with the gain value, further comprising:
and delaying the voltage input signal to obtain a delayed voltage input signal for multiplication with the gain value.
Preferably, the calculating to obtain the predicted displacement value according to the voltage input signal and the real-time temperature specifically includes:
calculating displacement offset related to the real-time temperature according to the real-time temperature;
calculating a first displacement predicted value according to the voltage input signal;
and superposing the displacement offset related to the real-time temperature with the first displacement predicted value to obtain the predicted displacement value.
Preferably, the expression of the predicted displacement value is:
wherein, bl, c, R, m, L, R is a linear parameter, bl (T) is the product of magnetic induction intensity and coil length of the speaker relative to temperature T, m is the mass of the speaker coil, R (T) is the mechanical damping of the speaker relative to temperature T, 1/c (T) is the mechanical spring coefficient of the speaker relative to temperature T, R (T) is the direct current resistance of the speaker relative to temperature T, L (T) is the equivalent inductance of the speaker relative to temperature T, os (T) is a displacement offset parameter, and the offset is relative to temperature T.
Preferably, in the acquiring the voltage input signal and the real-time temperature of the speaker, acquiring the real-time temperature of the speaker specifically includes:
acquiring the voltage of the input end of the loudspeaker and the real-time current of the input end of the loudspeaker;
calculating to obtain the direct current impedance of the loudspeaker according to the voltage of the input end of the loudspeaker and the real-time current of the input end of the loudspeaker;
and calculating according to the direct current impedance to obtain the real-time temperature of the loudspeaker corresponding to the direct current impedance.
The invention also provides a loudspeaker diaphragm control circuit and a loudspeaker, wherein the loudspeaker diaphragm control circuit is used for controlling the diaphragm of the loudspeaker.
According to the technical scheme, the loudspeaker diaphragm control circuit provided by the invention comprises a displacement prediction module, a displacement dynamic range control module, a temperature calculation module and a multiplier; the real-time temperature calculation module of the loudspeaker is added, and the temperature calculation module is connected with the displacement prediction module, namely, the real-time temperature of the environment where the loudspeaker is located can be obtained through the temperature calculation module, the real-time temperature is fed back to the displacement prediction module, and the displacement prediction result is corrected, so that the obtained predicted displacement value is related to the real-time temperature, the control accuracy of the displacement of the loudspeaker diaphragm is improved, the problem that the loudspeaker is damaged due to the fact that the temperature influences the loudspeaker diaphragm to exceed the specified maximum displacement value is avoided, and the loudspeaker is protected.
In addition, the invention also provides a loudspeaker diaphragm control method, which is used for detecting the real-time temperature of a loudspeaker, modeling is carried out based on the real-time temperature, a predicted displacement value related to the real-time temperature can be obtained by combining a corrected displacement model with a real-time input signal, and the displacement model is a displacement model dynamically adjusted by the real-time temperature of the loudspeaker in the control method, so that the displacement prediction module can accurately predict the actual displacement of the loudspeaker diaphragm at different temperatures, thereby ensuring that the displacement of the loudspeaker diaphragm at different temperatures such as high temperature does not exceed the specified maximum displacement, and protecting the loudspeaker.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a functional module of a loudspeaker diaphragm control circuit according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a functional module of a displacement dynamic range control module according to an embodiment of the present invention;
fig. 3 is a schematic diagram of speaker model establishment according to an embodiment of the present invention;
fig. 4 is a flowchart of a method for controlling a loudspeaker diaphragm according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
As described in the background section, the diaphragm displacement prediction accuracy of the speaker in the prior art is low, and the risk of damage to the speaker is high.
The inventor finds that the reason for the phenomenon is that the method for predicting the displacement of the loudspeaker diaphragm in the prior art does not relate to the influence of the temperature of the loudspeaker on the displacement of the loudspeaker diaphragm, namely, in the existing loudspeaker displacement protection algorithm, effective protection is not available for the situation that the actual displacement of the loudspeaker diaphragm is changed due to different temperatures and possibly exceeds the specified maximum displacement.
The inventors have found that when the loudspeaker is at different temperatures, particularly at high temperatures, the diaphragm displacement of the loudspeaker may change due to the fact that the air pressure on both sides of the loudspeaker cavity is not uniform due to the asymmetry of both sides of the loudspeaker cavity, and other physical non-ideal factors of the loudspeaker are added, resulting in the risk that the actual displacement exceeds the specified maximum displacement, thereby damaging the loudspeaker.
Based on this, the present invention provides a loudspeaker diaphragm control circuit, comprising:
the device comprises a displacement prediction module, a displacement dynamic range control module, a temperature calculation module and a multiplier;
the temperature calculation module is used for calculating the real-time temperature of the loudspeaker;
the displacement prediction module is connected with the output end of the temperature calculation module and is used for receiving a voltage input signal and calculating a predicted displacement value according to the voltage input signal and the real-time temperature;
the displacement dynamic range control module is used for receiving the predicted displacement value output by the displacement prediction module and calculating to obtain a gain value according to the received predicted displacement value;
the multiplier is used for multiplying the voltage input signal with the gain value output by the displacement dynamic range control module to obtain a voltage output signal;
the output end of the multiplier is connected with the input end of the loudspeaker and is used for driving the loudspeaker to emit sound.
The loudspeaker diaphragm control circuit provided by the invention comprises a displacement prediction module, a displacement dynamic range control module, a temperature calculation module, a multiplier and a loudspeaker; the real-time temperature calculation module of the loudspeaker is added, and the temperature calculation module is connected with the displacement prediction module, namely, the real-time temperature of the environment where the loudspeaker is located can be obtained through the temperature calculation module, the real-time temperature is fed back to the displacement prediction module, and the displacement prediction result is corrected, so that the obtained predicted displacement value is related to the real-time temperature, the control accuracy of the displacement of the loudspeaker diaphragm is improved, the problem that the loudspeaker is damaged due to the fact that the temperature influences the loudspeaker diaphragm to exceed the specified maximum displacement value is avoided, and the loudspeaker is protected.
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, fig. 1 is a schematic diagram of a functional module of a loudspeaker diaphragm control circuit according to an embodiment of the present invention; comprising the following steps: the device comprises a displacement prediction module 1, a displacement dynamic range control module 2, a temperature calculation module 3 and a multiplier 4; the temperature calculation module 3 is used for calculating and obtaining the real-time temperature of the loudspeaker; the displacement prediction module 1 is connected with the output end of the temperature calculation module 3 and is used for receiving a voltage input signal Din and calculating a predicted displacement value according to the voltage input signal Din and the real-time temperature; the displacement dynamic range control module 2 is used for receiving the predicted displacement value output by the displacement prediction module and calculating a Gain value Gain according to the received predicted displacement value; the multiplier 4 is used for multiplying the voltage input signal Din by the Gain value Gain output by the displacement dynamic range control module to obtain a voltage output signal Dout; the output end of the multiplier is connected with the input end of the loudspeaker and is used for driving the loudspeaker to make sound.
In this embodiment, the specific structure of the temperature calculation module is not limited, as long as the impedance corresponding to the direct current of the speaker can be calculated according to the input end voltage and the real-time current of the speaker, so that the real-time temperature of the speaker can be calculated, and optionally, the temperature calculation module includes: the device comprises a loudspeaker input end voltage sampling circuit, a resistor connected with the loudspeaker in series, a resistor two-end voltage sampling circuit and a temperature calculation sub-module; the loudspeaker input end voltage sampling circuit is used for acquiring the input end voltage of the loudspeaker; the temperature calculation sub-module is used for calculating and obtaining real-time current of the input end of the loudspeaker according to the resistance value of the resistor and the voltages at two ends of the resistor; the direct current impedance of the loudspeaker is calculated according to the voltage obtained by sampling of the input end voltage sampling circuit of the loudspeaker and the real-time current of the input end of the loudspeaker; and is used for calculating the real-time temperature of the loudspeaker corresponding to the direct current impedance according to the direct current impedance.
Specifically, as shown in fig. 1, a small resistor is connected in series in the wiring of the speaker, and in the embodiment of the present invention, the specific resistance value of the small resistor is not limited, alternatively, the resistance value of the small resistor is 0.2ohm, and the current flowing through the resistor, that is, the current I flowing through the speaker, can be calculated by detecting the voltages at two ends of the resistor. The voltage V of the loudspeaker can be obtained by directly detecting the voltages at the two ends of the loudspeaker. The real-time direct current impedance of the loudspeaker can be obtained through calculation through the voltage V and the current I of the loudspeaker. Because the material of the coil of the loudspeaker is a specific alloy, the temperature rise coefficient is relatively fixed. The real-time temperature of the loudspeaker can be converted by comparing the calculated real-time direct current impedance with the direct current impedance value at 25 ℃.
The specific calculation process is as follows:
t in the formula 0 For the reference temperature value, 25 degrees celsius is typically set. R is R 0 Is T 0 And a corresponding direct current impedance value at temperature. Alpha is the temperature rise coefficient of the speaker coil and is generally related to the coil material of the speaker. R is R e The real-time temperature T corresponding to the loudspeaker coil can be calculated by the method.
It should be noted that, in this embodiment, the bit dynamic range control (Dynamic range control, dynamic range control, abbreviated as DRC) module may only include a gain generating module, where the gain generating module is configured to receive the predicted displacement value, calculate a gain value of the displacement dynamic range control module, and the gain value of the displacement dynamic range control module is at least a correlation function of a control threshold, a smooth transition parameter of a gain curve, and a pressing slope of the gain curve.
However, since DRC needs a certain time for smooth transition according to the predicted displacement to adjust the Gain, in order to prevent the Gain from suddenly changing and causing the sound of the speaker to be suddenly changed, in the embodiment of the present invention, before the voltage input signal Din is multiplied by the Gain, the voltage input signal Din is first subjected to a delay unit 5, so that the delay time of the input signal Din is bound with the hold-down time of the Gain, and the input signal and the Gain modulation can reach the multiplier at the same time for further processing.
Correspondingly, the bit movement range control module in this embodiment may further include a gain smoothing module; the gain smoothing module receives the output signal of the gain generating module, the output signal of the gain smoothing module is transmitted to the other input end of the multiplier, and the output signal of the gain smoothing module is the gain value output by the displacement dynamic range control module; the gain smoothing module is used for modulating the pressing time and the releasing time of the gain value output by the gain generating module, and the pressing time is bound with the delay time of the delayer, so that the adjustment time of the gain value is matched with the time of the input signal reaching the multiplier, and the time when the gain adjustment is finished and the time when the input signal reaches the multiplier are identical.
Fig. 2 is a schematic functional block diagram of a displacement dynamic range control module according to an embodiment of the present invention; the displacement DRC in this embodiment includes a Gain generator and a Gain smoothing module Gain Smooth. The Gain Computer comprises three parameters, namely a Threshold, a Gain curve smoothly transiting the Gain curve, and a compression slope Ratio of the Gain curve. For the control requirement of displacement, the pressing slope Ratio of the gain curve is generally set to 0, so that the displacement can be forced to be pressed below a Threshold value Threshold. The gain curve smooth transition Knee is generally set to be 5 dB-20 dB, so that the gain curve is ensured to be not pressed and a smooth transition exists in the middle of pressing, and the sound hearing of the final loudspeaker does not have an excessively hard feeling.
The Gain smoothing module has the Gain pressing time Attacktime as the pressing time of the modulation Gain, the Gain release time Releasetime as the release time of the modulation Gain, and the Gain is ensured not to have abrupt change, so that the hearing of a loudspeaker/loudspeaker with negligence is not caused, for example, if the temperature is increased, the control threshold value is reduced, the Gain is also reduced, the Gain is required to be adjusted from-3 dB to-6 dB, and the Gain pressing time Attacktime refers to the time required to be adjusted from-3 dB to-6 dB. If the temperature drops, the control threshold value becomes larger, the gain also becomes larger, and the gain is released from-7 dB to-2 dB, so that the gain release time Releasetime is the time required for adjusting from-7 dB to-2 dB.
It should be noted that, in this embodiment, the gain suppressing time atacktime is bound to the delay time of the delayer 5, so that the delay time of the delayer is matched with the time required by gain adjustment, thereby ensuring that the final actual displacement of the speaker/loudspeaker does not exceed the specified maximum displacement.
Referring to fig. 3, fig. 3 is a schematic diagram illustrating speaker model establishment according to an embodiment of the present invention; wherein R is the DC resistance of the loudspeaker, and L is the equivalent inductance of the loudspeaker.
L2 and R2 are inductance and resistance equivalent to the eddy current effect of the loudspeaker at high frequency. The two parameters have less influence on the loudspeaker model, and can be ignored under the condition that the model precision requirement is not very strict.
m is the mass of the speaker coil, r is the mechanical damping of the speaker, and 1/c is the mechanical spring rate of the speaker.
In the equivalent model of the loudspeaker there are two loops, as shown in fig. 3, the voltage loop on the left and the mechanical loop on the right. The mathematical expression can be expressed as:
wherein U (t) is a real-time input voltage value, I (t) is a real-time current value, and x (t) is a real-time displacement of the diaphragm of the small loudspeaker.
The two formulas are converted into Laplace domain (S domain) expression by using the system knowledge of the digital signals:
combining the two formulas of the laplace domain and eliminating I(s) to obtain the expression of x(s) about U(s):
for small speakers of a particular specification, bl, c, R, m, L, r is a linear parameter that can be measured directly, a known quantity. Bl is the product of magnetic induction intensity and coil length of the loudspeaker, m is the mass of the coil of the loudspeaker, R is the mechanical damping of the loudspeaker, 1/c is the mechanical spring coefficient of the loudspeaker, R is the direct current resistance of the loudspeaker, and L is the equivalent inductance of the loudspeaker. Where S is a variable of the laplace domain, and is frequency dependent.
Therefore, by the above equation, the real-time displacement of the loudspeaker diaphragm can be predicted from the input real-time voltage data.
Correcting the transfer function of displacement with respect to voltage as:
since the horn coil mass m does not vary with temperature, it is a fixed constant. And (5) hooking other linear parameters and the temperature T, and dynamically updating the linear parameter values by different temperatures. And a displacement offset parameter os is added, which offset is temperature dependent, since the pressure difference across the speaker/horn chamber will be different for different temperatures, resulting in different os.
Therefore, by the displacement prediction module which can be dynamically adjusted according to the temperature after correction, more accurate predicted displacement can be obtained according to the real-time voltage and the real-time temperature. Thereby ensuring more accurate control of the speaker/horn displacement at various temperatures (particularly high temperatures) without exceeding a prescribed maximum displacement.
In summary, the working principle of the loudspeaker diaphragm control circuit provided by the embodiment of the invention includes:
with continued reference to fig. 1, the voltage input signal Din is subjected to a temperature-dependent displacement prediction module (ex-cursion Model) to obtain a predicted displacement value. DRC (Dynamic range control ), i.e. dynamically adjusting different gains Gain according to the amplitude of the input signal, and the multiplier outputs the result of multiplying the voltage input signal Din by the Gain, i.e. the voltage output signal Dout, to the loudspeaker, thereby dynamically adjusting the amplitude of the displacement of the diaphragm of the loudspeaker.
The specific adjustment method comprises the following steps: when the predicted displacement exceeds the control threshold, the Gain will be reduced and the voltage output signal Dout will be correspondingly reduced, so that the actual displacement of the final loudspeaker is just equal to or slightly less than the prescribed maximum displacement.
It should be noted that, considering the variability of some speakers and the aging that may exist in the application, a margin is usually properly set, so that the adjusted displacement is not exactly equal to the specified maximum displacement of the speaker, and in the embodiment of the present invention, the slightly smaller than the specified maximum displacement may be 1% -10% of the specified maximum displacement, including the end point value, that is, the actual displacement of the final speaker is 90% -99% of the specified maximum displacement, including the end point value. According to different application scenes, the setting slightly smaller than the setting can be flexibly set, for example, the maximum displacement of the micro horn is only 0.3mm, and the maximum displacement is slightly smaller than 0.28mm. If the other large-sized loudspeaker is 1mm, the size of the large-sized loudspeaker is slightly smaller than 0.9mm, and the large-sized loudspeaker can be confirmed according to the practical situation of the application.
When the predicted displacement value is smaller than the control threshold, the Gain is 1 (or 0 dB), or is properly increased, so that the final displacement can not exceed the control threshold and even be increased, and the loudness of the loudspeaker is improved. For example, the control threshold is 0.3mm, if the predicted displacement value generated by the original input signal is 0.2mm, the purpose of improving the final displacement of the loudspeaker can be achieved by changing the gain value, so long as the improved displacement does not exceed the specified maximum displacement.
The loudspeaker diaphragm control circuit provided by the invention comprises a displacement prediction module, a displacement dynamic range control module, a temperature calculation module and a multiplier; the real-time temperature calculation module of the loudspeaker is added, and the temperature calculation module is connected with the displacement prediction module, namely, the real-time temperature of the environment where the loudspeaker is located can be obtained through the temperature calculation module, and the real-time temperature is fed back to the displacement prediction module, so that the obtained predicted displacement value is related to the real-time temperature, the control accuracy of the displacement of the loudspeaker diaphragm is improved, the problem that the loudspeaker is damaged due to the fact that the temperature influences the loudspeaker diaphragm to exceed the specified maximum displacement value is avoided, and the loudspeaker is protected.
Based on the same inventive concept, the embodiment of the invention also provides a method for controlling the loudspeaker diaphragm, as shown in fig. 4, which is a schematic flow chart of the method for controlling the loudspeaker diaphragm provided by the embodiment of the invention; the loudspeaker diaphragm control method based on the loudspeaker diaphragm control circuit described in the above embodiment specifically includes:
s101: acquiring a voltage input signal and a real-time temperature of the loudspeaker;
s102: calculating to obtain a predicted displacement value according to the voltage input signal and the real-time temperature;
s103: calculating according to the predicted displacement value to obtain a gain value;
s104: and multiplying the voltage input signal with the gain value, outputting a voltage output signal, and controlling the loudspeaker to sound.
Wherein, obtaining the real-time temperature of the speaker may include: acquiring the voltage of the input end of the loudspeaker and the real-time current of the input end of the loudspeaker; calculating to obtain the direct current impedance of the loudspeaker according to the voltage of the input end of the loudspeaker and the real-time current of the input end of the loudspeaker; and calculating according to the direct current impedance to obtain the real-time temperature of the loudspeaker corresponding to the direct current impedance. The specific calculation process may be performed according to the above embodiment, and in conjunction with fig. 1, which is not described in detail in this embodiment.
It should be noted that, since the DRC needs a certain time to smoothly transition to adjust the Gain according to the predicted displacement, in order to prevent the sudden change of the Gain from causing the sound of the speaker to be negligibly small, the embodiment of the present invention further includes, before multiplying the voltage input signal Din by the Gain: and delaying the voltage input signal to obtain a delayed voltage input signal, and multiplying the delayed voltage input signal with the Gain.
The calculating to obtain a predicted displacement value according to the voltage input signal and the real-time temperature specifically comprises the following steps: calculating displacement offset related to the real-time temperature according to the real-time temperature; calculating a first displacement predicted value according to the voltage input signal; and superposing the displacement offset related to the real-time temperature with the first displacement predicted value to obtain the predicted displacement value.
The expression of the predicted displacement value is as follows:
wherein, bl, c, R, m, L, R is a linear parameter, bl (T) is the product of magnetic induction intensity and coil length of the speaker relative to temperature T, m is the mass of the speaker coil, R (T) is the mechanical damping of the speaker relative to temperature T, 1/c (T) is the mechanical spring coefficient of the speaker relative to temperature T, R (T) is the direct current resistance of the speaker relative to temperature T, L (T) is the equivalent inductance of the speaker relative to temperature T, os (T) is a displacement offset parameter, and the offset is relative to temperature T.
According to the loudspeaker diaphragm control method provided by the embodiment of the invention, the real-time temperature of the loudspeaker is detected, modeling is carried out based on the real-time temperature, the predicted displacement value related to the real-time temperature can be obtained by combining the corrected displacement model with the real-time input signal, and the displacement model is the displacement model dynamically adjusted by the real-time temperature of the loudspeaker in the control method, so that the displacement prediction module can accurately predict the actual displacement of the loudspeaker diaphragm at different temperatures, and therefore, the displacement of the loudspeaker diaphragm at different temperatures such as high temperature is ensured not to exceed the specified maximum displacement, and the loudspeaker is protected.
The use of the delay device is added in the protection scheme, so that not only is the soft transition of subjective hearing ensured, namely the sound of the loudspeaker is not suddenly and negligibly reduced, but also the amplitude of the loudspeaker is ensured not to exceed the specified maximum displacement in the gain adjustment process of the DRC.
Based on the same inventive concept, the present invention further provides an electronic device, and fig. 5 may be referred to, where fig. 5 is a schematic structural diagram of an electronic device provided in an embodiment of the present invention; the electronic equipment comprises the loudspeaker diaphragm control circuit shown in fig. 1 and a loudspeaker 6, wherein the loudspeaker diaphragm control circuit is used for controlling the diaphragm of the loudspeaker, so that the phenomenon that the actual displacement of the loudspeaker exceeds the specified maximum displacement of the loudspeaker in a high-temperature environment is avoided, and the loudspeaker is ensured to work within the maximum displacement of the loudspeaker, and the loudspeaker is protected.
It should be noted that, in the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described as different from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other.
It is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in an article or apparatus that comprises such element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A loudspeaker diaphragm control circuit, comprising:
the device comprises a displacement prediction module, a displacement dynamic range control module, a temperature calculation module and a multiplier;
the temperature calculation module is used for calculating the real-time temperature of the loudspeaker;
the displacement prediction module is connected with the output end of the temperature calculation module and is used for receiving a voltage input signal and calculating a predicted displacement value according to the voltage input signal and the real-time temperature;
the displacement dynamic range control module is used for receiving the predicted displacement value output by the displacement prediction module and calculating to obtain a gain value according to the received predicted displacement value;
the displacement dynamic range control module includes: a gain generation module;
the gain generation module is used for receiving the predicted displacement value, calculating to obtain a gain value of the displacement dynamic range control module, wherein the gain value of the displacement dynamic range control module is a correlation function of a control threshold value, a gain curve smooth transition parameter and a pressing slope of the gain curve;
the multiplier is used for multiplying the voltage input signal with the gain value output by the displacement dynamic range control module to obtain a voltage output signal;
the output end of the multiplier is connected with the input end of the loudspeaker and is used for driving the loudspeaker to emit sound.
2. The loudspeaker diaphragm control circuit of claim 1, wherein the temperature calculation module comprises:
the device comprises a loudspeaker input end voltage sampling circuit, a resistor connected with the loudspeaker in series, a voltage sampling circuit at two ends of the resistor and a temperature calculation sub-module;
the loudspeaker input end voltage sampling circuit is used for acquiring the input end voltage of the loudspeaker;
the temperature calculation sub-module is used for calculating and obtaining the real-time current of the input end of the loudspeaker according to the resistance value of the resistor and the voltages at the two ends of the resistor;
the direct current impedance of the loudspeaker is calculated according to the input end voltage of the loudspeaker and the input end real-time current;
and the real-time temperature of the loudspeaker corresponding to the direct current impedance is obtained through calculation according to the direct current impedance.
3. The loudspeaker diaphragm control circuit of claim 1, further comprising a delay;
the input end of the delay device is used for receiving a voltage input signal;
the delayer is used for carrying out delay processing on the voltage input signal, and outputting the delayed voltage input signal to one input end of the multiplier so as to multiply the gain value output by the displacement dynamic range control module.
4. The loudspeaker diaphragm control circuit of claim 3, wherein the dynamic range control module further comprises:
a gain smoothing module;
the input end of the gain smoothing module is connected with the output end of the gain generating module, the output end of the gain smoothing module is connected with the other input end of the multiplier, and the gain value output by the displacement dynamic range control module is output;
the gain smoothing module is used for modulating the pressing time and the releasing time of the gain value output by the gain generating module, and the pressing time is bound with the delay time of the delayer.
5. A loudspeaker diaphragm control method, characterized in that based on the loudspeaker diaphragm control circuit according to any one of claims 1-4, the loudspeaker diaphragm control method comprises:
acquiring a voltage input signal and a real-time temperature of the loudspeaker;
calculating to obtain a predicted displacement value according to the voltage input signal and the real-time temperature;
calculating according to the predicted displacement value to obtain a gain value;
and multiplying the voltage input signal with the gain value, outputting a voltage output signal, and controlling the loudspeaker to sound.
6. The loudspeaker diaphragm control method of claim 5, further comprising, prior to multiplying the voltage input signal with the gain value:
and delaying the voltage input signal to obtain a delayed voltage input signal for multiplication with the gain value.
7. The method according to claim 5, wherein the calculating the predicted displacement value according to the voltage input signal and the real-time temperature specifically includes:
calculating displacement offset related to the real-time temperature according to the real-time temperature;
calculating a first displacement predicted value according to the voltage input signal;
and superposing the displacement offset related to the real-time temperature with the first displacement predicted value to obtain the predicted displacement value.
8. The loudspeaker diaphragm control method of claim 7, wherein the predictive displacement value expression is:
wherein, bl, c, R, m, L, R is a linear parameter, bl (T) is the product of magnetic induction intensity and coil length of the speaker relative to temperature T, m is the mass of the speaker coil, R (T) is the mechanical damping of the speaker relative to temperature T, 1/c (T) is the mechanical spring coefficient of the speaker relative to temperature T, R (T) is the direct current resistance of the speaker relative to temperature T, L (T) is the equivalent inductance of the speaker relative to temperature T, os (T) is a displacement offset parameter, and the offset is relative to temperature T.
9. The method according to claim 5, wherein, in the acquiring the voltage input signal and the real-time temperature of the speaker, acquiring the real-time temperature of the speaker specifically includes:
acquiring the voltage of the input end of the loudspeaker and the real-time current of the input end of the loudspeaker;
calculating to obtain the direct current impedance of the loudspeaker according to the voltage of the input end of the loudspeaker and the real-time current of the input end of the loudspeaker;
and calculating according to the direct current impedance to obtain the real-time temperature of the loudspeaker corresponding to the direct current impedance.
10. An electronic device comprising a loudspeaker diaphragm control circuit as claimed in any one of claims 1 to 4 and a loudspeaker, the loudspeaker diaphragm control circuit being arranged to control the diaphragm of the loudspeaker.
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| US10381994B2 (en) * | 2017-12-21 | 2019-08-13 | Harman International Industries, Incorporated | Constrained nonlinear parameter estimation for robust nonlinear loudspeaker modeling for the purpose of smart limiting |
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| CN109327780A (en) * | 2018-11-16 | 2019-02-12 | 泉州昆泰芯微电子科技有限公司 | A kind of speaker drive protection system |
| CN109905812A (en) * | 2019-01-31 | 2019-06-18 | 维沃移动通信有限公司 | A kind of input power control method and device, terminal device |
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