A power amplifier muting circuit

Abstract

The application discloses a power amplifier mute circuit, which comprises a battery state judging module, a power supply abnormality judging module and a mute module. The input end of the battery state judging module receives a battery state signal. The output end of the battery state judging module is connected with the output end of the power supply abnormality judging module and the input end of the mute module. The input end of the power supply abnormality judging module receives a power supply signal. The output end of the mute module is used for outputting a mute control signal. The battery state judging module is used for outputting a first abnormal signal when the battery state signal is lower than a first preset value. The first abnormal signal is used for representing that the current state of the battery is abnormal. The power supply abnormality judging module is used for outputting a second abnormal signal when the power supply signal is lower than a second preset value. The second abnormal signal is used for representing that the state of the power supply is abnormal. The mute module is used for outputting the mute control signal when the first abnormal signal and the second abnormal signal are received. The mute control signal is used for controlling the power amplifier circuit to stop working.

Description

Technical Field

[0001] This utility model relates to the field of circuit design technology, and in particular to a power amplifier mute circuit. Background Technology

[0002] Currently, portable audio playback devices (such as Bluetooth speakers) generally use a power supply solution that combines built-in rechargeable batteries and external AC power. Under normal use, these devices can operate stably regardless of whether they are powered by batteries or AC power, without experiencing sudden power outages.

[0003] However, in practical applications, when the device battery is removed or the battery itself malfunctions, the device will rely entirely on external AC power to operate. In this case, when the AC power fails, the power supply voltage of the amplifier circuit will drop rapidly, resulting in abnormal power failure noise, and may even damage the speaker unit of the audio playback device. Utility Model Content

[0004] The main purpose of this application is to provide a power amplifier mute circuit, which aims to solve the technical problem that abnormal noise is generated when the power supply also becomes abnormal when the battery is in an abnormal state in existing power supply equipment that uses a combination of battery and power supply.

[0005] To achieve the above objectives, this application proposes a power amplifier mute circuit, comprising: The system includes a battery status detection module, a power supply abnormality detection module, and a mute module. The input of the battery status detection module receives the battery status signal, and the output of the battery status detection module is connected to the output of the power supply abnormality detection module and the input of the mute module. The input of the power supply abnormality detection module receives the power signal. The output of the mute module is used to output a mute control signal. The battery status judgment module is used to output a first abnormal signal when the battery status signal is lower than a first preset value. The first abnormal signal is used to indicate that the current battery status is abnormal. The power supply abnormality detection module is used to output a second abnormality signal when the power supply signal is lower than a second preset value. The second abnormality signal is used to indicate that the power supply state is abnormal. The mute module is used to output a mute control signal when it receives the first abnormal signal and the second abnormal signal. The mute control signal is used to control the power amplifier circuit to stop working. Attached Figure Description

[0006] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0007] Figure 1 This is a schematic diagram of the power amplifier mute circuit in one embodiment of the present invention; Figure 2 This is a schematic diagram showing the connection of each unit of the power amplifier mute circuit in one embodiment of the present invention; Figure 3 This is a detailed circuit diagram of the power amplifier mute circuit in one embodiment of the present invention.

[0008] Explanation of icon numbers: 1. Battery status judgment module; 11. First resistor unit; 12. First switch unit; 3. Power abnormality judgment module; 31. Second resistor unit; 32. Second switch unit; 5. Mute module; 51. Third resistor unit; 52. Third switch unit.

[0009] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0010] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0011] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0012] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0013] Currently, portable audio playback devices generally employ a power supply solution that combines a built-in rechargeable battery with an external AC power source. Under normal use, these devices operate stably regardless of whether they are powered by the battery or AC power, without experiencing sudden power outages.

[0014] However, in practical applications, when the device battery is removed (for removable battery designs) or the battery itself fails, the device will rely entirely on external AC power. Under these conditions, if the AC power supply experiences an abnormal power outage due to a loose plug, grid fluctuations, or other reasons, the power amplifier circuit's supply voltage will drop rapidly. This sudden change will cause a violent transient response in the amplifier's output stage, manifesting as a harsh noise or popping sound in the speaker—a type of abnormal power-down noise—which poses a risk of damaging the speaker units.

[0015] In one embodiment, the present invention provides a power amplifier mute circuit, see reference. Figure 1 ,include: The system includes a battery status judgment module 1, a power abnormality judgment module 3, and a mute module 5. The input terminal of the battery status judgment module 1 receives the battery status signal, and the output terminal of the battery status judgment module 1 is connected to the output terminal of the power abnormality judgment module 3 and the input terminal of the mute module 5. The input terminal of the power abnormality judgment module 3 receives the power signal, and the output terminal of the mute module 5 is used to output a mute control signal. The battery status judgment module 1 is used to output a first abnormal signal when the battery status signal is lower than a first preset value. The first abnormal signal is used to indicate that the current battery status is abnormal. The power supply abnormality judgment module 3 is used to output a second abnormality signal when the power supply signal is lower than a second preset value. The second abnormality signal is used to indicate that the power supply state is abnormal. The mute module 5 is used to output a mute control signal when it receives the first abnormal signal and the second abnormal signal. The mute control signal is used to control the power amplifier circuit to stop working.

[0016] It should be noted that the battery status judgment module 1 monitors the working status of the battery in real time, compares the received battery status signal with a first preset value, and determines that the current battery status is abnormal when the battery status signal is lower than the first preset value.

[0017] The power supply anomaly detection module 3 monitors the working status of the system's main power supply in real time, compares the received power signal with a second preset value, and determines that the power supply status is abnormal when the power signal is lower than the second preset value.

[0018] The mute module 5 is the module that ultimately outputs the control signal. It is connected to the output terminal of the battery status judgment module 1 and the output terminal of the power abnormality judgment module 3. Upon receiving the first abnormal signal and the second abnormal signal, it outputs a mute control signal to stop the power amplifier circuit from working and prevent the power amplifier circuit from generating noise.

[0019] Additionally, it should be noted that the battery status signal is the voltage signal output by the battery, and under normal circumstances, the voltage of this signal is 3.3V.

[0020] The power signal is the power supply signal when AC voltage is inserted. Under normal circumstances, the voltage of this signal is 24V.

[0021] The mute control signal is output by mute module 5. When both the battery and power supply are faulty, this signal is low. When the power amplifier circuit receives this low-level signal, it immediately stops working to avoid generating noise.

[0022] For example, the first preset value can be set to 3.3V. When the battery status signal received by the battery status judgment module 1 is lower than 3.3V, it indicates that the battery is not supplying power, and the battery status judgment module 1 outputs a low-level first abnormal signal.

[0023] The second preset value can be set to 11.2V. When the power signal received by the power abnormality judgment module 3 is lower than 11.2V, it indicates that the power supply has failed and the power abnormality judgment module 3 outputs a low-level second abnormal signal.

[0024] It is understood that the first and second preset values ​​can be adjusted as needed, and both are within the scope of protection of this application.

[0025] It should be noted that an abnormal battery status can be caused by two things: either the battery is damaged or the battery is not inserted.

[0026] The working process of the above power amplifier mute circuit is as follows: The battery status judgment module 1 receives the battery status signal and compares the battery status signal with the first preset value. When the battery status signal is greater than or equal to the first preset value, the current battery status is judged to be normal. The mute module 5 does not receive the first abnormal signal. At this time, regardless of whether the power abnormality judgment module 3 outputs the second abnormal signal, the mute module 5 does not output the mute control signal, and the power amplifier circuit works normally. When the battery status signal is less than the first preset value, the current battery status is determined to be abnormal, and the first abnormal signal is output to the mute module 5. The power abnormality judgment module 3 receives the power signal and compares the power signal with the second preset value. When the power signal is greater than or equal to the second preset value, the power status is determined to be normal. The mute module 5 does not receive the second abnormal signal and does not output the mute control signal. The power amplifier circuit works normally. When the battery status signal is less than the first preset value and the power signal is less than the second preset value, it is determined that the current battery status is abnormal and the power status is also abnormal. The first abnormal signal and the second abnormal signal are output. At this time, the mute module 5 simultaneously receives the first abnormal signal and the second abnormal signal, and outputs a mute control signal to control the power amplifier circuit to stop working.

[0027] In this embodiment, the power amplifier mute circuit includes a battery status judgment module, a power supply abnormality judgment module, and a mute module. The battery status judgment module determines the current battery status, and the power supply abnormality judgment module determines the power supply status. When both the battery status and the power supply status are abnormal, the mute module simultaneously receives a first abnormality signal and a second abnormality signal, and then outputs a mute control signal to stop the power amplifier circuit from operating. By receiving the first and second abnormality signals through the mute module, the power amplifier circuit is stopped when both battery and power supply are abnormal, thus preventing noise generation in the power amplifier circuit and reducing the risk of damage to the speaker units.

[0028] In one embodiment, see Figure 2 The battery status determination module 1 includes: The first resistor unit 11 and the first switch unit 12 are connected to the control terminal of the first switch unit 12. One end of the first resistor unit 11 receives the battery status signal SOC_MUTE, and the other end of the first resistor unit 11 is connected to the control terminal of the first switch unit 12. The input terminal of the first switching unit 12 is connected to the output terminal of the power abnormality judgment module 3 and the input terminal of the mute module 5, and the output terminal of the first switching unit 12 is grounded. The first resistor unit 11 is used to step down the battery status signal SOC_MUTE and output the stepped-down battery status signal. The first switching unit 12 is used to turn off and output a first abnormal signal when the battery status signal after voltage reduction is less than a third preset value.

[0029] It should be noted that the first resistor unit 11 is the signal conditioning unit in the battery status judgment module 1. One end of it receives the battery status signal SOC_MUTE from the battery. Its main function is to step down the input battery status signal SOC_MUTE, processing it into a stepped-down battery status signal suitable for subsequent circuit processing. Then, it is output to the control terminal of the first switch unit 12 as the judgment basis.

[0030] The first switch unit 12 is the unit for signal output and logic execution in the battery status judgment module 1. Its on / off state is controlled by the stepped-down battery status signal output by the first resistor unit 11. When the signal is greater than or equal to the third preset value, it is turned on and the first abnormal signal is not output; when the signal is less than the third preset value, it is turned off and the first abnormal signal is output.

[0031] The third preset value refers to the condition value for the first switch unit 12 to be turned on. It can be understood that after the voltage is reduced by the first resistor unit 11, the third preset value is less than the first preset value.

[0032] The working process of the above power amplifier mute circuit is as follows: The first resistor unit 11 receives the battery status signal SOC_MUTE, performs step-down processing on the battery status signal SOC_MUTE to obtain the stepped-down battery status signal, and outputs it to the control terminal of the first switch unit 12 through the output terminal of the first resistor unit 11. The control terminal of the first switching unit 12 receives the stepped-down battery status signal and compares it with the third preset value. When the stepped-down battery status signal is greater than or equal to the third preset value, the first switching unit 12 is turned on, and the stepped-down battery status signal is led to the ground terminal. The first abnormal signal is not output, and the current battery status is determined to be normal. When the battery status signal after voltage reduction is less than the third preset value, the first switch unit 12 is turned off and outputs the first abnormal signal, determining that the current battery status is abnormal.

[0033] In this embodiment, a first resistor unit and a first switch unit are set in the battery status judgment module. The first resistor unit receives the battery status signal, performs voltage reduction processing, and then outputs it to the control terminal of the first switch unit. The first switch unit judges whether the voltage-reduced battery status signal is less than a third preset value. When the voltage-reduced battery status signal is greater than or equal to the third preset value, the first switch unit is turned on; when the voltage-reduced battery status signal is less than the third preset value, the first switch unit is turned off and outputs a first abnormal signal. When the mute module receives both the first and second abnormal signals, it outputs a mute control signal to control the power amplifier circuit to stop working. By receiving the first and second abnormal signals through the mute module, the power amplifier circuit is controlled to stop working when there are battery or power supply abnormalities, avoiding noise generation in the power amplifier circuit and reducing the risk of damage to the speaker unit.

[0034] In one embodiment, see Figure 2 The power supply anomaly detection module 3 includes: The second resistor unit 31 and the second switch unit 32 are connected to the control terminal of the second switch unit 32. One end of the second resistor unit 31 receives the power signal AC_IN_24V, and the other end of the second resistor unit 31 is connected to the control terminal of the second switch unit 32. The input terminal of the second switch unit 32 is connected to the output terminal of the battery status judgment module 1 and the input terminal of the mute module 5, and the output terminal of the second switch unit 32 is grounded. The second resistor unit 31 is used to step down the power signal AC_IN_24V and output the stepped-down power signal. The second switching unit 32 is used to turn off and output a second abnormal signal when the stepped-down power signal is less than a third preset value.

[0035] It should be noted that the second resistor unit 31 is the signal conditioning unit in the power supply anomaly judgment module 3. One end of it receives the power signal AC_IN_24V from the power supply. Its main function is to step down the input power signal AC_IN_24V, processing it into a stepped-down power signal suitable for subsequent circuit processing. Then, it is output to the control terminal of the second switching unit 32 as the judgment basis.

[0036] The second switching unit 32 is the unit for signal output and logic execution in the power supply abnormality judgment module 3. Its on / off state is controlled by the stepped-down power supply signal output by the second resistor unit 31. When the signal is greater than or equal to the third preset value, it is turned on and no second abnormal signal is output; when the signal is less than the third preset value, it is turned off and the second abnormal signal is output.

[0037] It is understood that the third preset value involved in this embodiment may be the same as or different from the third preset value involved in the previous embodiment in this application, and may be adjusted as needed, all of which are within the protection scope of this application.

[0038] The working process of the above power amplifier mute circuit is as follows: The second resistor unit 31 receives the power signal AC_IN_24V, performs step-down processing on the power signal AC_IN_24V, obtains the stepped-down power signal, and outputs it to the control terminal of the second switch unit 32 through the output terminal of the second resistor unit 31. The control terminal of the second switching unit 32 receives the stepped-down power signal and compares it with the third preset value. When the stepped-down power signal is greater than or equal to the third preset value, the second switching unit 32 remains on, leads the stepped-down power signal to the ground terminal, does not output the second abnormal signal, and determines that the current power supply status is normal. When the stepped-down power signal is less than the third preset value, the second switch unit 32 is turned off and outputs the second abnormal signal, determining that the power state is abnormal.

[0039] In this embodiment, a second resistor unit and a second switch unit are included in the power supply anomaly detection module. The second resistor unit receives the power signal, performs voltage reduction processing, and then outputs it to the control terminal of the second switch unit. The second switch unit determines whether the voltage-reduced power signal is less than a third preset value. When the voltage-reduced power signal is greater than or equal to the third preset value, the second switch unit remains on; when the voltage-reduced power signal is less than the third preset value, the second switch unit is off and outputs a second anomaly signal. When the mute module simultaneously receives the first and second anomaly signals, it outputs a mute control signal to stop the power amplifier circuit from operating. By receiving the first and second anomaly signals through the mute module, the power amplifier circuit is controlled to stop operating when there are battery or power supply anomalies, avoiding noise generation in the power amplifier circuit and reducing the risk of damage to the speaker unit.

[0040] In one embodiment, see Figure 2 The silent module 5 includes: The third resistor unit 51 and the third switch unit 52 are connected. The first end L1 of the third resistor unit 51 is connected to the power supply SYS_3V3, the second end L2 of the third resistor unit 51 is connected to the control end of the third switch unit 52, and the third end L3 of the third resistor unit 51 is connected to the input end of the third switch unit 52. The control terminal of the third switch unit 52 is also connected to the output terminal of the battery status judgment module 1 and the output terminal of the power abnormality judgment module 3. The output terminal of the third switch unit 52 is grounded. The third resistor unit 51 is used to step down the voltage signal output by the power supply SYS_3V3; The third switching unit 52 is used to output the mute control signal when it receives the first abnormal signal and the second abnormal signal.

[0041] It should be noted that the third resistor unit 51 is the signal conditioning unit in the mute module 5. Its first terminal receives the voltage signal from the power supply SYS_3V3. Its main function is to step down the input voltage signal, processing it into a voltage signal suitable for subsequent circuit processing. Then, it outputs the signal to the control terminal of the third switch unit 52 as a judgment criterion.

[0042] It should be noted that the power supply SYS_3V3 connected to the third resistor unit 51 and the power signal AC_IN_24V received by the second resistor unit are not the same power supply. The power supply SYS_3V3 connected to the third resistor unit 51 is the 3.3V power supply for the system's main control unit.

[0043] The third switch unit 52 is the unit for signal output and logic execution in the mute module 5. Its on / off state is controlled by the stepped-down voltage signal, the first abnormal signal, and the second abnormal signal output by the third resistor unit 51. When the control terminal of the third switch unit 52 receives the first abnormal signal, the second abnormal signal, and the stepped-down voltage signal, it is turned on; otherwise, it remains closed.

[0044] The working process of the above power amplifier mute circuit is as follows: The first terminal L1 of the third resistor unit 51 receives the voltage signal output by the power supply SYS_3V3, performs voltage step-down processing on the voltage signal output by the power supply SYS_3V3, and obtains the stepped-down voltage signal, which is then output to the control terminal of the third switch unit 52 through the second terminal L2 of the third resistor unit 51. When the third switch unit 52 receives only the first abnormal signal or the second abnormal signal, it remains in the off state and does not output the mute control signal, and the power amplifier circuit continues to work normally. When the third switch unit 52 receives the first abnormal signal and the second abnormal signal simultaneously, it is turned on. At this time, it outputs a mute control signal to the power amplifier circuit, causing the power amplifier circuit to stop working.

[0045] In this embodiment, a third resistor unit and a third switch unit are included in the mute module. The voltage signal output from the power supply is stepped down by the third resistor unit and then output to the control terminal of the third switch unit. When the control terminal of the third switch unit simultaneously receives a first abnormal signal and a second abnormal signal, the third switch unit is turned on and outputs a mute control signal, causing the power amplifier circuit to stop working. By receiving the first and second abnormal signals through the mute module, the power amplifier circuit is controlled to stop working when the battery or power supply is abnormal, thus avoiding noise generation in the power amplifier circuit and reducing the risk of damage to the speaker unit.

[0046] In one embodiment, see Figure 3 The first resistor unit 11 includes: The first resistor R100 and the second resistor R101 are connected. One end of the first resistor R100 receives the battery status signal SOC_MUTE. The other end of the first resistor R100 is connected to the control terminal of the first switching unit 12 and one end of the second resistor R101. The other end of the second resistor R101 is grounded.

[0047] The first resistor R100 can have a value of 10KΩ, and the second resistor R101 can have a value of 100KΩ. When the battery status signal SOC_MUTE is 3.3V, the voltage is stepped down by the first resistor R100 and the second resistor R101 to obtain the stepped-down battery status signal. The stepped-down battery status signal is then output to the control terminal of the first switching unit 12 through the other end of the first resistor R100.

[0048] In this embodiment, a first resistor and a second resistor are set in the first resistor unit to step down the battery status signal before outputting it to the control terminal of the first switching unit. This provides a judgment signal for the subsequent first switching unit. The first switching unit compares the stepped-down battery status signal with a third preset value to determine whether to output a first abnormal signal to the mute module. When the mute module receives both the first and second abnormal signals simultaneously, it outputs a mute control signal to stop the power amplifier circuit from working. By receiving the first and second abnormal signals through the mute module, the power amplifier circuit is controlled to stop working when there are battery or power supply abnormalities, avoiding noise generation in the power amplifier circuit and reducing the risk of damage to the speaker unit.

[0049] In one embodiment, see Figure 3 The first switching unit 12 includes: The first switching transistor Q100 has its control terminal connected to the other end of the first resistor R100, its input terminal connected to the output terminal of the power supply abnormality judgment module 3 and the input terminal of the mute module 5, and its output terminal grounded.

[0050] The first switching transistor Q100 can be an MMBT3904. Its control terminal (base) turn-on voltage is 0.7V. It can be understood that this turn-on voltage is the third preset value.

[0051] The control terminal of the first switch Q100 receives the stepped-down battery status signal output from the other end of the first resistor R100. When the stepped-down battery status signal is greater than or equal to the third preset value, the first switch Q100 is turned on, the current battery status is normal, and the first abnormal signal is not output. When the battery status signal after voltage reduction is less than the third preset value, the first switch Q100 is turned off, the current battery status is abnormal, and the first abnormal signal is output to the mute module 5.

[0052] In this embodiment, a first switching transistor is provided in the first switching unit. The first switching transistor receives the stepped-down battery status signal and compares it with a third preset value. When the stepped-down battery status signal is greater than or equal to the third preset value, the first switching transistor is turned on and no first abnormal signal is output; when the stepped-down battery status signal is less than the third preset value, the first switching transistor is turned off and the first abnormal signal is output. When the mute module receives both the first and second abnormal signals simultaneously, it outputs a mute control signal to control the power amplifier circuit to stop working. By receiving the first and second abnormal signals through the mute module, the power amplifier circuit is controlled to stop working when there are battery or power supply abnormalities, avoiding noise generation in the power amplifier circuit and reducing the risk of damage to the speaker unit.

[0053] In one embodiment, see Figure 3 The second resistor unit 31 includes: The third resistor R103 and the fourth resistor R102 are connected. One end of the third resistor R103 receives the power signal AC_IN_24V, and the other end of the third resistor R103 is connected to the control terminal of the second switch unit 32 and one end of the fourth resistor R102. The other end of the fourth resistor R102 is grounded.

[0054] The third resistor R103 can have a value of 300KΩ, and the fourth resistor R102 can have a value of 20KΩ. When the power supply signal AC_IN_24V is greater than 11.2V, it is stepped down by the third resistor R103 and the fourth resistor R102 to obtain a stepped-down power supply signal. The stepped-down power supply signal is then output to the control terminal of the second switching unit 32 through the other end of the third resistor R103.

[0055] In this embodiment, a third and fourth resistor are set in the second resistor unit to step down the power signal before outputting it to the control terminal of the second switching unit. This provides a judgment signal for the subsequent second switching unit. The second switching unit compares the stepped-down power signal with a third preset value to determine whether to output a second abnormal signal to the mute module. When the mute module receives both the first and second abnormal signals simultaneously, it outputs a mute control signal to stop the power amplifier circuit from working. By receiving the first and second abnormal signals through the mute module, the power amplifier circuit is controlled to stop working when there are battery or power abnormalities, avoiding noise generation in the power amplifier circuit and reducing the risk of damage to the speaker unit.

[0056] In one embodiment, see Figure 3 The second switching unit 32 includes: The second switch Q101 has its control terminal connected to the other end of the third resistor R103, its input terminal connected to the output terminal of the battery status judgment module 1 and the input terminal of the mute module 5, and its output terminal grounded.

[0057] The second switching transistor Q101 can be an MMBT3904. Its control terminal (base) turn-on voltage is 0.7V. This turn-on voltage is understood to be the third preset value.

[0058] The control terminal of the second switch Q101 receives the stepped-down power signal output from the other end of the third resistor R103. When the stepped-down power signal is greater than or equal to the third preset value, the second switch Q101 is turned on, the power supply status is normal, and no second abnormal signal is output. When the stepped-down power signal is less than the third preset value, the second switch Q101 is turned off, the battery is in an abnormal state, and the second abnormal signal is output to the mute module 5.

[0059] In this embodiment, a second switching transistor is provided in the second switching unit. The second switching transistor receives the stepped-down power signal and compares it with a third preset value. When the stepped-down power signal is greater than or equal to the third preset value, the second switching transistor is turned on and no second abnormal signal is output; when the stepped-down power signal is less than the third preset value, the second switching transistor is turned off and the second abnormal signal is output. When the mute module receives both the first and second abnormal signals simultaneously, it outputs a mute control signal to control the power amplifier circuit to stop working. By receiving the first and second abnormal signals through the mute module, the power amplifier circuit is controlled to stop working when there are battery or power failures, avoiding noise generation in the power amplifier circuit and reducing the risk of damage to the speaker unit.

[0060] In one embodiment, see Figure 3 The third resistor unit 51 includes: The fifth resistor R104, the sixth resistor R105, and the seventh resistor R106 are connected to the power supply SYS_3V3 at one end and to the output of the battery status judgment module 1, the output of the power abnormality judgment module 3, one end of the sixth resistor R105, and the control terminal of the third switch unit 52. The other end of the sixth resistor R105 is grounded; One end of the seventh resistor R106 is connected to the power supply SYS_3V3, and the other end of the seventh resistor R106 is connected to the input terminal of the third switch unit 52.

[0061] The fifth resistor R104 can have a value of 10KΩ, the sixth resistor R105 can have a value of 100KΩ, and the seventh resistor R106 can have a value of 10KΩ. The power supply SYS_3V3 outputs a 3.3V voltage signal. After being stepped down by the fifth resistor R104 and the sixth resistor R105, a stepped-down voltage signal is obtained. This stepped-down voltage signal is then output to the control terminal of the third switching unit 52 through the other end of the fifth resistor R104. The other end of the seventh resistor R106 serves as the output terminal of the mute module 5. When the third switching unit is off, the other end of the seventh resistor R106 outputs a 3.3V voltage signal, and the power amplifier circuit operates normally. When the third switching unit is on, the other end of the seventh resistor R106 outputs a 0V voltage signal, serving as a mute control signal to stop the power amplifier circuit from operating.

[0062] In this embodiment, a fifth, sixth, and seventh resistor are configured in the third resistor unit to step down the voltage signal before outputting it to the control terminal of the third switching unit. When the control terminal of the third switching unit simultaneously receives the first and second abnormal signals, it outputs a mute control signal to stop the power amplifier circuit from operating. By receiving the first and second abnormal signals through the mute module, the power amplifier circuit is controlled to stop operating when there are battery or power supply abnormalities, thus avoiding noise generation in the power amplifier circuit and reducing the risk of damage to the speaker unit.

[0063] In one embodiment, see Figure 3 The third switching unit 52 includes: The third switch Q102 is connected to the other end of the fifth resistor R104, the output of the battery status judgment module 1, the output of the power supply abnormality judgment module 3, and one end of the sixth resistor R105. The input of the third switch Q102 is connected to the other end of the seventh resistor R106, and the output of the third switch Q102 is grounded.

[0064] The third switching transistor, Q102, can be an MMBT3904. Its control terminal (base) turn-on voltage is 0.7V.

[0065] When the control terminal of the third switch Q102 does not receive any abnormal signal, or only receives one of the first or second abnormal signals, the third switch Q102 remains off and does not output a mute control signal. When the control terminal of the third switch Q102 simultaneously receives the first abnormal signal and the second abnormal signal, the third switch Q102 receives the stepped-down voltage signal output from the other end of the fifth resistor R104 and turns on, leading the stepped-down battery signal to the ground terminal. The other end of the seventh resistor R106 serves as the output terminal of the mute module 5, outputting a 0V voltage signal as a mute control signal, which is then output to the power amplifier circuit to stop the power amplifier circuit from working.

[0066] In this embodiment, a third switching transistor is provided in the third switching unit. When the control terminal of the third switching unit simultaneously receives the first abnormal signal and the second abnormal signal, it receives the stepped-down voltage signal and turns on; otherwise, it remains off. After the third switching unit turns on, the output terminal of the mute module outputs a mute control signal to the power amplifier circuit, causing the power amplifier circuit to stop working. This avoids noise generation in the power amplifier circuit and reduces the risk of damage to the speaker unit caused by it.

[0067] See Figure 3 The working process of the power amplifier mute circuit is as follows: The battery status signal SOC_MUTE received at one end of the first resistor R100 is stepped down by the first resistor R100 and the second resistor R101 to obtain the stepped-down battery status signal, which is then output to the control terminal of the first switch Q100 through the other end of the first resistor R100. The control terminal of the first switch Q100 receives the stepped-down battery status signal and compares it with the third preset value. When the stepped-down battery status signal is greater than or equal to the third preset value, the first switch Q100 is turned on, and the battery is in normal condition. At this time, regardless of whether the second switch Q101 is turned on, the third switch Q102 remains off. The signal AMP_MUTE output from the other end of the seventh resistor R106 is 3.3V, which enables the power amplifier circuit to work normally. When the stepped-down battery status signal is less than the third preset value, the first switch Q100 is turned off, and the current battery status is abnormal; one end of the third resistor R103 receives the power signal AC_IN_24V, and after being stepped down by the third resistor R103 and the fourth resistor R102, the stepped-down power signal is obtained, and is output to the control terminal of the second switch Q101 through the other end of the third resistor R103; The control terminal of the second switch Q101 receives the stepped-down power signal and compares it with the third preset value. When the stepped-down power signal is greater than or equal to the third preset value, the second switch Q101 is turned on, the power supply is normal, the third switch Q102 remains off, and the signal AMP_MUTE output from the other end of the seventh resistor R106 is 3.3V, which enables the power amplifier circuit to work normally. When the stepped-down power signal is less than the third preset value, the second switch Q101 is turned off, the power state is abnormal, and the voltage signal SYS_3V3 received by the fifth resistor R104 is stepped down by the fifth resistor R104 and the sixth resistor R105 to obtain the stepped-down voltage signal, which is output to the control terminal of the third switch Q102 through the other end of the fifth resistor R104. After receiving the stepped-down power signal, the control terminal of the third switch Q102 is turned on, leading the voltage signal SYS_3V3 to the ground terminal. At this time, the signal AMP_MUTE output from the other end of the seventh resistor R106 is 0V, that is, the mute control signal is output, causing the power amplifier circuit to stop working.

[0068] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A power amplifier mute circuit, characterized in that, The power amplifier mute circuit includes: The system includes a battery status detection module, a power supply anomaly detection module, and a mute module. The input terminal of the battery status detection module receives a battery status signal, and the output terminal of the battery status detection module is connected to the output terminal of the power supply anomaly detection module and the input terminal of the mute module. The input terminal of the power supply anomaly detection module receives a power signal, and the output terminal of the mute module is used to output a mute control signal. The battery status determination module is used to output a first abnormal signal when the battery status signal is lower than a first preset value. The first abnormal signal is used to indicate that the current battery status is abnormal. The power supply anomaly detection module is used to output a second anomaly signal when the power supply signal is lower than a second preset value. The second anomaly signal is used to indicate that the power supply state is abnormal. The mute module is used to output a mute control signal when it receives the first abnormal signal and the second abnormal signal. The mute control signal is used to control the power amplifier circuit to stop working.

2. The power amplifier mute circuit as described in claim 1, characterized in that, The battery status determination module includes: A first resistor unit and a first switch unit, wherein one end of the first resistor unit receives the battery status signal and the other end of the first resistor unit is connected to the control terminal of the first switch unit; The input terminal of the first switching unit is connected to the output terminal of the power supply abnormality judgment module and the input terminal of the mute module, and the output terminal of the first switching unit is grounded; The first resistor unit is used to step down the battery status signal and output the stepped-down battery status signal. The first switching unit is used to turn off and output the first abnormal signal when the battery status signal after voltage reduction is less than a third preset value.

3. The power amplifier mute circuit as described in claim 1, characterized in that, The power supply anomaly detection module includes: The second resistor unit and the second switch unit, one end of the second resistor unit receives the power signal, and the other end of the second resistor unit is connected to the control terminal of the second switch unit; The input terminal of the second switching unit is connected to the output terminal of the battery status judgment module and the input terminal of the mute module, and the output terminal of the second switching unit is grounded; The second resistor unit is used to step down the power signal and output the stepped-down power signal; The second switching unit is used to turn off and output the second abnormal signal when the stepped-down power signal is less than a third preset value.

4. The power amplifier mute circuit as described in claim 1, characterized in that, The noise reduction module includes: A third resistor unit and a third switch unit, wherein the first end of the third resistor unit is connected to the power supply, the second end of the third resistor unit is connected to the control terminal of the third switch unit, and the third end of the third resistor unit is connected to the input terminal of the third switch unit; The control terminal of the third switch unit is also connected to the output terminal of the battery status judgment module and the output terminal of the power abnormality judgment module, and the output terminal of the third switch unit is grounded; The third resistor unit is used to step down the voltage signal output by the power supply. The third switching unit is used to output the mute control signal when it receives the first abnormal signal and the second abnormal signal.

5. The power amplifier mute circuit as described in claim 2, characterized in that, The first resistor unit includes: A first resistor and a second resistor, one end of the first resistor receives the battery status signal, the other end of the first resistor is connected to the control terminal of the first switching unit and one end of the second resistor, and the other end of the second resistor is grounded.

6. The power amplifier mute circuit as described in claim 5, characterized in that, The first switching unit includes: The first switching transistor has its control terminal connected to the other end of the first resistor, its input terminal connected to the output terminal of the power supply abnormality judgment module and the input terminal of the mute module, and its output terminal grounded.

7. The power amplifier mute circuit as described in claim 3, characterized in that, The second resistor unit includes: The third resistor and the fourth resistor are connected as follows: one end of the third resistor receives the power signal, the other end of the third resistor is connected to the control terminal of the second switching unit and one end of the fourth resistor, and the other end of the fourth resistor is grounded.

8. The power amplifier mute circuit as described in claim 7, characterized in that, The second switching unit includes: The second switch is connected to the other end of the third resistor, the input of the second switch is connected to the output of the battery status judgment module and the input of the mute module, and the output of the second switch is grounded.

9. The power amplifier mute circuit as described in claim 4, characterized in that, The third resistor unit includes: The fifth resistor, the sixth resistor, and the seventh resistor are provided. One end of the fifth resistor is connected to the power supply, and the other end of the fifth resistor is connected to the output terminal of the battery status judgment module, the output terminal of the power supply abnormality judgment module, one end of the sixth resistor, and the control terminal of the third switch unit. The other end of the sixth resistor is grounded; One end of the seventh resistor is connected to the power supply, and the other end of the seventh resistor is connected to the input terminal of the third switching unit.

10. The power amplifier mute circuit as described in claim 9, characterized in that, The third switching unit includes: The third switch is connected to the other end of the fifth resistor, the output of the battery status judgment module, the output of the power supply abnormality judgment module, and one end of the sixth resistor. The input of the third switch is connected to the other end of the seventh resistor, and the output of the third switch is grounded.

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