CN222897238U - A car amplifier overheating automatic volume reduction protection circuit - Google Patents
A car amplifier overheating automatic volume reduction protection circuit Download PDFInfo
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- CN222897238U CN222897238U CN202421461040.1U CN202421461040U CN222897238U CN 222897238 U CN222897238 U CN 222897238U CN 202421461040 U CN202421461040 U CN 202421461040U CN 222897238 U CN222897238 U CN 222897238U
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Abstract
The utility model discloses an automatic volume reduction protection circuit for automobile power amplifier overheat, which comprises a transmission end, a front-stage amplifying/tone circuit, a power amplifying circuit, a temperature detection control circuit and audio equipment, wherein when the temperature of an audio equipment radiator is below 70 ℃, the transmission end inputs audio signal voltage to the circuit, the front-stage amplifying/tone circuit amplifies power after receiving the audio signal voltage, the power amplifying circuit transmits the processed audio signal voltage to the power amplifying circuit, the power amplifying circuit amplifies the processed audio signal voltage again to achieve an ideal vehicle-mounted effect, and when the temperature of the audio equipment radiator is above 75 ℃, the temperature detection control circuit can attenuate the audio signal voltage passing through the front-stage amplifying/tone circuit, so that the audio signal voltage reaching the power amplifying circuit is reduced, the signal output volume of the power amplifying circuit is reduced, the temperature rise of the audio equipment is controlled, and the like.
Description
Technical Field
The utility model relates to the field of circuits, in particular to an automatic volume reduction protection circuit for automobile power amplifier overheat.
Background
The power amplifier is overheated and can have great influence on the driving of the automobile, such as the reduction of sound quality, the shortening of service life of equipment, the initiation of other faults and the like, the damage of electronic elements of the audio equipment can be caused by the overhigh temperature of the power amplifier, the electrical characteristics of the elements are influenced, so that the sound quality is poor, the electronic elements can be aged or deformed under the condition of overhigh temperature, and the performance and service life of the audio equipment are caused, the electronic elements can be expanded under the condition of overhigh temperature, the space between the elements is reduced, the electrical parameters of the elements are influenced, and finally the performance of the equipment is reduced. In addition, the power amplifier temperature is too high, which may cause circuit damage and even cause serious consequences such as fire.
Therefore, the overheating of the power amplifier of the automobile is a problem which needs to be concerned, and the owner should check the heat dissipation condition of the power amplifier device periodically to ensure that the power amplifier device operates within the normal working temperature range so as to ensure the sound effect and the safety of the device. If the overheat condition of the power amplifier is found, measures should be taken in time to solve the problem, such as adding heat dissipation equipment, adjusting the power setting of the sound system, and the like.
All current automobile power amplifiers have the traditional overheat protection function, and are designed for preventing users from being damaged by overheat when the power amplifier is used in severe environments with higher air temperature and poor heat dissipation conditions or is used in improper overload. When the temperature of the radiator reaches about 80 ℃, the power amplifier stops working, and besides the music cannot be continuously heard, various original car prompt sounds such as navigation sound of part of car types, front and rear radar prompt sounds and the like cannot be broadcast for reminding, so that driving safety is affected.
How to prompt the car owner in time when the power amplifier of the car is overheated and improve the driving safety is a technical problem which needs to be solved by the technicians in the field.
Disclosure of utility model
The utility model aims to provide an automatic volume reduction protection circuit for automobile power amplifier overheat, so as to solve the problems in the background technology.
In order to achieve the above purpose, the present utility model provides the following technical solutions:
The automatic volume reduction protection circuit for the overheat of the automobile power amplifier is characterized by comprising a transmission end, a pre-stage amplifying/tone circuit, a power amplifying circuit, a temperature detection control circuit, sound equipment and a switch tube;
the transmission end inputs the audio signal voltage to the circuit, the front-stage amplifying/tone circuit amplifies power after receiving the audio signal voltage, selects and preprocesses the audio signal voltage, amplifies the power, transmits the processed audio signal voltage to the power amplifying circuit, amplifies the power amplifying circuit again to achieve an ideal vehicle-mounted effect, and then the power amplifying circuit drives the sound equipment to emit sound;
The junction of the front stage amplifying/tone circuit and the power amplifying circuit is provided with a voltage division point, the switching tube is connected with the voltage division point and grounded, the temperature detection control circuit is connected with the switching tube, and the temperature detection control circuit outputs high and low levels to the switching tube by detecting the temperature change of the power amplifying circuit and controls whether the switching tube is conducted or not.
Further, the temperature detection control circuit is provided with a voltage comparator, two lines are arranged at the power supply and are respectively connected to the anode and the cathode of the voltage comparator, the output end of the voltage comparator is communicated with the base electrode of the switching tube, and the collector electrode of the switching tube is connected with the voltage division point.
Further, the temperature detection control circuit comprises a third resistor and a thermistor, positive poles and negative poles are arranged on two lines connected with the power supply and the voltage comparator, and the third resistor and the thermistor are respectively connected with the positive poles and the negative poles and are grounded.
Further, when the temperature of the power amplifying circuit is below a limit value, the resistance value of the thermistor is not smaller than the resistance value of the third resistor.
Further, when the temperature of the power amplifying circuit is at the limit value, the resistance value of the thermistor is smaller than that of the third resistor.
Further, when the temperature of the power amplifying circuit is below a limit value, the voltage comparator outputs a low level, and the switching tube is in a cut-off state.
Further, when the temperature of the power amplifying circuit is at a limit value, the output of the voltage comparator is high level, the switching tube is conducted, and a part of current output from the front amplifying/tone circuit is shunted from the switching tube, so that the voltage of the audio signal reaching the power amplifying circuit is reduced.
Further, the temperature detection control circuit comprises a first resistor and a second resistor, one end of the first resistor is connected with a power supply, the other end of the first resistor is connected with a third resistor and the positive electrode of a voltage comparator, and one end of the second resistor is connected with the power supply, and the other end of the second resistor is connected with the negative electrode of the thermistor and the negative electrode of the voltage comparator.
Further, the temperature detection control circuit comprises a fourth resistor, one end of the fourth resistor is connected with the output end of the voltage comparator, and the other end of the fourth resistor is connected to the base electrode of the switching tube.
The power amplifier comprises a power amplifying circuit, a power amplifying circuit and a capacitor, and is characterized by further comprising an eighth resistor, a fifth resistor, a sixth resistor and a seventh resistor, and the capacitor, wherein one end of the eighth resistor is connected with the first resistor, the other end of the eighth resistor is connected with the first resistor, one end of the fifth resistor is connected with the fourth resistor and is connected with the switching tube in parallel, the other end of the fifth resistor is grounded, a part of current output by the connection of the pre-amplifying/tone circuit flows to the seventh resistor through the sixth resistor, a part of current flows to the capacitor, the seventh resistor is connected with the capacitor in parallel, the other end of the seventh resistor is connected with the switching tube, and the other end of the capacitor is connected to the power amplifying circuit.
Compared with the prior art, the utility model has the beneficial effects that:
The utility model provides an automatic volume reduction protection circuit for automobile power amplifier overheat, which is added into a power amplifier circuit by using a temperature monitoring control circuit composed of a voltage comparator and a temperature sensor, and can coexist with the traditional overheat protection function. When the temperature of the power amplifier radiator rises to the upper limit of about 75 ℃ of the set highest temperature, the temperature detection control circuit pulls down the audio signal of the input power amplifier circuit to attenuate, so that the volume of the audio signal is reduced by about 50%, the output power is reduced, the temperature of the power amplifier radiator is controlled to continuously rise, and when the temperature of the power amplifier radiator is reduced to the lower limit of about 70 ℃ of the set recovery temperature, the temperature detection control circuit stops pulling down the audio signal of the input power amplifier circuit to attenuate, and the power amplifier recovers to the normal volume level. Compared with the existing automobile power amplifier, the utility model has the advantages that the power amplifier does not stop working due to overheat, but limits the continuous rising of the power amplifier temperature by adopting a volume reduction mode, so that the problems that the power amplifier cannot continuously listen to music and cannot normally broadcast the original automobile safety prompt tone due to overheat protection are greatly reduced, and the circuit can be applied to all power amplifier products.
Drawings
FIG. 1 illustrates an auto power amplifier overheat auto-down volume protection circuit diagram according to one embodiment of the present utility model;
the marks of all the components in the drawing are as follows, a 1 front stage amplifying/tone circuit, a 2 power amplifying circuit, a 3 temperature detection control circuit, 4 sound equipment, a 5 transmission end, a 6 voltage division point, a 7 output end, an 8 negative pole, a 9 positive pole, an R1 first resistor, an R2 second resistor, an R3 third resistor, an R4 fourth resistor, an R5 fifth resistor, an R6 sixth resistor, an R7 seventh resistor, an R8 eighth resistor, an IC1 voltage comparator, a TH1 thermistor, a Q1 switching tube and a PE grounding point.
Detailed Description
The following description of the embodiments of the present utility model 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 utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
Referring to fig. 1, an automatic volume reduction protection circuit for an automobile power amplifier is disclosed, which comprises a transmission end 5, a front-stage amplifying/tone circuit 1, a power amplifying circuit 2, a temperature detection control circuit 3 and an audio device 4;
When the temperature of the power amplifier radiator rises to a set value, the temperature control detection circuit pulls down the audio signal of the input power amplifier circuit to attenuate, and when the temperature of the power amplifier radiator is reduced to the set value, the temperature control detection circuit stops pulling down the audio signal of the input power amplifier circuit to attenuate.
Specifically, when the temperature of the power amplification circuit 2 is below 70 ℃, the transmission end 5 inputs the audio signal voltage to the circuit, the pre-amplification/tone circuit 1 amplifies power after receiving the audio signal voltage, selects and pre-processes the audio signal voltage, amplifies the power, transmits the processed audio signal voltage to the power amplification circuit 2, amplifies the power amplification circuit 2 again to achieve an ideal vehicle-mounted effect, and then the power amplification circuit 2 drives the sound equipment to emit sound;
The junction of the front stage amplifying/tone circuit 1 and the power amplifying circuit 2 is provided with a voltage division point 6, the other end of the switch tube Q1 is connected with the voltage division point 6 and grounded, the other end of the switch tube Q1 is connected with the temperature detection control circuit 3, the temperature detection control circuit 3 outputs high and low levels to control whether the switch tube Q1 is conducted or not by detecting the temperature change of the power amplifying circuit 2, when the temperature of the power amplifying circuit 2 is above 75 ℃, the temperature detection control circuit 3 can attenuate the voltage of an audio signal passing through the front stage amplifying/tone circuit 1, so that the voltage of the audio signal reaching the power amplifying circuit 2 is reduced, the signal output volume of the power amplifying circuit 2 is reduced, and the temperature rise of the power amplifying circuit 2 is controlled.
Specifically, the temperature detection control circuit 3 is provided with a voltage comparator IC1 and a switching tube Q1, two lines are respectively connected to the positive electrode and the negative electrode of the voltage comparator IC1 from the power supply, the output end 7 of the voltage comparator IC1 is communicated with the base electrode of the switching tube Q1, and the collector electrode of the switching tube Q1 is connected with the front-stage amplifying/tone circuit 1.
The temperature detection control circuit 3 comprises a third resistor R3 and a thermistor TH1, positive poles 9 and negative poles 8 are arranged on two lines connected with the voltage comparator IC1, and the third resistor R3 and the thermistor TH1 are respectively connected with the positive poles 9 and the negative poles 8 and grounded.
When the temperature of the power amplification circuit 2 is below 70 ℃, the resistance value of the thermistor TH1 is larger than that of the third resistor R3.
When the temperature of the power amplification circuit 2 is 75 ℃, the resistance value of the thermistor TH1 is smaller than that of the third resistor R3.
When the temperature of the power amplification circuit 2 is 70 ℃ or lower, the negative voltage of the voltage comparator IC1 is higher than the reference voltage set by the positive electrode of the voltage comparator IC1, the output is low, and the switching transistor Q1 is turned off.
When the temperature of the power amplification circuit 2 is 75 ℃, the negative voltage of the voltage comparator IC1 is lower than the reference voltage set by the positive electrode of the voltage comparator IC1, a high level is output, the switching tube Q1 is turned on, and a part of the current output from the pre-amplification/tone circuit 1 is split from the switching tube Q1, so that the voltage of the audio signal reaching the power amplification circuit 2 is reduced.
The transmission end 5, the third resistor R3, the thermistor TH1, the fifth resistor R5, the emitter of the switching tube Q1 and the sound equipment 4 are all provided with grounding points, and the grounding points are conducted.
Specifically, the power supply circuit comprises a first resistor R1 and a second resistor R2, wherein one end of the first resistor R1 is connected with a power supply, the other end of the first resistor R1 is connected with a third resistor R3 and the positive electrode of a voltage comparator IC1, and one end of the second resistor R2 is connected with the power supply, and the other end of the second resistor R2 is connected with the thermistor TH1 and the negative electrode of the voltage comparator IC 1. The voltage comparator comprises a fourth resistor R4, wherein one end of the fourth resistor R4 is connected with the output end of the voltage comparator IC1, and the other end of the fourth resistor R4 is connected to the base electrode of the switching tube Q1. Comprises an eighth resistor R8, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7 and a capacitor, wherein one end of the eighth resistor R8 is connected with the first resistor R1, the other end of the eighth resistor R8 is connected with the first resistor R1, one end of the fifth resistor R5 is connected with the fourth resistor R4 and is connected with a switch tube in parallel, the other end of the fifth resistor R5 is grounded, the current output by the connection of the front-stage amplifying/tone circuit 1 flows to the seventh resistor R7 through a part of the sixth resistor R6, a part of the current flows to the capacitor, the seventh resistor R7 is connected with the capacitor in parallel, the other end of the seventh resistor R7 is connected with the switch tube Q1, the other end of the capacitor is connected with the power amplifying circuit 2,
Preferably, the resistance of the first resistor R1 is 10kΩ, the resistance of the second resistor R2 is 13kΩ, the resistance of the third resistor R3 is 10kΩ, the resistance of the fourth resistor R4 is 4.7kΩ, the resistance of the fifth resistor R5 is 10kΩ, the resistance of the sixth resistor R6 is 2kΩ, the resistance of the seventh resistor R7 is 2kΩ, the resistance of the eighth resistor R8 is 100deg.kΩ, the thermistor TH1 is preferably a negative temperature coefficient NTC thermistor 100K, and the model of the voltage comparator IC1 is preferably TJM4558D.
When the working temperature is in a normal range, the voltage of the pin 2 of the voltage comparator IC1 is higher than the reference voltage set by the pin 3 of the voltage comparator IC1, the pin 1 of the voltage comparator IC1 outputs a low level according to the working characteristic of the voltage comparator IC1, and the low level passes through the fourth resistor R4 to the base electrode of the switching tube Q1, at the moment, the low level of the base electrode of the switching tube Q1 does not meet the on voltage, the switching tube Q1 is in an off state, and the voltage of an audio signal passing through the sixth resistor R6 cannot be pulled down and attenuated. When the power amplifier continuously increases in working temperature and reaches the upper limit of the highest working temperature, the resistance value of the thermistor TH1 is reduced along with the temperature increase, and the voltage of the pin 2 of the voltage comparator IC1 is reduced until the voltage of the pin 2 of the voltage comparator IC1 is lower than the reference voltage set by the pin 3 of the voltage comparator IC1, according to the working characteristics of the voltage comparator IC1, the pin 1 of the voltage comparator IC1 outputs a high level, the voltage is divided by the fourth resistor R4 and the fifth resistor R5 and then reaches the base electrode of the switching tube Q1, at the moment, the base electrode of the switching tube Q1 is forward biased, the collector electrode of the switching tube Q1 is in a low level, the voltage of an audio signal reaching the power amplifier circuit 2 is reduced by the forced attenuation of the seventh resistor R6, the signal output volume of the power amplifier circuit 2 is reduced, the temperature of the power amplifier circuit 2 is controlled to be increased, and the temperature of the power amplifier circuit 2 is also gradually reduced along with the temperature reduction according to the working characteristics of the voltage comparator IC1, and meanwhile, the voltage of the pin 2 of the voltage comparator IC1 is increased until the voltage of the pin 2 of the voltage comparator IC1 is higher than the reference voltage of the voltage comparator IC1, the voltage of the voltage comparator IC1 is not higher than the base electrode of the fourth resistor R1, the voltage is in a low level, the voltage is not reduced by the base electrode of the switching tube Q1, the voltage is not in the high level, and the voltage of the audio signal is not reduced by the fourth resistor R1 is in the high level, and the voltage is in the state of the voltage of the power amplifier IC1 is not normally, and the voltage is in the high level, and the voltage level is not in the voltage level. The eighth resistor R8 is a positive feedback resistor for setting the temperature at which the normal volume is restored.
The utility model provides an automatic volume reduction protection circuit for automobile power amplifier overheat, which is characterized in that a temperature detection control circuit 3 consisting of a voltage comparator IC1 and a thermistor TH1 is added into a power amplifier circuit, and the automatic volume reduction protection circuit can coexist with the traditional overheat protection function. When the temperature of the power amplifying circuit 2 rises to the upper limit of about 75 ℃ of the set highest temperature, the temperature detection control circuit 3 pulls down the audio signal of the input power amplifying circuit 2 to attenuate, the volume of the audio signal is reduced by about 50%, the output power is reduced, the temperature of the power amplifying circuit 2 is controlled to continuously rise, and when the temperature of the power amplifying circuit 2 is reduced to the lower limit of about 70 ℃ of the set recovery temperature, the temperature detection control circuit 3 stops pulling down the audio signal of the input power amplifying circuit 2 to attenuate, and the power amplifier recovers to the normal volume level. Compared with the existing automobile power amplifier, the utility model has the advantages that the power amplifier does not stop working due to overheat, but limits the continuous rising of the power amplifier temperature by adopting a volume reduction mode, so that the problems that the power amplifier cannot continuously listen to music and cannot normally broadcast the original automobile safety prompt tone due to overheat protection are greatly reduced, and the circuit can be applied to all power amplifier products.
The foregoing is only a preferred embodiment of the present utility model, but the scope of the present utility model is not limited thereto, and any person skilled in the art, who is within the scope of the present utility model, should make equivalent substitutions or modifications according to the technical scheme of the present utility model and the inventive concept thereof, and should be covered by the scope of the present utility model.
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202421461040.1U CN222897238U (en) | 2024-06-25 | 2024-06-25 | A car amplifier overheating automatic volume reduction protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202421461040.1U CN222897238U (en) | 2024-06-25 | 2024-06-25 | A car amplifier overheating automatic volume reduction protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN222897238U true CN222897238U (en) | 2025-05-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202421461040.1U Active CN222897238U (en) | 2024-06-25 | 2024-06-25 | A car amplifier overheating automatic volume reduction protection circuit |
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| CN (1) | CN222897238U (en) |
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- 2024-06-25 CN CN202421461040.1U patent/CN222897238U/en active Active
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