JP2004343414A - Audio apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an audio apparatus provided with a power source capable of supplying power corresponding to an operation condition with power consumption as small as possible. <P>SOLUTION: When a set value of a volume of an audio output set by a volume setting means 6 becomes low, the switching frequency of a boosting converter 2 becomes low, loss due to its switching operation is reduced, and power saving in the low power of the audio output can be realized. When a recording medium processing section 18 is not performing a reading operation, the switching frequency of a boosting converter 3 becomes low, loss due to its switching operation is reduced, and power saving can be expected in the low load while the section 18 is not performing the reading operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an audio device such as a portable disk reproducing device, a portable disk recording / reproducing device, and a portable radio, and more particularly to an audio device having a function of effectively utilizing electric energy of a battery mounted as a power supply.
[0002]
[Prior art]
For example, in a portable disk reproducing device used as an audio device, a recording medium processing unit that reads an audio PCM (Pulse Code Modulation) signal from a mini disk (MD) as a recording medium, and converts the read audio PCM signal into, for example, A signal processing unit having a 1-bit conversion unit that converts a 1-bit signal such as an audio PDM (Pulse Duration Modulation) signal or a PWM (Pulse Width Modulation) signal, an audio amplifier that switches and amplifies the converted 1-bit signal, Volume setting means for setting the volume of audio output by controlling the audio amplifier.
[0003]
Also, in this portable disk reproducing apparatus, a battery is used as a power supply of the apparatus because the apparatus is carried by a user. In order to stabilize an output voltage of a power supply circuit using the battery, a power supply circuit is used as a switching power supply. A circuit is used.
[0004]
As such a switching power supply circuit, for example, a DC-DC converter described in Patent Document 1 is known. The DC-DC converter includes a voltage resonance circuit including a primary winding of a switching transformer and a first capacitor for voltage resonance, a DC output current detection unit, and a second capacitor connected in parallel to the first capacitor. Switching means for switching whether or not to activate the capacitor according to the output of the DC output current detection means, wherein the connection of the second capacitor is switched in accordance with the load current to change the switching frequency.
[0005]
That is, in this DC-DC converter, when the power consumption of the load increases, the load current is detected, and the switching frequency is changed stepwise depending on whether or not to enable the capacitor of the switching circuit. It responds to changes in load current.
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 8-126312
[Problems to be solved by the invention]
However, in the above-described conventional DC-DC converter, since the switching frequency is set depending on whether or not the capacitor of the switching circuit is enabled, it is difficult to set the switching frequency finely. Further, a peripheral circuit for determining whether or not the capacitor is effective is required. Further, since the switching frequency is switched after detecting the load fluctuation, the stabilization of the voltage is delayed, and a malfunction or the like may occur during the operation of the device.
[0008]
SUMMARY An advantage of some aspects of the invention is to provide an audio device including a power supply that can supply power corresponding to an operation state with as little power consumption as possible.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an audio apparatus having audio amplifying means for amplifying a predetermined processed audio signal, wherein the switching frequency of a switching power supply for supplying power to the audio amplifying means is set to There is provided an audio device comprising switching frequency control means for controlling according to a set value of a volume.
[0010]
In this configuration, the switching frequency of the switching power supply changes according to the set value of the audio output volume. For example, when the set value of the volume of the audio output increases, the switching frequency of the switching power supply increases, thereby increasing the power supply capability to the audio amplifying unit, and preparing for an increase in the audio output. On the other hand, when the set value of the volume of the audio output decreases, the switching frequency of the switching power supply decreases, thereby reducing the loss due to the switching operation of the switching power supply and reducing power consumption when the audio output is low. Can be achieved.
[0011]
That is, according to this configuration, it is possible to provide an audio device including a power supply that can supply power corresponding to the operation state with as little power consumption as possible. In particular, when a battery is used as a power source, the battery can be used for a long time.
[0012]
According to the present invention, there is provided a recording medium processing means for performing predetermined processing of an audio information signal on a recording medium; Signal processing means having 1-bit conversion means for converting an audio information signal into a predetermined 1-bit signal; audio amplification means for switching and amplifying the converted 1-bit signal; and audio output by controlling the audio amplification means A first switching power supply for supplying power to the audio amplifying means, and a second switching for supplying power to the recording medium processing means. Power supply means and audio output set by the volume setting means Switching frequency control means for controlling a switching frequency of the first switching power supply means in accordance with a set value of a volume and controlling the second switching frequency in accordance with an operation state of the recording medium processing means. An audio device characterized by the following.
[0013]
In this configuration, the switching frequency of the first switching power supply changes according to the set value of the volume of the audio output. For example, when the set value of the volume of the audio output set by the volume setting unit is increased, the switching frequency of the first switching power supply unit is increased, whereby the power supply capability to the audio amplification unit is increased, Be prepared for increased audio output. On the other hand, when the set value of the volume of the audio output decreases, the switching frequency of the first switching power supply decreases, thereby reducing the loss due to the switching operation of the first switching power supply and reducing the audio output. Power saving during output can be achieved.
[0014]
Also, the switching frequency of the second switching power supply changes according to the operation state of the recording medium processing means. For example, when the recording medium processing unit reads an audio information signal from a recording medium, the switching frequency of the second switching power supply unit is increased, thereby increasing the power supply capability to the recording medium processing unit, and It can be prepared at the time of the read operation of the medium processing means. On the other hand, when the recording medium processing unit is not performing a read operation or a write operation, the switching frequency of the second switching power supply unit is reduced, thereby reducing the loss due to the switching operation of the second switching power supply unit, Power saving can be achieved at a low load when the recording medium processing means is not performing a read operation or a write operation.
[0015]
That is, according to this configuration, it is possible to provide an audio device including a power supply that can supply power corresponding to the operation state with as little power consumption as possible. In particular, when a battery is used as a power source, the battery can be used for a long time.
[0016]
Further, the switching frequency control means reduces the switching frequency of the first switching power supply means when the set value of the audio output volume set by the volume setting means is low, and sets the switching frequency when the set value of the volume is high. Since the control for increasing the switching frequency of the first switching power supply is performed, when the set value of the volume of the audio output increases, the switching frequency of the first switching power supply can be increased. When the set value of the volume of the audio output decreases, the switching frequency of the first switching power supply can be reduced. That is, by providing the switching frequency control means, the power to be supplied can be adjusted according to the audio output, so that the power consumption can be reduced.
[0017]
Further, the switching frequency control means increases the switching frequency of the second switching power supply means when the recording medium processing means reads an audio information signal from a recording medium or writes an audio information signal to a recording medium, Since the control is performed such that the switching frequency of the second switching power supply unit is lowered except at the time of reading or at the time of writing, the recording medium processing unit reads the audio information signal from the recording medium, or When an audio information signal is written to the second switching power supply, the switching frequency of the second switching power supply can be increased. On the other hand, when the recording medium processing means is not performing a read operation or a write operation, the second switching power supply can be used. Switching means It is possible to lower the wave number. That is, by providing the switching frequency control means, the power to be supplied can be adjusted according to the operation state of the recording medium processing means, so that the power consumption can be reduced.
[0018]
Further, the first and second switching power supply means comprise an external synchronous type DC-DC converter which outputs power supplied from a battery as a power supply as a stabilized power supply and performs a switching operation in synchronization with an external input frequency. Therefore, this DC-DC converter can change the switching frequency by changing the external input frequency, the circuit configuration for changing the switching frequency can be simplified, and the switching frequency can be finely or continuously changed. And the voltage can be stabilized quickly.
[0019]
A signal read from the recording medium and generated is an audio PCM signal, and a 1-bit signal obtained by converting the audio PCM signal by the 1-bit conversion means is a PDM signal or a PWM signal. Therefore, the audio PCM signal from the recording medium can be converted into a 1-bit signal such as a PDM signal or a PWM signal, and the 1-bit signal can be switched and amplified to output an audio signal.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of a mini-disc reproducing device as an audio device according to an embodiment of the present invention. In FIG. 1, the mini disc reproducing apparatus includes a recording medium processing unit (recording medium processing means) 18 for reading an audio PCM signal recorded on a mini disc 17, an RF amplifier 11, a decoder / signal processing circuit, a servo circuit, LSI (signal processing means) 12 having a circuit, audio amplifier (audio amplification means) 13, speaker 16, battery 1 as a power supply, volume setting means 6, boost converter 2 as first switching power supply means, second switching A microcomputer (microcomputer) 5 having a boost converter 3, a boost converter 4 as a power supply means, and a switching frequency control means 19 is provided.
[0021]
The recording medium processing unit 18 irradiates the recording surface of the mini-disc 17 with a laser beam and receives the reflected light, thereby detecting an audio PCM signal recorded on the mini-disc 17. A spindle motor 9 for rotating the mini-disc 17, a slide motor 8 for driving the optical pickup 10 stepwise in the radial direction of the mini-disc, and an optical pickup / controller for controlling the drive of the slide motor 8, the spindle motor 9 and the optical pickup 10. And a motor drive circuit 7.
[0022]
As a feature of this embodiment, in general, when the values of the coil and the capacitor used in the boost converter (DC-DC converter) are constant, the higher the switching frequency of the boost converter, the higher the current supply capability to the load. Utilize that it gets higher.
[0023]
That is, in a mini-disc reproducing apparatus as an audio apparatus, for example, an external synchronous boost converter 2 that performs a switching operation in synchronization with an external input frequency in accordance with a set value of a volume for controlling an audio output which is a cause of a load change. By changing the switching frequency, a fine or continuous switching frequency can be set, and a power supply that can supply power corresponding to the operation state with as little power consumption as possible is provided.
[0024]
Further, in this mini-disc reproducing apparatus, the microcomputer 5 grasps the operation state of the optical pickup / motor drive circuit 7 driven for reading the signal from the mini-disc 17, and performs the switching operation in synchronization with the external input frequency. By changing the switching frequency of the external synchronous boost converter 3 to be performed, a power supply capable of supplying power corresponding to the operating state with as little power consumption as possible is provided.
[0025]
Next, the operation of the mini-disc reproducing apparatus of the present embodiment will be described. The recording surface of the mini disc (MD) 17 has concentric or spiral tracks, and audio information signals such as audio / music data are digitally recorded along the tracks. The mini-disc 17 includes, in addition to an audio information signal (main information) such as audio / music data, a disc title, each track title, and address information of a memory storing audio / music data. U-TOC (user table of contents) information is also recorded.
[0026]
When reproducing the audio information signal recorded on the mini-disc 17, the mini-disc reproducing apparatus rotates the mini-disc 17 at a constant linear velocity or a constant angular velocity by a spindle motor 9 and also controls the optical pickup 10 to slide motor 8 Thus, the mini disc 17 is driven stepwise in the radial direction. The audio information signal is read by irradiating a laser beam from the optical pickup 10 positioned on a predetermined track toward the track, and detecting the intensity change of the reflected light again by the optical pickup 10.
[0027]
Here, the optical pickup 10 includes a light emitting element that emits a laser beam, an optical system including a collimator lens, a beam splitter, and an objective lens for guiding the light emitted from the light emitting element to the recording surface of the mini disc 17; It is composed of actuators for controlling the position of an objective lens for performing tracking and focusing of a laser beam on a read track of the mini-disc 17, respectively, and a photodetector (neither is shown) for detecting reflected light from the mini-disc 17. ing. The drive control of the optical pickup 10, the slide motor 8, and the spindle motor 9 is all performed by the optical pickup / motor drive circuit 7.
[0028]
The optical pickup 10 sends an audio information signal (compressed data) read from the mini disc 17 to the RF amplifier 11. The RF amplifier 11 amplifies the audio information signal and sends it to an LSI 12 having a decoder / signal processing circuit, and generates a servo control signal such as a tracking error signal and a focus error signal based on the audio information signal. , And to the servo circuit in the LSI 12.
[0029]
The servo circuit in the LSI 12 picks up an optical pickup according to the servo control signal, an address signal from a signal processing circuit in the LSI 12, and a control signal (F-control B) from a microcomputer 5 for a system controller. By controlling the motor drive circuit 7, servo control of various operations such as tracking, focusing, and disk spin is performed.
[0030]
In addition, this mini-disc reproducing apparatus is equipped with a battery 1 (for example, a dry battery or a nickel-metal hydride rechargeable battery) as an operation power supply unit of the terminal, and this battery 1 has a boost converter realized by a DC-DC converter. 2, 3 and 4 are connected via a DC input terminal 20. Among the boost converters 2, 3, and 4, the boost converters 2 and 3 are external synchronous boost converters that perform a switching operation in synchronization with an external input frequency (frequency of a signal from the microcomputer 5). The boost converter 2 supplies power to the audio amplifier 13, the boost converter 3 supplies power to the optical pickup / motor drive circuit 7, and the boost converter 4 supplies power to the RF amplifier 11, the LSI 12, and the microcomputer 5.
[0031]
On the other hand, a signal processing circuit in the LSI 12 performs processes such as extraction of an address signal, demodulation of a main signal, and error correction on the audio information signal amplified by the RF amplifier 11. Then, the processed audio information signal is sent to an audio decompression circuit in the LSI 12. The audio decompression circuit in the LSI 12 decompresses the audio information signal (compressed data) input from the RF amplifier 11 by decompressing it in the time axis according to a predetermined format to generate an audio PCM signal. The audio PCM signal is converted into an audio PDM signal or an audio PWM signal which is a 1-bit audio signal.
[0032]
The audio PDM signal or the audio PWM signal, which is a 1-bit audio signal, is sent to the audio amplifier 13 and is switched and amplified by the audio amplifier 13. The audio is output from the audio output terminals 14 and 15, and audio (sound / music) is output from the speaker 16 connected to the audio output terminals 14 and 15.
[0033]
The boost converter 2 as a first switching power supply means supplies a power (electric power) for switching and amplifying an audio PDM signal or an audio PWM signal which is a 1-bit audio signal by the audio amplifier 13. . The microcomputer 5 also has a switching frequency control means 19 for controlling the switching frequency of the boost converters 2, 3.
[0034]
Further, when the volume setting value of the mini-disc reproducing apparatus is set to a large value by the volume setting means 6, the microcomputer 5 increases the switching frequency of the boost converter 2 to increase the voltage of the power supply for switching amplification, It operates to increase the output voltage of the boost converter 2. On the other hand, when the set value of the volume is set to a small value, the switching frequency of the boost converter 2 is reduced to lower the voltage of the power supply, and the output of the boost converter 2 is reduced. Operates to lower the voltage.
[0035]
That is, the switching frequency control means 19 of the microcomputer 5 increases the switching frequency of the boost converter 2 when the volume setting value set by the volume setting means 6 for adjusting the audio output is large, and sets the volume setting value. Is smaller, the switching frequency of boost converter 2 is lowered. Thus, the power required for driving the switching elements in boost converter 2 can be reduced.
[0036]
By performing such an operation, as a result, an audio signal having a magnitude corresponding to the set value detected by the microcomputer 5 (the set value set by the volume setting means 6) is output from the audio amplifier 13. Become.
[0037]
Next, the switching frequency changing operation of the boost converter 2 according to the set value of the volume will be described with reference to the flowchart shown in FIG.
[0038]
First, in step m1, after the initialization processing of the microcomputer 5 is completed, in step m2, it is confirmed whether or not the volume setting value of the mini disk reproducing device has been changed by the volume setting means 6. If the set value of the volume has been changed, the process proceeds to step m3, and if not, the process returns to step m2. In step m3, it is checked whether the set value of the volume has become higher than before the setting. When the set value of the volume is increased, in step m5, the switching frequency of the boost converter 2 is increased according to the set value of the increased volume, the power supply capability to the audio amplifier 13 is increased, and Prepare for an increase in output.
[0039]
Conversely, if the set value of the volume has not become high, that is, if the set value of the volume has been lowered by the volume setting means 6, the switching frequency of the boost converter 2 is set in step m4 to the setting of the lowered volume. The power consumption of the mini-disc reproducing device is reduced by reducing the power loss due to the switching operation of the boost converter 2 in accordance with the value.
[0040]
FIG. 4 is a graph showing the operation of the F-control A, that is, a graph showing the relationship between the set value of the volume set by the volume setting means 6 and the switching frequency to the boost converter 2. The microcomputer 5 controls the boost converter 2 so that the switching frequency increases as the volume increases, for example, as indicated by a line L1 in FIG.
[0041]
On the other hand, the switching frequency of the boost converter 3 as the second switching power supply is also controlled by the switching frequency control means 19 of the microcomputer 5 (controlled by the F-control B) to read the signal from the mini disk 17. When the servo is ON, the switching frequency of the boost converter 3 is increased, and when the servo is not required to read a signal, the switching frequency of the boost converter 3 is decreased.
[0042]
For example, as shown in the table of FIG. 5, when the servo is on, the control frequency (switching frequency) is 300 kHz, and when the servo is off, the control frequency (switching frequency) is 100 kHz. As a result, it is possible to reduce the power required for driving the switching elements in the boost converter 3, especially when the servo is turned off without reading the signal from the mini disk 17.
[0043]
Next, the switching frequency changing operation of the boost converter 3 as the second switching power supply means according to the operation state of the recording medium processing unit 18 will be described with reference to the flowchart shown in FIG.
[0044]
First, in step n1, after the initialization process of the microcomputer 5 is completed, in step n2, the slide motor 8, the spindle motor 9, the optical pickup 10 And check if the servo is turned on. When the servo is turned on, the process proceeds to step n4. When the servo is not required to read the signal from the mini disk 17, the process proceeds to step n3.
[0045]
In step n3, the switching frequency of the boost converter 3 is reduced to a predetermined value (for example, 100 kHz), so that the power loss due to the switching operation of the boost converter 3 is reduced, and the power consumption of the mini disk reproducing device is reduced. On the other hand, since the servo is turned on, when the process proceeds to step n4, the switching frequency shifts from a low frequency (for example, 100 kHz) when the servo is turned off to a high frequency (for example, 300 kHz), and the power supply capability is increased.
[0046]
By the way, the boost converters 3 and 4 can supply a large output current by increasing the switching frequency, but the power consumption of the circuits of the boost converters 3 and 4 increases. On the other hand, if the switching frequency is reduced, the power consumption of the circuits of the boost converters 3 and 4 can be small, but a large output current cannot be made to flow. In designing the circuit, the switching frequency of the boost converters 3 and 4 is set assuming the required maximum current. However, when the output current (load current) is small, the circuits of the boost converters 3 and 4 themselves are used. Current consumption remains large.
[0047]
Therefore, in this embodiment, the operation state of the audio amplifier 13 (set value of the volume of the audio output) and the operation state of the recording medium processing unit 18 (the state of whether or not the audio information signal is read from the mini disk 17). ), An appropriate current can be supplied to the audio amplifier 13 and the recording medium processing unit 18, and in particular, the current consumption of the mini-disc reproducing apparatus when the load is light can be reduced, and power saving can be achieved. be able to.
[0048]
In the above-described embodiment, the power saving for the portable mini-disc reproducing apparatus as the audio device has been described. However, the present invention is not limited to this, and the power saving can be achieved for the portable mini-disc recording / reproducing apparatus and the portable radio. it can. Further, the reproducing apparatus and the recording / reproducing apparatus are not limited to those using an optical disk system such as a mini disk as a recording medium, but may be a conventional tape recorder using a magnetic tape as a recording medium. Further, the reproducing device, the recording / reproducing device, and the radio are not limited to the portable type.
[0049]
At the time of the recording operation in the portable mini-disc recording and reproducing apparatus, for example, assuming that the recording medium processing unit 18 in FIG. When there is no drive, the mini disk 17 and the optical pickup 10 are not driven. At this time, the power saving can be achieved by lowering the switching frequency of the boost converter 3 as the second switching power supply means. Further, with respect to the portable radio, power saving can be achieved by changing the switching frequency of the boost converter 2 as the first switching power supply means according to the set value of the audio output volume.
[0050]
【The invention's effect】
As described above, according to the present invention, in an audio device including an audio amplifying unit that amplifies a predetermined processed audio signal, the switching frequency of a switching power supply unit that supplies power to the audio amplifying unit is set to the volume of the audio output. Since the switching frequency control means for controlling according to the set value is provided, when the set value of the volume of the audio output is reduced, the switching frequency of the switching power supply means can be lowered, thereby reducing the loss due to the switching operation of the switching power supply means. In other words, it is possible to save power when the audio output is low.
[0051]
According to the present invention, there is provided a recording medium processing means for performing predetermined processing of an audio information signal on a recording medium, and wherein the predetermined processing is processing for reading an audio information signal from the recording medium, and Signal processing means having 1-bit converting means for converting the information signal into a predetermined 1-bit signal; audio amplifying means for switching and amplifying the converted 1-bit signal; In an audio apparatus having volume setting means for setting a volume setting value, first switching power supply means for supplying power to audio amplification means, and second switching power supply means for supplying power to recording medium processing means. Of the audio output volume set by the volume setting means And a switching frequency control means for controlling the second switching frequency in accordance with the operation state of the recording medium processing unit controls the switching frequency of the first switching power supply unit according to value.
[0052]
Therefore, according to the present invention, when the set value of the volume of the audio output is reduced, the switching frequency of the first switching power supply unit can be reduced, thereby reducing the loss due to the switching operation of the first switching power supply unit, It is possible to save power when the audio output is low.
[0053]
Further, the switching frequency of the second switching power supply can be changed according to the operation state of the recording medium processing unit. For example, when the recording medium processing means is not performing a read operation or a write operation, the switching frequency of the second switching power supply means can be lowered, thereby reducing the loss due to the switching operation of the second switching power supply means, and Power saving can be achieved at a low load when the processing means is not performing a read operation or a write operation.
[0054]
That is, according to these inventions, it is possible to supply power corresponding to the operation state with as little power consumption as possible. In particular, when a battery is used as a power source, the battery can be used for a long time.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a mini-disc reproducing device as an audio device according to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining a switching frequency changing operation of a boost converter according to a volume in the mini disc reproducing apparatus of the embodiment.
FIG. 3 is a flowchart for explaining a switching frequency changing operation of a boost converter according to an operation state of a recording medium processing unit in the mini disk reproducing device of the embodiment.
FIG. 4 is a diagram for explaining an operation example of F-control A from the microcomputer to the boost converter in the mini-disc reproducing apparatus of the embodiment.
FIG. 5 is a diagram for explaining an operation example of F-control B from the microcomputer to the boost converter in the mini disc reproducing apparatus of the embodiment.
[Explanation of symbols]
1 Battery 2 Boost Converter (First Switching Power Supply Means)
3. Boost converter (second switching power supply means)
6 volume setting means 12 LSI (signal processing means)
13. Audio amplifier (audio amplification means)
17 Mini disk (recording medium)
18. Recording medium processing unit (recording medium processing means)
19 Switching frequency control means

Claims (6)

In an audio apparatus having an audio amplifier for amplifying a predetermined processed audio signal, a switching frequency for controlling a switching frequency of a switching power supply for supplying power to the audio amplifier in accordance with a set value of an audio output volume. An audio device comprising control means. A recording medium processing unit for performing predetermined processing of an audio information signal on a recording medium; and, if the predetermined processing is processing of reading an audio information signal from the recording medium, converting the audio information signal read from the recording medium to a predetermined Signal processing means having 1-bit conversion means for converting into a 1-bit signal; audio amplification means for switching and amplifying the converted 1-bit signal; and controlling the audio amplification means to set a set value of an audio output volume. A first switching power supply for supplying power to the audio amplification means, a second switching power supply for supplying power to the recording medium processing means, Set the audio output volume set by the setting means. Switching frequency control means for controlling the switching frequency of the first switching power supply means in accordance with the value and controlling the second switching frequency in accordance with the operation state of the recording medium processing means. Audio equipment. The switching frequency control means reduces the switching frequency of the first switching power supply means when the audio output volume set value set by the volume setting means is low, and the first frequency when the volume setting value is high. 3. The audio equipment according to claim 2, wherein control is performed to increase the switching frequency of the switching power supply means. The switching frequency control means increases the switching frequency of the second switching power supply means when the recording medium processing means reads an audio information signal from a recording medium or writes an audio information signal to a recording medium, and performs the read operation. 3. The audio device according to claim 2, wherein control is performed to lower the switching frequency of the second switching power supply unit at the time of writing or other than at the time of writing. The first and second switching power supply means may be an external synchronous DC-DC converter that outputs power supplied from a battery as a power supply as a stabilized power supply and performs a switching operation in synchronization with an external input frequency. The audio device according to claim 2, wherein: The signal read from the recording medium and generated is an audio PCM signal, and the 1-bit signal obtained by converting the audio PCM signal by the 1-bit conversion means is a PDM signal or a PWM signal. 3. The audio device according to 2.

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