CN218387861U - Loudspeaker protection circuit - Google Patents
Loudspeaker protection circuit Download PDFInfo
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- CN218387861U CN218387861U CN202222136512.3U CN202222136512U CN218387861U CN 218387861 U CN218387861 U CN 218387861U CN 202222136512 U CN202222136512 U CN 202222136512U CN 218387861 U CN218387861 U CN 218387861U
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Abstract
The utility model relates to a loudspeaker protection circuit, which comprises a power amplifier circuit module and a signal impact protection circuit module, wherein the power amplifier and loudspeaker module comprises a power amplifier based on an LM4766 dual-track integrated power amplifier chip and a loud loudspeaker matched with the power, impedance and frequency band thereof, and adopts a multi-gear potentiometer to realize adjustable power; the signal impact protection circuit module comprises a main control module, a signal monitoring module, a control module and a power supply module, wherein three relays on the signal impact protection and temperature protection circuit board determine a path of linear power output and a broadband power amplifier, the power supply and the power amplifier of the protection board are both from double alternating currents output by a transformer, the protection board firstly introduces two alternating current lines from the transformer, and the protection board supplies power to the single chip microcomputer after rectification, filtering, voltage reduction and voltage stabilization. The utility model provides a speaker circulation be interrupted the easy distortion of transmission ultrasonic signal and very easily damaged a difficult problem.
Description
Technical Field
The utility model relates to a protection circuit technical field especially relates to a speaker protection circuit.
Background
The aluminum strip type loudspeaker is characterized in that a layer of aluminum metal film is placed on a magnet, and a high-frequency signal is generated after the aluminum strip type loudspeaker is electrified. In scientific research experiments, sometimes an aluminum tape type loudspeaker is needed to circularly and discontinuously emit ultrasonic signals with the frequency of more than 20kHz, the power is adjustable, a power amplification circuit needs low distortion, otherwise the ultrasonic signals are seriously attenuated, and great obstruction is brought to practical application. And because the aluminium strip loudspeaker vibrating diaphragm is very weak, unstable impact produced when the sound source inputs or breaks off suddenly is very easy to damage the aluminium strip loudspeaker, and make the loudspeaker send sharp plosive, and this kind of strong plosive can reduce the loudspeaker life-span, lets the listener produce discomfort, can injure people's hearing even.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects of the prior art, the invention aims to provide an aluminum strip type power amplifier protection circuit for a high pitch loudspeaker, which can ensure that when the loudspeaker circularly and discontinuously emits ultrasonic signals with the frequency of more than 20kHZ, the power is adjustable and the distortion is low, and eliminate the impact influence on the loudspeaker when the signals are suddenly switched on or off.
In order to achieve the above object, the utility model discloses a following technical scheme, a speaker protection circuit, including power amplifier circuit module, signal impact protection circuit module, wherein:
the power amplifier circuit module comprises a power amplifier based on an LM4766 dual-track integrated power amplifier chip, a high pitch loudspeaker connected with the output end of the power amplifier, and a positive phase end of the power amplifier is connected with a signal source;
the signal impact protection circuit module comprises a main control module, a signal monitoring module, a control module and a power module, wherein a three-way relay, a transformer and a protection board are arranged on a protection circuit board for signal impact protection and temperature, the three-way relay determines the path of linear power output and broadband power amplification, the power and power amplification input end of the protection board are electrically connected with the output end of the transformer, and the output end of the protection board is electrically connected with the input end of the single chip microcomputer.
As a preferred scheme of a speaker protection circuit, wherein: the multi-gear potentiometer switches the resistance value of the control resistor to realize the adjustable output power.
As the utility model discloses a preferred scheme of speaker protection circuit, wherein: a full-wave rectification filter circuit is introduced into the power amplifier circuit, double alternating currents are converted into positive and negative double power supplies to supply LM4766, and meanwhile a power supply interface is arranged for connection of heat dissipation equipment.
As the utility model discloses a preferred scheme of speaker protection circuit, wherein: the MCU voltage-adding comparator circuit monitors the voltage of the signal source and monitors the input signal source in real time.
As the utility model discloses a preferred scheme of speaker protection circuit, wherein: the isolation power supply of the power supply module adopts the AC-to-DC isolation power supply module to isolate the power supply of the power amplification board and the protection board, and eliminates the short circuit phenomenon and the common ground noise.
As a preferred scheme of a speaker protection circuit, wherein: the access of power amplifier circuit is equipped with the adjustable normally open temperature detect switch of threshold value, prevents that LM4766 from getting into the excess temperature protection state because of operating time overlength.
As the utility model discloses a preferred scheme of speaker protection circuit, wherein: the coupling capacitor of the control module is a ceramic capacitor and biases the input signal to a positive voltage range.
Compared with the prior art, the beneficial effects of the utility model are that: the utility model discloses a when the speaker circulation is interrupted the ultrasonic signal of emission more than 20kHZ frequency, power is adjustable and the low distortion to insert suddenly or break off the signal and carry out the impact protection automatically.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail with reference to the accompanying drawings and detailed embodiments, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor. Wherein:
fig. 1 is a schematic circuit diagram of the present invention;
FIG. 2 is a general hardware frame diagram of the signal surge protection effect of the present invention;
fig. 3 is the circuit diagram of the signal monitoring module of the present invention:
fig. 4 is a circuit diagram of the power module of the present invention:
fig. 5 is a flow chart of the signal impact protection procedure of the present invention;
FIG. 6 shows the signal impact protection test effect of the present invention without the protection circuit;
fig. 7 shows the signal impact protection test effect when the protection circuit is present in the device of the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and embodiments.
Example 1:
referring to fig. 1 and fig. 2, in order to achieve the above object, the present invention adopts the following technical solutions: a loudspeaker protection circuit comprises a power amplifier circuit module and a signal impact protection circuit module, wherein the power amplifier circuit module comprises a power amplifier based on an LM4766 dual-track integrated power amplifier chip and a loud speaker, the power, impedance and frequency band of the loud speaker and the power amplifier are matched, and a multi-gear potentiometer is adopted in the module to switch a feedback resistor R f The resistance value mode realizes the change of the current in the circuit, further realizes the output power adjustment of the circuit, a full wave rectification filter circuit is introduced into the power amplifier circuit to convert double alternating current into positive and negative double power supplies to the LM4766, and simultaneously, the power amplifier circuit is provided with electricityThe source interface is connected with the heat dissipation device.
The signal impact protection circuit module comprises a main control module, a signal monitoring module, a control module and a power module, wherein three relays on a signal impact protection and temperature protection circuit board determine the path of linear power output and broadband power amplification, the power supply and the power amplifier of a protection board are both from double alternating currents output by a transformer, an MCU voltage-adding comparator circuit is used for monitoring the voltage of a signal source to monitor an input signal source in real time, when the signal is monitored to be input, the MCU is triggered to be externally interrupted and counted, the protection board firstly introduces two alternating current lines from the transformer and supplies power to a single chip after rectification, filtering, voltage reduction and voltage stabilization, the power supply for isolating the power amplification board and the protection board by adopting an AC-to-DC isolation power supply module eliminates the short-circuit phenomenon and the common ground noise, a 60-temperature control switch is used for monitoring the temperature of an LM4766 chip in real time to prevent the LM4766 from entering an over-temperature protection state due to overlong working time, and a ceramic capacitor is used as a coupling capacitor to bias the input signal to a positive voltage range.
The working flow of the protection circuit is as follows: firstly, for a sudden signal input process, a signal monitoring module is adopted to monitor an input signal in real time, when the signal is input, continuous pulses are generated to trigger external interruption of a main control chip, the interruption is counted, and when a count value exceeds a threshold value (a specific value is determined according to test debugging until no plosive is generated), the interruption is disabled, so that the effects of signal input and delay identification are achieved, then a three-way optical coupling isolation relay can be controlled to be connected with a power supply of a power amplification circuit, and then a timer is started to time. Secondly, for the process of ending signal output, the time length t needs to be set through the time length setting key according to the time length of the ultrasonic signal transmitted by the system before use 0 At the time t 0 The first 5s controls the three-way optical coupling isolation relay to disconnect the power supply of the power amplification circuit. Then, the signal input external interrupt is re-enabled and the timer is initialized to wait for the sudden input and output ending process of the next signal of the system.
Example 2
As shown in fig. 1, an aluminum strip type tweeter broadband power amplifier automatic protection circuit comprises a power amplifier circuit module and a signal impact protection circuit module, wherein the power amplifier and speaker module comprises a power amplifier based on an LM4766 dual-channel integrated power amplifier chip and a tweeter connected with the output end of the power amplifier, and the positive phase end of the power amplifier is connected with a signal source;
the signal of the signal impact protection circuit module comprises a main control module, a signal monitoring module, a control module and a power supply module, and a multi-gear potentiometer is adopted to switch a feedback resistor R f The method of resistance value realizes the change of current magnitude in the circuit, and then realizes the output power adjustment of the circuit, introduce the full-wave rectification filter circuit in the power amplifier circuit and convert the double-alternating current into positive and negative double power supplies and supply LM4766, set up the power interface to supply the heat dissipating apparatus to connect at the same time, monitor the signal source voltage with MCU voltage comparator circuit, monitor the input signal source in real time, for the sudden input process of the signal source, adopt STM32F031F6P6 MCU voltage comparator TS391ILT scheme of real-time monitoring input signal source, trigger MCU external interruption and count when monitoring the signal source input, the power that the ring transformer supplies to the power amplifier circuit is put through when counting and exceeding the threshold, then can't break and start the timer to time outside; for the process of finishing the output of the signal source, the input peripheral equipment such as a key is used for triggering the MCU to be externally interrupted to set the time length t of the initialization work 0 When the timer counts up (t) 0 -10) s, the power supply of the power amplifier circuit supplied by the toroidal transformer is cut off, and then the system software is reset to the initialization state of the program so as to wait for the next sudden input of the signal source
The power supply with the AC-to-DC isolation power supply module for isolating the power amplification board and the protection board eliminates the short circuit phenomenon and the common ground noise, the temperature of the LM4766 chip is monitored in real time by the 60 ℃ temperature control switch, the LM4766 is prevented from entering an over-temperature protection state due to overlong working time, and the ceramic capacitor is used as a coupling capacitor to bias an input signal to a positive voltage range.
As shown in fig. 3, considering the cost and performance comprehensively, the main control chip selects STM32F031F6P6 MCU and designs the minimum system circuit. 2-4, the voltage comparator adopts a TS391ILT chip, in order to avoid influencing the input signal, a 1uF ceramic capacitor is adopted as a coupling capacitor, the input signal is biased to a positive voltage range, and the voltage threshold is designed to be about 2.7V.
As shown in fig. 4 and 5, it is found through experiments that if the protection board power is rectified and filtered from the alternating current output by the toroidal transformer, the two rectifier bridges of the power amplification board and the protection board can cause a power short circuit phenomenon, and in addition, the signal can introduce common ground interference, which causes the speaker to emit a great current sound. Therefore, an AC-to-DC isolation power supply module (HLK-10D 11005) is adopted to isolate the power supply of the power amplification plate and the protection plate and eliminate the short circuit phenomenon and the common ground noise
In combination with the work flow and hardware deployment of the protection circuit, the programming of the main control chip is shown in fig. 5.
As shown in fig. 6, the signal impact protection test effect is shown, the power amplifier circuit, the aluminum strip type high pitch loudspeaker, the signal impact protection circuit, the USB sound card and the PC are connected, the program is controlled to emit the ultrasonic wave of 40kHz and 20s duration and record in the quiet environment, and the effectiveness of protection is judged by monitoring the human ear and analyzing the time domain of the recorded signal.
As shown in fig. 7, the recorded signal without the protection circuit is shown, and it is known that an extremely unstable impact signal is generated at the beginning, which is expressed as a strong harsh plosive, and at the same time, at the end of the signal output, the recorded signal has a similar impact at 20 s. The recorded signal connected to the protection circuit shows that the extremely unstable impact generated when the signal is suddenly input is eliminated, no harsh plosive is emitted, but the signal is delayed for several seconds, and the tail of the recorded signal has no unstable impact and no harsh plosive is emitted.
It should be noted that, in this document, 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. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, 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 process, method, article, or apparatus.
The present invention is not limited to the above-described embodiments, which are intended to be illustrative only and not limiting; those skilled in the art, having the benefit of this disclosure, may effect numerous modifications thereto without departing from the scope and spirit of the invention as set forth in the claims that follow.
Claims (7)
1. The utility model provides a loudspeaker protection circuit which characterized in that, includes power amplifier circuit module, and signal strikes protection circuit module, wherein:
the power amplifier circuit module comprises a power amplifier based on an LM4766 dual-track integrated power amplifier chip, a high pitch loudspeaker connected with the output end of the power amplifier, and a positive phase end of the power amplifier is connected with a signal source;
the signal impact protection circuit module comprises a main control module, a signal monitoring module, a control module and a power supply module, wherein the main control module is a single chip microcomputer, a three-way relay, a transformer and a protection board are arranged on a protection circuit board for signal impact protection and temperature, the three-way relay determines a path of linear power output and broadband power amplification, a power supply and a power amplification input end of the protection board are electrically connected with an output end of the transformer, and an output end of the protection board is electrically connected with an input end of the single chip microcomputer.
2. The speaker protection circuit according to claim 1, further comprising a multi-stage potentiometer, wherein the multi-stage potentiometer switches the resistance of the control resistor to adjust the output power.
3. The loudspeaker protection circuit according to claim 1, wherein a full-wave rectification filter circuit is introduced into the power amplifier circuit, the dual ac power is converted into a positive and negative dual power to supply to the LM4766, and a power interface is provided for connection of a heat dissipation device.
4. The speaker protection circuit of claim 1, further comprising an MCU voltage comparator, wherein the MCU voltage comparator circuit monitors the signal source voltage and monitors the input signal source in real time.
5. The speaker protection circuit of claim 1, wherein the isolated power supply of the power supply module, wherein the power supply of the power amplifier board and the protection board is isolated by using an AC-to-DC isolated power supply module to eliminate short circuit and common ground noise.
6. The loudspeaker protection circuit according to claim 1, wherein a threshold-adjustable normally-open temperature-controlled switch is arranged on a path of the power amplifier circuit to prevent the LM4766 from entering an over-temperature protection state due to an excessively long working time.
7. The speaker protection circuit of claim 3, wherein the coupling capacitor of the control module is a ceramic capacitor and biases the input signal to a positive voltage range.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222136512.3U CN218387861U (en) | 2022-08-15 | 2022-08-15 | Loudspeaker protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222136512.3U CN218387861U (en) | 2022-08-15 | 2022-08-15 | Loudspeaker protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218387861U true CN218387861U (en) | 2023-01-24 |
Family
ID=84967205
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222136512.3U Active CN218387861U (en) | 2022-08-15 | 2022-08-15 | Loudspeaker protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218387861U (en) |
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2022
- 2022-08-15 CN CN202222136512.3U patent/CN218387861U/en active Active
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