A Class D ultrasonic power amplifier and underwater acoustic transmitter

Abstract

The present application provides a Class D ultrasonic power amplifier and underwater acoustic transmitter, wherein the Class D ultrasonic power amplifier includes: an audio power amplifier unit, which modulates and amplifies the fundamental wave signal and outputs a pulse width modulated signal (PWM); a module for compatible design of ultrasonic power amplifier and audio power amplifier, which performs low-pass filtering on the pulse width modulated signal (PWM) while meeting the requirements of load matching and impedance transformation; a compatible control module, which is used to control whether the module for compatible design of ultrasonic power amplifier and audio power amplifier is working; and a transformer, which performs signal processing including low-pass filtering and voltage conversion on the pulse width modulated signal (PWM) while meeting the requirements of load matching and impedance transformation. The present application uses a transformer to replace the traditional "low-pass filter + matching component + transformer" structure mode, which has a simple structure. Through the design of the module for compatible design of ultrasonic power amplifier and audio power amplifier, the circuit has the characteristics of compatibility with audio power amplifier and ultrasonic power amplifier.

Description

Technical Field

[0001] The present application relates to the field of underwater acoustic technology, and in particular to a Class D ultrasonic power amplifier and an underwater acoustic transmitter. Background Art

[0002] Communication technologies typically use radio waves, light waves, and sound waves as carriers. The advantages of radio and light waves are their high frequency, large information capacity, and high transmission efficiency. However, their disadvantage is significant energy loss during transmission in water. Research has found that electromagnetic waves of different frequencies experience varying losses underwater, with blue-green light experiencing the least loss. Even with increasing laser power, the current maximum transmission distance of blue-green light is only a little over 100 meters. Sound waves are the only known carrier capable of long-distance underwater communication. They are also subject to transmission loss: higher sound frequencies increase transmission loss. Therefore, increasing bandwidth requires either reducing transmission distance or increasing power. Sound waves with frequencies below 20 Hz are considered infrasound, those above 20 kHz are considered ultrasonic, and those between 20 Hz and 20 kHz are audible to humans. However, as long as the required bandwidth is below megahertz, using sound waves for communication still offers significant advantages.

[0003] Class D power amplifiers are highly efficient and digital circuits, making them easy to integrate. This highly efficient class D power amplifier can be incorporated into acoustic communication. The switching transistors, driver circuits, and protection circuits are integrated on a single chip, significantly reducing the size of the amplifier. Class D power amplifier technology is now mature, and power outputs can reach hundreds of watts. Therefore, using audio amplifiers to amplify ultrasonic power is both highly compatible and practical. However, most Class D power amplifiers are designed for audio (audible sound waves) and cannot be directly used in ultrasonic communication transmitters.

[0004] Conventional integrated audio amplifiers offer mature technology and widespread application. They are convenient and durable, requiring minimal development time for underwater acoustic transmitters. However, direct use of these amplifiers for ultrasonic communication transmitters can lead to severe waveform distortion and poor signal quality. This is fundamentally due to the fact that the audio amplifier's low-pass filter is designed for the audio frequency band, typically with a center frequency of 10 kHz. Consequently, waveform distortion occurs when used for secondary wave or ultrasonic transmission. Reusing existing audio amplifier chips requires targeted modifications and design of the entire underwater acoustic transmitter's amplifier.

[0005] Figure 1 This is a system block diagram of an underwater acoustic transmitter, such as Figure 1As shown, current underwater acoustic transmitters primarily include: a signal generator, an audio power amplifier unit, a low-pass filter, matching components, a transformer, and a transducer. To improve efficiency, existing Class D power amplifiers in the audio field typically filter the output signal of the Class D power amplifier with a low-pass filter to obtain a fundamental signal. This electrical signal is then converted into an acoustic signal through matching and impedance transformation. Furthermore, the load of current underwater acoustic transmitters is the transducer, which is often a capacitive load. Therefore, when driving the transducer, the power amplifier typically uses inductive matching components to offset the capacitive component of the transducer load. Furthermore, the impedance of the load may not necessarily meet the matching impedance requirements of the power amplifier, necessitating a transformer to transform the transducer impedance so that the amplifier can drive the load at maximum power.

[0006] based on Figure 1 The modified underwater acoustic transmitter also includes a "low-pass filter + matching components + transformer" structure between the audio amplifier unit and the load transducer. The low-pass filter typically uses an LC filter circuit. The design of a low-pass filter often requires consideration of the size and material of capacitors and inductors, requiring continuous testing and verification to ultimately design a low-pass filter for the appropriate frequency band. While audio amplifier design technology is mature, suitable capacitors and inductors can often be found online. However, ultrasound amplifier reference designs are relatively scarce, often requiring this repetitive testing and verification. This design is very complex, has low compatibility, and is highly limited. Summary of the Invention

[0007] The purpose of this application is to solve the defects of the prior art.

[0008] The present application provides a Class D ultrasonic power amplifier and underwater acoustic transmitter, which improves the traditional "low-pass filter + matching components + transformer" structural model and designs compatibility between the functions of the audio power amplifier and the ultrasonic power amplifier.

[0009] In the first aspect, the present application provides a Class D ultrasonic power amplifier, which includes: an audio power amplifier unit, which is used to modulate and power amplify the input fundamental signal to obtain a pulse width modulated signal (PWM); an ultrasonic power amplifier and audio power amplifier compatible design module, which is used to low-pass filter the pulse width modulated signal (PWM) while meeting the load matching and impedance transformation requirements; a compatible control module, when the compatible control module is in the disconnected state, the ultrasonic power amplifier and audio power amplifier compatible design module does not work due to the open circuit, and when the compatible control module is in the on state, the ultrasonic power amplifier and audio power amplifier compatible design module is in the working state; a transformer, which is used to filter the pulse width modulated signal The signal is processed by a PWM circuit, including low-pass filtering and voltage conversion, to obtain an amplified fundamental wave signal, and the transformer ratio and the number of winding turns of the transformer are changed to meet the matching and impedance conversion requirements of the load; wherein, when the input fundamental wave signal is an ultrasonic signal, the compatible control module is in a disconnected state, the ultrasonic power amplifier and audio power amplifier compatible design module does not work due to the open circuit, and the transformer plays the role of low-pass filtering, voltage conversion, matching and impedance conversion; when the input fundamental wave signal is an audio signal, the compatible control module is in a conducting state, the ultrasonic power amplifier and audio power amplifier compatible design module is in an operating state, and plays the role of low-pass filtering, matching and impedance conversion, and the transformer only plays the role of voltage conversion.

[0010] In a feasible embodiment, the class D ultrasonic power amplifier further includes: a differential processing unit for performing differential processing on the fundamental wave signal to obtain a fundamental wave differential signal, and the fundamental wave differential signal is used as an input signal of the audio power amplifier unit.

[0011] In a feasible embodiment, the differential processing unit includes: at least one DC blocking circuit and at least one operational amplifier.

[0012] In a feasible embodiment, the operational amplifier includes: an operational amplifier chip with overvoltage protection capability, such as NE5532, which can prevent the input voltage from being too large.

[0013] In a feasible embodiment, the audio power amplifier unit includes: an integrated audio amplifier unit, or a non-integrated audio amplifier unit.

[0014] In a feasible embodiment, the transformer further includes: a transformer whose primary turns meet the requirement of preventing core saturation and whose primary-secondary transformation ratio is less than 1.

[0015] In a feasible embodiment, the ultrasonic power amplifier and audio power amplifier compatible design module includes: an LC filter circuit for low-pass filtering the pulse width modulation (PWM) signal for modulation and power amplification, the LC filter circuit including an LC filter inductor and / or an LC filter capacitor; matching components for matching and impedance transformation between the Class D ultrasonic power amplifier and the load.

[0016] In a feasible embodiment, the class D ultrasonic power amplifier further includes: a power supply system, and the design parameters of the power supply system are determined according to specific parameters of the selected circuit, chip, power amplifier, etc.

[0017] In a second aspect, the present application provides an underwater acoustic transmitter, which includes: a signal generating device for generating a signal in a certain form; a Class D ultrasonic power amplifier for generating an amplified fundamental wave signal using the signal in a certain form as an input signal; and a transducer for converting the amplified fundamental wave signal into an acoustic signal and radiating it into a medium.

[0018] This application is based on the fact that the transformer itself is an inductive component and has filtering capabilities. By reasonably designing the transformer's transformation ratio and number of winding turns, the transformer is used to replace the traditional "low-pass filter + matching components + transformer" structure mode, and it is also compatible with audio power amplifiers and ultrasonic power amplifiers.

[0019] This application provides a Class D ultrasonic power amplifier, comprising a differential processing unit, an audio power amplifier unit, a design module compatible with both ultrasonic and audio power amplifiers, and a transformer. This application uses a transformer to replace the traditional "low-pass filter + inductive matching component + transformer" structure, resulting in a simple structure. Furthermore, the design module compatible with both ultrasonic and audio power amplifiers allows for compatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A system block diagram of an underwater acoustic transmitter as background technology of this application;

[0021] Figure 2 This is a schematic diagram of the design principle of a Class D ultrasonic power amplifier according to an embodiment of the present application;

[0022] Figure 3 This is a schematic diagram showing the design principle of a Class D ultrasonic power amplifier that is compatible with both an ultrasonic power amplifier and an audio power amplifier according to an embodiment of the present application;

[0023] Figure 4 This is a system block diagram of an underwater acoustic transmitter according to an embodiment of the present application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of this application more clear, the present application is further described in detail below in conjunction with the accompanying drawings and examples. Obviously, the described embodiments are part of the embodiments of this application, rather than all of the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application.

[0025] In order to make the public have a better understanding of this application, some specific details are described in detail in the detailed description of this application below. Those skilled in the art can also fully understand this application without the description of these details.

[0026] The present application provides a class D ultrasonic power amplifier, comprising:

[0027] The audio power amplifier unit is used to modulate and amplify the input fundamental wave signal to obtain a pulse width modulation signal (PWM);

[0028] An ultrasonic power amplifier and audio power amplifier compatible design module, used to perform low-pass filtering on the pulse width modulation (PWM) signal while meeting the requirements of load matching and impedance transformation;

[0029] A compatible control module, wherein when the compatible control module is in an off state, the ultrasonic power amplifier and audio power amplifier compatible design module does not work due to a broken circuit; when the compatible control module is in an on state, the ultrasonic power amplifier and audio power amplifier compatible design module is in an operating state;

[0030] A transformer for performing signal processing on the pulse width modulated (PWM) signal, including low-pass filtering and voltage conversion, to obtain an amplified fundamental signal, and for meeting load matching and impedance transformation requirements by changing the transformer's transformation ratio and number of turns;

[0031] Among them, when the input fundamental wave signal is an ultrasonic signal, the compatible control module is in a disconnected state, the ultrasonic power amplifier and audio power amplifier compatible design module does not work due to the open circuit, and the transformer plays the role of low-pass filtering, voltage conversion, matching and impedance conversion. When the input fundamental wave signal is an audio signal, the compatible control module is in a conductive state, the ultrasonic power amplifier and audio power amplifier compatible design module is in a working state, and plays the role of low-pass filtering, matching and impedance conversion, and the transformer only plays the role of voltage conversion.

[0032] Example 1

[0033] Figure 2This is a block diagram of a Class D ultrasonic power amplifier according to an embodiment of the present application.

[0034] like Figure 2 The differential processing unit is further described as shown in FIG. Differential processing is required for the input signal. The specific implementation method is as follows: the input fundamental signal is a single-ended signal, a DC blocking circuit is used to remove the DC from the single-ended signal, and an operational amplifier is used to obtain the differential signal and perform preliminary amplification. The operational amplifier uses an operational amplifier chip with overvoltage protection, such as the NE5532, to prevent excessive input voltage.

[0035] like Figure 2 As shown, the audio power amplifier unit is further described. The audio power amplifier unit can be an integrated audio amplifier unit or a non-integrated audio amplifier unit. Due to the simple structure of the integrated audio amplifier unit, this application adopts the integrated audio amplifier unit. The differential signal is input to the input end of the integrated audio amplifier unit chip, and a reasonable configuration and design are performed to output a pulse width modulation signal (PWM) for power amplification.

[0036] like Figure 2 The transformer is further described in the figure. A pulse-width modulated (PWM) signal, modulated and amplified, is input into the transformer. The transformer design requires a sufficient number of primary turns to prevent core saturation, and the primary-to-secondary ratio should be less than 1. The output from the transformer is an amplified fundamental differential signal in the ultrasonic frequency range (ultrasonic frequency range: Generally, audio amplifier carrier frequencies are generated using hardware and are several megahertz, so the fundamental (ultrasonic) signal frequency is 60 kHz to 120 kHz).

[0037] like Figure 2 As shown, the embodiment of the present application also includes a power supply system. The design of the power supply system should be based on specific parameters such as the selected circuit and chip and the required amplification factor.

[0038] The ultrasonic power amplifier and audio power amplifier compatible design module of this embodiment achieves compatibility with both ultrasonic and audio power amplifiers by replacing the transformer. Specifically, the transformers of this embodiment are divided into two categories: one suitable for ultrasonic power amplifiers and the other suitable for audio power amplifiers. Both transformers are used to process the pulse width modulated (PWM) signal for modulation and power amplification, including low-pass filtering and voltage conversion to obtain an amplified differential signal. Furthermore, by changing the transformer's ratio and number of turns, they are used to meet load matching and impedance transformation requirements. Switching between the two transformers is performed based on the specific application scenario.

[0039] The compatible control module of this embodiment can realize the switching between the two transformers by using various means such as chip control, electronic component control, and manual installation and removal control.

[0040] Example 2

[0041] Figure 3 This is a design principle structure diagram of a Class D ultrasonic power amplifier that is compatible with an ultrasonic power amplifier and an audio power amplifier according to an embodiment of the present application. Figure 3 As shown, the class D ultrasonic power amplifier compatible with the ultrasonic power amplifier and the audio power amplifier includes:

[0042] A differential processing unit is used to perform differential processing on the fundamental wave signal (single-ended signal), including DC isolation and operational amplifier, to obtain a fundamental wave differential signal, which is used as an input signal for the audio power amplifier unit;

[0043] The audio power amplifier unit, which in this embodiment is an integrated audio power amplifier unit, is used to modulate and power amplify the fundamental wave signal to obtain a modulated and power-amplified pulse width modulation signal (PWM);

[0044] Ultrasonic power amplifier and audio power amplifier compatible design module, used to perform low-pass filtering on the pulse width modulation (PWM) signal for modulation and power amplification, while meeting the requirements of load matching and impedance transformation;

[0045] A compatible control module, wherein when the compatible control module is in an off state, the ultrasonic power amplifier and audio power amplifier compatible design module does not work due to a broken circuit; when the compatible control module is in an on state, the ultrasonic power amplifier and audio power amplifier compatible design module is in an operating state;

[0046] A transformer for performing signal processing on the modulated and power-amplified pulse width modulated (PWM) signal, including low-pass filtering and voltage conversion, to obtain an amplified differential signal, and for meeting load matching and impedance transformation requirements by changing the transformer's transformation ratio and number of turns;

[0047] Among them, when the input fundamental wave signal is an ultrasonic signal, the compatible control module is in a disconnected state, the ultrasonic power amplifier and audio power amplifier compatible design module does not work due to the open circuit, and the transformer plays the role of low-pass filtering, matching and impedance transformation. When the input fundamental wave signal is an audio signal, the compatible control module is in a conductive state, the ultrasonic power amplifier and audio power amplifier compatible design module are in a working state, and play the role of low-pass filtering, matching and impedance transformation, and the transformer only plays the role of voltage conversion.

[0048] The design principles of the differential processing unit, audio power amplifier unit, and transformer part of the class D ultrasonic power amplifier of this embodiment are consistent with those of embodiment 1 and are not described in detail here.

[0049] like Figure 3 As shown, the difference between this embodiment and embodiment 1 mainly lies in the ultrasonic power amplifier and audio power amplifier compatibility design module and the ultrasonic power amplifier and compatibility control module.

[0050] The ultrasonic power amplifier and audio power amplifier compatibility design module is located between the audio power amplifier unit and the transformer. The ultrasonic power amplifier and audio power amplifier compatibility design module includes an LC filter circuit for low-pass filtering the pulse width modulated (PWM) signal used for modulation and power amplification; and matching components for matching and impedance conversion between the Class D ultrasonic power amplifier and the load. The LC filter circuit in this embodiment includes an LC filter inductor and / or an LC filter capacitor, and the matching components in this embodiment include a matching inductor.

[0051] The compatible control module can be implemented using a variety of means such as chip control, electronic component control, manual installation and removal control, etc. The compatible control module has two working states: disconnected and on. When in the disconnected state, the ultrasonic power amplifier and audio power amplifier compatible design module does not work due to the open circuit, which is equivalent to directly connecting the pulse width modulation signal (PWM) of the modulation and power amplification output by the audio power amplifier unit to the primary of the transformer, and the secondary of the transformer is directly connected to the load, such as a transducer, to perform ultrasonic power amplification. When in the on state, the ultrasonic power amplifier and audio power amplifier compatible design module are in working state and can perform audio power amplification. Thereby, the Class D ultrasonic power amplifier of this embodiment has the characteristics of being compatible with ultrasonic power amplifiers and audio power amplifiers.

[0052] Example 3

[0053] Figure 4 This is a block diagram of an underwater acoustic transmitter according to an embodiment of the present application.

[0054] like Figure 4 As shown, this embodiment provides an underwater acoustic transmitter, which includes: a signal generating device for generating a signal in a certain form; the Class D ultrasonic power amplifier, which uses the signal in a certain form as an input signal to generate an amplified fundamental wave signal; and a transducer for converting the amplified fundamental wave signal into an acoustic signal and radiating it into a medium.

[0055] In underwater communication applications, underwater acoustic transmitters are generally connected to transducers, such as Figure 4 As shown, the load of the class D ultrasonic power amplifier of the present application can be a transducer or other loads.

[0056] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. Therefore, it is understood that the above is only one of the specific implementation methods of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A class D ultrasonic power amplifier, characterized in that: The class D ultrasonic power amplifier comprises: The audio power amplifier unit is used to modulate and amplify the input fundamental wave signal to obtain a pulse width modulation signal (PWM); An ultrasonic power amplifier and audio power amplifier compatible design module, used to perform low-pass filtering on the pulse width modulation (PWM) signal while meeting the requirements of load matching and impedance transformation; A compatible control module, wherein when the compatible control module is in an off state, the ultrasonic power amplifier and audio power amplifier compatible design module does not work due to a broken circuit; when the compatible control module is in an on state, the ultrasonic power amplifier and audio power amplifier compatible design module is in an operating state; A transformer for performing signal processing on the pulse width modulated (PWM) signal, including low-pass filtering and voltage conversion, to obtain an amplified fundamental signal, and for meeting load matching and impedance transformation requirements by changing the transformer's transformation ratio and number of turns; Among them, when the input fundamental wave signal is an ultrasonic signal, the compatible control module is in a disconnected state, the ultrasonic power amplifier and audio power amplifier compatible design module does not work due to the open circuit, and the transformer plays the role of low-pass filtering, voltage conversion, matching and impedance conversion. When the input fundamental wave signal is an audio signal, the compatible control module is in a conductive state, the ultrasonic power amplifier and audio power amplifier compatible design module is in a working state, and plays the role of low-pass filtering, matching and impedance conversion, and the transformer only plays the role of voltage conversion.

2. The class D ultrasonic power amplifier according to claim 1, wherein: The class D ultrasonic power amplifier further includes: The differential processing unit is used to perform differential processing on the fundamental wave signal to obtain a fundamental wave differential signal, and the fundamental wave differential signal is used as an input signal of the audio power amplifier unit.

3. The class D ultrasonic power amplifier according to claim 2, wherein: The differential processing unit includes: at least one DC blocking circuit and at least one operational amplifier.

4. The class D ultrasonic power amplifier according to claim 3, wherein: The operational amplifier includes an operational amplifier chip with overvoltage protection capability, which can prevent the input voltage from being too large.

5. The class D ultrasonic power amplifier according to claim 1, wherein: The audio power amplifier unit includes: an audio integrated amplifier unit, or an audio non-integrated amplifier unit.

6. The class D ultrasonic power amplifier according to claim 1, wherein: The transformer also includes: a transformer whose primary turns meet the requirement of preventing core saturation and whose primary-secondary transformation ratio is less than 1.

7. The class D ultrasonic power amplifier according to claim 1, wherein: The ultrasonic power amplifier and audio power amplifier compatible design module includes: An LC filter circuit, configured to modulate and perform low-pass filtering on a pulse width modulation (PWM) signal of power amplification, the LC filter circuit comprising an LC filter inductor and / or an LC filter capacitor; Matching components are used for matching and impedance transformation between the class D ultrasonic power amplifier and the load.

8. The class D ultrasonic power amplifier according to any one of claims 1 to 7, characterized in that: The class D ultrasonic power amplifier further includes: The power supply system determines the design parameters of the power supply system according to the specific parameters of the selected circuit, chip and power amplifier.

9. An underwater acoustic transmitter, characterized in that: The underwater acoustic transmitter comprises: A signal generating device, used to generate a signal of a certain form; The class D ultrasonic power amplifier according to any one of claims 1 to 8, which uses the signal in the certain form as an input signal to generate an amplified fundamental wave signal; The transducer is used to convert the amplified fundamental wave signal into an acoustic signal and radiate it into a medium.

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