A volume control system based on sensor

Abstract

The present invention discloses a volume control system based on a sensor, comprising: an environmental volume acquisition unit, which is used to collect the sound decibels of the device environment in real time when the device is working; a control unit, which is used to adjust the device volume automatically or manually; an auxiliary calculation unit; a device protection module, which is used to prevent large currents from damaging the speakers in the device; and a display module, which is used to display the device adjustment volume and the environmental comprehensive volume in real time. The present invention can adjust the unit value of the volume adjustment in real time according to the environmental volume data and the current calculation of the device, thereby ensuring that the device adjusts the volume according to different unit values ​​of the volume adjustment under different volume outputs and environmental influences, avoiding the problem that too loud volume will affect the environment and even cause harm to the body of the device user, and too low volume will cause the sound to be inaudible.

Description

Technical Field

[0001] The present invention belongs to the field of volume, and more specifically, particularly relates to a volume control system based on a sensor. Background Art

[0002] In common living environments, when people watch or play videos through a video player, in order to ensure clear and smooth communication without interference, they need to adjust the volume of the video player through a control device.

[0003] When adjusting the volume in the existing system, the unit value of the volume is fixed, which results in the volume being unable to be adjusted to an ideal state in many cases. If the volume is too loud, it will affect the environment and even cause physical harm to the user of the device. If the volume is too low, it will lead to the inability to hear the sound accurately. Therefore, we propose a sensor-based volume control system, which can calculate according to the ambient volume data and the current volume value of the device, and adjust the unit value of the volume in real time. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings existing in the prior art, and a sensor-based volume control system is proposed. The system can calculate according to the environmental volume data and the current volume adjustment value of the device, and adjust the unit value of the volume adjustment in real time, so as to ensure that the device adjusts the volume according to different unit values ​​of the volume adjustment under different volume outputs and environmental influences, avoiding the problem that too loud volume may affect the environment or even cause harm to the body of the device user, and too low volume may cause the inability to hear the sound accurately.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A volume control system based on a sensor, comprising:

[0007] An environmental volume collection unit, which is used to collect the sound decibels of the device environment in real time when the device is working;

[0008] A control unit, the control unit is used to adjust the volume of the device automatically or manually;

[0009] An auxiliary calculation unit, the auxiliary calculation unit receives the ambient volume data collected by the ambient volume collection unit, performs a ratio calculation based on the specific decibel number of the received data and the maximum volume data of the device, and determines a unit value for adjusting the volume based on the calculation result;

[0010] A device protection module, which is used to prevent a loudspeaker in the device from being damaged by a large current;

[0011] The display module is used to display the device adjustment volume and the environment comprehensive volume in real time.

[0012] Preferably, the auxiliary calculation unit calculates and determines the unit value for adjusting the volume using the specific calculation formula:

[0013]

[0014] The auxiliary calculation unit calculates the real-time unit value of the device when adjusting the decibel value of the volume of the device in the current real-time environment according to the above calculation formula.

[0015] Preferably, the control unit adopts a voltage divider circuit composed of resistors, and the output voltage of the voltage divider circuit is calculated as follows:

[0016]

[0017] Where: U i is the input voltage; U o is the output voltage; R1 and R2 are voltage-dividing resistors;

[0018] In the calculation formula, since the denominator R1+R2 is greater than the numerator R2, the output voltage is less than the input voltage; the voltage divider circuit is a circuit that attenuates the input signal voltage. Changing the resistance value of R1 or R2 changes the output voltage U o size.

[0019] Preferably, the device protection module includes:

[0020] A device protection circuit, the device protection circuit comprising:

[0021] 1) A protection circuit that prevents large signal currents from flowing through the speaker, which works in conjunction with the main power amplifier protection circuit;

[0022] 2) Prevent overcurrent damage to the speaker caused by changes in the DC voltage at the output of the main power amplifier when a circuit failure occurs;

[0023] It also includes a main power amplifier protection circuit, which includes an overvoltage protection circuit and an overload protection circuit.

[0024] Preferably, the overvoltage protection circuit comprises: output tubes VT1 and VT2 of the main power amplifier, and voltage stabilizing diodes VD1 and VD2;

[0025] By setting the breakdown voltage of the Zener diode to be greater than the DC operating voltage, VD1 and VD2 will not break down during normal operation, and the internal resistance is very large, which is equivalent to an open circuit; when high voltage appears, VD1 and VD2 will break down, clamp the voltage, and protect the power amplifier output tubes VT1 and VT2.

[0026] Preferably, the overload protection circuit comprises:

[0027] The composite complementary power amplifier output stage circuit VT3, VT4, VT5, VT6, the overload protection circuit VT1, VT2, VD1, VD2 and the sampling resistors R8 and R9;

[0028] When the circuit is working normally, the current flowing through the sampling resistors R8 and R9 from the emitters of VT5 and VT6 is at a normal value, and the sampling voltage across the sampling resistors is normal. The sampling voltage added to the bases of VT1 and VT2 is not enough to turn on the two transistors, so the protection circuit cannot operate and has no effect on the normal operation of the main power amplifier.

[0029] Preferably, when the overload protection circuit fails and causes the emitter current of VT5 and VT6 to be higher than the normal value, the current flowing through the sampling resistors R8 and R9 increases, and the sampling voltage across the sampling resistors increases. The sampling voltage is added to the bases of VT1 and VT2 tubes, so that the two transistors are turned on. VT1 is turned on to turn on VD1, and VT2 is turned on to turn on VD2, which greatly shunts the input signal, and the input signal added to the main power amplifier is greatly reduced, so that the operating current of VT5 and VT6 tubes is greatly reduced.

[0030] Preferably, the environmental volume collection unit includes:

[0031] A pickup unit and a determination unit for transmitting sound signals therewith;

[0032] The pickup unit includes a sound sensor, a microphone signal distributor, a multi-stage amplification unit, an A / D converter and a signal distributor;

[0033] The sound sensor transmits the received sound signal to the microphone signal distributor, and the microphone signal distributor distributes the sound signal to each input channel; the multi-stage amplification unit performs different levels of amplification processing on the sound signal in each input channel; the A / D converter performs analog-to-digital conversion on the amplified sound signal, and the signal distributor receives each sound signal that has undergone analog-to-digital conversion.

[0034] Preferably, the judgment unit comprises a register judgment device and a stream signal real-time judgment device arranged in parallel; the register judgment device and the stream signal real-time judgment device respectively receive the sound signal transmitted by the signal distributor;

[0035] The real-time flow signal judgment device comprises: a judgment module and a digital processor; the real-time flow signal judgment device judges and outputs the sound signal according to the level;

[0036] The register-type judgment device comprises a buffer, a distortion judgment module, a signal judgment module and a memory; the distortion judgment module and the signal judgment module are respectively connected to the buffer, and the signal judgment module is connected to the memory.

[0037] Technical effects and advantages of the present invention: Compared with the prior art, the sensor-based volume control system provided by the present invention can calculate according to the environmental volume data and the current volume adjustment value of the device, and adjust the unit value of the volume adjustment in real time, thereby ensuring that the device adjusts the volume according to different unit values ​​of the volume adjustment under different volume outputs and environmental influences, avoiding the problem that the volume is too loud, which may affect the environment or even cause harm to the body of the device user, and the volume is too low, which may cause the sound to be inaudible;

[0038] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a diagram of the structure of the volume control system based on the sensor of the present invention;

[0040] Figure 2 A resistor voltage divider circuit diagram in an embodiment of the present invention;

[0041] Figure 3 A signal cut-off protection circuit diagram in an embodiment of the present invention;

[0042] Figure 4 A power cut-off protection circuit diagram in an embodiment of the present invention;

[0043] Figure 5 A load cut-off protection circuit diagram in an embodiment of the present invention;

[0044] Figure 6 This is a circuit diagram of an overvoltage protection circuit for a main power amplifier in an embodiment of the present invention;

[0045] Figure 7 This is a main power amplifier overload protection circuit diagram in an embodiment of the present invention;

[0046] Figure 8 The device protection circuit in the embodiment of the present invention Figure 1 ;

[0047] Fig. 9 The device protection circuit in the embodiment of the present invention Figure 2 ;

[0048] Fig.10FIG. 1 is a circuit diagram of a volume controller in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0050] The present invention provides a volume control system based on a sensor, such as Figure 1 As shown, including:

[0051] An environmental volume collection unit, which is used to collect the sound decibels of the device environment in real time when the device is working; the environmental volume collection unit includes:

[0052] A pickup unit and a determination unit for transmitting sound signals therewith;

[0053] The pickup unit includes a sound sensor, a microphone signal distributor, a multi-stage amplification unit, an A / D converter and a signal distributor;

[0054] The sound sensor transmits the received sound signal to the microphone signal distributor, and the microphone signal distributor distributes the sound signal to each input channel; the multi-stage amplification unit performs different levels of amplification processing on the sound signal in each input channel; the A / D converter performs analog-to-digital conversion on the amplified sound signal, and the signal distributor receives each sound signal that has undergone analog-to-digital conversion.

[0055] The judgment unit includes a register judgment device and a stream signal real-time judgment device arranged in parallel; the register judgment device and the stream signal real-time judgment device respectively receive the sound signal transmitted by the signal distributor;

[0056] The real-time flow signal judgment device comprises: a judgment module and a digital processor; the real-time flow signal judgment device judges and outputs the sound signal according to the level;

[0057] The register-type judgment device comprises a buffer, a distortion judgment module, a signal judgment module and a memory; the distortion judgment module and the signal judgment module are respectively connected to the buffer, and the signal judgment module is connected to the memory.

[0058] A control unit is used to adjust the volume of the device automatically or manually; the control unit uses a voltage divider circuit composed of resistors, such as Figure 2As shown, the output voltage calculation method of the voltage divider circuit is:

[0059]

[0060] Where: U i is the input voltage; U o is the output voltage; R1 and R2 are voltage-dividing resistors;

[0061] In the calculation formula, since the denominator R1+R2 is greater than the numerator R2, the output voltage is less than the input voltage; the voltage divider circuit is a circuit that attenuates the input signal voltage. Changing the resistance value of R1 or R2 changes the output voltage U o size.

[0062] It should be noted that in this embodiment, the input voltage U i , R2 resistance is fixed, when R1 resistance decreases, output voltage U o Increases, when the resistance of R1 increases, the output voltage U o reduce;

[0063] It is helpful to remember with the help of limit case analysis: when the resistance of R1 is reduced to 0Ω (R1 is short-circuited), the output end of the voltage divider circuit is connected to the input end, and the output voltage is equal to U i ; When the resistance of R1 increases to an open circuit, the output voltage is 0V.

[0064] In the above voltage divider circuit analysis, if the input voltage is a DC voltage, the output voltage will be a DC voltage; if the input voltage is an AC voltage, the output voltage will be an AC voltage; if the input voltage is the superposition voltage of the DC voltage and the AC voltage, the output voltage will be the superposition voltage of the DC voltage and the AC voltage.

[0065] An auxiliary calculation unit, the auxiliary calculation unit receives the ambient volume data collected by the ambient volume collection unit, performs a ratio calculation based on the specific decibel number of the received data and the maximum volume data of the device, and determines a unit value for adjusting the volume based on the calculation result;

[0066] The auxiliary calculation unit calculates and determines the unit value for adjusting the volume by a specific calculation formula:

[0067]

[0068] The auxiliary calculation unit calculates the real-time unit value of the device when adjusting the decibel value of the volume of the device in the current real-time environment according to the above calculation formula.

[0069] A device protection module, which is used to prevent large currents from damaging speakers in the device; Figure 3-7 As shown, the device protection module includes:

[0070] A device protection circuit, the device protection circuit comprising:

[0071] 1) A protection circuit that prevents large signal currents from flowing through the speaker, which works in conjunction with the main power amplifier protection circuit;

[0072] 2) Prevent overcurrent damage to the speaker caused by changes in the DC voltage at the output of the main power amplifier when a circuit failure occurs;

[0073] It also includes a main power amplifier protection circuit, which includes an overvoltage protection circuit and an overload protection circuit.

[0074] Furthermore, the overvoltage protection circuit includes: output tubes VT1 and VT2 of the main power amplifier, and voltage stabilizing diodes VD1 and VD2;

[0075] By setting the breakdown voltage of the voltage-stabilizing diode to be greater than the DC working voltage, VD1 and VD2 will not break down during normal operation, and the internal resistance will be very large, which is equivalent to an open circuit; when high voltage appears, VD1 and VD2 will break down, clamp the voltage, and protect the power amplifier output tubes VT1 and VT2;

[0076] The overload protection circuit comprises:

[0077] The composite complementary power amplifier output stage circuit VT3, VT4, VT5, VT6, the overload protection circuit VT1, VT2, VD1, VD2 and the sampling resistors R8 and R9;

[0078] When the circuit is working normally, the current flowing through the sampling resistors R8 and R9 from the emitters of VT5 and VT6 is at a normal value, and the sampling voltage at both ends of the sampling resistor is normal. The sampling voltage added to the base of VT1 and VT2 is not enough to turn on the two transistors, and the protection circuit cannot work, which has no effect on the normal operation of the main power amplifier. When the overload protection circuit fails and causes the emitter current of VT5 and VT6 to be higher than the normal value, the current flowing through the sampling resistors R8 and R9 increases, and the sampling voltage at both ends of the sampling resistor increases. The sampling voltage is added to the base of VT1 and VT2, turning on the two transistors. VT1 turns on VD1, and VT2 turns on VD2, which greatly shunts the input signal, greatly reduces the input signal added to the main power amplifier, and greatly reduces the working current of VT5 and VT6.

[0079] The display module is used to display the device adjustment volume and the environment comprehensive volume in real time.

[0080] In this embodiment, it should be noted that Figure 3-5As shown in the figure, the signal cut-off protection circuit, when the main power amplifier outputs a large signal, the detection circuit detects the overload signal, and controls the input signal of the main power amplifier circuit after amplification, so that the input signal of the main power amplifier is greatly reduced, so that the signal current output by the main power amplifier is greatly reduced, and the current flowing through the speaker in the sound box is greatly reduced, so as to achieve the purpose of protecting the sound box;

[0081] The power cut-off protection circuit directly cuts off the DC working voltage of the main power amplifier, so that the main power amplifier has no current output, thus achieving the purpose of protecting the speakers in the sound box;

[0082] The load cut-off protection circuit cuts off the speaker circuit through the relay when an overload occurs, so that no signal current flows through the speaker in the speaker, thereby achieving the purpose of protecting the speaker.

[0083] In specific implementation, the device protection circuit adopts the following two methods, specifically:

[0084] 1) If Figure 8 As shown in the circuit, J1 is a relay, and its contacts are normally closed to connect the speaker BL1 circuit; VT1, VT2, VT3 and VT4 are control tubes in the protection circuit, among which VT4 is the driving tube of relay J1;

[0085] The working principle analysis of the circuit can be divided into the following three situations:

[0086] When the DC voltage at the output end of the main power amplifier is 0V, the VT1 tube is cut off because there is no bias voltage; the emitter and base voltages of the VT2 tube are both 0V, and the VT2 tube is cut off; because the VT2 tube is cut off, the base current of the VT3 tube has no loop, so the VT3 tube is also cut off; the VT3 tube is cut off, and its emitter voltage is high, which makes the base voltage of the VT4 tube high. The VT4 tube is a PNP type triode, so the VT4 tube is also cut off. At this time, all 4 triodes are cut off, the relay J1 is connected, the speaker is normally connected to the circuit, and the sound works normally.

[0087] When the DC voltage at the output end of the main power amplifier is higher than +0.7V, this voltage is added to the base of VT1 tube through R1, so that VT1 tube is turned on, and its collector is at a low level. This low level is added to the base of VT4 tube through R3, so that VT4 tube is turned on, and its collector current flows through relay J1. J1 operates to cut off the BL1 circuit of the speaker, thereby protecting the speaker.

[0088] When the DC voltage at the output end of the main power amplifier is lower than -0.7V, this voltage is added to the emitter of VT2 through R1, turning on VT2 and VT3, and its emitter is at a low level. This low level is added to the base of VT4 through R3, turning on VT4, and its collector current flows through relay J1. J1 operates to cut off the BL1 circuit of the speaker, thereby protecting the speaker.

[0089] Working principle of the circuit: When the power is just turned on, the DC working voltage +V appears. Since the voltage across capacitor 3C39 cannot change suddenly, the base current of 3VT2 charges capacitor 3C39 through 3R45 and 3R44, making VT2 tube conductive, J1 and J2 coils energized, J1 and J2 contacts disconnected (J1 and J2 are normally closed contacts), and the left and right channel speakers are cut off at the same time, so that the impact noise during startup cannot be added to the speakers, achieving the purpose of startup noise reduction, and protecting the speakers from large current impact during startup.

[0090] After powering on, since capacitor 3C39 is fully charged, C1 and C2 in the circuit are connected in reverse series to form a non-polar capacitor, bypassing the AC audio signal at the output end of the main power amplifier to the ground, so that the audio signal cannot be added to VT1 and VT2 tubes, and the protection circuit does not malfunction.

[0091] 2) If Fig. 9 As shown, the four mono power amplifier integrated circuits A1-A4 in the circuit constitute a BTL power amplifier; other components constitute a speaker protection circuit; CK9 and CK10 are left and right channel speaker sockets, and CK11 is a stereo headphone socket;

[0092] Working principle of the circuit: When the power is just turned on, the DC working voltage +V appears. Since the voltage across capacitor 3C39 cannot change suddenly, the base current of 3VT2 charges capacitor 3C39 through 3R45 and 3R44, making VT2 tube conductive, J1 and J2 coils energized, J1 and J2 contacts disconnected (J1 and J2 are normally closed contacts), and the left and right channel speakers are cut off at the same time, so that the impact noise during startup cannot be added to the speakers, achieving the purpose of startup noise reduction, and protecting the speakers from large current impact during startup.

[0093] After turning on the power, since the capacitor 3C39 is fully charged, there is no base current in the VT2 tube, the VT2 tube is cut off, the J1 and J2 coils are powered off, the J1 and J2 contacts are connected, the left and right channel speakers are connected, and the speakers enter the normal connected working state.

[0094] When the main power amplifier works normally, the DC voltage at the output terminals of A1-A4 is 0V. At this time, the diodes VD1-VD4 cannot be turned on, VT1 and VT2 are in the cut-off state, and the protection circuit does not work.

[0095] The two capacitors 3C37 and 3C38 in the circuit are connected in reverse series to form a non-polarized capacitor, which acts as an audio signal bypass. 3R30, 3R40, 3R41 and 3R42 are isolation resistors at the output ends of A1-A4 respectively, to avoid short circuit at the output end of the amplifier when 3C37 and 3C38 are connected.

[0096] When the DC voltage at the output end of one of the integrated circuits A1-A4 is higher than +2.1V, this circuit turns on 3VD2, 3VT1 and 3VD3. Since 3VT1 is turned on, its collector is at a low level, and the 3VT2 tube is turned on through the resistor 3R45, the J1 and J2 coils are energized, the J1 and J2 contacts are disconnected, and the left and right channel speakers are cut off at the same time, achieving the purpose of protecting the speakers.

[0097] When the DC voltage at the output of one of the integrated circuits A1-A4 is lower than -2.1V, this circuit turns on 3VD4, 3VT1 and 3VD1. Since 3VT1 is turned on, its collector is at a low level, and the 3VT2 tube is turned on through the resistor 3R45, the J1 and J2 coils are energized, the J1 and J2 contacts are disconnected, and the left and right channel speakers are cut off at the same time, achieving the purpose of protecting the speakers.

[0098] 3VD5 in the circuit is a protection diode for driving transistor 3VT2 to prevent transistor 3VT2 from being damaged when the relay coil is powered off.

[0099] It should be noted that in this embodiment, the control unit also has a built-in volume controller, such as Fig.10 As shown, in the circuit, VT1 and VT2 form a differential amplifier, VT3 forms a constant current tube for the emitter loop of VT1 and VT2; RP1 is a volume potentiometer; Ui is the audio input signal, and Uo is the output signal after being controlled by the electronic volume controller;

[0100] The audio signal transmission circuit is: the audio signal Ui is coupled through C1, added to the base of VT1, and output from its collector after amplification and control.

[0101] The working principle of the electronic volume control circuit is: the sum of the emitter currents of VT1 and VT2 is equal to the collector current of VT3, and the collector current of VT3 is controlled by the RP1 rotor.

[0102] Circuit analysis: when the RP1 rotor is at the lowest end, the base voltage of VT3 is 0, its collector current is 0, VT1 and VT2 are cut off, there is no output signal, and the volume is in the off state.

[0103] Circuit analysis: when the RP1 moving piece slides upward from the bottom, the VT3 base voltage gradually increases, and the base and collector currents also gradually increase. Since the base current of VT2 is determined by R4, the emitter current of VT2 remains basically unchanged. In this way, the increase of VT3 collector current leads to the gradual increase of VT1 emitter current. The increase of VT1 emitter current means that its amplification ability increases, which increases the output signal, that is, the volume increases.

[0104] Circuit analysis shows that when the RP1 moving piece slides to the uppermost end, the collector current of VT3 and the emitter current of VT1 are the largest, and the volume is the largest at this time.

[0105] From the above analysis, we can know that by controlling the base voltage of VT3, the gain of VT1 can be controlled, thereby controlling the size of the audio output signal Uo. Therefore, this circuit is actually a voltage-controlled gain circuit, that is, the size of VT1 gain can be controlled by controlling the DC voltage on the base of VT3.

[0106] In the circuit, C3 is used to eliminate the noise caused by the poor contact of the RP1 rotor. When the RP1 rotor has poor contact, the voltage across C3 cannot change suddenly, which ensures that the voltage added to the VT3 base is relatively stable, thus eliminating the noise caused by the poor contact of RP1. In addition, it can be seen from the circuit that the audio signal is only transmitted through VT1 but not RP1.

[0107] In the dual-channel circuit, a set of VT1, VT2 and VT3 voltage control gain circuit is set up, and the RPI rotor voltage can be used to control the volume of the left and right channels. In this way, the purpose of synchronously controlling the volume of the left and right channels with a single potentiometer RP1 can be achieved.

[0108] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A volume control system based on a sensor, characterized in that: include: An environmental volume collection unit, which is used to collect the sound decibels of the device environment in real time when the device is working; A control unit, the control unit is used to adjust the volume of the device automatically or manually; the control unit uses a voltage divider circuit composed of resistors, and the output voltage of the voltage divider circuit is calculated as follows: ； Where: U i is the input voltage; U o is the output voltage; R1 and R2 are voltage-dividing resistors; In the calculation formula, since the denominator R1+R2 is greater than the numerator R2, the output voltage is less than the input voltage; the voltage divider circuit is a circuit that attenuates the input signal voltage. Changing the resistance value of R1 or R2 changes the output voltage U o size; The auxiliary calculation unit receives the ambient volume data collected by the ambient volume collection unit, performs a ratio calculation based on the specific decibel number of the received data and the maximum volume data of the device, and determines the unit value of the volume adjustment based on the calculation result; the specific calculation formula for the unit value of the volume adjustment calculated by the auxiliary calculation unit is: ； The auxiliary calculation unit calculates the real-time unit value of the device when adjusting the decibel value of the device volume in the current real-time environment according to the above calculation formula; A device protection module, which is used to prevent a loudspeaker in the device from being damaged by a large current; The display module is used to display the device adjustment volume and the environment comprehensive volume in real time.

2. A volume control system based on a sensor according to claim 1, characterized in that: The device protection module comprises: A device protection circuit, the device protection circuit comprising: 1) A protection circuit that prevents large signal currents from flowing through the speaker, which works in conjunction with the main power amplifier protection circuit; 2) Prevent overcurrent damage to the speaker caused by changes in the DC voltage at the output of the main power amplifier when a circuit failure occurs; It also includes a main power amplifier protection circuit, which includes an overvoltage protection circuit and an overload protection circuit.

3. A volume control system based on a sensor according to claim 2, characterized in that: The overvoltage protection circuit includes: the output tube VT1 and VT2 of the main power amplifier 2、 Zener diodes VD1 and VD2; By setting the breakdown voltage of the Zener diode to be greater than the DC operating voltage, VD1 and VD2 will not break down during normal operation, and the internal resistance is very large, which is equivalent to an open circuit; when high voltage appears, VD1 and VD2 will break down, clamp the voltage, and protect the power amplifier output tubes VT1 and VT2.

4. A volume control system based on a sensor according to claim 3, characterized in that: The overload protection circuit comprises: The composite complementary power amplifier output stage circuit VT3, VT4, VT5, VT6, the overload protection circuit VT1, VT2, VD1, VD2 and the sampling resistors R8 and R9; When the circuit is working normally, the current flowing from the emitters of VT5 and VT6 through the sampling resistors R8 and R9 is at a normal value, the sampling voltage across the sampling resistors is normal, and the sampling voltage added to the bases of VT1 and VT2 is not enough to turn on the two transistors. The protection circuit cannot operate and has no effect on the normal operation of the main power amplifier.

5. A volume control system based on a sensor according to claim 4, characterized in that: When the overload protection circuit fails and the emitter current of VT5 and VT6 is higher than the normal value, the current flowing through the sampling resistors R8 and R9 increases, and the sampling voltage across the sampling resistors increases. The sampling voltage is added to the bases of VT1 and VT2, turning on the two transistors. VT1 turns on VD1, and VT2 turns on VD2, which greatly shunts the input signal. The input signal added to the main power amplifier is greatly reduced, which greatly reduces the working current of VT5 and VT6.

6. A volume control system based on a sensor according to claim 1, characterized in that: The environmental volume acquisition unit comprises: A pickup unit and a determination unit for transmitting sound signals therewith; The pickup unit includes a sound sensor, a microphone signal distributor, a multi-stage amplification unit, an A / D converter and a signal distributor; The sound sensor transmits the received sound signal to the microphone signal distributor, and the microphone signal distributor distributes the sound signal to each input channel; the multi-stage amplification unit performs different levels of amplification processing on the sound signal in each input channel; the A / D converter performs analog-to-digital conversion on the amplified sound signal, and the signal distributor receives each sound signal that has undergone analog-to-digital conversion.

7. A volume control system based on a sensor according to claim 6, characterized in that: The judgment unit includes a register judgment device and a stream signal real-time judgment device arranged in parallel; the register judgment device and the stream signal real-time judgment device respectively receive the sound signal transmitted by the signal distributor; The real-time flow signal judgment device comprises: a judgment module and a digital processor; the real-time flow signal judgment device judges and outputs the sound signal according to the level; The register-type judgment device comprises a buffer, a distortion judgment module, a signal judgment module and a memory; the distortion judgment module and the signal judgment module are respectively connected to the buffer, and the signal judgment module is connected to the memory.

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