Megaphone output circuit, circuit board and megaphone
By designing an automatically controlled loudspeaker output circuit, the problem of the existing loudspeaker requiring manual opening is solved, and the loudspeaker is automatically opened and closed, which improves user experience and safety.
Patent Information
- Application Number
- CN202422520055.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-17
- Publication Date
- 2025-09-05
- Estimated Expiration
- 2034-10-17
AI Technical Summary
Existing megaphones require manual activation of the loudspeaker switch, which causes the user to be distracted and inconvenient to operate in special situations, affecting safety.
A shouting output circuit is designed, which includes a microphone, a first-level power amplifier module, a shouting detection module, a main control module and a speaker. The microphone detects sound and automatically controls the opening and closing of the shouting function, eliminating the shouting switch.
The automatic opening and closing of the loudspeaker is realized, which improves the user experience, especially in special occasions such as bus driving, reduces operational interference and improves safety.
Smart Images
Figure CN223309935U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of electronic circuits, and in particular to a loudspeaker output circuit, a circuit board, and a loudspeaker. Background Art
[0002] In some public places with a large number of people or where order needs to be maintained, such as buses, parks and scenic spots, the voices of managers are easily covered by noisy environmental sounds, human voices and other sounds due to the large number of people. For this reason, managers usually need to use loudspeakers to speak to passengers, tourists and other people to maintain on-site order, inform information and other activities.
[0003] A megaphone uses a microphone to receive external sounds, converts them into electrical signals, amplifies them, and drives speakers to output the amplified sound, thereby achieving a sound amplification effect. However, existing megaphones typically require a switch to be turned on to amplify the sound, a process that can be inconvenient for the user. In some situations, users need to be distracted looking for the switch, losing focus on the task at hand. For example, if a bus driver needs to be distracted looking for the switch while driving, it can cause operational inconvenience and even compromise driving safety. Utility Model Content
[0004] The present application provides a loudspeaker output circuit, a circuit board and a loudspeaker, which solves the technical problem in the related art that the loudspeaker is not convenient to turn on. The present application can provide a loudspeaker with automatic detection of the loudspeaker function, without the need for a loudspeaker switch, and can automatically turn on and off the loudspeaker function, which can more flexibly adapt to user use and improve the user experience.
[0005] In a first aspect, the present application provides a voice output circuit, which includes a microphone, a primary power amplifier module, a voice detection module, a main control module, a secondary power amplifier module and a speaker.
[0006] Among them, the microphone is used to detect sound and convert it into an electrical signal; the input end of the first-level power amplifier module is connected to the output end of the microphone, and the first-level power amplifier module is used to power amplify the electrical signal output by the microphone; the input end of the shouting detection module is connected to the output end of the first-level power amplifier module, and the shouting detection module is used to determine whether the microphone detects sound; the detection input end of the main control module is connected to the output end of the shouting detection module, and the main control module is used to output a control signal when receiving a shouting signal. The shouting signal is the output signal output by the shouting detection module after determining that the microphone detects sound; the input end of the second-level power amplifier module is connected to the output end of the first-level power amplifier module, and the control end of the second-level power amplifier module is connected to the control output end of the main control module. The second-level power amplifier module is used to power amplify the electrical signal output by the first-level power amplifier module after receiving the control signal; the output end of the speaker is connected to the output end of the second-level power amplifier module, and the speaker is used to convert the received electrical signal into sound and play it outward.
[0007] In a second aspect, the present application also provides a circuit board, which includes the above-mentioned voice output circuit.
[0008] In a third aspect, the present application also provides a loudspeaker, which includes the above-mentioned circuit board.
[0009] The shouting output circuit of the present application can provide an automatic detection and shouting function without the need for a shouting switch. It can automatically turn on and off the shouting function, thereby more flexibly adapting to user use and improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 A schematic diagram of the structure of a voice output circuit provided in one embodiment of the present application;
[0011] Figure 2 A schematic diagram of the circuit structure of a voice detection unit provided in an embodiment of the present application;
[0012] Figure 3 A schematic diagram of the circuit structure of a continuous shouting detection unit provided in one embodiment of the present application;
[0013] Figure 4 This is a schematic diagram of the circuit structure of the voice output circuit provided in one embodiment of the present application. DETAILED DESCRIPTION
[0014] The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and examples. It will be understood that the specific embodiments described herein are merely used to explain the embodiments of the present application, rather than to limit the embodiments of the present application. It should also be noted that, for ease of description, only portions related to the embodiments of the present application, rather than all structures, are shown in the accompanying drawings. After reading this specification, those skilled in the art should be able to understand that, as long as the technical features do not contradict each other, any combination of the technical features may constitute an optional embodiment.
[0015] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated before and after are in an "or" relationship. In the description of this application, "multiple" means two or more, and "several" means one or more.
[0016] Existing megaphones typically require a switch to be turned on to amplify the sound, a process that can be inconvenient for the user. The inventors discovered that in some situations, users need to be distracted by searching for the switch, losing focus on their current tasks. For example, if a bus driver needs to be distracted by searching for the switch while driving, this can cause operational inconvenience and even affect driving safety.
[0017] In this regard, the present application provides a shouting output circuit that can eliminate the shouting switch, making it more convenient for users. Users do not need to be distracted by looking for the shouting switch and can focus more on the current matter. Figure 1 This is a structural diagram of a voice output circuit provided in an embodiment of the present application, as shown in FIG. Figure 1 As shown, it includes a microphone 101, a primary power amplifier module 102, a shouting detection module 103, a main control module 104, a secondary power amplifier module 105 and a speaker 106.
[0018] The input of the primary power amplifier module 102 is connected to the output of the microphone 101, the output of the primary power amplifier module 102 is connected to the input of the voice detection module 103, and the output of the voice detection module 103 is connected to the detection input of the main control module 104. The input of the secondary power amplifier module 105 is connected to the output of the primary power amplifier module 102, the control terminal of the secondary power amplifier module 105 is connected to the control output of the main control module 104, and the output of the speaker 106 is connected to the output of the secondary power amplifier module 105.
[0019] It is understood that microphone 101 detects sound and converts it into an electrical signal, which is then transmitted to primary power amplifier module 102. Primary power amplifier module 102 then amplifies the electrical signal output by microphone 101. Furthermore, the amplified electrical signal is connected to voice detection module 103 and secondary power amplifier module 105. Voice detection module 103 is used to determine whether microphone 101 has detected sound, and then, upon determining that microphone 101 has detected sound, outputs a voice signal to main control module 104. It is conceivable that the voice signal is the output signal output by the voice detection module after determining that the microphone has detected sound. Upon receiving the voice signal, main control module 104 outputs a control signal to secondary power amplifier module 105, causing secondary power amplifier module 105 to amplify the electrical signal output by primary power amplifier module 102. This converts the amplified electrical signal from secondary power amplifier module 105 into sound and plays it outwardly through speaker 106.
[0020] In this regard, the shouting output circuit of the present application can provide an automatic detection shouting function without the need for a shouting switch. It can automatically turn on the shouting function and automatically turn off the shouting function, thereby more flexibly adapting to user use and improving the user experience.
[0021] In some embodiments, the shouting detection module includes a start-up shouting detection unit and a continuous shouting detection unit, wherein the start-up shouting detection unit and the continuous shouting detection unit are both connected to the main control module. Specifically, the input end of the start-up shouting detection unit is connected to the output end of the first-level power amplifier module, and the output end of the start-up shouting detection unit is connected to the first detection interface of the main control module; the input end of the continuous shouting detection unit is connected to the output end of the microphone, and the output end of the continuous shouting detection unit is connected to the second detection interface of the main control module.
[0022] It is understood that the voice detection unit is activated to detect the electrical signal output by the primary power amplifier module, that is, to detect whether the microphone has detected sound. To this end, when the input voltage corresponding to the received electrical signal is greater than the first reference voltage, the voice detection unit is activated to output a first detection signal to the main control module. The continuous voice detection unit can also detect whether the microphone has detected sound, and when the input voltage corresponding to the received electrical signal is greater than the second reference voltage, the continuous voice detection unit outputs a second detection signal to the main control module.
[0023] It's worth noting that the first reference voltage is greater than the second reference voltage. Therefore, the start-up voice detection unit outputs a first detection signal upon determining that the microphone has detected a loud sound, while the continuous voice detection unit outputs a second detection signal upon determining that the microphone has detected a quiet sound. The terms "larger" and "smaller" above refer to a comparative relationship between two sounds, meaning that one sound is louder (or quieter) than the other.
[0024] In addition, the main control module starts detecting the second detection interface on it when receiving the first detection signal, and outputs a control signal when receiving the second detection signal. In other words, the main control module needs to receive both the first detection signal and the second detection signal before outputting the control signal to control the operation of the secondary power amplifier module. If the main control module only detects the second detection signal, the main control module will not output the control signal.
[0025] In this regard, in actual applications, when a user uses a megaphone with a shouting output circuit, the user needs to first trigger the megaphone to start at a high volume, and then continue to shout at a relatively low volume. The setting of the shouting detection module is in line with the user's usage habits of using the megaphone. Usually, when using a megaphone, users have the habit of first testing whether the megaphone can work normally in the initial stage before shouting. Therefore, by setting different reference voltages, the start-up shouting detection unit and the continuous shouting detection unit can correspond to different stages of the shouting process. As a result, the megaphone can automatically turn on the shouting function while also more flexibly adapting to the user's usage habits, improving the user experience.
[0026] In some embodiments, both the start-up and continuous-speaking detection units include a filter subunit, a reference voltage subunit, and a comparator. The filter subunit's input is connected to the output of the primary power amplifier module, the filter subunit's output is connected to the comparator's non-inverting input, the reference voltage subunit is connected to the comparator's inverting input, and the comparator's output serves as the output of the start-up and continuous-speaking detection unit. The reference voltage subunit for the start-up and continuous-speaking detection units provides a first reference voltage, while the reference voltage subunit for the continuous-speaking detection units provides a second reference voltage.
[0027] Specifically, in one embodiment, the filter subunit includes a first filter resistor, a first filter capacitor, a DC blocking capacitor, and a second filter resistor, wherein the first end of the first filter capacitor is connected to the first end of the first filter resistor and the first end of the DC blocking capacitor, the first end of the second filter resistor is connected to the second end of the DC blocking capacitor and the first input terminal of the comparator, and the second end of the first filter capacitor and the second end of the second filter resistor are both grounded. It is understood that the first filter resistor and the first filter capacitor form a low-pass filter circuit, while the DC blocking capacitor and the second filter resistor form a high-pass filter circuit, thereby filtering the signal connected to the comparator.
[0028] In one embodiment, the reference voltage subunit includes a first voltage-dividing resistor, a second voltage-dividing resistor, and a second filter capacitor. The first voltage-dividing resistor and the second voltage-dividing resistor are connected in series, the second filter capacitor is connected in parallel to the second voltage-dividing resistor, the first voltage-dividing resistor is also connected to a power supply, the first end of the second voltage-dividing resistor is connected to the second input terminal of the comparator, and the second end of the second voltage-dividing resistor is grounded. It is understandable that the first voltage-dividing resistor and the second voltage-dividing resistor are connected in series to divide the voltage, and the second voltage-dividing resistor is connected to the inverting input terminal of the comparator, that is, the voltage drop across the second voltage-dividing resistor serves as the corresponding reference voltage. The second filter capacitor acts as a DC block.
[0029] Among them, the first reference voltage used by the reference voltage subunit in the start-up shouting detection unit is greater than the second reference voltage used by the reference voltage subunit in the continuous shouting detection unit, so that the sound required when the start-up shouting detection unit outputs a detection signal is higher than the sound required when the continuous shouting detection unit outputs a detection signal.
[0030] Figure 2 A schematic diagram of the circuit structure of the start-up call detection unit provided in an embodiment of the present application is shown as follows: Figure 2 As shown, the start-up shouting detection unit includes a load resistor R8, a resistor R2, a resistor R3, a resistor R6, a resistor R9, a capacitor C4, a capacitor C6, a capacitor C8 and a comparator U2A.
[0031] The two ends of load resistor R8 are connected to the output terminal and common ground of the first-stage power amplifier module, respectively. Resistor R6 acts as a filter resistor, with one end of resistor R6 connected to the positive output terminal of the first-stage power amplifier module and the other end of resistor R6 connected to one end of capacitor C8, which serves as a filter capacitor. The other end of capacitor C8 is grounded. Therefore, resistor R6 and capacitor C8 form a low-pass filter circuit. Capacitor C6 acts as a DC blocking capacitor. Resistor R6 is connected to comparator U2A via capacitor C6. That is, one end of capacitor C6 is connected to resistor R6, and the other end of capacitor C6 is connected to the non-inverting input terminal of comparator U2A. Resistor R9 acts as a filter resistor, with one end of resistor R9 connected to the non-inverting input terminal of comparator U2A and the other end of resistor R9 is grounded. Therefore, capacitor C6 and resistor R9 form a high-pass filter circuit.
[0032] Resistors R2 and R3 both act as voltage divider resistors. One end of resistor R2 is connected to the voltage provided by the power supply. Resistors R2 and R3 are connected in series, with one end of resistor R3 grounded. The end of resistor R3 connected to resistor R2 is also connected to the inverting input of comparator U2A. Therefore, through the voltage divider circuit formed by resistors R2 and R3, the inverting input of comparator U2A can be connected to a corresponding reference voltage for comparison with the electrical signal connected to its non-inverting input. Capacitor C4 acts as a filter capacitor, connected in parallel with resistor R3, to filter the voltage signal connected to the inverting input of comparator U2A.
[0033] Figure 3 This is a circuit diagram of a continuous shouting detection unit provided in an embodiment of the present application, as shown in FIG. Figure 3 As shown, the continuous shouting detection unit includes resistors R4, R5, R7, and R 10 , capacitor C5, capacitor C7, capacitor C9 and comparator U3A.
[0034] Among them, the resistor R7 is used as a filter resistor, one end of the resistor R7 is connected to the positive output terminal of the first-stage power amplifier module, and the other end of the resistor R7 is connected to one end of the capacitor C9 as a filter capacitor, and the other end of the capacitor C9 is grounded. In this regard, the resistor R7 and the capacitor C9 form a low-pass filter circuit. The capacitor C7 is used as a DC blocking capacitor. The resistor R7 is connected to the comparator U3A through the capacitor C7, that is, one end of the capacitor C7 is connected to the resistor R7, and the other end of the capacitor C7 is connected to the non-inverting input terminal of the comparator U2A, and the resistor R 10 As a filter resistor, the resistor R 10 One end is connected to the non-inverting input of comparator U3A, and the resistor R 10 The other end of the ground, the capacitor C7 and the resistor R 10 A high-pass filter circuit is formed.
[0035] Resistors R4 and R5 both act as voltage divider resistors. One end of resistor R4 is connected to the voltage provided by the power supply. Resistors R4 and R5 are connected in series, with one end of resistor R5 grounded. The end of resistor R5 connected to resistor R4 is also connected to the inverting input of comparator U3A. Therefore, through the voltage divider circuit formed by resistors R4 and R5, the inverting input of comparator U3A can be connected to a corresponding reference voltage for comparison with the electrical signal connected to its non-inverting input. Capacitor C5 acts as a filter capacitor, connected in parallel with resistor R5, to filter the voltage signal connected to the inverting input of comparator U3A.
[0036] It is conceivable that, in one embodiment, the resistance ratio of the first voltage-dividing resistor and the second voltage-dividing resistor in the reference voltage subunit corresponding to the start-up voice detection unit is a first resistance ratio, and the resistance ratio of the first voltage-dividing resistor and the second voltage-dividing resistor in the reference voltage subunit corresponding to the continuous voice detection unit is a second resistance ratio, wherein the first resistance ratio is less than the second resistance ratio. Figure 2 and Figure 3 The first resistance ratio is R2 / R3, and the second resistance ratio is R4 / R5. In this regard, when the resistors R2 and R4 have the same value, the resistance of the resistor R3 is greater than the resistance of the resistor R5.
[0037] In one embodiment, the main control module includes a microcontroller, a third voltage-dividing resistor, a third filter capacitor, a fourth filter capacitor, and a fifth filter capacitor. A start pin of the microcontroller is connected to the grounded third voltage-dividing resistor, a reset pin of the microcontroller is connected to the grounded third filter capacitor, a dedicated power pin of the microcontroller is connected to an operating voltage and to the grounded fourth filter capacitor, an internal voltage pin of the microcontroller is connected to a first end of the fifth filter capacitor, a common ground pin of the microcontroller is connected to a second end of the fifth filter capacitor, the first end of the fifth filter capacitor is connected to the operating voltage, and the second end of the fifth filter capacitor is grounded.
[0038] The microcontroller connects two GPIO pins to activate the output of the voice detection unit and the output of the continuous voice detection unit. Upon receiving a first detection signal, the microcontroller activates detection of the other GPIO pin, and upon receiving a second detection signal, outputs a control signal. In other words, the microcontroller needs to receive both the first and second detection signals before outputting a control signal to control the operation of the secondary power amplifier module. If the microcontroller only detects the second detection signal, it will not output a control signal.
[0039] Optionally, the primary power amplifier module and the secondary power amplifier module may adopt the same or different circuit structures, for example, a Class A amplifier, a Class AB amplifier, or the like.
[0040] Figure 4 A schematic diagram of the circuit structure of a voice output circuit provided in an embodiment of the present application is shown in FIG. Figure 4 As shown, the microphone 101 is connected to the resistor R 11 The power supply voltage is connected, and the input end of the first-stage power amplifier module 102 is connected to the microphone 101. The first-stage power amplifier module 102 includes a capacitor C 10 , resistor R 12 , resistor R 13 , resistor R 14 And operational amplifier OPA1. Capacitor C 10 As a DC blocking capacitor, it is used to isolate DC signals. Capacitor C 10One end is connected to the output of microphone 101, capacitor C 10 The other end is connected to the non-inverting input of the operational amplifier OPA1. 14 One end is connected to the non-inverting input of the operational amplifier OPA1, and the resistor R 14 The other end is grounded. The inverting input of the operational amplifier OPA1 is connected to the ground through the resistor R 12 grounded, and the inverting input of the operational amplifier OPA1 is connected to the 13 Connect to the output of operational amplifier OPA1.
[0041] The shouting detection module 103 includes a start-up shouting detection unit and a continuous shouting detection unit, wherein the start-up shouting detection unit includes a load resistor R8, a resistor R2, a resistor R3, a resistor R6, a resistor R9, a capacitor C4, a capacitor C6, a capacitor C8 and a comparator U2A. The continuous shouting detection unit includes a resistor R4, a resistor R5, a resistor R7, a resistor R 10 , capacitor C5, capacitor C7, capacitor C9 and comparator U3A.
[0042] Specifically, in the voice detection unit, one end of the load resistor R8 is connected to the output of the operational amplifier OPA1, and the other end of the load resistor R8 is grounded. Resistor R6 acts as a filter resistor, with one end of the resistor R6 connected to the positive output of the first-stage power amplifier module and the other end of the resistor R6 connected to one end of the capacitor C8, which serves as a filter capacitor. The other end of the capacitor C8 is grounded. Therefore, the resistor R6 and the capacitor C8 form a low-pass filter circuit. Capacitor C6 acts as a DC blocking capacitor, and the resistor R6 is connected to the comparator U2A via the capacitor C6. That is, one end of the capacitor C6 is connected to the resistor R6, and the other end of the capacitor C6 is connected to the non-inverting input of the comparator U2A. Resistor R9 acts as a filter resistor, with one end of the resistor R9 connected to the non-inverting input of the comparator U2A and the other end of the resistor R9 is grounded. Therefore, the capacitor C6 and the resistor R9 form a high-pass filter circuit.
[0043] Resistors R2 and R3 both act as voltage divider resistors. One end of resistor R2 is connected to the voltage provided by the power supply. Resistors R2 and R3 are connected in series, with one end of resistor R3 grounded. The end of resistor R3 connected to resistor R2 is also connected to the inverting input of comparator U2A. Therefore, through the voltage divider circuit formed by resistors R2 and R3, the inverting input of comparator U2A can be connected to a corresponding reference voltage for comparison with the electrical signal connected to its non-inverting input. Capacitor C4 acts as a filter capacitor, connected in parallel with resistor R3, to filter the voltage signal connected to the inverting input of comparator U2A.
[0044] In the continuous shouting detection unit, resistor R7 is used as a filter resistor. One end of resistor R7 is connected to the output of operational amplifier OPA1, and the other end of resistor R7 is connected to one end of capacitor C9 as a filter capacitor, and the other end of capacitor C9 is grounded. Therefore, resistor R7 and capacitor C9 form a low-pass filter circuit. Capacitor C7 is used as a DC blocking capacitor. Resistor R7 is connected to comparator U3A through capacitor C7, that is, one end of capacitor C7 is connected to resistor R7, and the other end of capacitor C7 is connected to the non-inverting input of comparator U2A, and resistor R 10 As a filter resistor, the resistor R 10 One end is connected to the non-inverting input of comparator U3A, and the resistor R 10 The other end of the ground, the capacitor C7 and the resistor R 10 A high-pass filter circuit is formed.
[0045] Resistors R4 and R5 both act as voltage divider resistors. One end of resistor R4 is connected to the voltage provided by the power supply. Resistors R4 and R5 are connected in series, with one end of resistor R5 grounded. The end of resistor R5 connected to resistor R4 is also connected to the inverting input of comparator U3A. Therefore, through the voltage divider circuit formed by resistors R4 and R5, the inverting input of comparator U3A can be connected to a corresponding reference voltage for comparison with the electrical signal connected to its non-inverting input. Capacitor C5 acts as a filter capacitor, connected in parallel with resistor R5, to filter the voltage signal connected to the inverting input of comparator U3A.
[0046] The main control module 104 includes a microcontroller U1, a resistor R1, a capacitor C1, a capacitor C2, and a capacitor C3. The boot pin BOOT0 of the microcontroller U1 is connected to the grounded resistor R1, which acts as a voltage divider. The reset pin NRST of the microcontroller U1 is connected to the grounded capacitor C1, which acts as a filter capacitor. The dedicated power pin VDDA of the microcontroller U1 is connected to the operating voltage and to the grounded capacitor C2, which also acts as a filter capacitor. The internal voltage pin VDD of the microcontroller U1 is connected to the first terminal of the capacitor C3, and the common ground pin VSS of the microcontroller U1 is connected to the second terminal of the capacitor C3. The first terminal of the capacitor C3 is connected to the operating voltage and the second terminal of the capacitor C3 is grounded, which also acts as a filter.
[0047] The microcontroller U1 is connected to the output end of the start-up shouting detection unit and the output end of the continuous shouting detection unit through its two GPIO pins. As shown in the figure, the microcontroller U1 is connected to the output end of the comparator U1A through its GPIO pin PA7, and the microcontroller U1 is connected to the output end of the comparator U2A through its GPIO pin PA6.
[0048] The secondary power amplifier module 105 includes a capacitor C 11 , resistor R15 , resistor R 16 , resistor R 17 And operational amplifier OPA2. Capacitor C 11 As a DC blocking capacitor, it is used to isolate DC signals. Capacitor C 11 One end is connected to the output of the operational amplifier OPA1, and the capacitor C 11 The other end is connected to the non-inverting input of the operational amplifier OPA2. 17 One end is connected to the non-inverting input of the operational amplifier OPA2, and the resistor R 17 The other end is grounded. The inverting input of the operational amplifier OPA2 is connected to the ground through the resistor R 15 Connect the GPIO pin PA5 of the microcontroller U1 and the inverting input of the operational amplifier OPA2 through the resistor R 16 The output end of the operational amplifier OPA2 is connected to the speaker 106.
[0049] In practice, when a user uses a megaphone equipped with a voice output circuit, they first trigger the megaphone at a high volume. This triggers the electrical signal amplified by the primary power amplifier module 102, which is then detected by the voice detection module. Comparator U1A outputs a corresponding first detection signal. In response, microcontroller U1 activates detection of GPIO pin PA6 upon receiving the first detection signal, and then outputs a control signal upon receiving a second detection signal. At this point, the user can continue speaking at a relatively low volume. Upon detecting the user's voice, comparator U2A outputs a corresponding second detection signal, allowing microcontroller U1 to determine receipt of the first and second detection signals and, in turn, output a control signal to activate secondary power amplifier module 105 to amplify the electrical signal and produce sound through speaker 106.
[0050] Furthermore, when the user stops speaking, microcontroller U1 stops outputting control signals, and the megaphone stops playing sound, achieving an automatic shutoff function. Therefore, the megaphone can automatically turn on and off the speaking function while also flexibly adapting to the user's usage habits, improving the user experience.
[0051] The embodiment of the present application also provides a circuit board, which includes the shouting output circuit provided by the above embodiment and has the beneficial effects of the shouting output circuit. When it is used on the corresponding device or equipment, it can provide the user with the function of automatically detecting shouting, and amplify the output at any time when shouting, which is more convenient for users to use.
[0052] An embodiment of the present application also provides a loudspeaker, which includes the circuit board of the above embodiment. The loudspeaker can have the function of automatically detecting and shouting, eliminating the need for a shouting switch, thereby being more convenient to use. For example, while driving, a bus driver can directly use the loudspeaker to speak to passengers in the car, and the loudspeaker will automatically turn off after the shouting is finished.
[0053] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.
[0054] Note that the above are only preferred embodiments of the present application and the technical principles employed. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present application. The scope of the present application is determined by the scope of the appended claims.
Claims
1. A voice output circuit, characterized in that: include: A microphone, configured to detect sound and convert it into an electrical signal; a first-stage power amplifier module, wherein the input end of the first-stage power amplifier module is connected to the output end of the microphone, and the first-stage power amplifier module is used to power amplify the electrical signal output by the microphone; A voice detection module, wherein the input end of the voice detection module is connected to the output end of the first-stage power amplifier module, and the voice detection module is used to determine whether the microphone detects sound; A main control module, wherein the detection input end of the main control module is connected to the output end of the voice detection module, and the main control module is configured to output a control signal when receiving a voice signal, wherein the voice detection module outputs the control signal after determining that the microphone has detected a sound; A secondary power amplifier module, wherein the input end of the secondary power amplifier module is connected to the output end of the primary power amplifier module, the control end of the secondary power amplifier module is connected to the control output end of the main control module, and the secondary power amplifier module is used to power amplify the electrical signal output by the primary power amplifier module after receiving the control signal; A speaker, wherein the output end of the speaker is connected to the output end of the secondary power amplifier module, and the speaker is used to convert the received electrical signal into sound and play it outward.
2. The voice output circuit according to claim 1, characterized in that: The shouting detection module includes a start-up shouting detection unit and a continuous shouting detection unit; The input end of the start-up shouting detection unit is connected to the output end of the primary power amplifier module, and the output end of the start-up shouting detection unit is connected to the first detection interface of the main control module. The start-up shouting detection unit is configured to output a first detection signal when the input voltage corresponding to the received electrical signal is greater than the first reference voltage; The input end of the continuous shouting detection unit is connected to the output end of the primary power amplifier module, and the output end of the continuous shouting detection unit is connected to the second detection interface of the main control module. The continuous shouting detection unit is configured to output a second detection signal when the input voltage corresponding to the received electrical signal is greater than the second reference voltage; The first reference voltage is greater than the second reference voltage, and the main control module is configured to start detection of the second detection interface of the main control module upon receiving the first detection signal, so as to output a control signal upon receiving the second detection signal.
3. The voice output circuit according to claim 2, characterized in that: The start-speaking detection unit and the continuous speaking detection unit both include a filtering subunit, a reference voltage subunit and a comparator; The input end of the filter subunit is connected to the output end of the first-stage power amplifier module, and the output end of the filter subunit is connected to the non-inverting input end of the comparator; the reference voltage subunit is connected to the inverting input end of the comparator, and the output end of the comparator serves as the output end of the start-up call detection unit; The reference voltage subunit corresponding to the start-speaking detection unit provides the first reference voltage, and the reference voltage subunit corresponding to the continuous-speaking detection unit provides the second reference voltage.
4. The voice output circuit according to claim 3, characterized in that: The start-up voice detection unit also includes a load resistor, a first end of the load resistor is connected to the output end of the first-level power amplifier module, a second end of the load resistor is grounded, and the load resistor is used to access the electrical signal output by the first-level power amplifier module.
5. The voice output circuit according to claim 3, characterized in that: The filter subunit includes a first filter resistor, a first filter capacitor, a DC blocking capacitor and a second filter resistor, wherein the first end of the first filter capacitor is connected to the first end of the first filter resistor and the first end of the DC blocking capacitor, the first end of the second filter resistor is connected to the second end of the DC blocking capacitor and the first input end of the comparator, and the second end of the first filter capacitor and the second end of the second filter resistor are both grounded.
6. The voice output circuit according to any one of claims 3 to 5, characterized in that: The reference voltage subunit includes a first voltage-dividing resistor, a second voltage-dividing resistor and a second filter capacitor, the first voltage-dividing resistor and the second voltage-dividing resistor are connected in series, the second filter capacitor is connected in parallel to the second voltage-dividing resistor, the first voltage-dividing resistor is also connected to a power supply, the first end of the second voltage-dividing resistor is connected to the second input end of the comparator, and the second end of the second voltage-dividing resistor is grounded.
7. The voice output circuit according to claim 6, characterized in that: The ratio of the resistance values of the first voltage-dividing resistor and the second voltage-dividing resistor in the reference voltage subunit corresponding to the start-speaking detection unit is a first resistance ratio, and the ratio of the resistance values of the first voltage-dividing resistor and the second voltage-dividing resistor in the reference voltage subunit corresponding to the continuous speaking detection unit is a second resistance ratio, wherein the first resistance ratio is less than the second resistance ratio.
8. The voice output circuit according to claim 1, characterized in that: The main control module includes a microcontroller, a third voltage-dividing resistor, a third filter capacitor, a fourth filter capacitor and a fifth filter capacitor; The start pin of the microcontroller is connected to the grounded third voltage-dividing resistor, the reset pin of the microcontroller is connected to the grounded third filter capacitor, the dedicated power pin of the microcontroller is connected to the operating voltage and connected to the grounded fourth filter capacitor, the internal voltage pin of the microcontroller is connected to the first end of the fifth filter capacitor, the common ground pin of the microcontroller is connected to the second end of the fifth filter capacitor, the first end of the fifth filter capacitor is connected to the operating voltage, and the second end of the fifth filter capacitor is grounded.
9. A circuit board, characterized in that: The invention comprises the shouting output circuit as described in any one of claims 1 to 8.
10. A megaphone, characterized in that: Comprising the circuit board as claimed in claim 9.