A power amplifier and audio broadcast system

Abstract

The utility model discloses a kind of power amplifier and audio broadcast system, wherein, the power amplifier includes master control module, local audio module, impact sound elimination module, priority control module and fixed voltage power amplifier module;The first output end of the local audio module is connected to the master control module, and the second output end and the third output end of the local audio module are connected to the first input end of the priority control module;The input end of the impact sound elimination module is connected to the master control module, and the output end of the impact sound elimination module is connected to the second input end of the priority control module;The output end of the priority control module is connected to the fixed voltage power amplifier module.The power amplifier can inhibit the impact sound generated by power amplifier equipment in power-on, power-off moment.The utility model relates to the technical field of electronic circuit.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a power amplifier and an audio broadcasting system. Background Technology

[0002] Impact sound refers to the popping sound produced by the transient impact of audio devices (mainly audio power amplifiers) at the moment of power-on and power-off.

[0003] Currently, constant voltage power amplifiers in related technologies are usually pure power amplifiers, which directly amplify the audio input signal and output it to the audio speaker for audio broadcasting. This method is prone to producing impact noise when the power amplifier is powered on and off.

[0004] Therefore, the problems with the relevant technologies still need to be solved and optimized. Utility Model Content

[0005] The purpose of this utility model is to solve, to a certain extent, the technical problems existing in the related technologies.

[0006] Therefore, one objective of this utility model is to provide a power amplifier and an audio broadcasting system, wherein the power amplifier can suppress the impact noise generated by the power amplifier device at the moment of power-on and power-off.

[0007] To achieve the above-mentioned technical objectives, on the one hand, this utility model embodiment provides a power amplifier, including: a main control module, a local audio module, an impact sound cancellation module, a priority control module, and a constant voltage power amplifier module; The first output terminal of the local audio module is connected to the main control module, and the second and third output terminals of the local audio module are connected to the first input terminal of the priority control module. The input terminal of the impact noise cancellation module is connected to the main control module, and the output terminal of the impact noise cancellation module is connected to the second input terminal of the priority control module. The output of the priority control module is connected to the constant voltage power amplifier module.

[0008] In addition, a power amplifier according to an embodiment of the present invention may also have the following additional technical features: Optionally, in one embodiment of the present invention, the local audio module includes a first audio input unit and a second audio input unit; The input terminal of the first audio input unit is connected to a local input audio source, the first output terminal of the first audio input unit is connected to the input terminal of the second audio input unit, and the second output terminal of the first audio input unit is connected to the first input terminal of the priority control module. The first output terminal of the second audio input unit is connected to the main control module, and the second output terminal of the second audio input unit is connected to the first input terminal of the priority control module.

[0009] Optionally, in one embodiment of the present invention, the impact sound cancellation module includes a power detection unit, a first noise control unit, and a second noise control unit; The power detection unit is connected to the first mute control unit and the second mute control unit respectively; The input terminal of the first mute control unit is connected to the main control module, and the output terminal of the first mute control unit is connected to the second input terminal of the priority control module. The input terminal of the second mute control unit is connected to the main control module, and the output terminal of the second mute control unit is connected to the second input terminal of the priority control module.

[0010] Optionally, in one embodiment of the present invention, the power detection unit includes a first resistor, a second resistor, a third resistor, a first capacitor, a second capacitor, a first diode, a second diode, and a first transistor; One end of the first resistor is connected to the power supply of the power amplifier, the other end of the first resistor is connected to the positive terminal of the first diode, the negative terminal of the first diode is connected to the emitter of the first transistor, and the emitter of the first transistor is connected to ground through the first capacitor. One end of the second resistor is connected to the other end of the first resistor, and the other end of the second resistor is connected to the base of the first transistor via the third resistor. The cathode of the second diode is connected to the other end of the first resistor, and the anode of the second diode is connected to the other end of the second resistor. One end of the second capacitor is connected to the other end of the second resistor, and the other end of the second capacitor is connected to ground.

[0011] Optionally, in one embodiment of the present invention, the first silent control unit includes a third diode, a second transistor, and a fourth resistor; The positive terminal of the third diode is connected to the main control module, the negative terminal of the third diode is connected to the collector of the second transistor, the base of the second transistor is connected to the power detection unit via the fourth resistor, and the emitter of the second transistor is connected to ground.

[0012] Optionally, in one embodiment of the present invention, the second silent control unit includes a fourth diode, a third transistor, a fifth resistor, and a sixth resistor; The positive terminal of the fourth diode is connected to the main control module, the negative terminal of the fourth diode is connected to the collector of the third transistor, the base of the third transistor is connected to the power detection unit via the fifth resistor, and the emitter of the third transistor is connected to ground. One end of the sixth resistor is connected to the power detection unit, and the other end of the sixth resistor is connected to the emitter of the third transistor.

[0013] Optionally, in one embodiment of the present invention, the priority control module includes an input control unit and a signal amplification unit; The first input terminal of the input control unit is connected to the second and third output terminals of the local audio module, and the second input terminal of the input control unit is connected to the output terminal of the impact sound cancellation module. The output terminal of the input control unit is connected to the input terminal of the signal amplification unit, and the output terminal of the signal amplification unit is connected to the constant voltage power amplifier module.

[0014] Optionally, in one embodiment of the present invention, the main control module includes a control chip and a network interface, wherein the network interface is connected to the control chip.

[0015] Optionally, in one embodiment of the present invention, the constant voltage power amplifier module includes a power amplifier chip and a transformer unit, wherein the power amplifier chip is connected to the transformer unit.

[0016] On the other hand, this utility model embodiment provides an audio broadcasting system, including a host server, a speaker module, and the aforementioned power amplifier; The host server is communicatively connected to the main control module in the power amplifier, and the speaker module is connected to the constant voltage power amplifier module in the power amplifier.

[0017] The advantages and beneficial effects of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention: This application discloses a power amplifier and audio broadcasting system. The power amplifier includes a main control module, a local audio module, an impact noise cancellation module, a priority control module, and a constant voltage power amplifier module. The first output terminal of the local audio module is connected to the main control module, and the second and third output terminals of the local audio module are connected to the first input terminal of the priority control module. The input terminal of the impact noise cancellation module is connected to the main control module, and the output terminal of the impact noise cancellation module is connected to the second input terminal of the priority control module. The output terminal of the priority control module is connected to the constant voltage power amplifier module. This power amplifier uses the impact noise cancellation module to detect power-on and power-off moments and inputs the detection signal to the priority control module for mute control, which can suppress the impact noise generated by the power amplifier device at the moment of power-on and power-off. Attached Figure Description

[0018] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0019] Figure 1 A schematic diagram of the frame of a power amplifier provided for one embodiment of the present invention; Figure 2 A circuit diagram of a second audio input unit in a local audio module provided as an embodiment of the present invention; Figure 3 A circuit schematic diagram of a first audio input unit in a local audio module provided as an embodiment of the present invention; Figure 4 A circuit diagram of an impact sound cancellation module provided for one embodiment of the present invention; Figure 5 A circuit diagram of an input control unit in a priority control module provided as an embodiment of the present invention; Figure 6 A circuit diagram of a signal amplification unit in a priority control module provided as an embodiment of the present invention; Figure 7 This is a circuit diagram of a constant voltage power amplifier module provided for one embodiment of the present invention. Detailed Implementation

[0020] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0021] In the description of this utility model, it should be understood that the terms "length," "upper," "lower," "front," "rear," "left," "right," "top," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0022] Currently, constant voltage power amplifiers in related technologies are usually pure power amplifiers, which directly amplify the audio input signal and output it to the audio speaker for audio broadcasting. This method is prone to producing knocking noise when the power amplifier is powered on and off. Furthermore, when the power amplifier has local audio signal input and network audio signal input, it cannot selectively amplify the local audio signal and / or network audio signal based on the priority of the local audio signal and network audio signal for audio broadcasting, resulting in poor flexibility in audio amplification and broadcasting.

[0023] It should be noted that the aforementioned related technologies are only used to assist in understanding the technical solutions of this application and do not mean that they belong to the publicly disclosed prior art.

[0024] In view of this, the present invention provides a power amplifier and an audio broadcasting system. The power amplifier uses an impact noise cancellation module to detect the instantaneous power-on and power-off noises and inputs the detection signal to a priority control module for mute control, which can suppress the impact noise generated by the power amplifier during power-on and power-off. Furthermore, the power amplifier uses the priority control module to preferentially amplify the network audio signal and / or local audio signal output from the local audio module for audio broadcasting, effectively improving the flexibility of audio amplification and broadcasting.

[0025] Reference Figure 1 Specifically, a power amplifier in this application embodiment includes: a main control module, a local audio module, an impact noise cancellation module, a priority control module, and a constant voltage power amplifier module; The first output terminal of the local audio module is connected to the main control module, and the second and third output terminals of the local audio module are connected to the first input terminal of the priority control module. The input terminal of the impact noise cancellation module is connected to the main control module, and the output terminal of the impact noise cancellation module is connected to the second input terminal of the priority control module. The output of the priority control module is connected to the constant voltage power amplifier module.

[0026] Reference Figure 2 and Figure 3 In some embodiments, the local audio module includes a first audio input unit and a second audio input unit; The input terminal of the first audio input unit is connected to a local input audio source, the first output terminal of the first audio input unit is connected to the input terminal of the second audio input unit, and the second output terminal of the first audio input unit is connected to the first input terminal of the priority control module. The first output terminal of the second audio input unit is connected to the main control module, and the second output terminal of the second audio input unit is connected to the first input terminal of the priority control module.

[0027] Reference Figure 4 In some embodiments, the impact sound cancellation module includes a power detection unit 301, a first noise control unit 303, and a second noise control unit 302; The power detection unit 301 is connected to the first mute control unit 303 and the second mute control unit 302 respectively; The input terminal of the first mute control unit 303 is connected to the main control module, and the output terminal of the first mute control unit 303 is connected to the second input terminal of the priority control module. The input terminal of the second mute control unit 302 is connected to the main control module, and the output terminal of the second mute control unit 302 is connected to the second input terminal of the priority control module.

[0028] In some embodiments, the power detection unit 301 includes a first resistor R5, a second resistor R10, a third resistor R11, a first capacitor E1, a second capacitor E2, a first diode D2, a second diode D3, and a first transistor Q1; One end of the first resistor R5 is connected to the power supply of the power amplifier, and the other end of the first resistor R5 is connected to the positive terminal of the first diode D2. The negative terminal of the first diode D2 is connected to the emitter of the first transistor Q1, and the emitter of the first transistor Q1 is connected to the ground terminal through the first capacitor E1. One end of the second resistor R10 is connected to the other end of the first resistor R5, and the other end of the second resistor R10 is connected to the base of the first transistor Q1 via the third resistor R11. The cathode of the second diode D3 is connected to the other end of the first resistor R5, and the anode of the second diode D3 is connected to the other end of the second resistor R10. One end of the second capacitor E2 is connected to the other end of the second resistor R10, and the other end of the second capacitor E2 is connected to ground.

[0029] In some embodiments, the first mute control unit 303 includes a third diode D1, a second transistor Q1, and a fourth resistor R7; The positive terminal of the third diode D1 is connected to the main control module, the negative terminal of the third diode D1 is connected to the collector of the second transistor Q1, the base of the second transistor Q1 is connected to the power detection unit 301 via the fourth resistor R7, and the emitter of the second transistor Q1 is connected to ground.

[0030] In some embodiments, the second mute control unit 302 includes a fourth diode D6, a third transistor Q3, a fifth resistor R42, and a sixth resistor R23; The positive terminal of the fourth diode D6 is connected to the main control module, the negative terminal of the fourth diode D6 is connected to the collector of the third transistor Q3, the base of the third transistor Q3 is connected to the power detection unit 301 via the fifth resistor R42, and the emitter of the third transistor Q3 is connected to ground. One end of the sixth resistor R23 is connected to the power detection unit 301, and the other end of the sixth resistor R23 is connected to the emitter of the third transistor Q3.

[0031] Reference Figure 5 and Figure 6 In some embodiments, the priority control module includes an input control unit and a signal amplification unit; The first input terminal of the input control unit is connected to the second and third output terminals of the local audio module, and the second input terminal of the input control unit is connected to the output terminal of the impact sound cancellation module. The output terminal of the input control unit is connected to the input terminal of the signal amplification unit, and the output terminal of the signal amplification unit is connected to the constant voltage power amplifier module.

[0032] Reference Figure 7 In some embodiments, the constant voltage power amplifier module includes a power amplifier chip and a transformer unit, with the power amplifier chip connected to the transformer unit.

[0033] This application provides an audio broadcasting system, including a host server, a speaker module, and the power amplifier described above; The host server is communicatively connected to the main control module in the power amplifier, and the speaker module is connected to the constant voltage power amplifier module in the power amplifier.

[0034] The power amplifier and audio broadcasting system provided in this application will be described in detail below with a specific embodiment: To address the aforementioned deficiencies in the prior art, this application provides a power amplifier. The power amplifier is configured as follows: Figure 1 As shown, it includes: a main control module, a local audio module, an impact noise cancellation module, a priority control module, and a constant voltage power amplifier module; while the audio broadcasting system includes a host server and a speaker module connected to the power amplifier.

[0035] The working principle of this power amplifier and audio broadcasting system is as follows: For network audio signals, the control chip in the main control module (such as an ARM Cortex-A7 core chip) receives the network audio digital signal from the host server through the network cable interface. After being decoded into a network audio analog signal by the control chip, it is amplified by the local audio module, priority control module, and constant voltage power amplifier module before being input to the speaker module (such as a loudspeaker) for network audio broadcasting. For local audio signals, the local audio module amplifies the local audio signal through the priority control module and constant voltage power amplifier module before being input to the speaker module (such as a loudspeaker) for local audio broadcasting.

[0036] Meanwhile, the impact noise cancellation module detects whether the power amplifier is powered on or off. When the power amplifier is powered on or off, the priority control module outputs a mute control signal to the constant voltage power amplifier module to suppress and eliminate the impact noise. During normal operation of the power amplifier, the priority control module selectively outputs network audio signals and / or local audio signals based on the priority control signal provided by the control chip.

[0037] This application embodiment uses a control chip that uses three GPIOs: AUX_IN_IO1 for detecting whether there is local input audio, DAC_MUTE_EN for controlling the mute of the network decoded output audio, AUX_MUTE_EN for controlling the mute of local input audio, and an RJ45 network interface for connecting to the host server. A preferred embodiment of the power amplifier is as follows: Reference Figure 2 and Figure 3The local input audio source, AUX_IN, is input from jack P1. After passing through C18, C19, R15, and R16, it enters the first pin of operational amplifier U2 (such as the SGM8904 chip) for primary amplification. Then, it splits into two paths. One path outputs from the second pin of operational amplifier U2, passes through C1 and R1, enters operational amplifier U1 for secondary amplification, and then passes through C8, D4, D5, R14, R18, C21, R22, and R24, triggering transistors Q4 and Q5 to conduct, pulling AUX_IN_IO1 low and informing the control chip of a local signal input. The other path outputs from the second pin of operational amplifier U2, after adjusting the amplification factor through adjustable resistor RP1, and enters the tenth pin of operational amplifier U2. After amplification by operational amplifier U2, it is output from the ninth pin of operational amplifier U2 to obtain the AUX_In local audio source signal. Adjusting the amplification factor allows for adjustment of the sensitivity of the local input signal, enabling the connection of preamplifier input signals with different sensitivities. Meanwhile, the local audio module receives the network audio signal decoded and output by the control chip. This network audio signal passes through C2, C3, R2, and R3 and is then preamplified by operational amplifier U1 to obtain the signal DAC_IN.

[0038] Reference Figure 4 When the device is powered on, a +24V power input is available. Due to the charging circuit consisting of R10 and E2, the base of Q2 remains low, keeping transistor Q2 continuously conducting. The power supply voltage then passes through D2 and Q2, triggering transistors Q1 and Q3 to conduct, causing the mute control pin (the collectors of transistors Q1 and Q3) to go low. This results in the device (e.g., a power amplifier) ​​outputting a mute signal upon power-up. When the device loses power, the presence of D3 causes E2 to discharge relatively quickly, while the unidirectional conductivity of D2 slows down the discharge of capacitor E1. Therefore, when power is lost, the base of transistor Q2 is quickly pulled low. Since capacitor E1 still has charge, it conducts through Q2, outputting a high level to Q1 and Q3, causing the mute control pin to go low, thus outputting a mute signal when the device loses power. This reduces the impact noise when the device loses power. The AUX_MUTE_EN and DAC_MUTE_EN signals are mute control signals output by the control chip. They are used to control the priority of local audio source output. For example, when the control chip receives the AUX_IN_IO1 signal, it can provide the AUX_MUTE_EN signal but not the DAC_MUTE_EN signal, so that the local audio source signal is output and played first.

[0039] Reference Figure 5 and Figure 6The preamplified local audio signal AUX_IN and the network-decoded audio signal DAC_IN enter the first and third pins of the U3 chip (such as the SGM4808 chip, which is used to reduce or eliminate clicking and impact sounds caused by various factors such as switching action, signal interference, power instability, etc.) of the priority control module input control unit. After the impact sound is removed by the U3 chip, it is output from the eleventh and twelfth pins.

[0040] Figure 4 The AUX_MUTE and DAC_MUTE signals are input to... Figure 5 Pins 14 and 15 of the U3 chip are used to control the U3 chip to process network audio signals (DAC) or local audio signals (AUX), and then output the processed signals to the subsequent signal amplification unit to achieve playback priority control.

[0041] The audio signal output from chip U3 passes through C22, C24, R32, and R29, then enters the U4 operational amplifier (such as the SGM8904 chip) from the first pin of U4 for amplification. After amplification, the AUX_AMP audio signal is output from the second pin of U4 via interface P3 to the constant-voltage power amplifier module for further amplification. Additionally, the audio signal output from chip U3 passes through C23, C25, R30, and R31, then enters the U4 operational amplifier from the tenth pin for amplification. Finally, the AUX_OUT audio signal is output from the ninth pin of U4 via interface P2 to other lines, which can be a combination of another speaker module and its connected constant-voltage power amplifier module.

[0042] Reference Figure 7 The power amplifier chip IC1 can be a TPA3255 chip. Figure 7 The AUX_AMP audio signal passes through C80 and R80 and then enters the operational amplifier U1A for preamplification. After that, it enters the power amplifier TPA3255 for power amplification. The output audio signal is then stepped up by transformer T1 (i.e., transformer unit) and input to the speaker module for audio broadcasting.

[0043] It is worth mentioning that this power amplifier does not involve any software improvements; the software aspects can be easily derived from existing technology.

[0044] In the description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0045] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A power amplifier, characterized in that, It includes a main control module, a local audio module, an impact noise cancellation module, a priority control module, and a constant voltage power amplifier module; The first output terminal of the local audio module is connected to the main control module, and the second and third output terminals of the local audio module are connected to the first input terminal of the priority control module. The input terminal of the impact noise cancellation module is connected to the main control module, and the output terminal of the impact noise cancellation module is connected to the second input terminal of the priority control module. The output of the priority control module is connected to the constant voltage power amplifier module.

2. The power amplifier according to claim 1, characterized in that, The local audio module includes a first audio input unit and a second audio input unit; The input terminal of the first audio input unit is connected to a local input audio source, the first output terminal of the first audio input unit is connected to the input terminal of the second audio input unit, and the second output terminal of the first audio input unit is connected to the first input terminal of the priority control module. The first output terminal of the second audio input unit is connected to the main control module, and the second output terminal of the second audio input unit is connected to the first input terminal of the priority control module.

3. The power amplifier according to claim 2, characterized in that, The impact noise cancellation module includes a power detection unit, a first noise control unit, and a second noise control unit. The power detection unit is connected to the first mute control unit and the second mute control unit respectively; The input terminal of the first mute control unit is connected to the main control module, and the output terminal of the first mute control unit is connected to the second input terminal of the priority control module. The input terminal of the second mute control unit is connected to the main control module, and the output terminal of the second mute control unit is connected to the second input terminal of the priority control module.

4. The power amplifier according to claim 3, characterized in that, The power detection unit includes a first resistor, a second resistor, a third resistor, a first capacitor, a second capacitor, a first diode, a second diode, and a first transistor; One end of the first resistor is connected to the power supply of the power amplifier, the other end of the first resistor is connected to the positive terminal of the first diode, the negative terminal of the first diode is connected to the emitter of the first transistor, and the emitter of the first transistor is connected to ground through the first capacitor. One end of the second resistor is connected to the other end of the first resistor, and the other end of the second resistor is connected to the base of the first transistor via the third resistor. The cathode of the second diode is connected to the other end of the first resistor, and the anode of the second diode is connected to the other end of the second resistor. One end of the second capacitor is connected to the other end of the second resistor, and the other end of the second capacitor is connected to ground.

5. The power amplifier according to claim 3, characterized in that, The first noise control unit includes a third diode, a second transistor, and a fourth resistor; The positive terminal of the third diode is connected to the main control module, the negative terminal of the third diode is connected to the collector of the second transistor, the base of the second transistor is connected to the power detection unit via the fourth resistor, and the emitter of the second transistor is connected to ground.

6. The power amplifier according to claim 3, characterized in that, The second noise control unit includes a fourth diode, a third transistor, a fifth resistor, and a sixth resistor; The positive terminal of the fourth diode is connected to the main control module, the negative terminal of the fourth diode is connected to the collector of the third transistor, the base of the third transistor is connected to the power detection unit via the fifth resistor, and the emitter of the third transistor is connected to ground. One end of the sixth resistor is connected to the power detection unit, and the other end of the sixth resistor is connected to the emitter of the third transistor.

7. The power amplifier according to claim 1, characterized in that, The priority control module includes an input control unit and a signal amplification unit; The first input terminal of the input control unit is connected to the second and third output terminals of the local audio module, and the second input terminal of the input control unit is connected to the output terminal of the impact sound cancellation module. The output terminal of the input control unit is connected to the input terminal of the signal amplification unit, and the output terminal of the signal amplification unit is connected to the constant voltage power amplifier module.

8. The power amplifier according to claim 1, characterized in that, The main control module includes a control chip and a network interface, and the network interface is connected to the control chip.

9. The power amplifier according to claim 1, characterized in that, The constant voltage power amplifier module includes a power amplifier chip and a transformer unit, with the power amplifier chip connected to the transformer unit.

10. An audio broadcasting system, characterized in that, Includes a host server, a speaker module, and a power amplifier as described in any one of claims 1-9; The host server is communicatively connected to the main control module in the power amplifier, and the speaker module is connected to the constant voltage power amplifier module in the power amplifier.

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