Method for operating an audio system for a vehicle, and audio system

Abstract

The invention relates to a method for operating an audio system (1) for a vehicle. According to the invention, by means of a logic-based controller (9.1) activity states (A1 to An) of audio sources (10.1 to 10.n) are monitored and at least one loudspeaker channel (3, 4) of a digital output stage (16) is deactivated if all audio sources (10.1 to 10.n) allocated to this loudspeaker channel (3, 4) are inactive. The invention also relates to an audio system (1) for a vehicle.

Description

[0001] Method for operating an audio system for a vehicle and audio system

[0002] The invention relates to a method for operating an audio system for a vehicle.

[0003] The invention further relates to an audio system for a vehicle according to the preamble of claim 8.

[0004] DE 198 15 923 A1 discloses a control device for an audio amplifier for reducing interference with reproduced audio signals. When interference with the reproduced audio signals occurs, the control device reduces the power of the audio amplifier to reduce the playback volume of the audio signals. Once the interference with the reproduced audio signals has ceased, the control device increases the power of the audio amplifier to the value set before the reduction.

[0005] Furthermore, US 2017 / 0250654 A1 discloses a method and a device for dynamically managing a dead time between switching on transistors in output power stages in audio amplifiers. A driver signal is generated based on an input signal, wherein the driver signal is amplified by alternately driving a first transistor and a second transistor with a time between deactivating the first transistor and activating the second transistor. The time is set based on a parameter of the input signal or the driver signal during amplification. The parameter is an amplitude of the input signal, a duty cycle of the driver signal, or a duty cycle of a pulse-width-modulated signal generated based on the input signal. The input signal is a digital audio input signal.

[0006] DE 102021 003 593 A1 discloses an audio system that is deactivated to save energy when there is no audio signal or when a mute command is issued. US 2019 / 0007777 A1 discloses an audio system that switches between two modes depending on the seat occupancy. The invention is based on the object of specifying a novel method for operating an audio system for a vehicle and a novel audio system for a vehicle.

[0007] The object is achieved according to the invention by a method having the features specified in claim 1 and by an audio system having the features specified in claim 8.

[0008] Advantageous embodiments of the invention are the subject of the subclaims.

[0009] In the method for operating an audio system for a vehicle, according to the invention, activity states of audio sources are monitored by means of a logic-based control and at least one loudspeaker channel of a digital audio power amplifier is deactivated if all audio sources assigned to this loudspeaker channel are inactive.

[0010] In today's audio entertainment systems in vehicles, in addition to the acoustic output of classic entertainment content, such as radio content, there is also an acoustic output of a sound design and audio signals assigned to various vehicle functions, such as direction indicator tones, warning tones, parking aid tones, etc. Due to the large number of loudspeakers installed in or on the vehicle, audio amplifiers in audio entertainment systems consume energy even when not all loudspeaker channels are needed.This results from the fact that, for example, using a so-called audio programming platform on the audio power amplifier itself, audio signals are generated and passed on to another amplifier system or the loudspeakers for playback. The conversion components used in this process, in particular a digital-to-analog converter and the audio power amplifier, cause power losses even when the audio output is not being used, i.e., when the signal content is zero. While completely shutting down the audio power amplifier, including its power supply, offers significant savings potential, this only allows for the deactivation of all loudspeaker channels.

[0011] In contrast, the present method enables speaker channels to be switched on and off very dynamically during runtime using complex logic conditions based on current system states in the vehicle, thus saving energy for unused speaker channels. However, activating and deactivating a speaker channel takes time and thus disrupts the response behavior during audio signal playback, which can lead to audible audio artifacts. By taking into account the activity of the audio sources, in particular in addition to the signal content of an output audio signal, the present method enables predictive deactivation and activation of the speaker channels, so that audible audio artifacts and the "swallowing" of sounds can be effectively avoided during activation. Thus, the functionality of the audio system is not impaired from the user's perspective.As a result, energy consumption during real-world vehicle operation can be reduced without any restrictions for the vehicle user. In particular, the method can be implemented using flexibly adaptable software. This increases the reliability of eliminating audio artifacts, as a software component can be programmed by a vehicle manufacturer within sound functions. This also allows the deactivation of speaker channels to be easily handled differently between different vehicle series or different audio systems.

[0012] In one possible embodiment of the method, audio signals from active audio sources are bundled on at least one loudspeaker channel. This bundling allows, for example, audio signals processed on infrequently used loudspeaker channels to be transmitted to other loudspeaker channels, allowing the infrequently used loudspeaker channels to be deactivated.

[0013] In a further possible embodiment of the method, a driving state of the vehicle and / or operating parameters of the vehicle and / or operating parameters of vehicle systems are or will be taken into account when monitoring the activity states of the audio sources. This enables an assessment of which audio signals or audio content must be reproduced, so that in a particularly advantageous manner only those loudspeaker channels are deactivated whose use is considered particularly unlikely in a currently detected situation. For example, the output of signal tones from a parking aid is not required when the vehicle is driving at speeds of more than 30 km / h, so that loudspeaker channels that emit these signal tones can be deactivated even if other audio sources using these loudspeaker channels are inactive.In another possible embodiment of the method, when deactivating a loudspeaker channel, the loudspeaker channel is first muted and then an amplifier module located in the loudspeaker channel is deactivated. This prevents audible noises, such as crackling or popping, when deactivating the corresponding loudspeaker channel.

[0014] In another possible embodiment of the method, audio signals output by coupled audio sources are amplified by amplifier modules located in the loudspeaker channels in an activated state. This enables separate amplification of the audio signals for each loudspeaker channel.

[0015] In another possible embodiment of the method, a received digital audio signal for each activated loudspeaker channel is converted into an analog audio signal using pulse width modulation before being transmitted to the corresponding loudspeaker. This enables the processing of digital audio signals and the output of analog audio signals.

[0016] In another possible embodiment of the method, muting a loudspeaker channel is performed by deactivating the pulse width modulation. This represents a simple and reliable deactivation.

[0017] An audio system for a vehicle comprises multiple audio sources and at least one digital audio amplifier coupled to the audio sources, having multiple speaker channels. The speaker channels each amplify audio signals output by at least one audio source and transmit the amplified audio signals to at least one coupled speaker.

[0018] According to the invention, at least one control unit with a logic-based control is provided, wherein the control unit is designed to monitor activity states of audio sources and to deactivate at least one loudspeaker channel if all audio sources assigned to this loudspeaker channel are inactive.

[0019] The audio system enables speaker channels to be switched on and off very dynamically during runtime using complex logic conditions based on the current system states in the vehicle, thus saving energy when using unused speaker channels. However, activating and deactivating a speaker channel takes time and thus disrupts the response of audio signals, which can lead to audible audio artifacts. However, by taking the activity of the audio sources into account, in particular in addition to considering the signal content of an output audio signal, the audio system enables predictive deactivation and activation of the speaker channels, effectively preventing audible audio artifacts and the "swallowing" of sounds during activation. This means that the audio system's functionality is not impaired from the user's perspective.As a result, energy consumption during real-world vehicle operation can be reduced without any restrictions for the vehicle user. In particular, a deactivation function for the loudspeaker channels can be implemented using flexibly adaptable software. This increases the reliability of eliminating audio artifacts, as a software component can be programmed by a vehicle manufacturer within sound functions. This also allows the deactivation of the loudspeaker channels to be easily handled differently between different vehicle series or different audio systems.

[0020] In one possible embodiment of the audio system, the control unit is further configured to bundle audio signals from active audio sources onto at least one loudspeaker channel. This bundling allows, for example, audio signals processed on infrequently used loudspeaker channels to be transmitted to other loudspeaker channels, allowing the infrequently used loudspeaker channels to be deactivated.

[0021] Embodiments of the invention are explained in more detail below with reference to a drawing.

[0022] It shows:

[0023] Fig. 1 shows a schematic block diagram of an audio system for a vehicle.

[0024] The single figure 1 shows a block diagram of an audio system 1 for a vehicle.

[0025] The audio system 1 comprises a distribution module 2, two loudspeaker channels 3, 4, a digital audio output stage 16 with two amplifier modules 5, 6, two loudspeakers 7, 8, a control unit 9 and a plurality of audio sources 10.1 to 10.n. Furthermore, the audio system comprises a data source 11 for driving state parameters F of the vehicle, a data source 12 for special operating parameters B of the vehicle and / or vehicle systems and a data source 13 for transmitting activity states A1 to An of the audio sources 10.1 to 10.n to the control unit 9. A mute device 14, 15 is arranged in each of the loudspeaker channels 3, 4.

[0026] In the audio system 1, audio processing software implemented in the distribution module 2 distributes audio content to be played back from the audio sources 10.1 to 10.n to the various loudspeaker channels 3, 4 present in the vehicle. In exemplary embodiments not shown in detail, any other plurality of loudspeaker channels 3, 4 and loudspeakers 7, 8 is possible, deviating from the two loudspeaker channels 3, 4 shown to explain the audio system 1. The audio content is converted into electrical signals and amplified so that the loudspeakers 7, 8 can emit a corresponding sound. This amplification takes place in the amplifier modules 5, 6, which generate power loss even when no audio signal is present for amplification. However, when the amplifier modules 5, 6 are deactivated, they do not generate any power loss.

[0027] Activating and deactivating the amplifier modules 5, 6 can be achieved in various ways, enabling different energy-saving potentials depending on the method. Either the entire audio power amplifier 16 can be activated or deactivated, or, as is possible with digital audio power amplifiers 16, pulse width modulation, by means of which a digital audio signal output by the audio sources 10.1 to 10.n is converted into an analog audio signal before being passed on to the corresponding loudspeaker 7, 8, is activated or deactivated. While activating and deactivating the entire audio power amplifier 16 usually affects several loudspeaker channels 3, 4, activating and deactivating pulse width modulation with digital audio power amplifiers 16 enables separate activation and deactivation for each loudspeaker channel 3, 4.

[0028] However, both methods require a certain amount of time for a chip in the audio power amplifier 16 to power up or down. During this time, audio content cannot be played back. A response time of, for example, 50 ms to 500 ms for the audio power amplifier 16 or the amplifier modules 5, 6 to power up is so long that the resulting dead time can be perceived as annoying by a vehicle user. If the loudspeakers 7, 8 are also used to emit advisory and / or warning tones, shorter response times are prescribed by law. Therefore, deactivating the audio power amplifier 16 or the amplifier modules 5, 6 solely based on an analysis of whether or not audio data is available for a loudspeaker channel 7, 8 is not a useful control variable for activation and deactivation.

[0029] In order to minimize the power loss and thus energy consumption of the audio system 1 and consequently of the vehicle, it is provided that at least one loudspeaker channel 3, 4 of the digital audio power amplifier 16 is deactivated by means of a logic-based controller 9.1 implemented in the control unit 9 when all audio sources 10.1 to 10.n assigned to this loudspeaker channel 3, 4 are inactive. In this case, the activity states A1 to An of the audio sources 10.1 to 10.n are monitored by means of the control unit 9. In addition, the driving state parameters F of the vehicle and operating parameters B of the vehicle and / or vehicle systems can be taken into account when activating and deactivating the loudspeaker channels 3, 4.

[0030] The logic-based controller 9.1 is implemented, for example, as a software module in the control unit 9 and comprises, for example, so-called communication middleware for Ethernet communication in the vehicle and is designed, for example, for serialization and message exchange. The logic-based controller 9.1 thus decides, depending on various input parameters, which loudspeaker channel 3, 5 can be activated or deactivated. For example, based on the activity states A1 to An, it is checked whether a radio function is generally active or whether permanent sound synthesis is active. Based on the driving state parameter F, it is checked, for example, how high the vehicle's driving speed is, according to which it can be assessed which information or warning tones must be played via the loudspeakers 7, 8.For example, it can be specified that no vehicle warning sound generator (Acoustic Vehicle Alert System; AVAS for short) is active at driving speeds above 30 km / h, and / or that all loudspeakers 7, 8 in the vehicle interior must always be active at driving speeds below 20 km / h, for example, because parking aid sounds are to be emitted. Based on the operating parameters B of the vehicle and / or vehicle systems, it can be checked, for example, whether a special energy-saving mode has been activated.

[0031] Depending on the activity states A1 to An, as well as, if applicable, the driving state parameter F and the operating parameter B, the control unit 9 generates an output signal S, by means of which the corresponding loudspeaker channel 3, 4 is first muted in the event of deactivation by means of the muting devices 14, 15, and only then is the respective amplifier module 5, 6 deactivated. This avoids audible noise, in particular crackling, which can arise from deactivating the respective amplifier module 5, 6.

[0032] Additionally, the output signal S can also be used to influence the audio processing software implemented in the distribution module 2, for example, instructing it not to include certain loudspeaker channels 3, 4 in the audio playback or to set an emergency channel mix. This can prevent interference experienced by the user during switching or in the event of a fault.

[0033] By separately controlling individual speaker channels 3, 4, it can be ensured that the speaker channels 3, 4 required for a given operating state remain active, while all other speaker channels 3, 4 can be considered for a power-saving state. Audio signals from active audio sources 10.1 to 10.n can also be bundled on at least one speaker channel 3, 4, allowing additional speaker channels 3, 4 to be deactivated to save energy.

[0034] For example, the software module implemented in control unit 9 to implement logic-based control 9.1 can be integrated using freely programmable middleware. This allows a deactivation algorithm for loudspeaker channels 3, 4 and associated parameters, such as deactivation speeds, to be flexibly adapted to a vehicle development process or transferred to vehicles via over-the-air updates. At the same time, this allows for harmonization of the scope of deactivation options for loudspeaker channels 3, 4 with the audio sources 10.1 to 10.n contained in the vehicle, their properties, the number of loudspeaker channels, the types of audio power amplifiers 16, and increasing experience and / or development progress.

[0035] It is also possible for more than one software module to be used to deactivate loudspeaker channels 3, 4. For example, one software module can be provided for controlling loudspeaker channels 3, 4 for loudspeakers 7, 8 located inside the vehicle, and another software module can be provided for loudspeakers 7, 8 located outside the vehicle and intended for emitting external noise. Since software for external noise is subject to certification, software modules for external loudspeakers 7, 8 may no longer be changed after a certain point in time. By separating the software module for deactivating internal and external loudspeaker channels 3, 4 as described, flexibility in the development process for the internal loudspeaker channels 3, 4 is maintained despite a so-called certification freeze for the external loudspeaker channels 3, 4.

[0036] The following table shows which speakers 7, 8 or speaker channels 3, 4 are used for certain audio sources 10.1 to 10. n in a vehicle, for example.

[0037]

[0038] Table 1

Claims

Patent claims Method for operating an audio system (1) with a plurality of audio sources (10.1 to 10.n) and a plurality of loudspeaker channels (3, 4) for a plurality of loudspeakers (7, 8) for a vehicle, characterized in that by means of a logic-based control (9.1) - Activity states (A1 to An) of the audio sources (10.1 to 10.n) are monitored and - at least one of the plurality of loudspeaker channels (3, 4) of a digital audio power amplifier (16) is deactivated if all audio sources (10.1 to 10.n) assigned to this loudspeaker channel (3, 4) are inactive. Method according to claim 1, characterized in that audio signals from active audio sources (10.1 to 10.n) are bundled onto at least one loudspeaker channel (3, 4). Method according to claim 1 or 2, characterized in that when monitoring the activity states (A1 to An) of the audio sources (10.1 to 10.n) - Driving condition parameters (F) of the vehicle and / or - Operating parameters (B) of the vehicle and / or - Operating parameters (B) of vehicle systems are taken into account. Method according to one of the preceding claims, characterized in that when deactivating a loudspeaker channel (3, 4), the loudspeaker channel (3, 4) is first muted and then an amplifier module (5, 6) located in the loudspeaker channel (3, 4) is deactivated. Method according to one of the preceding claims, characterized in that audio signals output by means of coupled audio sources (10.1 to 10.n) are amplified by means of amplifier modules (5, 6) located in the loudspeaker channels (3, 4) in an activated state. Method according to claim 5, characterized in that for each activated loudspeaker channel (3, 4), a received digital audio signal is converted into an analog audio signal by means of pulse width modulation before being forwarded to the corresponding loudspeaker (7, 8). Method according to one of claims 4 to 6, characterized in that the muting of a loudspeaker channel (3, 4) is carried out by deactivating the pulse width modulation. Audio system (1) for a vehicle with a plurality of audio sources (10.1 to 10.n) and at least one connected to the audio sources (10.1 to 10.n) coupled digital audio output stage (16) with a plurality of loudspeaker channels (3, 4) for a plurality of loudspeakers (7, 8), wherein the loudspeaker channels (3, 4) each amplify audio signals output by means of at least one audio source (10.1 to 10.n) and transmit the amplified audio signals to at least one coupled loudspeaker (7, 8), characterized in that at least one control unit (9) with a logic-based controller (9.1) is provided, wherein the control unit (9) is designed,. - to monitor activity states (A1 to An) of the audio sources (10.1 to 10.n) and - to deactivate at least one of the plurality of loudspeaker channels (3, 4) if all audio sources (10.1 to 10.n) assigned to this loudspeaker channel (3, 4) are inactive. Audio system (1) according to claim 8, characterized in that the control unit (9) is designed to bundle audio signals from active audio sources (10.1 to 10.n) on at least one loudspeaker channel (3, 4).

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