Power management system of digital audio player

Abstract

The utility model provides a power supply management system of a digital audio player, which comprises a battery module, a filtering module, an OTG power supply management module, a digital audio circuit power supply module, an ear amplifier circuit power supply module and a DAC circuit power supply module, and is characterized in that the OTG power supply management module is used for charging the battery module, supplying power to a main control module and realizing an OTG function; the digital audio circuit power supply module is used for outputting a group of linear voltage-stabilized power supply to the digital audio processor, the headphone amplifier circuit power supply module comprises a DC / DC conversion circuit and a first hybrid filter circuit, and the battery module is connected with the input end of the DC / DC conversion circuit after being subjected to primary filtering through the filter circuit; after secondary filtering is carried out through the first hybrid filter circuit, a power supply is output to the headphone amplifier circuit, and the two DAC power supply circuits are used for providing two mutually independent power supply voltages to the DAC circuits of the left sound channel and the right sound channel respectively. The power supply is composed of a plurality of power supply modules with excellent performance, and the effects of improving the anti-interference capability, maintainability and stability of the power supply are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of power management, and particularly relates to a power management system for a digital audio player. Background Art

[0002] With the continuous development of electronic information technology, the audio player industry has undergone a revolutionary transformation from CD to digital audio in the tide of the times, and higher-quality audio playback provides people with a better auditory experience. However, since the power supply circuit of the audio player has a direct power supply connection with each functional module, the quality of its output power has a great impact on the sound quality of the power amplifier. On the one hand, the performance of the power supply circuit may be affected by electromagnetic interference, which comes from other electronic components inside the device or external electromagnetic fields. The power supply affected by interference supplied to each functional module may cause distortion or instability of the audio signal, which to a certain extent limits the performance and reliability of the digital audio player. In addition, giving full play to the dynamic performance of the system is crucial for improving the overall performance of the system. This can not only improve the response speed and stability of the system, but also enhance the system's resistance to external interference. Therefore, it is a necessary issue to consider how to explore and give full play to the dynamic performance of the system in the design stage of the power supply system.

[0003] On the other hand, due to considerations of circuit complexity, cost, and miniaturization design in existing audio players, the power supply circuit system is often designed to be relatively simple. Usually, a certain power supply circuit output is often used to supply multiple functional modules simultaneously. This leads to the situation that once a certain power supply circuit fails, the normal operation of multiple modules will be affected, and even the whole machine may have serious failures. Therefore, the maintainability of its power supply circuit is poor. In addition, the power supply circuits of some existing audio players are designed to be relatively complex to meet the power consumption requirements of more modules, lacking consistency, which will reduce the performance and stability of the device.

[0004] Therefore, it is necessary to design a power management system for a digital audio player with strong anti-interference ability, capable of providing a large dynamic power supply, having multiple independent power supply circuits, and good circuit consistency. Summary of the Utility Model

[0005] A power management system for a digital audio player provided by the utility model is mainly used to solve problems such as the power supply design of existing audio players being vulnerable to interference, poor maintainability, and low stability, so as to achieve the effects of improving the anti-interference ability, maintainability, and stability of the power supply.

[0006] The utility model realizes the above object through the following technical solutions:

[0007] A power management system for a digital audio player, comprising a battery module and a filtering module for providing power, and further comprising an OTG power management module, a digital audio circuit power module, an earphone amplifier circuit power module, and a DAC circuit power module. The OTG power management module is connected to the battery module and is also connected to the USB interface module and the main control module of the audio player, and is used for charging the battery module, supplying power to the main control module, and implementing the USB OTG function. The digital audio circuit power module is connected to the OTG power management module and is used for outputting a set of linear regulated power supply to the digital audio processor of the audio player. The earphone amplifier circuit power module includes a DC / DC conversion circuit and a first hybrid filtering circuit. The battery module is connected to the input end of the DC / DC conversion circuit after being filtered once by the filtering circuit. The output end of the DC / DC conversion circuit is connected to the input end of the first hybrid filtering circuit, and is used for outputting a power supply to the earphone amplifier circuit of the audio player after being filtered at the second level by the first hybrid filtering circuit. The DAC circuit power module is connected to the OTG power management module and includes two DAC power circuits with the same circuit structure. The two DAC power circuits are used for providing two independent power supply voltages to the DAC circuits of the left and right channels of the audio player respectively.

[0008] A further solution is that the battery module adopts a lithium-ion battery pack with a series-two-parallel topology structure.

[0009] A further solution is that the filtering module includes a super capacitor and a filtering capacitor. The input end of the super capacitor is connected to the output end of the lithium-ion battery pack, and is used for providing the overall power supply for the whole machine together with the lithium-ion battery pack as an auxiliary power supply to improve the power dynamic performance of the system.

[0010] Wherein, the input end of the filtering capacitor is connected to the output end of the super capacitor, and is used for reducing the output ripple voltage and improving the load transient response.

[0011] A further solution is that the OTG power management module adopts a battery charging IC with the model number MP2731, which supports the PD2.0 protocol and the USB OTG function, and is used for realizing fast charging of the battery module, transmission and sharing of audio files through the USB interface module.

[0012] A further solution is that the digital audio circuit power supply module includes a digital audio processor power supply circuit and a femtosecond crystal oscillator power supply circuit. The digital audio processor power supply circuit includes three filter and voltage regulation circuits with the same circuit structure. The input ends of the three filter and voltage regulation circuits are respectively connected to the OTG power management module, and are used to filter and regulate the system voltage provided by the OTG power management module and then output linear regulated power supplies of 3.3V, 1.8V, and 1.2V to the digital audio processor respectively.

[0013] Among them, the femtosecond crystal oscillator power supply circuit includes one of the filter and voltage regulation circuits and a second hybrid filter circuit. The input end of one of the filter and voltage regulation circuits is connected to the OTG power management module, and is used to filter and regulate the system voltage provided by the OTG power management module and then output a 1.8V linear regulated power supply to the input end of the second hybrid filter circuit. The second hybrid filter circuit is used to perform secondary filtering on the 1.8V linear regulated power supply and then output it to the femtosecond crystal oscillator of the audio player.

[0014] A further solution is that the DC / DC conversion circuit uses a DC / DC converter of model LT8334, and its input voltage range is 2.8V to 40V, and is used to provide a power supply with a wide dynamic range for the headphone amplifier circuit.

[0015] A further solution is that the first hybrid filter circuit is composed of a π-type LC filter circuit in series with a π-type RC filter circuit.

[0016] A further solution is that the headphone amplifier circuit power supply module includes four headphone amplifier power supply circuits with the same circuit structure. The four headphone amplifier power supply circuits are all composed of the DC / DC conversion circuit and the first hybrid filter circuit, and are used to supply power to the four discrete headphone amplifier circuits of the headphone amplifier circuit respectively.

[0017] A further solution is that each DAC power supply circuit includes a voltage conversion circuit, a first LDO circuit, a second LDO circuit, and a third LDO circuit. The voltage conversion circuit is used to regulate the system voltage provided by the OTG power management module and then output it to the second LDO circuit and the third LDO circuit respectively. The first LDO circuit, the second LDO circuit, and the third LDO circuit respectively output a first power supply voltage, a second power supply voltage, and a VREFH voltage to the DAC circuit.

[0018] A further solution is that the third LDO circuit uses a linear voltage regulator of model LT3045, and the VREFH voltage output by it ranges from 0V to 15V, and is used to provide a power supply with a wide dynamic range for the DAC circuit.

[0019] As can be seen, the utility model has the following beneficial effects:

[0020] 1. The power management system of the utility model consists of multiple power modules, forming a power subsystem with a complex structure, excellent performance, and each performing its own functions. Each power subsystem can work in coordination under the control of the power management system, thus meeting the power supply requirements of various scenarios. Compared with the traditional audio player with a single power circuit structure, the utility model pursues a precision circuit with ultra-low noise, high stability, and high performance to improve the circuit integration, complexity, signal integrity, and electromagnetic compatibility, and can also improve the thermal management of the circuit, further reducing the impact of temperature on circuit performance.

[0021] 2. In order to fully explore and exert the dynamic performance of the circuit module to meet the requirements of the dynamic performance of the power supply for playing various types of audio files, the utility model uses a four-channel LT8334 high-current and large-dynamic voltage stabilization circuit to stably supply power to the four-channel headphone amplifier, thus fully exploring the high-current and large-dynamic potential of the discrete headphone amplifier circuit, and using an LT3045 ultra-low noise and large-dynamic LDO voltage stabilization circuit as the VREFH power supply in the DAC power circuits of the left and right channels respectively, so as to ensure that the dynamic performance of the DAC circuit can be fully exerted.

[0022] 3. The utility model is provided with a decoupling capacitor combination at the power supply terminals of multiple components, thus providing a stable power supply, reducing the noise coupled to the power supply terminal by the components, and indirectly reducing the influence of other components by the noise of this component.

[0023] 4. The power circuit structure of the utility model has excellent consistency. Compared with the traditional power circuit with a complex design, it can improve the stability and reliability of the system, reduce the failure rate, and improve the overall performance.

[0024] 5. The utility model provides independent power circuits for the DAC circuits, femtosecond crystal oscillators, audio processors, etc. of the left and right channels, which can reduce the interference between the power supplies, and the faulty power supply loop does not affect the non-faulty power circuit, improving the maintainability of the circuit.

[0025] 6. The utility model uses a hybrid LC and RC filter circuit for secondary filtering in multiple places, abandoning the conventional method of using a linear voltage regulator IC for secondary voltage regulation, and realizing the precise processing and filtering of signals.

[0026] The following further details the utility model in conjunction with the drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the power management system provided by the embodiment of the utility model.

[0028] Figure 2It is a schematic diagram of the power supply module of the digital audio circuit in this embodiment.

[0029] Figure 3 It is a schematic diagram of the power supply module of the headphone amplifier circuit in this embodiment.

[0030] Figure 4 It is a schematic diagram of the power supply module of the DAC circuit in this embodiment.

[0031] Figure 5 It is a schematic diagram of the power supply module of the IV conversion circuit and the VOL / PRE power supply module in this embodiment.

[0032] Figure 6 It is a schematic diagram of the NUTUBE power supply module in this embodiment. Specific implementation manners

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] An embodiment of a power management system of a digital audio player

[0035] See Figure 1, a power management system for a digital audio player according to the present utility model, includes a battery module 20 for providing power, a filtering module 40, an OTG power management module 10, a digital audio circuit power module 30, an earphone amplifier circuit power module 50, and a DAC circuit power module 60. The OTG power management module 10 is connected to the battery module 20 and is also connected to the USB interface module and the main control module of the audio player, and is used for charging the battery module 20, supplying power to the main control module, and implementing the USB OTG function. The digital audio circuit power module 30 is connected to the OTG power management module 10 and is used for outputting a group of linearly regulated power supplies to the digital audio processor of the audio player. The earphone amplifier circuit power module 50 includes a DC / DC conversion circuit 51 and a first hybrid filtering circuit 52. The battery module 20 is connected to the input end of the DC / DC conversion circuit 51 after being filtered once by a filtering circuit. The output end of the DC / DC conversion circuit 51 is connected to the input end of the first hybrid filtering circuit 52, and is used for outputting a power supply to the earphone amplifier circuit of the audio player after secondary filtering through the first hybrid filtering circuit 52. The DAC circuit power module 60 is connected to the OTG power management module 10 and includes two DAC power circuits with the same circuit structure. The two DAC power circuits 61 and 62 are used for providing two independent power supply voltages to the DAC circuits of the left and right channels of the audio player respectively.

[0036] In this embodiment, the battery module 20 adopts a lithium-ion battery pack with a topology structure of one series and two parallel connections.

[0037] Specifically, the topology structure of the lithium-ion battery pack in this embodiment is accurately measured and paired for parameters such as capacity and internal resistance and then used in parallel, which can provide a large-capacity power supply of 12570 mAh 3.8V and up to 48W, and uses a large-capacity version of the battery protection board with large current and low internal resistance, so as to ensure that the battery performance meets the extremely high performance requirements of audio reproduction.

[0038] Specifically, the use of a lithium-ion polymer battery with a capacity of 12570 mAh 3.8V and up to 48 Wh as the main power supply in this embodiment is only exemplary and not the only power supply capacity option. The power supply capacity can be designed according to the actual battery specifications used, and it is equally applicable to the power management system of this embodiment.

[0039] In this embodiment, the filtering module 40 includes a super capacitor and a filtering capacitor. The input end of the super capacitor is connected to the output end of the lithium-ion battery pack and is used for providing the whole machine power supply together with the lithium-ion battery pack as an auxiliary power supply to improve the power dynamic performance of the system.

[0040] Among them, the input end of the filtering capacitor is connected to the output end of the super capacitor and is used for reducing the output ripple voltage and improving the load transient response.

[0041] Specifically, the supercapacitor used in this embodiment is a Murata 470mF ultra-large capacity supercapacitor, which together with a low internal resistance lithium-ion polymer battery pack forms the power supply center of the whole machine to meet the extremely high requirements of various types of audio files on the dynamic performance of the power supply.

[0042] In this embodiment, the OTG power management module 10 uses a battery charging IC of model MP2731, supports the PD2.0 protocol and USB OTG function, and is used to realize fast charging of the battery module 20 and transmission and sharing of audio files through the USB interface module.

[0043] Specifically, this embodiment allows the audio player to act as a host and a peripheral through the USB OTG function, thereby providing users with convenient and efficient device connection and power management through the power management strategy.

[0044] See also Figure 2 In this embodiment, the digital audio circuit power supply module 30 includes a digital audio processor power supply circuit 31 and a femtosecond crystal oscillator power supply circuit 32. The digital audio processor power supply circuit 31 includes three filtering and voltage stabilizing circuits with the same circuit structure. The input ends of the three filtering and voltage stabilizing circuits are respectively connected to the OTG power management module 10, and are used to output 3.3V, 1.8V, and 1.2V linear regulated power supplies to the digital audio processor after filtering and voltage regulation of the system voltage provided by the OTG power management module 10.

[0045] Among them, the femtosecond crystal oscillator power supply circuit 32 includes a filtering and voltage stabilizing circuit and a second hybrid filtering circuit. The input end of the filtering and voltage stabilizing circuit is connected to the OTG power management module 10, and is used to output a 1.8V linear regulated power supply to the input end of the second hybrid filtering circuit after primary filtering and voltage regulation of the system voltage provided by the OTG power management module 10. The second hybrid filtering circuit is used to perform secondary filtering on the 1.8V linear regulated power supply and output it to the femtosecond crystal oscillator of the audio player.

[0046] Specifically, the present embodiment also includes an HDMI power supply circuit 33, which includes a filtering and voltage stabilizing circuit, the input end of which is connected to the OTG power management module 10, and is used to output the system voltage provided by the OTG power management module 10 to the HDMI interface circuit after filtering and voltage regulation.

[0047] Specifically, the filter and voltage regulation circuit structures of the power supply circuit 31 of the digital audio processor, the power supply circuit 32 of the femtosecond crystal oscillator, and the HDMI power supply circuit 33 in this embodiment are the same. All five filter and voltage regulation circuits include a linear voltage regulator of model LP5907 and two capacitor combinations composed of several NP0 / X7R capacitors. The input terminal of the linear voltage regulator of LP5907 is connected to the OTG power management module 10 through one of the capacitor combinations, and its output terminal is connected to the capacitor combination, and outputs voltages FPGA_3V3, FPGA_1V8, and FPGA_1V2 to the digital audio processor respectively, outputs the voltage Femtoclock_1V8 to the femtosecond oscillator after secondary filtering, and outputs the voltage HDMI_3V3 to the HDMI interface circuit.

[0048] See Figure 3 , in this embodiment, the DC / DC conversion circuit 51 uses a DC / DC converter of model LT8334, and its input voltage range is 2.8V to 40V, which is used to provide a power supply with a wide dynamic range for the headphone amplifier circuit.

[0049] Specifically, the DC / DC conversion circuit 51 in this embodiment further includes two capacitor combinations composed of several NP0 / X7R capacitors that are respectively connected in parallel to the input and output terminals of the DC / DC converter of LT8334.

[0050] In this embodiment, the first hybrid filter circuit 52 is composed of a π-type LC filter circuit and a π-type RC filter circuit connected in series.

[0051] In this embodiment, the headphone amplifier circuit power supply module 50 includes four headphone amplifier power supply circuits with the same circuit structure. The four headphone amplifier power supply circuits are all composed of a DC / DC conversion circuit 51 and a first hybrid filter circuit 52, and are used to supply power to the four discrete headphone amplifier circuits of the headphone amplifier circuit respectively.

[0052] It can be seen that the four headphone amplifier circuits of the present invention are powered by four LT8334 high-current and high-dynamic voltage regulation circuits, so as to fully exploit the high-current and high-dynamic potential of the discrete headphone amplifier circuit, and abandon the conventional method of secondary voltage regulation by a linear voltage regulation IC, and directly use a hybrid filter circuit to achieve secondary filtering and directly supply the headphone amplifier circuit.

[0053] See Figure 4 , in this embodiment, each DAC power supply circuit includes a voltage conversion circuit, a first LDO circuit, a second LDO circuit, and a third LDO circuit. The voltage conversion circuit is used to regulate the system voltage provided by the OTG power management module 10 and then output it to the second LDO circuit and the third LDO circuit respectively. The first LDO circuit, the second LDO circuit, and the third LDO circuit output the first power supply voltage, the second power supply voltage, and the VREFH voltage to the DAC circuit respectively.

[0054] Specifically, the voltage conversion circuit in this embodiment uses a DC / DC converter of model TPS61087, which also includes a capacitor combination composed of several NP0 / X7R capacitors. The output terminal of the DC / DC converter of TPS61087 is connected to this capacitor combination, and temperature compensation is performed through this capacitor combination to improve the stability and precision of the circuit.

[0055] Specifically, the DC / DC converter of TPS61087 used in this embodiment reduces noise by adding a common-mode choke coil and a π-type network at its input and output terminals, and has the characteristics of high efficiency and low noise.

[0056] Specifically, the first LDO circuit in this embodiment includes two linear regulators of model LP5907 and two capacitor combinations composed of several NP0 / X7R capacitors. The input terminals of the two LP5907 linear regulators are respectively connected to the OTG power management module 10, and their output terminals are respectively connected to this capacitor combination. Among them, the voltages input to the DAC circuit of the left channel from the LP5907 linear regulator are TVDD_L and DVDD_L, and the voltages input to the DAC circuit of the right channel from the LP5907 linear regulator are TVDD_R and DVDD_R.

[0057] Specifically, the second LDO circuit in this embodiment includes a linear regulator of model TPS7A2050 and a capacitor combination composed of several NP0 / X7R capacitors. The input terminals of the TPS7A2050 linear regulator are respectively connected to the output terminal of the DC / DC converter of TPS61087, and its output terminals are respectively connected to this capacitor combination. Among them, the voltage input to the DAC circuit of the left channel from the TPS7A2050 linear regulator is VDD_L, and the voltage input to the DAC circuit of the right channel from the TPS7A2050 linear regulator is VDD_R

[0058] In this embodiment, the third LDO circuit uses a linear regulator of model LT3045, and the output VREFH voltage range is from 0V to 15V, which is used to provide a power supply with a wide dynamic range for the DAC circuit, so as to ensure that the dynamic performance of the DAC circuit is fully exerted.

[0059] Specifically, the third LDO circuit in this embodiment further includes a capacitor combination composed of several NP0 / X7R capacitors and a four-way parallel RC filter circuit. The input end of the linear regulator of LT3045 is connected to the output end of the DC / DC converter of TPS61087. Its output end is respectively connected to the capacitor combination and the four-way parallel RC filter circuit, and outputs 4 groups of reference voltages to the DAC circuit. Among them, the 4 groups of reference voltages input to the DAC circuit of the left channel are voltages VREFH_L-1 to VREFH_L-4 and VREFL_L-1 to VREFL_L-4, and the 4 groups of reference voltages input to the DAC circuit of the right channel are voltages VREFH_R-1 to VREFH_R-4 and VREFL_R-1 to VREFL_R-4.

[0060] Specifically, LP5907, LT3045, TPS7A2050, etc. used in this embodiment are all ultra-low-noise low-dropout regulators, making this power management system have high performance.

[0061] See Figure 5 , specifically, the power management system in this embodiment further includes a second filtering module 41, an IV conversion circuit power supply module 70, and a VOL / PRE power supply module 80. The OTG power management module 10 performs primary filtering on one path of the output system voltage through the second filtering module 41 and then outputs it to the input ends of the DC / DC conversion circuit 51 and the VOL / PRE power supply module 80 respectively. The input end of the IV conversion circuit power supply module 70 is connected to the output end of the DC / DC conversion circuit 51.

[0062] The second filtering module 41 includes a POSCAP tantalum polymer capacitor and a capacitor combination composed of several NP0 / X7R capacitors. This POSCAP tantalum polymer capacitor, in cooperation with NP0 and X7R high-quality capacitors, can comprehensively improve the dynamic performance of the power supply system.

[0063] Among them, the IV conversion circuit power supply module 70 includes two IV power supply circuits with the same circuit structure. The two IV power supply circuits 71 and 72 are used to provide two independent power supply voltages to the IV conversion circuits of the left and right channels of the audio player respectively.

[0064] Specifically, the IV power supply circuit in this embodiment includes a power management chip of model LM27762 and a capacitor combination composed of several NP0 / X7R capacitors. The LM27762 chip inputs the direct current output from the TPS61087 DC / DC converter, and its output end is connected to the capacitor combination, and temperature compensation is performed through this capacitor combination to improve the stability and precision of the circuit.

[0065] See Figure 6, specifically, the power management system of this embodiment further includes a NUTUBE power module 90. The input end of the NUTUBE power module 90 is connected to the OTG power management module 10, which is used to output the NUTUBE anode power supply, the NUTUBE filament power supply, and the NUTUBE grid bias voltage to the NUTUBE electron tube chip respectively.

[0066] The above embodiments are only the preferred embodiments of the present invention, and cannot be used to limit the scope of protection of the present invention. Any non-substantive changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection required by the present invention.

Claims

1. A power management system for a digital audio player, comprising a battery module and a filter module for providing power, characterized in that: Also includes: OTG power management module, digital audio circuit power module, headphone amplifier circuit power module, DAC circuit power module, the OTG power management module is connected to the battery module, and is connected to the USB interface module and the main control module of the audio player, and is used for charging the battery module, powering the main control module and realizing the USB OTG function, the digital audio circuit power module is connected to the OTG power management module, and is used to output a set of linear regulated power supplies to the digital audio processor of the audio player, the headphone amplifier circuit power module includes a DC / DC conversion circuit and a first hybrid filter circuit, the battery module is connected to the input end of the DC / DC conversion circuit after a filtering by the filtering circuit, the output end of the DC / DC conversion circuit is connected to the input end of the first hybrid filter circuit, and is used to output power supply to the headphone amplifier circuit of the audio player after a secondary filtering by the first hybrid filter circuit, the DAC circuit power module is connected to the OTG power management module, and includes two DAC power circuits with the same circuit structure, and the two DAC power circuits are used to provide two independent power supply voltages to the DAC circuits of the left and right channels of the audio player respectively.

2. The power management system of a digital audio player according to claim 1, characterized in that: The battery module adopts a lithium-ion battery pack with a one-series and two-parallel topology structure.

3. The power management system of a digital audio player according to claim 2, characterized in that: The filter module includes a supercapacitor and a filter capacitor. The input end of the supercapacitor is connected to the output end of the lithium-ion battery pack and is used as an auxiliary power source to provide power to the whole machine together with the lithium-ion battery pack to improve the power dynamic performance of the system. The input end of the filter capacitor is connected to the output end of the super capacitor to reduce the output ripple voltage and improve the load transient response.

4. The power management system of a digital audio player according to claim 1, characterized in that: The OTG power management module adopts a battery charging IC model MP2731, supports PD2.0 protocol and USB OTG function, and is used to realize fast charging of the battery module, transmission and sharing of audio files through the USB interface module.

5. The power management system of a digital audio player according to claim 1, characterized in that: The digital audio circuit power supply module includes a digital audio processor power supply circuit and a femtosecond crystal oscillator power supply circuit. The digital audio processor power supply circuit includes three filtering and voltage stabilizing circuits with the same circuit structure. The input ends of the three filtering and voltage stabilizing circuits are respectively connected to the OTG power management module, and are used to output 3.3V, 1.8V, and 1.2V linear regulated power supplies to the digital audio processor after filtering and voltage regulation of the system voltage provided by the OTG power management module; The femtosecond crystal oscillator power supply circuit includes one filtering and voltage stabilizing circuit and a second hybrid filtering circuit. The input end of one filtering and voltage stabilizing circuit is connected to the OTG power management module, and is used to output a 1.8V linear voltage stabilizing power supply to the input end of the second hybrid filtering circuit after primary filtering and voltage regulation of the system voltage provided by the OTG power management module. The second hybrid filtering circuit is used to perform secondary filtering on the 1.8V linear voltage stabilizing power supply and output it to the femtosecond crystal oscillator of the audio player.

6. The power management system of a digital audio player according to claim 1, characterized in that: The DC / DC conversion circuit adopts a DC / DC converter of model LT8334, whose input voltage range is 2.8V to 40V, and is used to provide a power supply with a wide dynamic range for the headphone amplifier circuit.

7. The power management system of a digital audio player according to claim 1, characterized in that: The first hybrid filter circuit is composed of a π-type LC filter circuit and a π-type RC filter circuit connected in series.

8. The power management system of a digital audio player according to any one of claims 6 or 7, characterized in that: The headphone amplifier circuit power supply module includes four headphone amplifier power supply circuits with the same circuit structure, and the four headphone amplifier power supply circuits are all composed of the DC / DC conversion circuit and the first hybrid filter circuit, and are used to respectively power the four discrete headphone amplifier circuits of the headphone amplifier circuit.

9. The power management system of a digital audio player according to claim 1, characterized in that: Each of the DAC power supply circuits includes a voltage conversion circuit, a first LDO circuit, a second LDO circuit and a third LDO circuit. The voltage conversion circuit is used to regulate the system voltage provided by the OTG power management module and output it to the second LDO circuit and the third LDO circuit respectively. The first LDO circuit, the second LDO circuit and the third LDO circuit respectively output the first power supply voltage, the second power supply voltage and the VREFH voltage to the DAC circuit.

10. The power management system of a digital audio player according to claim 9, characterized in that: The third LDO circuit adopts a linear regulator of model LT3045, and the VREFH voltage range of the third LDO circuit is 0V to 15V, which is used to provide a power supply with a wide dynamic range for the DAC circuit.

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