USB (Universal Serial Bus) digital audio equipment for driving multi-unit earphone
By introducing an audio codec module and an operational amplifier module into the USB digital audio device of multi-unit headphones, the problem of insufficient audio chip driving capability is solved, audio quality is improved, and product size and cost are reduced.
Patent Information
- Application Number
- CN202520013901.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-04
- Publication Date
- 2025-12-16
- Estimated Expiration
- 2035-01-04
AI Technical Summary
In existing technologies, the audio chip driving capability of multi-unit headphones is insufficient, resulting in reduced audio quality, or the use of crossovers leads to increased product size and cost.
It adopts a USB digital audio device, which includes an audio codec module and an audio operational amplifier module. The audio codec module decodes the digital audio signal into at least two analog audio signals, and the audio operational amplifier module performs operational amplification on at least one signal, which is then output directly or after amplification to the unit of the multi-unit headphone, eliminating the need for a crossover.
It increases the audio output power of multi-driver headphones, improves audio quality, and reduces product size and cost.
Smart Images
Figure CN223681177U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to electronic technical field especially relates to a USB digital audio frequency equipment of driving multi -unit earphone. BACKGROUND
[0002] With the increase of music lovers, people's demand for earphone sound quality is higher and higher. Most of the earphones on the market are single-unit moving coil or moving iron earphones. Since the frequency response range of single-unit earphone is insufficient, it only performs well in single scene music, thus multi-unit earphone appears. Commonly used driving multi-unit earphone is generally parallelly connected at the output end, or multi-speaker plus frequency divider mode. However, a part of multi-unit earphone will increase the chip output power under the condition that the output amplitude is unchanged, thus the driving capacity of audio chip is required to be higher, and the more the units are, the more serious the distortion is, and this driving mode also greatly reduces the audio quality; another part of multi-unit earphone drives through the frequency divider to separate the frequency range, which can provide extensive audio performance and improve the audio quality, but since the frequency divider is needed to coordinate the work of multi-unit, the product size and cost are increased. SUMMARY
[0003] The utility model provides a kind of USB digital audio frequency equipment of driving multi -unit earphone, solve the application scene for multi -unit earphone, the problem that the driving capacity of audio chip in prior art is insufficient to cause audio quality to reduce, or use frequency divider to cause size and cost increase problem.
[0004] The utility model provides a kind of USB digital audio frequency equipment of driving multi -unit earphone, including USB interface, audio codec module, audio amplifier module, PCB wire pad interface, wherein:
[0005] The USB interface is electrically connected with the audio codec module and the external intelligent terminal respectively, for receiving the digital audio signal transmitted by the intelligent terminal, and outputting the digital audio signal to the audio codec module;
[0006] The audio codec module is electrically connected with the PCB wire pad interface and the audio amplifier module respectively, for decoding the digital audio signal into at least two analog audio signals, one of which is directly output to the PCB wire pad interface, and the other at least one is output to the audio amplifier module;
[0007] The audio amplifier module is electrically connected with the PCB wire pad interface, for operating amplification on the at least one analog audio signal, and outputting to the PCB wire pad interface;
[0008] The PCB wire bonding pad interface is connected with an external multi-unit earphone, and is used for outputting the analog audio signal of the one path to one unit of the multi-unit earphone, and outputting the amplified analog audio signal of the at least one path to at least one other unit of the multi-unit earphone.
[0009] As an optional implementation, the audio operational amplifier module is a multi-output type chip, and the audio operational amplifier module includes at least two groups of output pins, and the at least two groups of output pins of the audio operational amplifier module respectively output the amplified analog audio signal of the at least one path to the PCB wire bonding pad interface.
[0010] As an optional implementation, the audio operational amplifier module is provided with at least two, and the same group of pins of the audio codec module is connected in parallel with the at least two audio operational amplifier modules, and each of the audio operational amplifier modules outputs the amplified analog audio signal to the PCB wire bonding pad interface.
[0011] As an optional implementation, the audio codec module further includes a digital audio codec chip and a filter capacitor, a Vbus pin of the USB interface is electrically connected to a Vbus pin of the digital audio codec chip and a power supply V+ pin of the PCB wire bonding pad interface, the Vbus pin of the USB interface is further grounded through the filter capacitor, a positive data D+ pin of the USB interface is electrically connected to a positive data D+ pin of the digital audio codec chip, a negative data D- pin of the USB interface is electrically connected to a negative data D- pin of the digital audio codec chip, a first left channel HPL pin of the digital audio codec chip is electrically connected to a left channel SL+ pin of the PCB wire bonding pad interface, and a first right channel HPR pin of the digital audio codec chip is electrically connected to a right channel SR+ pin of the PCB wire bonding pad interface.
[0012] As an optional implementation, the audio operational amplifier module comprises an audio operational amplifier chip, a first RC circuit and a second RC circuit, a second left channel HPL pin of the digital audio codec chip is electrically connected to a left channel input pin of the audio operational amplifier chip, a second right channel HPR pin of the digital audio codec chip is electrically connected to a right channel input pin of the audio operational amplifier chip, a left channel output pin of the audio operational amplifier chip is electrically connected to a left channel L+ pin of the PCB wire bonding pad interface, and a right channel output pin of the audio operational amplifier chip is electrically connected to a right channel R+ pin of the PCB wire bonding pad interface; the first RC circuit comprises a first resistor and a first capacitor connected in parallel, and the second RC circuit comprises a second resistor and a second capacitor connected in parallel, one end of the first RC circuit is electrically connected to the left channel output pin of the audio operational amplifier chip, and one end of the second RC circuit is electrically connected to the right channel output pin of the audio operational amplifier chip.
[0013] As an optional implementation, the USB interface is a USB Type-C interface, and the PCB wire bonding pad interface comprises a 3.5 mm earphone jack and / or a USB Type-C interface.
[0014] As an optional implementation, the digital audio codec chip is of a CX31993, KT02H20, ALC5686 or CB1200 type.
[0015] As an optional implementation, the audio operational amplifier chip is of a MAX97220 or HT97220 type.
[0016] As an optional implementation, the PCB wire bonding pad interface is further configured to receive an analog microphone signal input by the multi-unit earphone and output the analog microphone signal to the audio codec module, and the audio codec module is further configured to encode the analog microphone signal into a digital microphone signal and output the digital microphone signal to the USB interface.
[0017] As an optional implementation, a microphone signal M pin of the PCB wire bonding pad interface is electrically connected to a microphone signal M pin of the digital audio codec chip, and a microphone ground wire G pin of the PCB wire bonding pad interface is electrically connected to a microphone ground wire G pin of the digital audio codec chip.
[0018] As can be seen from the above, in the USB digital audio device for driving multi-unit earphones of the utility model, including USB interface, audio codec module, audio operational amplifier module and PCB soldering pad interface, the audio codec module is electrically connected with the PCB soldering pad interface and the audio operational amplifier module respectively, and is used for decoding the digital audio signal transmitted from the USB interface into at least two analog audio signals, one of which is directly output to the PCB soldering pad interface, and the other at least one is output to the audio operational amplifier module, the audio operational amplifier module is used for amplifying the at least one analog audio signal and outputting to the PCB soldering pad interface, and the PCB soldering pad interface is used for outputting the one analog audio signal to one unit of the multi-unit earphones and outputting the amplified at least one analog audio signal to the other at least one unit of the multi-unit earphones. In this way, when responding to the multi-unit earphone application scenario, the other at least one analog audio signal output by the audio codec module is amplified through the audio operational amplifier module, effectively improving the output power, solving the problem of insufficient driving capacity of the audio chip in the prior art, and ensuring the output of high audio quality, thereby reducing or improving the audio distortion condition. Moreover, the audio codec module is amplified through the audio operational amplifier module, which is sufficient to improve the output power, and does not need to use a frequency divider to drive, and by omitting the frequency divider component, the product size can be reduced and the product cost can be reduced. BRIEF DESCRIPTION OF DRAWINGS
[0019] In order to more clearly illustrate the embodiments of the utility model, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.
[0020] Figure 1 It is the architecture schematic diagram of the USB digital audio device for driving multi-unit earphones provided by the embodiments of the utility model;
[0021] Figure 2 It is the architecture schematic diagram of another USB digital audio device for driving multi-unit earphones provided by the embodiments of the utility model;
[0022] Figure 3 It is the architecture schematic diagram of still another USB digital audio device for driving multi-unit earphones provided by the embodiments of the utility model;
[0023] Figure 4 It is the circuit schematic diagram of the USB digital audio device for driving multi-unit earphones provided by the embodiments of the utility model. DETAILED DESCRIPTION
[0024] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present utility model.
[0025] Please refer to Figure 1 , Figure 1 is a kind of architecture schematic diagram of the USB digital audio equipment of the driving multi-unit earphone provided in the embodiments of the present utility model, as shown in the USB digital audio equipment 100 of the driving multi-unit earphone, including USB interface 110, audio codec module 120, audio amplifier module 130, PCB soldering pad interface 140, wherein:
[0026] USB interface 110 is electrically connected with audio codec module 120 and external smart terminal respectively, for receiving digital audio signal transmitted by smart terminal, and outputting digital audio signal to audio codec module 120. Wherein, external smart terminal can be various terminals such as smart phone, tablet computer, notebook computer, handheld game machine, smart video playing equipment, etc., which is not limited here. In specific implementation, external smart terminal can be connected to USB interface 110 through data line, and digital audio signal is transmitted to USB interface through data line.
[0027] audio codec module 120 is electrically connected with PCB soldering pad interface 140 and audio amplifier module 130 respectively, for decoding digital audio signal into at least two analog audio signals, wherein one is directly output to PCB soldering pad interface 140, and the other at least one is output to audio amplifier module 130. In specific implementation, audio codec module 120 has the decoding function of digital-to-analog conversion, and audio codec module 120 can decode digital audio signal into analog audio signal.
[0028] audio amplifier module 130 is electrically connected with PCB soldering pad interface 140, for operating amplification of at least one analog audio signal, and outputting to PCB soldering pad interface 140. It should be understood that, since the total output power of audio codec module 120 has an upper limit, when outputting multiple analog audio signals, the power of each channel from the second channel will decrease, resulting in insufficient driving capacity, while audio amplifier module 130 can operate amplification of these analog audio signals, achieve the effect of power amplification, and improve the driving capacity. It should be pointed out that, the way of outputting at least two amplified analog audio signals by audio amplifier module 130 can be various, which can be as shown in Figure 2 , using a single multi-output type chip, or as shown in Figure 3The audio amplifier module is shown to be at least two, and the specific implementation mode is described in detail below.
[0029] The PCB wire bonding pad interface 140 is connected with an external multi-unit earphone, and is used to output one analog audio signal to one unit of the multi-unit earphone, and output at least one amplified analog audio signal to at least one other unit of the multi-unit earphone. Among them, the PCB wire bonding pad interface has multiple output pins, which can be respectively connected to each unit of the multi-unit earphone, such as units 1-n in Figures 1 to 3 It should be understood that the multi-unit earphone can respond to the analog audio signal through its multiple units to improve the frequency response range and have better sound quality than the single-unit earphone.
[0030] As can be seen from the above, when the multi-unit earphone application scenario is dealt with, the other at least one analog audio signal output by the audio codec module 120 is amplified by the audio amplifier module 130, effectively improving the output power, solving the problem of insufficient driving capability of the audio chip in the prior art, and ensuring the output of high audio quality, thereby reducing or improving the audio distortion condition; and the audio codec module 120 is amplified by the audio amplifier module 130, which is sufficient to improve the output power, without the need to use a frequency divider to drive, by omitting the frequency divider component, the product size can be reduced, and the product cost can be reduced.
[0031] Please refer to Figure 2 , Figure 2 is another architecture schematic diagram of the USB digital audio device for driving the multi-unit earphone provided by the embodiment of the utility model.
[0032] In the embodiment, the audio amplifier module 130 is a multi-output type chip, the audio amplifier module 130 includes at least two groups of output pins, and the at least two groups of output pins of the audio amplifier module 130 respectively output at least one amplified analog audio signal to the PCB wire bonding pad interface 140. Among them, the multi-output type chip refers to a chip with multiple groups of output pins, such as Figure 2 The audio amplifier module 130 shown in
[0033] Please refer to Figure 3 , Figure 3 is another architecture schematic diagram of the USB digital audio device for driving the multi-unit earphone provided by the embodiment of the utility model.
[0034] In the embodiment, the audio operational amplifier module 130 is provided with at least two, and the same group of pins of the audio codec module 120 is connected in parallel with the at least two audio operational amplifier modules 130, and each audio operational amplifier module 130 outputs the amplified analog audio signal to the PCB wire pad interface 140. Wherein, the same group of pins of the audio codec module 120 connected in parallel with the at least two audio operational amplifier modules 130 specifically refers to: the same group of pins of the audio codec module 120 is connected to the input pins of each audio operational amplifier module 130 through multiple groups of lines. Then, each audio operational amplifier module 130 respectively amplifies and outputs the analog audio signal, and each output corresponds to driving a unit 2-n of a multi-unit earphone.
[0035] Please refer to Figure 4 , Figure 4 is a circuit schematic diagram of a USB digital audio device for driving a multi-unit earphone provided by the embodiment of the utility model.
[0036] As an implementation manner, the audio codec module 120 further includes a digital audio codec chip U1 and a filter capacitor C, the Vbus pin of the USB interface 110 is electrically connected to the Vbus pin of the digital audio codec chip U1 and the power supply V+ pin of the PCB wire pad interface 140, and the Vbus pin of the USB interface 110 is further grounded through the filter capacitor C, the positive data D+ pin of the USB interface 110 is electrically connected to the positive data D+ pin of the digital audio codec chip U1, the negative data D- pin of the USB interface 110 is electrically connected to the negative data D- pin of the digital audio codec chip U1, the first left channel HPL1 pin of the digital audio codec chip U1 is electrically connected to the left channel SL+ pin of the PCB wire pad interface 140, and the first right channel HPR1 pin of the digital audio codec chip U1 is electrically connected to the right channel SR+ pin of the PCB wire pad interface 140. In addition, in order to realize the function of the digital audio codec chip U1, the audio codec module 120 can further include peripheral circuit components of the digital audio codec chip U1, such as decoupling capacitors, pull-down resistors, etc., which are not listed here.
[0037] In the specific implementation, the positive data D+ pin and the negative data D- pin of the USB interface 110 are used to receive the digital audio signal sent by the external intelligent terminal, the positive data D+ pin and the negative data D- pin of the digital audio codec chip U1 are used as input pins to receive the digital audio signal, and the digital audio codec chip U1 decodes the received digital audio signal to obtain an analog audio signal; one-way left-channel analog audio signal is output to the left-channel SL+ pin of the PCB wire bonding pad interface 140 through the first left-channel HPL1 pin of the digital audio codec chip U1, one-way right-channel analog audio signal is output to the right-channel SR+ pin of the PCB wire bonding pad interface 140 through the first right-channel HPR1 pin of the digital audio codec chip U1, and finally transmitted to one of the multiple-unit earphones to realize power amplification of the unit.
[0038] Optionally, the model of the digital audio codec chip U1 can be CX31993, KT02H20, ALC5686, or CB1200, and the like, and the present embodiment does not make an exhaustive list.
[0039] As an implementation form, the audio amplifier module 130 includes an audio amplifier chip U2, a first RC circuit, and a second RC circuit, wherein:
[0040] The second left-channel HPL2 pin of the digital audio codec chip U1 is electrically connected to the left-channel input pin of the audio amplifier chip U2, the second right-channel HPR2 pin of the digital audio codec chip U1 is electrically connected to the right-channel input pin of the audio amplifier chip U2, the left-channel output pin of the audio amplifier chip U2 is electrically connected to the left-channel L+ pin of the PCB wire bonding pad interface 140, and the right-channel output pin of the audio amplifier chip U2 is electrically connected to the right-channel R+ pin of the PCB wire bonding pad interface 140; the first RC circuit includes a first resistor R1 and a first capacitor C1 connected in parallel, and the second RC circuit includes a second resistor R2 and a second capacitor C2 connected in parallel, one end of the first RC circuit is electrically connected to the left-channel output pin of the audio amplifier chip U2, and one end of the second RC circuit is electrically connected to the right-channel output pin of the audio amplifier chip U2. In addition, in order to realize the function of the audio amplifier chip U2, the audio amplifier module 130 can further include peripheral circuit components of the audio amplifier chip U2, such as an external resistor circuit, and the like, and the present embodiment does not make an exhaustive list. Among them, the first RC circuit and the second RC circuit can improve the oscillation of the feedback signal, and the external resistor circuit can adjust the gain.
[0041] In a specific implementation, the analog audio signal of the left channel of the other route is output to the left channel input pin of the audio operational amplifier chip U2 through the second left channel HPL2 pin of the digital audio codec chip U1, and the analog audio signal of the right channel of the other route is output to the right channel input pin of the audio operational amplifier chip U2 through the second right channel HPR1 pin of the digital audio codec chip U1; the analog audio signal of the left channel of the other route is amplified by the audio operational amplifier chip U2 and then output to the left channel L+ pin of the PCB soldering pad interface 140 through the left channel output pin of the audio operational amplifier chip U2, and the analog audio signal of the right channel of the other route is amplified by the audio operational amplifier chip U2 and then output to the right channel R+ pin of the PCB soldering pad interface 140 through the right channel output pin of the audio operational amplifier chip U2, and finally transmitted to the other unit of the multi-unit earphone to realize the power amplification of the unit.
[0042] Optionally, the model of the audio operational amplifier chip U2 is MAX97220, HT97220, etc., and the present embodiment does not make an exhaustive enumeration.
[0043] As an implementation form, the USB interface 110 is a USB Type-C interface; and the PCB soldering pad interface 140 includes a 3.5mm earphone jack and / or a USB Type-C interface. The USB Type-C interface and the 3.5mm earphone jack have the advantages of multiple application scenarios and wide application range, and can be adapted to most data lines on the market at present.
[0044] As an implementation form, the PCB soldering pad interface 140 is also used for receiving the analog microphone signal input by the multi-unit earphone and outputting the analog microphone signal to the audio codec module 120; and the audio codec module 120 is also used for encoding the analog microphone signal into a digital microphone signal and outputting the digital microphone signal to the USB interface 110. In a specific implementation, the audio codec module 120 also has an analog-to-digital conversion encoding function, and the audio codec module 120 can encode the analog microphone signal into a digital microphone signal.
[0045] As an implementation form, the microphone signal M pin of the PCB soldering pad interface 140 is electrically connected to the microphone signal M pin of the digital audio codec chip U1, and the microphone ground wire G pin of the PCB soldering pad interface 140 is electrically connected to the microphone ground wire G pin of the digital audio codec chip U1.
[0046] In a specific implementation, the microphone signal M pin of the PCB wire bonding pad interface 140 is used to receive an analog microphone signal transmitted by a microphone on a multi-unit earphone, the microphone signal M pin of the digital audio codec chip U1 receives the analog microphone signal as an input pin, the digital audio codec chip U1 encodes the received analog microphone signal to obtain a digital microphone signal and outputs the digital microphone signal to the USB interface, and finally transmits the digital microphone signal to a smart terminal to realize power amplification of the microphone signal.
[0047] As can be seen from the above, in the USB digital audio device 100 for driving a multi-unit earphone, the USB interface 110, the audio codec module 120, the audio operational amplifier module 130, and the PCB wire bonding pad interface 140 are included, the audio codec module 120 is electrically connected to the PCB wire bonding pad interface 140 and the audio operational amplifier module 130, and is used to decode a digital audio signal transmitted at the USB interface 110 into at least two analog audio signals, one of which is directly output to the PCB wire bonding pad interface 140, and the other at least one is output to the audio operational amplifier module 130, the audio operational amplifier module 130 is used to amplify the at least one analog audio signal and output the at least one analog audio signal to the PCB wire bonding pad interface 140, and the PCB wire bonding pad interface 140 is used to output the one analog audio signal to one unit of the multi-unit earphone and output the amplified at least one analog audio signal to at least one other unit of the multi-unit earphone. In this way, when responding to a multi-unit earphone application scenario, the other at least one analog audio signal output by the audio codec module 120 is amplified by the audio operational amplifier module 130, effectively improving the output power, solving the problem of insufficient driving capability of the audio chip in the prior art, and ensuring the output of high audio quality, thereby reducing or improving the audio distortion situation. Furthermore, the audio codec module 120 is amplified by the audio operational amplifier module 130, which is sufficient to improve the output power, and a frequency divider is not needed to be used for driving, and by omitting the frequency divider, the product size can be reduced and the product cost can be reduced.
[0048] In summary, the USB digital audio device 100 for driving a multi-unit earphone has the following advantages:
[0049] 1. Improved audio playback quality and improved audio distortion situation. The other at least one analog audio signal output by the audio codec module 120 is amplified by the audio operational amplifier module 130, effectively improving the output power.
[0050] 2. Good cost control. The audio codec module 120 is amplified by the audio operational amplifier module 130, which is sufficient to improve the output power, and a frequency divider is not needed to be used for driving.
[0051] 3. Small size and easy to carry. Because it uses an audio operational amplifier module 130 for amplification, the crossover component is eliminated, thus reducing the product size.
[0052] 4. The U1 audio codec chip has high integration and good compatibility.
[0053] It should be noted that this utility model defines a design scheme for a USB digital audio device 100 that drives multi-unit headphones. The detailed description of the technical solution only describes the working principle and function of the audio circuit. No limitations are made on the model number of the audio circuit chip, the appearance of the interface, the soldering method, or the location. Therefore, the following solutions are all alternatives to this solution and are protected by this application:
[0054] 1. A solution that replaces the material supplier or model in the original design, but maintains the same circuit working principle and achieves the same function.
[0055] 2. Change the location and quantity of the audio operational amplifier chip U2 on the board.
[0056] 3. Changes to the definition order, shape, position, and other structural changes of PCB solder pads.
[0057] 4. Replace the PCB solder pads with a 3.5mm headphone jack or a USB Type-C interface.
[0058] The above description discloses only preferred embodiments of the present utility model, and is quite specific and detailed. However, it should not be construed as limiting the scope of the present utility model. Therefore, equivalent variations made according to the claims of the present utility model are still within the scope of the present utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present utility model, and these modifications and improvements all fall within the protection scope of the present utility model.
Claims
1. A USB digital audio device for driving multi-unit headphones, characterized in that, Includes a USB interface, audio codec module, audio operational amplifier module, and PCB solder pad interface, among which: The USB interface is electrically connected to the audio codec module and an external smart terminal, respectively, and is used to receive digital audio signals transmitted from the smart terminal and output the digital audio signals to the audio codec module. The audio codec module is electrically connected to the PCB solder pad interface and the audio operational amplifier module, respectively, and is used to decode the digital audio signal into at least two analog audio signals, one of which is directly output to the PCB solder pad interface, and the other at least one is output to the audio operational amplifier module. The audio operational amplifier module is electrically connected to the PCB bonding pad interface and is used to perform operational amplification on the at least one analog audio signal and output it to the PCB bonding pad interface. The PCB solder pad interface is connected to an external multi-unit headphone, and is used to output one of the analog audio signals to one of the units of the multi-unit headphone, and to output the amplified analog audio signal to at least one other unit of the multi-unit headphone.
2. The USB digital audio device for driving multi-unit headphones as described in claim 1, characterized in that, The audio operational amplifier module is a multi-output type chip, and the audio operational amplifier module includes at least two sets of output pins. The at least two sets of output pins of the audio operational amplifier module respectively output the amplified analog audio signal of at least one channel to the PCB bonding pad interface.
3. The USB digital audio device for driving multi-unit headphones as described in claim 1, characterized in that, The audio operational amplifier module is provided with at least two, and at least two audio operational amplifier modules are connected in parallel to the same set of pins of the audio codec module. Each audio operational amplifier module outputs the amplified analog audio signal to the PCB solder pad interface.
4. The USB digital audio device for driving multi-unit headphones as described in claim 1, characterized in that, The audio codec module also includes a digital audio codec chip and a filter capacitor. The Vbus pin of the USB interface is electrically connected to the Vbus pin of the digital audio codec chip and the power supply V+ pin of the PCB bonding pad interface. The Vbus pin of the USB interface is also grounded through the filter capacitor. The positive data D+ pin of the USB interface is electrically connected to the positive data D+ pin of the digital audio codec chip. The negative data D- pin of the USB interface is electrically connected to the negative data D- pin of the digital audio codec chip. The first left channel HPL pin of the digital audio codec chip is electrically connected to the left channel SL+ pin of the PCB bonding pad interface. The first right channel HPR pin of the digital audio codec chip is electrically connected to the right channel SR+ pin of the PCB bonding pad interface.
5. The USB digital audio device for driving multi-unit headphones as described in claim 4, characterized in that, The audio operational amplifier module includes an audio operational amplifier chip, a first RC circuit, and a second RC circuit. The second left channel HPL pin of the digital audio codec chip is electrically connected to the left channel input pin of the audio operational amplifier chip, the second right channel HPR pin of the digital audio codec chip is electrically connected to the right channel input pin of the audio operational amplifier chip, the left channel output pin of the audio operational amplifier chip is electrically connected to the left channel L+ pin of the PCB bonding pad interface, and the right channel output pin of the audio operational amplifier chip is electrically connected to the right channel R+ pin of the PCB bonding pad interface. The first RC circuit includes a first resistor and a first capacitor connected in parallel, and the second RC circuit includes a second resistor and a second capacitor connected in parallel. One end of the first RC circuit is electrically connected to the left channel output pin of the audio operational amplifier chip, and one end of the second RC circuit is electrically connected to the right channel output pin of the audio operational amplifier chip.
6. The USB digital audio device for driving multi-unit headphones as described in claim 1, characterized in that, The USB interface is a USB Type-C interface; the PCB solder pad interface includes a 3.5mm headphone jack and / or a USB Type-C interface.
7. The USB digital audio device for driving multi-unit headphones as described in claim 4, characterized in that, The digital audio codec chip is model CX31993, KT02H20, ALC5686 or CB1200.
8. The USB digital audio device for driving multi-unit headphones as described in claim 5, characterized in that, The audio operational amplifier chip is either MAX97220 or HT97220.
9. The USB digital audio device for driving multi-unit headphones as described in claim 4, characterized in that, The PCB solder pad interface is also used to receive the analog microphone signal input from the multi-unit earphone and output it to the audio codec module; the audio codec module is also used to encode the analog microphone signal into a digital microphone signal and output it to the USB interface.
10. The USB digital audio device for driving multi-unit headphones as described in claim 9, characterized in that, The microphone signal M pin of the PCB bonding pad interface is electrically connected to the microphone signal M pin of the digital audio codec chip, and the microphone ground G pin of the PCB bonding pad interface is electrically connected to the microphone ground G pin of the digital audio codec chip.