WO2024232062A1 - Audio device - Google Patents

Abstract

This audio device includes a first amplifier and one or more audio modules. The first amplifier is connected to a head unit that outputs audio data and control data, and processes the audio data on the basis of the control data. The one or more audio modules are connected to the first amplifier via an audio bus capable of two-way communication via serial communication, and function as an extension function or an additional function for the first amplifier. The first amplifier is operated by first electric power supplied from an external power supply. Second electric power is supplied from the first amplifier via the audio bus to at least one of the one or more audio modules. The at least one audio module operates by means of the second electric power.

Description

Audio Equipment

This disclosure relates to audio devices.

Patent Document 1 discloses a car audio device that is connected to an in-vehicle LAN (Local Area Network) such as a CAN (Controller Area Network) as an audio device having a head unit that outputs audio signals. Patent Document 1 also describes that the car audio device is supplied with power from a battery installed in the vehicle. Thus, in the car audio device of Patent Document 1, power is supplied to the head unit, main amplifier, and other accessories from a battery that serves as an external power source.

JP 2007-145182 A

In the car audio device described in Patent Document 1, a power supply harness is required for each device to supply power from the battery. As a result, the installation locations of the amplifiers and speakers may be restricted due to the need to route the power supply harness. Furthermore, when many amplifiers and speakers are installed in a vehicle, there is an issue that the weight of the vehicle increases due to the large number of power supply harnesses. In consideration of the above circumstances, one aspect of the present disclosure aims to increase the freedom of installation locations of the amplifiers and speakers while suppressing an increase in vehicle weight.

In order to solve the above problems, an audio device according to one aspect of the present disclosure includes a first amplifier connected to a head unit that outputs audio data and control data and processes the audio data based on the control data, and one or more audio modules that are connected to the first amplifier via an audio bus capable of bidirectional communication via serial communication and function as an extension or additional function for the first amplifier, the first amplifier operates on a first power supplied from an external power source, and at least one of the one or more audio modules is supplied with a second power from the first amplifier via the audio bus, and the at least one audio module operates on the second power.

1 is a schematic configuration diagram of an audio device according to a first embodiment. FIG. 2 is a diagram showing the configurations of a first amplifier and a second amplifier shown in FIG. 1 . FIG. 2 is a diagram showing an example of the configuration of an audio module. FIG. 4 is a perspective view showing the structure of the audio module of FIG. 3 . FIG. 4 is a side view showing the structure of the audio module of FIG. 3 . FIG. 2 is a diagram illustrating an example of the configuration of a headrest speaker. FIG. 1 is a diagram showing a vehicle according to an application example of an audio device.

A: First embodiment A1: Configuration of audio device

FIG. 1 is a schematic diagram of an audio device according to a first embodiment. Audio device 10 is a device that has expandable or addable audio functions. Audio device 10 is mounted, for example, in a vehicle.

As shown in FIG. 1, the audio device 10 includes a head unit 20, a first amplifier 30, a second amplifier 40_1, a third amplifier 40_2, a fourth amplifier 40_3, a fifth amplifier 40_4, a sixth amplifier 40_5, an additional function module 40_6, speakers 80_1, 80_2, 80_3, 80_4, 80_5, and 80_6, and a battery 90.

The second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 are each an example of an "audio module." Note that, below, the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 may each be referred to as an audio module 40.

The head unit 20 is a device that has the function of playing sound and accepting operations such as volume adjustment from the user. More specifically, the head unit 20 is, for example, a radio receiver, a CD (Compact Disc) player, a DVD (Digital Versatile Disc) player, a navigation system, or a combination of two or more of these devices. "CD" and "DVD" are each registered trademarks.

The head unit 20 outputs audio data DA and control data DS. The audio data DA is data indicating the sound to be reproduced, and is obtained by appropriately converting audio data read from a medium such as a CD, DVD, flash memory, or hard disk. Note that audio data input from an external device to an input terminal (not shown) conforms to various formats, and is appropriately converted into the format of the audio data DA. The format of the audio data DA is not particularly limited, and various known formats can be used.

The control data DS is data that indicates adjustment values such as the playback volume, the volume balance between the left and right speakers, the volume balance between the front and rear speakers, the equalizer, or the audio mode settings. Examples of the audio mode settings include a driver mode in which the volume balance is set to suit the driver's listening, and an all-seat mode in which the volume balance is set to suit listening in all seats. The control data DS is adjusted, for example, in response to a user's operation on an operating unit (not shown).

The first amplifier 30 is connected to the head unit 20 via the vehicle bus 50 and bus 60. The control data DS output from the head unit 20 is input to the first amplifier 30 via the vehicle bus 50. In addition, the audio data DA output from the head unit 20 is input to the first amplifier 30 via the bus 60.

The in-vehicle bus 50 is a communication network that allows intercommunication between multiple ECUs (Electronic Control Units) installed in the vehicle. Here, the head unit 20 and the first amplifier 30 are each a type of ECU. For example, the in-vehicle bus 50 is a vehicle bus that uses CAN (Controller Area Network) as a communication protocol.

Although not shown, in addition to the head unit 20 and the first amplifier 30, multiple ECUs are connected to the in-vehicle bus 50. The multiple ECUs include a diagnostic ECU. The diagnostic ECU performs fault diagnosis on devices such as the head unit 20 and the first amplifier 30 connected to the in-vehicle bus 50 using a diagnostic communication protocol such as UDS (Unified Diagnostic Service). Note that the in-vehicle bus 50 is not limited to a vehicle bus using CAN, and may be a vehicle bus using a communication protocol other than CAN, such as LIN (Local Interconnect Network) or FlexRay (registered trademark).

The bus 60 is a bus having a communication line for transmitting audio data DA from the head unit 20 to the first amplifier using a communication protocol different from that of the in-vehicle bus 50. The bus 60 is not particularly limited as long as it is a bus capable of transmitting the audio data DA, and is, for example, an in-vehicle audio bus such as an A ² B bus, AVB (Audio Video Bridging), or MOST (Media Oriented Systems Transport). "A ² B" and "MOST" are registered trademarks. The communication protocol used in the bus 60 may be the same as or different from the communication protocol used in the audio bus 70.

The first amplifier 30 is an audio amplifier. A speaker 80_1 is connected to the first amplifier 30. The speaker 80_1 is a device that converts an electrical audio signal into sound. The speaker 80_1 emits sound based on the audio signal output from the first amplifier 30.

The first amplifier 30 has the functions of amplifying an audio signal based on audio data DA, controlling the operation of each audio module 40, and acquiring status data DD for fault diagnosis. More specifically, the first amplifier 30 processes the audio data DA based on the control data DS to generate an audio signal based on the audio data DA. The first amplifier 30 amplifies the generated audio signal by an amplification factor based on the control data DS, and then outputs it to the speaker 80_1.

The first amplifier 30 is connected to the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 via the audio bus 70. In the example shown in FIG. 1, the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 are daisy-chained to the first amplifier 30 via the audio bus 70.

More specifically, the first amplifier 30 and the second amplifier 40_1 are connected to each other via a cable 70a. The second amplifier 40_1 and the third amplifier 40_2 are connected to each other via a cable 70b. The third amplifier 40_2 and the fourth amplifier 40_3 are connected to each other via a cable 70c. The fourth amplifier 40_3 and the fifth amplifier 40_4 are connected to each other via a cable 70d. The fifth amplifier 40_4 and the sixth amplifier 40_5 are connected to each other via a cable 70e. The sixth amplifier 40_5 and the additional function module 40_6 are connected to each other via a cable 70f.

The first amplifier 30 acquires status data DD from the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 via the audio bus 70 at a specific time, such as when requested by the diagnostic ECU or when the audio device 10 is started up.

The audio bus 70 is a bus capable of bidirectional communication via serial communication using a communication protocol different from that of the in-vehicle bus 50. For example, the audio bus 70 is an in-vehicle audio bus such as an ^A2B bus. The ^A2B bus is a high-bandwidth bidirectional digital audio bus, and is capable of transmitting not only the audio data DA and additional audio data DF but also the control data DS and command data via serial communication using an unshielded twisted pair cable.

The A ² B bus can supply power. That is, the A ² B bus supports so-called bus power. The upper limit of power that the A ² B bus can supply is, for example, 50 W. Therefore, when the power consumption of the audio module 40 is less than 50 W, the audio module 40 can operate only with power via the A ² B bus, and in this case, the audio module 40 does not require power from an external power source. Note that 50 W, which is the upper limit of power that the A ² B bus can supply, is merely an example and is not particularly limited to this. The audio bus 70 is not particularly limited to the A ² B bus as long as it is a bidirectional communication bus that supports bus power.

The audio bus 70 transmits audio data DA, control data DS, additional audio data DF, and status data DD between the head unit 20 and each audio module 40. The frame format for data transmission in the audio bus 70 includes, for example, four data slots for downstream, upstream, control, and response. The downstream data slot is used to transmit audio data DA. The upstream data slot is used to transmit additional audio data DF. The control data slot is used to transmit control data DS and command data. The response data slot is used to transmit response data such as status data DD output from the audio module 40.

The first amplifier 30 outputs the acquired status data DD to the diagnostic ECU via the vehicle bus 50. The status data DD is data indicating the status of the first amplifier 30, the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6, such as the presence or absence of a malfunction. The status data DD is data in a format that complies with a diagnostic communication protocol such as UDS.

The first amplifier 30 outputs audio data DA and control data DS to the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 via the audio bus 70. In addition to the audio data DA and control data DS, the first amplifier 30 outputs command data to the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 via the audio bus 70. The command data includes information indicating the audio module 40 that is to process the audio data DA and the control data DS.

The second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 are each driven based on command data from the first amplifier 30. That is, the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 each function as a replica with the first amplifier 30 as the primary.

The audio data DA and control data DS output from the first amplifier 30 are input via the audio bus 70 to the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6.

Each of the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5 is an audio module 40 that functions as an extension function for the first amplifier 30 using audio data DA and control data DS input via the audio bus 70. The extension function is an audio amplifier function. That is, each of the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5 is an audio amplifier. Each of the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5 processes the audio data DA based on the control data DS to generate an audio signal based on the audio data DA.

　Speakers 80_2, 80_3, 80_4, 80_5, and 80_6 are connected to the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5, respectively. The speakers 80_2, 80_3, 80_4, 80_5, and 80_6 are devices that convert electrical audio signals into sound, similar to the speaker 80_1.

Speaker 80_2 emits sound based on the audio signal output from the second amplifier 40_1. Speaker 80_3 emits sound based on the audio signal output from the third amplifier 40_2. Speaker 80_4 emits sound based on the audio signal output from the fourth amplifier 40_3. Speaker 80_5 emits sound based on the audio signal output from the fifth amplifier 40_4. Speaker 80_6 emits sound based on the audio signal output from the sixth amplifier 40_5.

Note that in FIG. 1, for convenience, each of speakers 80_1, 80_2, 80_3, 80_4, 80_5, and 80_6 is shown as a single speaker. However, typically, as described later with reference to FIG. 2, each of speakers 80_1, 80_2, 80_3, 80_4, 80_5, and 80_6 is composed of multiple speakers. The configurations of speakers 80_1, 80_2, 80_3, 80_4, 80_5, and 80_6 may be the same as each other or may be different. For example, the specifications of speakers 80_1, 80_2, 80_3, 80_4, 80_5, and 80_6, such as size, frequency characteristics, and rated output, may be the same as each other or may be different. In the following, each of speakers 80_1, 80_2, 80_3, 80_4, 80_5, and 80_6 may be simply referred to as speaker 80.

Each audio signal is amplified by an amplification factor based on the control data DS, and then output from the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5 to the speakers 80_2, 80_3, 80_4, 80_5, and 80_6, respectively. Note that additional audio data DF, which will be described later, is input to each of the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5 as necessary. Each of the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5 processes the additional audio data DF in the same manner as the audio data DA, and generates an audio signal indicating a composite sound of the sound indicated by the audio data DA and the sound indicated by the additional audio data DF.

Furthermore, the configurations of the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5 may be the same or different from each other. For example, the specifications of the number of channels, frequency characteristics, rated output, etc. of the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5 may be the same or different from each other.

The additional function module 40_6 is an audio module 40 that functions as an additional function for the first amplifier 30. The additional function may be any audio function that can be added to the first amplifier 30, and is not particularly limited, but examples include a road noise canceling function, a noise canceling function, a karaoke function, an ICC (In-Car Communication) function, an equalizer function, etc. The additional function module 40_6 has one or more of these functions.

The additional function module 40_6 generates additional audio data DF. The additional audio data DF is data indicating a sound to be added to the sound indicated by the audio data DA. For example, if the additional function module 40_6 has a road noise canceling function or a noise canceling function, the additional audio data DF is data indicating a canceling sound that is in the opposite phase to the noise picked up by a microphone installed in the vehicle. If the additional function module 40_6 has a karaoke function or an ICC function, the additional audio data DF is data indicating a sound picked up by a microphone installed in the vehicle.

The additional function module 40_6 receives audio data DA and control data DS via the audio bus 70 as necessary. For example, the additional function module 40_6 adjusts the volume of the sound indicated by the additional audio data DF based on the control data DS as necessary. For example, the additional function module 40_6 switches between using and not using the additional function as necessary. For example, from the viewpoint of preferably using the road noise canceling function or the karaoke function, the additional function module 40_6 uses the additional function when the vehicle window is closed based on the control data DS, and stops the additional function when the vehicle window is open. Furthermore, when the additional function module 40_6 has the road noise canceling function or the noise canceling function, it uses the output value of the acceleration sensor and the audio data DA to extract noise from the sound picked up by a microphone installed in the vehicle.

The additional function module 40_6 outputs additional audio data DF. The additional audio data DF output from the additional function module 40_6 is input to the first amplifier 30, the second amplifier 40_1, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5 via the audio bus 70.

The battery 90 generates a DC voltage of 12V. The battery 90 is connected to the head unit 20, the first amplifier 30, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 by the power supply harness 100. The battery 90 supplies power to the head unit 20, the first amplifier 30, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 via the power supply harness 100. That is, the battery 90 functions as an external power source for the head unit 20, the first amplifier 30, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6. The battery 90 may be a lead-acid battery, a lithium-ion battery, or the like. The voltage generated by the battery 90 is not particularly limited to 12V, and may be 24V or 48V.

The power supply harness 100 is not connected to the second amplifier 40_1 and the third amplifier 40_2. Therefore, power is not supplied from the battery 90 to the second amplifier 40_1 and the third amplifier 40_2. In this example, the total power consumption of the second amplifier 40_1 and the third amplifier 40_2 is 50 W or less. Therefore, the second amplifier 40_1 and the third amplifier 40_2 can operate using power via the audio bus 70.

A2: First Amplifier and Audio Module FIG. 2 is a diagram showing the configuration of the first amplifier 30 and the second amplifier 40_1 in FIG. 1. In FIG. 2, the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 are omitted. In the following, the second amplifier 40_1 will be described as a representative of the multiple audio modules 40. Note that the third amplifier 40_2, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5 are each configured in the same manner as the second amplifier 40_1. The additional function module 40_6 is configured in the same manner as the second amplifier 40_1, except that it has an additional function instead of an amplifier function.

As shown in FIG. 2, the head unit 20 has a communication circuit 21 and a communication circuit 22. The communication circuit 21 is a transceiver for data transmission using the vehicle bus 50, and is connected to a node of the vehicle bus 50. The communication circuit 21 transmits control data DS to the vehicle bus 50, and receives status data DD from the vehicle bus 50. The communication circuit 22 is a transceiver for data transmission using the bus 60, and is connected to a node of the bus 60. The communication circuit 22 transmits audio data DA to the bus 60.

The first amplifier 30 has a communication circuit 31, a communication circuit 33, a communication circuit 37, a processing circuit 32, a processing circuit 34, a memory circuit 35, and an amplifier circuit 36.

The communication circuit 31 is a transceiver for data transmission using the vehicle bus 50, and is connected to a node of the vehicle bus 50. Therefore, the communication circuit 31 is connected to the head unit 20 via the vehicle bus 50. The communication circuit 31 receives control data DS from the vehicle bus 50 and transmits status data DD to the vehicle bus 50 using a communication protocol for the vehicle bus 50.

The processing circuit 32 is an integrated circuit such as an MCU (Micro Control Unit) that controls the operation of each part of the first amplifier 30 based on the control data DS from the communication circuit 31.

The communication circuit 33 is a transceiver for data transmission using the bus 60, and is connected to a node of the bus 60. Therefore, the communication circuit 33 is connected to the head unit 20 via the bus 60. The communication circuit 33 receives the audio data DA from the bus 60 using a communication protocol for the bus 60.

The processing circuit 34 is a processor such as a DSP (digital signal processor) that processes the audio data DA from the communication circuit 33 based on the control data DS from the processing circuit 32. For example, the processing circuit 34 adjusts audio characteristics such as the frequency characteristics of the sound represented by the audio data DA based on the control data DS, and performs digital signal processing on the audio data DA so that it is output in a predetermined number of channels. In the example shown in FIG. 2, the processing circuit 34 outputs 12-channel audio signals. Note that part or all of the processing circuit 34 may be configured as an integrated circuit integrated with the processing circuit 32.

The memory circuit 35 stores various programs executed by the processing circuit 34 and various data processed by the processing circuit 34. The memory circuit 35 includes one or both of the following semiconductor memories: a volatile memory such as a RAM (Random Access Memory) and a non-volatile memory such as a ROM (Read Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory) or a PROM (Programmable ROM).

The amplifier circuit 36 amplifies the audio signal from the processing circuit 34 based on the control data DS. In the example shown in FIG. 2, the amplifier circuit 36 has an amplifier circuit 36a, an amplifier circuit 36b, and an amplifier circuit 36c. The amplifier circuit 36 amplifies 12-channel audio signals. Each of the amplifier circuits 36a, 36b, and 36c is an amplifier circuit such as a class AB amplifier circuit or a class D amplifier circuit that amplifies 4-channel audio signals.

Each channel corresponds to one speaker. Thus, speaker 80_1 is made up of 12 speakers. Four speakers of speaker 80_1 are connected to amplifier circuit 36a, amplifier circuit 36b, and amplifier circuit 36c, respectively. That is, speaker 80_1 is connected to amplifier circuit 36. Note that amplifier circuit 36 is not limited to the configuration shown in FIG. 2, and for example, amplifier circuit 36a, amplifier circuit 36b, and amplifier circuit 36c may be configured as an integrated unit.

The communication circuit 37 is a transceiver for data transmission using the audio bus 70, and is connected to a node of the audio bus 70. Therefore, the communication circuit 37 is connected to each audio module 40 via the audio bus 70. In the example shown in FIG. 2, the communication circuit 37 is connected to the second amplifier 40_1 via a cable 70a. The communication circuit 37 transmits audio data DA and control data DS to the audio bus 70 using a communication protocol for the audio bus 70, and receives additional audio data DF and status data DD from the audio bus 70. The communication circuit 37 also transmits command data to the audio bus 70 to request acquisition of the status data DD as necessary.

In this way, the first amplifier 30 includes a communication circuit 31 and a communication circuit 37, and controls the operation of the audio module 40 based on the control data DS. The communication circuit 31 is connected to the head unit 20 via the in-vehicle bus 50. This allows the head unit 20 and the first amplifier 30 to communicate with each other. This allows devices such as the head unit 20 connected to the in-vehicle bus 50 to control the first amplifier 30 and provide information about the first amplifier 30 to said devices.

The communication circuit 37 is also connected to the audio module 40 via the audio bus 70, and outputs audio data DA and control data DS using a communication protocol different from that of the in-vehicle bus 50. This allows the audio module 40 and the first amplifier 30 to communicate with each other. Furthermore, because the communication circuit 37 outputs the audio data DA and control data DS, the operation of the audio module 40 can be controlled as if the audio module 40 were part of the first amplifier 30. Furthermore, the configuration for controlling the operation of the audio module 40 is simplified, and the processing load on the audio module 40 is reduced.

The second amplifier 40_1 has a communication circuit 41, a processing circuit 42, a memory circuit 43, an amplifier circuit 44, and a switch 45.

The communication circuit 41 is a transceiver for data transmission using the audio bus 70, and is connected to a node of the audio bus 70. Therefore, the communication circuit 41 is connected to the first amplifier 30 and each of the other audio modules 40 via the audio bus 70. In the example shown in FIG. 2, the communication circuit 41 is connected to the communication circuit 37 of the first amplifier 30 via a cable 70a. The communication circuit 41 is also connected to the third amplifier 40_2 (not shown) via a cable 70b.

The communication circuit 41 receives audio data DA and control data DS from the cable 70a using the communication protocol for the audio bus 70, and transmits additional audio data DF and status data DD to the cable 70a. The communication circuit 41 also transmits audio data DA and control data DS to the cable 70b using the communication protocol for the audio bus 70, and receives additional audio data DF and status data DD from the cable 70a.

The processing circuit 42 is a processor such as a DSP that processes the audio data DA from the communication circuit 41 based on the control data DS from the communication circuit 41. For example, the processing circuit 42 adjusts audio characteristics such as the frequency characteristics of the sound represented by the audio data DA based on the control data DS, and performs digital signal processing on the audio data DA so that it is output through a predetermined number of channels. In the example shown in FIG. 2, the processing circuit 42 outputs a four-channel audio signal.

The memory circuit 43 stores various programs executed by the processing circuit 42 and various data processed by the processing circuit 34. The memory circuit 43 includes semiconductor memory, such as a volatile memory such as a RAM, or a non-volatile memory such as a ROM, an EEPROM, or a PROM, or both.

The amplifier circuit 44 amplifies the audio signal from the processing circuit 42 based on the control data DS. In the example shown in FIG. 2, the amplifier circuit 44 is an amplifier circuit such as a class AB amplifier circuit or a class D amplifier circuit that amplifies four-channel audio signals. A speaker 80_2 consisting of four speakers is connected to the amplifier circuit 44.

The switch 45 is an example of a "selection unit." The switch 45 is an electrically operated switch. Here, "electrically operated" means that the switch 45 operates according to an electrical signal input to the switch 45. The switch 45 selects and outputs either the first power or the second power based on the control data DS output from the head unit 20. The first power is power supplied from the battery 90 via the power supply harness 100. The second power is power supplied from the first amplifier 30 via the audio bus 70.

The switch 45 is connected to the processing circuit 42. The processing circuit 42 and the switch 45 communicate with each other via a bus capable of two-way communication. The bus capable of two-way communication between the processing circuit 42 and the switch 45 may be any bus capable of transmitting control data DS, and is not particularly limited thereto. A control bus such as an ^I2C (Inter-Integrated Circuit) bus or an SPI (Serial Peripheral Interface) bus is preferable.

As described above, the second amplifier 40_1 is not supplied with the first power from the battery 90. Therefore, the second amplifier 40_1 needs to be operated with the second power. A program is stored in advance in the memory circuit 43 so that the processing circuit 42 causes the switch 45 to select the second power. The processing circuit 42 causes the switch 45 to select the second power in accordance with the program. This enables the second amplifier 40_1 to operate with the second power. There is no need to connect the power supply harness 100 to the second amplifier 40_1. This increases the degree of freedom in the arrangement of the second amplifier 40_1.

In addition, in the memory circuit of the third amplifier 40_2, a program is stored in advance so that the processing circuit of the third amplifier 40_2 causes the switch of the third amplifier 40_2 to select the second power, similar to the second amplifier 40_1. The processing circuit of the third amplifier 40_2 causes the switch of the third amplifier 40_2 to select the second power according to the program.

Furthermore, a program is stored in advance in the memory circuit of the fourth amplifier 40_3 so that the processing circuit of the fourth amplifier 40_3 causes the switch of the fourth amplifier 40_3 to select the first power. The processing circuit of the fourth amplifier 40_3 causes the switch of the fourth amplifier 40_3 to select the first power in accordance with the program. Each of the processing circuits of the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 causes the switch of each audio module 40 to select the first power, similar to the processing circuit of the fourth amplifier 40_3.

In this way, by allowing the switch of each audio module 40 to select either the first power or the second power, there is no need to prepare multiple types of audio modules 40 to match different power supply forms. This improves the efficiency of product development and enables the product to be versatile.

In addition, in the audio device 10, the audio modules 40 function as an expansion function or additional function for the first amplifier 30, so that the first amplifier 30 can be made more multifunctional or more highly functional by appropriately adding audio modules 40 without replacing the first amplifier 30. Therefore, by appropriately changing the type, number, and combination of audio modules 40 used in the audio device 10, it is possible to diversify or highly functionalize the first amplifier 30 while reducing costs, without having to prepare multiple types of first amplifiers 30 with different functions in advance.

A3: Configuration of Audio Module Fig. 3 is a diagram showing an example of the configuration of the audio module 40a. The audio module 40a has a substrate 200 and a speaker 80_2a. The substrate 200 is equipped with a circuit for realizing the function of the second amplifier 40_1. The speaker 80_2a is one of the four speakers that make up the speaker 80_2.

The board 200 is equipped with a switch 45, a first signal connector 210, a second signal connector 220, a power connector 230, a first speaker connector 240, a second speaker connector 250, a third speaker connector 260, a fourth speaker connector 270, a control IC 280, and an amplifier IC 290.

Each of the first signal connector 210 and the second signal connector 220 is a connector for the audio bus 70. For example, a cable 70a is connected to the first signal connector 210. For example, a cable 70b is connected to the second signal connector 220. In this manner, the audio bus 70 is connected to the board 200.

The power connector 230 is a connector for connecting the power supply harness 100.

Each of the first speaker connector 240, the second speaker connector 250, the third speaker connector 260, and the fourth speaker connector 270 is a connector for connecting each of the speakers 80_2, which is made up of four speakers. Speaker 80_2a is connected to the first speaker connector 240. Speaker 80_2b is connected to the second speaker connector 250. Speaker 80_2c is connected to the third speaker connector 260. Speaker 80_2d is connected to the fourth speaker connector 270.

The control IC 280 has the communication circuit 41, processing circuit 42, and memory circuit 43 shown in FIG. 2.

The amplifier IC 290 has the amplifier circuit 44 shown in FIG. 2. The amplifier IC 290 generates a speaker drive signal based on the audio data DA input to the control IC 280, and outputs it to each of the speakers 80_2a, 80_2b, 80_2c, and 80_2d. Therefore, a speaker drive signal based on the audio data DA is input to each of the speakers 80_2a, 80_2b, 80_2c, and 80_2d.

In the example shown in FIG. 3, the control IC 280 and the amplifier IC 290 are separate, but the form of the IC is not limited to this, and the control IC 280 and the amplifier IC 290 may be integrated.

A4: Structure of the Audio Module Fig. 4 is a perspective view showing the structure of the audio module 40a in Fig. 3. Fig. 5 is a side view showing the structure of the audio module 40a in Fig. 3, as viewed from the direction of arrow A in Fig. 4. As shown in Fig. 4 and Fig. 5, the audio module 40a has a structure in which the substrate 200 is mounted on the speaker 80_2a.

Speaker 80_2a has a speaker frame 81 and a yoke 82, as well as a voice coil, a magnet, a diaphragm, etc. (not shown). Speaker frame 81 is a member having a sloping portion that shows the side shape of a truncated cone, and a circular ring portion that surrounds the sloping portion. Speaker frame 81 houses a diaphragm inside the sloping portion. Speaker frame 81 is made of resin. Note that speaker frame 81 may also be made of metal.

The yoke 82 is a cylindrical component with one end protruding radially like a flange. In Figures 4 and 5, the yoke 82 is placed over a ring-shaped magnet, voice coil, etc. with the flange-like protruding portion facing upwards, and is fixed to the center of the speaker frame 81. The center portion corresponds to the top surface of the truncated cone. The top surface of the yoke 82 is flat. The yoke 82 is made of metal. The yoke 82 and the magnet are configured to come into contact with each other.

The fixing member 300 is attached to the speaker 80_2a. The fixing member 300 is a member for fixing the substrate 200 to the speaker 80_2a. The fixing member 300 has a cylindrical portion 310 and four protrusions 321, 322, 323, and 324. The cylindrical portion 310 has a cylindrical shape. The inner diameter of the cylindrical portion 310 is larger than the outermost diameter of the yoke 82. The protrusions 321, 322, 323, and 324 protrude from one end of the cylindrical portion 310 in the same direction along the central axis of the cylindrical portion 310. The end faces of the protrusions 321, 322, 323, and 324 are flat. The heights h from one end of the cylindrical portion 310 to the end faces of the protrusions 321, 322, 323, and 324 are the same.

The fixing member 300 is fixed to the center of the speaker frame 81 by fitting or gluing. The height h of each of the protrusions 321, 322, 323, and 324 is designed in advance so that when the fixing member 300 is fixed to the center of the speaker frame 81, the end faces of each of the protrusions 321, 322, 323, and 324 are in the same plane as the top surface of the yoke 82.

The substrate 200 is attached to the fixing member 300 with the mounting surface of the amplifier IC 290 facing the yoke 82. More specifically, four spacers 401, 402, 403, and 404 are provided between the substrate 200 and the four protrusions 321, 322, 323, and 324, respectively. The substrate 200 is fixed to the protrusions 321, 322, 323, and 324, respectively, via the four spacers 401, 402, 403, and 404 using four screws 501, 502, 503, and 504. The heights of the four spacers 401, 402, 403, and 404 are the same as the height of the amplifier IC 290. With the above configuration, the surface of the amplifier IC 290 and the upper surface of the yoke 82 come into contact with each other.

It is preferable that a heat dissipating silicone paste is applied to the surface of the amplifier IC 290. A heat dissipating silicone gel sheet may also be sandwiched between the surface of the amplifier IC 290 and the upper surface of the yoke 82.

In FIG. 5, the sound emitting surface S1 of the speaker 80_2a faces downward on the page. The sound emitting surface S1 is the surface from which sound waves are radiated into the air by vibration of the diaphragm of the speaker 80_2a. The top surface of the yoke 82 is the surface opposite the sound emitting surface S1 of the speaker 80_2a. Therefore, the amplifier IC 290 is in contact with the surface opposite the sound emitting surface S1 of the speaker 80_2a. Therefore, the heat generated from the amplifier IC 290 is transferred to the metal yoke 82, and dissipated from the yoke 82 into the air, a magnet, etc.

Thus, the audio module 40a has a board 200 to which the audio bus 70 is connected, and a speaker 80_2a to which a speaker drive signal based on the audio data DA is input. An electrically operated switch 45 is mounted on the board 200.

The switch 45 selects either the first power or the second power based on the control data DS output from the head unit 20 via the audio bus 70.

A5: Configuration Example of Headrest Speaker Fig. 6 is a diagram showing a configuration example of a headrest speaker. A headrest speaker is a speaker that is installed in a headrest of a seat of a vehicle. The headrest speaker is provided on each of the left and right sides of the headrest.

As shown in FIG. 6, an audio module 40a and a speaker 80_2b are arranged in a headrest 601 of the left front seat. As shown in FIG. 4 etc., the audio module 40a has a speaker 80_2a. A speaker 80_2c and a speaker 80_2d are arranged in a headrest 602 of the right front seat.

The head unit 20 and the first amplifier 30 are disposed, for example, at the front of the vehicle interior. The head unit 20 and the first amplifier 30 are connected by an in-vehicle bus 50 and a bus 60. The head unit 20 and the first amplifier 30 are each supplied with a first power from a battery 90 via a power supply harness 100. A speaker 80_1 is connected to the first amplifier 30. The first amplifier 30 and the audio module 40a are connected by a cable 70a.

The first amplifier 30 drives the speaker 80_1. The amplifier IC 290 drives the speakers 80_2a, 80_2b, 80_2c, and 80_2d.

The speakers placed in the headrest emit sound close to the user's ears, so speakers with a relatively small rated output are selected for placement in the headrest. Therefore, the rated output of each of speaker 80_2a, speaker 80_2b, speaker 80_2c, and speaker 80_2d is smaller than the rated output of speaker 80_1.

With the above configuration, the power consumption of the amplifier IC 290 is relatively small, and is set to, for example, 50 W or less. In this case, the power consumption of the amplifier IC can be covered by only the second power. Therefore, there is no need to connect the power supply harness 100 to the audio module 40a. In this way, when installing headrest speakers in the headrest 601 of the left front seat and the headrest 602 of the right front seat, wiring is possible with only one audio module, three speakers, one audio bus, and three speaker cables. In other words, in this example, the audio module 40a is supplied with the second power from the first amplifier 30 via the audio bus 70, and the audio module 40a operates using the second power.

A6: Application Example of Audio Device Fig. 7 is a diagram showing a vehicle relating to an application example of audio device 10. Fig. 7 shows a schematic example of the layout of each part of audio device 10 mounted on vehicle 900. Vehicle 900 includes audio device 10 and in-vehicle bus 50.

In the example shown in FIG. 7, 30 speakers 80 are installed in the vehicle 900. More specifically, a set of three-way speakers is installed in each of the right front door 901R, the left front door 901L, the right rear door 902R, and the left rear door 902L, i.e., a total of 12 speakers 80 are installed in the four doors. In addition, one speaker 80 is installed on the dashboard 903 as a center speaker. One speaker 80 is installed on each of the right D pillar 904R and the left D pillar 904L.

Furthermore, two speakers 80 are installed in each of the headrests 602 of the right front seat 905R, 601 of the left front seat 905L, 906R and 906L, making a total of eight speakers 80. Also, one speaker 80 is installed as a subwoofer in the trunk room 907. Three speakers 80 are installed in each of the front and center of the ceiling 908, making a total of six speakers 80.

Furthermore, the head unit 20 and the first amplifier 30 are each disposed near the dashboard 903. The second amplifier 40_1 is disposed in the headrest 601 of the left front seat 905L. The third amplifier 40_2 is disposed in the headrest 603 of the left rear seat 906L. The fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 are each disposed near the trunk 907. As described above, the first amplifier 30, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 operate on the first power. Furthermore, the power supply harness 100 is not connected to the second amplifier 40_1 and the third amplifier 40_2, and the second amplifier 40_1 and the third amplifier 40_2 operate on the second power.

The first amplifier 30 drives a three-way speaker installed in the right front door 901R, a three-way speaker installed in the left front door 901L, a center speaker installed in the dashboard 903, and three speakers installed in front of the ceiling 908.

The second amplifier 40_1 drives two speakers installed in the headrest 602 of the right front seat 905R and two speakers installed in the headrest 601 of the left front seat 905L. The third amplifier 40_2 drives two speakers installed in the headrest 603 of the right rear seat 906R and two speakers installed in the headrest 604 of the left rear seat 906L.

The fourth amplifier 40_3 drives a three-way speaker installed in the left rear door 902L and one speaker installed in the left rear of the ceiling 908. The fifth amplifier 40_4 drives one speaker installed in the right D pillar 904R, one speaker installed in the left D pillar 904L, a subwoofer installed in the trunk room 907, and one speaker installed in the center rear of the ceiling 908. The sixth amplifier 40_5 drives a three-way speaker installed in the right rear door 902R and one speaker installed in the right rear of the ceiling 908.

With the above configuration, the user can fully experience the immersive feeling of stereophonic sound such as Dolby Atmos (registered trademark), regardless of where they are seated in the vehicle.

Note that the audio device 10 shown in FIG. 7 is merely an example, and the arrangement of each part of the audio device 10 and the number of speakers 80 are not particularly limited to this example.

A3: Summary of the First Embodiment As described above, the audio device 10 according to the first embodiment includes a first amplifier 30 and an audio module 40. The first amplifier 30 is connected to the head unit 20 that outputs audio data DA and control data DS, and processes the audio data DA based on the control data DS. The audio module 40 is connected to the first amplifier 30 via an audio bus 70 capable of bidirectional communication by serial communication, and functions as an extended function or additional function for the first amplifier 30. The first amplifier 30 operates with a first power supplied from a battery 90. The second amplifier 40_1 and the third amplifier 40_2 are supplied with a second power from the first amplifier 30 via the audio bus 70, and the second amplifier 40_1 and the third amplifier 40_2 operate with the second power.

According to the audio device 10 according to the first embodiment, the second amplifier 40_1 and the third amplifier 40_2 are supplied with the second power, and the second amplifier 40_1 and the third amplifier 40_2 operate on the second power. Since the power supply harness 100 for supplying the first power is not required for the audio module that operates on the second power, the degree of freedom in the installation location can be increased, and thus an increase in the vehicle weight is suppressed.

In the first embodiment, the battery 90 is an example of an "external power source," the speaker 80_1 is an example of a "first speaker," the speaker 80_2a is an example of a "second speaker," and the speakers 80_2b, 80_2c, and 80_2d are examples of a "third speaker."

Furthermore, the first power and the second power are supplied to the audio module 40 except for the second amplifier 40_1 and the third amplifier 40_2. The audio module 40 has a selection unit that selects either the first power or the second power. The audio module 40 operates with the first power or the second power selected by the selection unit instead of the second power.

With this configuration, the audio module 40 operates on the first power or the second power. The power supply harness 100 is not required for the audio module 40 that operates on the second power, which allows for greater freedom in installation location and thus prevents an increase in vehicle weight. The power supply harness 100 is required for the audio module 40 that operates on the first power, but it is possible to supply power that is greater than the supply capacity of the second power.

The audio module 40a also has a board 200 to which the audio bus 70 is connected, and a speaker 80_2a to which a speaker drive signal based on the audio data DA is input.

In this configuration, the audio bus 70 is connected to the board 200 of the audio module 40a, so that audio data DA is input to the board 200 via the audio bus 70. Then, a speaker drive signal based on the input audio data DA is sent to the speaker 80_2a.

The board 200 also includes an amplifier IC 290 that generates a speaker drive signal based on the audio data DA.

With this configuration, audio data DA is input to the board 200 via the audio bus 70, and a speaker drive signal is generated in the amplifier IC 290 based on the audio data DA. Therefore, the speaker 80_2a can emit sound based on the speaker drive signal.

The substrate 200 is also mounted on the speaker 80_2a.

With this configuration, the board 200 and the speaker 80_2a are integrated, making it possible to miniaturize the audio module 40a.

The amplifier IC 290 also contacts the surface of the speaker 80_2a opposite the sound emitting surface.

This configuration allows the amplifier IC 290 to dissipate heat with a simple structure, eliminating the need for additional heat dissipation components, thereby reducing the number of components in the speaker 80_2a.

The audio module 40a also has a board 200 to which the audio bus 70 is connected, and a speaker 80_2a to which a speaker drive signal based on the audio data DA is input. An electrically operated switch 45 is mounted on the board 200.

This configuration makes it easier to switch the power that operates the audio module 40a between the first power and the second power.

The switch 45 also selects either the first power or the second power based on the control data DS output from the head unit 20 via the audio bus 70.

With this configuration, the power that operates the audio module 40a can be switched more easily between the first power and the second power without manual intervention.

The first amplifier 30 drives the speaker 80_1, and the audio module 40a is used to drive the speakers 80_2a, 80_2b, 80_2c, and 80_2d, which have a smaller rated output than the speaker 80_1.

With this configuration, the audio module 40a can operate using the second power. When the audio module 40a can operate using the second power, the power supply harness 100 that connects the battery 90 and the audio module 40a becomes unnecessary. This increases the degree of freedom in the layout of the audio module 40a and the speakers 80_2b, 80_2c, and 80_2d that correspond to the audio module 40a.

Furthermore, the first amplifier 30 drives the speaker 80_1. The amplifier IC 290 drives the speakers 80_2a, 80_2b, 80_2c, and 80_2d. The rated output of the speaker 80_2a is smaller than the rated output of the speaker 80_1. The rated output of the speakers 80_2b, 80_2c, and 80_2d is smaller than the rated output of the speaker 80_1.

With this configuration, the amplifier IC 290 can operate using the second power. When the amplifier IC 290 can operate using the second power, the power supply harness 100 that connects the battery 90 and the board 200 on which the amplifier IC 290 is mounted becomes unnecessary. This increases the degree of freedom in the layout of the amplifier IC 290 and the speakers 80_2a, 80_2b, 80_2c, and 80_2d that correspond to the amplifier IC 290.

Speakers 80_2a, 80_2b, 80_2c, and 80_2d are headrest speakers arranged in headrests 601 and 602 of the vehicle.

This configuration makes it easier to install multiple speakers in the vehicle's headrest, helping to improve the acoustic characteristics inside the vehicle.

B: Modifications The present invention is not limited to the above embodiment, and various modifications can be adopted within the scope of the present invention. Specific modification modes are exemplified below. In addition, two or more modes arbitrarily selected from the following examples can be appropriately combined within a range that does not contradict each other. In the modifications exemplified below, for elements whose actions and functions are equivalent to those of the above embodiment, the symbols used in the above explanation will be used and detailed explanations of each will be omitted as appropriate.

B1: First Modification In the above embodiment, a program is stored in advance in the storage circuit of each audio module 40 so that the processing circuit of each audio module 40 selects the first power or the second power through the switch of each audio module 40. Also, in the above embodiment, the power supply harness 100 is not connected in advance to the second amplifier 40_1 and the third amplifier 40_2 for which the second power is selected.

However, the power supply harness 100 may be connected so that the first power is supplied to each of all audio modules 40, and the worker setting up the audio device 10 in the vehicle may use the head unit 20 to set whether the switch of each audio module 40 selects the first power or the second power. In this way, when the worker uses the head unit 20 to set the switches of each audio module 40, information regarding the setting is sent as part of the control data DS to the processing circuit of each audio module 40, and each switch is set.

B2: Second Modification When the first power is supplied to each of all audio modules 40, the power consumption of each audio module 40 may be detected, and the audio module 40 that operates with the second power may be determined based on the detected power consumption of each audio module 40.

More specifically, in this modified example, each audio module 40 is provided with a power detection circuit capable of detecting power consumption. Either the processing circuits 32, 34 of the first amplifier 30 or the processing circuits of each audio module 40 becomes a master processing circuit and acquires information regarding the power consumption of each audio module 40. Based on the acquired information regarding the power consumption of each audio module 40, the master processing circuit determines which audio modules 40 are to be operated using the first power and which audio modules 40 are to be operated using the second power.

With this configuration, the audio module 40 that operates with the first power can operate stably without a shortage of power. Also, the audio module 40 that operates with the second power does not need to be connected to the power supply harness 100, which increases the freedom of positioning of the audio module 40.

B3: Third Modification In the above embodiment, the switch 45 is an electrically operated switch, but may be a mechanically operated switch. In this case, a slide switch, a toggle switch, or the like is used as the switch. The switch is switched by an operator who sets up the audio device 10 in the vehicle. For example, when the power consumption of the audio module 40 is estimated to be greater than 50 W, the switch 45 is set by an operator at the stage of setting up the audio device 10 in the vehicle so that the audio module 40 operates with the first power. On the other hand, when the power consumption of the audio module 40 is estimated to be 50 W or less, the switch 45 is set by an operator at the stage of setting up the audio device 10 in the vehicle so that the audio module 40 operates with the second power.

This configuration eliminates the need to prepare multiple types of audio modules 40 to suit different power supply forms. This improves the efficiency of product development and enables the product to be versatile.

Note that although the switch 45 is used as an example of a "selection unit," a jumper chip or jumper wire may be used as the selection unit instead of an electrically or mechanically operated switch. Also, either the first power supply path or the second power supply path on the board may be patterned to be cuttable.

B4: Fourth Modification As with the headrest speakers, speakers with relatively small rated output are selected for the ceiling speakers installed in the ceiling 908 of the vehicle 900. Therefore, the rated output of each of the ceiling speakers is smaller than the rated output of the speaker 80_1.

With this configuration, the power consumption of the amplifiers that drive the ceiling speakers can be relatively small, and is set to, for example, 50 W or less. In this case, the power consumption of the amplifiers that drive the ceiling speakers can be covered by the second power alone. Therefore, in the configuration shown in FIG. 7, the six ceiling speakers are driven by the first amplifier 30, the fourth amplifier 40_3, the fifth amplifier 40_4, and the sixth amplifier 40_5, respectively, but instead of this, the following configuration may be used.

For example, in this modified example, one of the three ceiling speakers in the front row and one of the three ceiling speakers in the rear row are each replaced with an audio module 40a as shown in FIG. 4, etc. The two speakers in the front row are connected to the audio module 40a in the front row, and the two speakers in the rear row are connected to the audio module 40a in the rear row. In this case, the amplifier IC mounted in each audio module 40a may be an amplifier IC with three or more channels.

In this way, the speakers mounted on the audio module 40a and the speakers connected to the audio module 40a are ceiling speakers arranged on the ceiling 908 of the vehicle. This makes it easier to install multiple speakers on the ceiling 908 of the vehicle 900, which contributes to improving the acoustic characteristics inside the vehicle cabin.

B5: Fifth Modification In the above embodiment, the additional function module 40_6 generates the additional audio data DF, but instead, the head unit 20 may generate data similar to the additional audio data DF. In this case, the data similar to the additional audio data DF is transmitted from the head unit 20 to the first amplifier via the bus 60 together with the audio data DA.

B6: Sixth Modification In the above embodiment, the yoke 82 and the magnet are in contact with each other, but the yoke 82 and the magnet do not have to be in contact with each other. In this case, the heat of the amplifier IC 290 is dissipated from the yoke 82 into the air.

B7: Seventh Modification In the above embodiment, the end faces of the protrusions 321, 322, 323, 324 and the upper surface of the yoke 82 are designed to be included in the same plane, and the upper surface of the yoke 82 and the surface of the amplifier IC 290 are brought into contact with each other by using spacers 401, 402, 403, 404 having a height equal to that of the amplifier IC 290. The structure for bringing the upper surface of the yoke 82 into contact with the surface of the amplifier IC 290 is not particularly limited to this. The fixing member may be designed taking into account the height of the amplifier IC 290, and the spacer may be omitted. Furthermore, the structure and shape of the fixing member are not particularly limited to those in the above embodiment, and are arbitrary.

B8: Eighth Modification In the above embodiment, a cone-type speaker is exemplified as the speaker 80, but the structure of the speaker is not particularly limited to this. The speaker may be a dome type, a horn type, or the like, as long as it has a structure using a voice coil and a magnet.

B9: Ninth Modification In the above embodiment, the fourth amplifier 40_3, the fifth amplifier 40_4, the sixth amplifier 40_5, and the additional function module 40_6 are supplied with the first power and the second power, and the switch of each audio module 40 is caused to select the first power. However, the audio module 40 operated by the first power does not necessarily need to be supplied with the second power. For example, the audio module 40 operated by the first power may not have a switch. In other words, the audio module 40 operated by the first power may be configured to be directly supplied with the first power without going through a switch.

B10: Tenth Modification In the above embodiment, the second amplifier 40_1 has the switch 45, and the third amplifier 40_2 has a switch similar to the switch 45, but the second amplifier 40_1 and the third amplifier 40_2 to which only the second power is supplied do not necessarily have to have a switch. That is, the second amplifier 40_1 and the third amplifier 40_2 may be configured to be supplied with the second power directly without passing through a switch.

C: Supplementary Note From the above-described exemplary embodiments, the following configurations, for example, can be understood.

An audio device according to one aspect (aspect 1) of the present disclosure includes a first amplifier connected to a head unit that outputs audio data and control data and processes the audio data based on the control data, and one or more audio modules that are connected to the first amplifier via an audio bus capable of bidirectional communication via serial communication and function as an extension or additional function for the first amplifier, the first amplifier operates on a first power supplied from an external power source, and at least one of the one or more audio modules is supplied with a second power from the first amplifier via the audio bus, and the at least one audio module operates on the second power.

According to this aspect, the second power is supplied to each audio module, and each audio module operates using the second power. Since a power supply harness for supplying the first power is not required for audio modules that operate using the second power, the degree of freedom in installation location can be increased, thereby suppressing an increase in vehicle weight.

In an audio device according to one aspect (aspect 2) of the present disclosure, the at least one audio module is supplied with the first power and the second power, the at least one audio module has a selection unit that selects either the first power or the second power, and the at least one audio module operates with the first power or the second power selected by the selection unit instead of the second power.

According to this aspect, each audio module operates on the first power or the second power. Since a power supply harness is not required for an audio module that operates on the second power, the degree of freedom in installation location can be increased, thereby suppressing an increase in vehicle weight. Although a power supply harness is required for an audio module that operates on the first power, it is possible to supply power that is greater than the supply capacity of the second power.

In an audio device according to one aspect (aspect 3) of the present disclosure, the at least one audio module has a board to which the audio bus is connected and a speaker to which a speaker drive signal based on the audio data is input.

In this embodiment, an audio bus is connected to the board of each audio module, so that audio data is input to the board via the audio bus, and a speaker drive signal based on the input audio data is sent to the speaker.

In an audio device according to one aspect (aspect 4) of the present disclosure, the board is equipped with an amplifier IC that generates the speaker drive signal based on the audio data.

According to this embodiment, audio data is input to the board via the audio bus, and the amplifier IC generates a speaker drive signal based on the audio data, so that the speaker can emit sound based on the speaker drive signal.

In an audio device according to one aspect (aspect 5) of the present disclosure, the substrate is mounted on the speaker.

In this embodiment, the board and the speaker are integrated, making it possible to miniaturize the audio module.

In an audio device according to one aspect (aspect 6) of the present disclosure, the amplifier IC contacts the surface of the speaker opposite the sound emitting surface.

In this embodiment, the amplifier IC can dissipate heat with a simple structure, eliminating the need for additional heat dissipation components, thereby reducing the number of speaker components.

In an audio device according to one aspect (aspect 7) of the present disclosure, the at least one audio module has a board to which the audio bus is connected and a speaker to which a speaker drive signal based on the audio data is input, and the board is equipped with the selection unit, which is an electrically operated switch.

According to this aspect, the power that operates the audio module can be more easily switched between the first power and the second power.

In an audio device according to one aspect (aspect 8) of the present disclosure, the switch selects either the first power or the second power based on the control data output from the head unit via the audio bus.

According to this aspect, the power that operates the audio module can be more easily switched between the first power and the second power without manual intervention.

In an audio device according to one aspect (aspect 9) of the present disclosure, the first amplifier drives a first speaker, and each of the at least one audio module is used to drive a second speaker having a lower rated output than the first speaker.

According to this aspect, each audio module can operate using the second power. When each audio module can operate using the second power, a power supply harness connecting an external power source to each audio module is not required, which increases the freedom of layout of each audio module and the speakers corresponding to each audio module.

In an audio device according to one aspect (aspect 10) of the present disclosure, the first amplifier drives a first speaker, the amplifier IC drives a second speaker and a third speaker, the rated output of the second speaker is smaller than the rated output of the first speaker, and the rated output of the third speaker is smaller than the rated output of the first speaker.

According to this aspect, each amplifier IC can operate using the second power. When each amplifier IC can operate using the second power, a power supply harness connecting an external power source and a board on which each amplifier IC is mounted becomes unnecessary, which increases the degree of freedom in the layout of each amplifier IC and the speakers corresponding to each amplifier IC.

In an audio device according to one aspect (aspect 11) of the present disclosure, the second speaker is a ceiling speaker arranged in the ceiling of the vehicle or a headrest speaker arranged in the headrest of the vehicle, and the third speaker is a ceiling speaker arranged in the ceiling of the vehicle or a headrest speaker arranged in the headrest of the vehicle.

This aspect makes it easier to install multiple speakers in the ceiling or headrest of a vehicle, helping to improve the acoustic characteristics inside the vehicle.

10...audio device, 20...head unit, 30...first amplifier, 40, 40a...audio module, 45...switch, 70...audio bus, 80, 80_1, 80_2a, 80_2b, 80_2c, 80_2d...speakers, 90...battery, 200...substrate, 290...amplifier IC, 601, 602, 603, 604...headrest, 900...vehicle, 908...ceiling, DA...audio data, DS...control data, S1...sound emission surface.

Claims (11)

a first amplifier connected to a head unit that outputs audio data and control data, the first amplifier processing the audio data based on the control data;
one or more audio modules that are connected to the first amplifier via an audio bus capable of bidirectional serial communication and function as an extended function or an additional function for the first amplifier;
the first amplifier is operated by a first power supplied from an external power supply;
a second power is supplied to at least one of the one or more audio modules from the first amplifier via the audio bus, and the at least one audio module is operated by the second power;
Audio equipment. the at least one audio module is supplied with the first power and the second power;
the at least one audio module has a selection unit that selects either the first power or the second power;
the at least one audio module operates using the first power or the second power selected by the selection unit instead of the second power;
2. The audio device of claim 1. the at least one audio module has a board to which the audio bus is connected and a speaker to which a speaker drive signal based on the audio data is input;
3. An audio device according to claim 1 or 2. an amplifier IC for generating the speaker driving signal based on the audio data is mounted on the substrate;
4. An audio device as claimed in claim 3. The substrate is mounted to the speaker.
5. An audio device as claimed in claim 4. The amplifier IC is in contact with the surface of the speaker opposite to the sound emitting surface.
6. An audio device as claimed in claim 5. the at least one audio module has a board to which the audio bus is connected and a speaker to which a speaker drive signal based on the audio data is input;
The selection unit is mounted on the substrate, and the selection unit is an electrically operated switch.
3. An audio device as claimed in claim 2. The switch selects either the first power or the second power based on the control data output from the head unit via the audio bus.
8. An audio device as claimed in claim 7. the first amplifier drives a first speaker;
Each of the at least one audio module is used to drive a second speaker having a rated output lower than that of the first speaker.
3. An audio device according to claim 1 or 2. the first amplifier drives a first speaker;
The amplifier IC drives a second speaker and a third speaker,
The rated output of the second speaker is smaller than the rated output of the first speaker,
The rated output of the third speaker is smaller than the rated output of the first speaker.
5. An audio device as claimed in claim 4. The second speaker is a ceiling speaker disposed in a ceiling of the vehicle or a headrest speaker disposed in a headrest of the vehicle.
The third speaker is a ceiling speaker disposed in a ceiling of the vehicle or a headrest speaker disposed in a headrest of the vehicle.
11. An audio device as claimed in claim 10.

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