Techniques for improving power efficiency of a playback device

Abstract

A playback device includes a processor that executes program instructions such that the playback device is configured to receive first audio data representative of audio content, generate and output second audio data based on the first audio data, and at least partially contemporaneous with generating and outputting the second audio data, generate and output a control signal associated with the second audio data to vary a supply voltage of an audio amplifier. The playback device also includes a switch mode power supply (SMPS) that varies the supply voltage of the audio amplifier based on the control signal. The playback device also includes an amplifier circuit that includes the audio amplifier powered by the supply voltage from the SMPS. The amplifier circuit is configured to receive the second audio data and generate an analog audio signal based on the second audio data to drive a loudspeaker.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application 62 / 994,049, filed March 23, 2020, entitled "Techniques for Improving the Power Efficiency of a Playback Device," and U.S. Provisional Application 63 / 158,132, filed March 8, 2021, entitled "Techniques for Improving the Power Efficiency of a Playback Device." The disclosures of U.S. Provisional Applications 62 / 994,049 and 63 / 158,132 are incorporated herein by reference in their entirety. Technical Field

[0003] This invention relates to consumer products, and more particularly, to methods, systems, products, features, services and other elements or aspects thereof for media playback. Background Technology

[0004] Before SONOS Ltd. began developing a new playback system in 2002, options for accessing and listening to digital audio outdoors were limited. Sonos subsequently filed its first patent application in 2003, entitled "Method for Synchronizing Audio Playback between Multiple Networked Devices," and began selling its first media playback system in 2005. Sonos' wireless home audio system allows people to experience music from many sources via one or more networked playback devices. Through a software control application installed on a controller (e.g., a smartphone, tablet, computer, voice input device), people can play whatever they want in any room with a networked playback device. Media content (e.g., songs, podcasts, video audio) can be streamed to the playback devices, allowing each room with a playback device to play different media content. Furthermore, rooms can be grouped together to synchronously play the same media content, and / or the same media content can be heard synchronously in all rooms. Attached Figure Description

[0005] The features, aspects, and advantages of the currently disclosed technology can be better understood from the following description, appended claims, and accompanying drawings, as set forth below. Those skilled in the art will understand that the features shown in the drawings are for illustrative purposes, and variations in the inclusion of different and / or additional features and their arrangement are possible.

[0006] Figure 1A This is a partial cross-sectional view of an environment with a media playback system, based on the example.

[0007] Figure 1B It is based on the example. Figure 1A A schematic diagram of a media playback system and one or more networks.

[0008] Figure 1C It is a block diagram of the playback device based on the example.

[0009] Figure 1D It is a block diagram of the playback device based on the example.

[0010] Figure 1E This is a block diagram based on the example network microphone device.

[0011] Figure 1F This is a block diagram based on the example network microphone device.

[0012] Figure 1G It is a block diagram of the playback device based on the example.

[0013] Figure 1H This is a partial schematic diagram of the control device based on the example.

[0014] Figure 1I To IL is a schematic diagram of the corresponding media playback system area based on the example.

[0015] Figure 1M This is a schematic diagram of the media playback system area based on the example.

[0016] Figure 2 A circuit logic diagram of a playback device based on an example is shown.

[0017] Figure 3 The example illustrates an operation that can be performed to generate control signals for the power supply to change the amplifier's power supply voltage.

[0018] Figure 4A The first approach, according to the example, is shown, in which the control signal can be configured to control the power supply to output the amplifier power supply voltage.

[0019] Figure 4B A second approach, based on the example, is shown, where the control signal can be configured to control the power supply to output the amplifier power supply voltage.

[0020] Figure 4C A third approach, based on the example, is shown, in which the control signal can be configured to control the power supply to output the amplifier power supply voltage.

[0021] Figure 5A variation of the operation performed by the playback device, based on the example, is shown.

[0022] Figure 6 A logic diagram of circuit 600 according to the example is shown, which is Figure 2 A variant of the circuit 200 shown.

[0023] Figure 7A The example is shown. Figure 6 The logic diagram of the circuit limiter.

[0024] Figure 7B The example is shown. Figure 6 The logic diagram of another limiter in the circuit.

[0025] Figure 7C The example is shown. Figure 6 The logic diagram of another limiter in the circuit.

[0026] Figure 8A The example shows the power supply voltage provided by the circuit's power source, where the power supply voltage momentarily drops below a low voltage threshold.

[0027] Figure 8B The amplifier power supply voltage and envelope associated with the audio output during a sudden increase are shown in the example.

[0028] Figure 9 The examples illustrate operations that can be performed by the playback devices and / or circuitry described herein.

[0029] Figure 10 A logic diagram of an entity is shown to minimize the likelihood of performing amplifier power supply voltage limiting operation, based on the example collaboration.

[0030] Figure 11 The examples illustrate operations that can be performed by the playback devices and / or circuitry described herein.

[0031] The accompanying drawings are for illustrative purposes, but those skilled in the art should understand that the techniques disclosed herein are not limited to the arrangements and / or means shown in the drawings. Detailed Implementation

[0032] I. Overview

[0033] For over a decade, SONOS Ltd. has been a consistent innovator in the audio field, earning a reputation for creating products with exceptional sound quality that can be seamlessly integrated into their environments, such as users' homes, businesses, or other commercial establishments. In contrast to competitors who integrate low-quality sensors into their products to produce passable sound, SONOS Ltd. takes an uncompromising approach to the design of its sensors and amplifiers, driving them to deliver a superior sound experience.

[0034] As SONOS Ltd. expands into new product categories, including battery-powered playback devices, it remains committed to delivering a best-in-class audio experience for each product. Providing a truly superior audio experience to the end user in battery-powered playback devices presents various challenges. Given that the power consumption of audio amplifiers typically increases with playback volume, one challenge is to simultaneously achieve significantly higher volume levels than comparable battery-powered devices while still maintaining at least the same battery-powered runtime.

[0035] To improve the power efficiency of playback devices (and the total runtime of battery-powered playback devices), some playback devices employ switching amplifiers (e.g., Class D amplifiers) to drive sensors. Switching amplifiers are generally much more power efficient than linear amplifiers (e.g., Class A, Class B, Class AB, and Class C amplifiers). Switching amplifiers typically include one or more switches connected to the power rail of the switching amplifier, which generate a series of pulses with characteristics that vary based on the input signal (e.g., pulse width, pulse density, etc.). This series of pulses can then be filtered (e.g., using a low-pass filter) to generate the output signal. While switching amplifiers can provide power savings compared to other types of amplifiers (e.g., linear amplifiers), the power savings from using a switching amplifier alone may not be sufficient to provide best-in-class audio performance during extended battery-powered operation in a battery-powered playback device.

[0036] Various aspects of this invention demonstrate that conventional playback device designs use a fixed supply voltage for the amplifier. Typically, the fixed supply voltage is set to a sufficiently high level to support distortion-free amplification of the input signal in the worst-case scenario (e.g., maximum amplitude). However, such a worst-case input signal occurs relatively infrequently during normal operation. Therefore, the fixed supply voltage is often significantly higher than the voltage required for the amplifier to amplify the input signal. Furthermore, reducing the amplifier's supply voltage to just above the voltage level required for distortion-free amplification of the input signal can improve the power efficiency of the playback device.

[0037] Given the significantly higher power requirements of audio amplification compared to other applications (e.g., radio stations), a key technical challenge is successfully varying the amplifier supply voltage without compromising the power efficiency of other components in the device. One approach, for example, would be to use a linear power supply to generate the amplifier supply voltage based on the input signal to the amplifier. The large bandwidth of a linear power supply allows for rapid changes in the amplifier supply voltage, enabling it to closely track the minimum voltage required for amplifier operation. While this approach works in applications with relatively low power levels (e.g., in radio), this design doesn't necessarily perform well at higher power levels. At the power levels typically required for audio amplification, linear power supplies are generally far less power efficient than other types of power supplies with smaller bandwidths (e.g., switch-mode power supplies (SMPS)). Therefore, the gain from varying the supply voltage with a linear power supply may be entirely offset by the lower power efficiency of the linear power supply. In some cases, a playback device employing a fixed amplifier supply voltage generated by a high-efficiency, low-bandwidth power supply can actually outperform (e.g., with lower overall power consumption) a design that uses a linear power supply to vary the amplifier supply voltage.

[0038] Therefore, aspects of the present invention relate to techniques capable of generating varying power supply voltages for amplifiers (e.g., switching amplifiers) using highly efficient (e.g., and / or low-bandwidth) power supplies without causing distortion (e.g., clipping). Thus, the power efficiency of amplifiers can be improved without the trade-off of using power supplies with low power efficiency (e.g., high bandwidth). In some examples, control signals for the power supply are generated in a feedforward control loop based on future data that has not yet reached the amplifier. In these examples, specific events in the audio that may require a significant rise in the amplifier power supply voltage (e.g., the soundtrack of an action movie in an explosion scene) can be well predicted before that portion of the audio reaches the amplifier. When such an event is detected, the power supply voltage can rise slowly in anticipation of the event, successfully avoiding rapid swaying of the amplifier power supply voltage. Therefore, varying amplifier power supply voltages can be generated using power supplies with lower bandwidth and higher power efficiency (e.g., SMPS).

[0039] Look-ahead in audio can be achieved in several ways. In some implementations, it can be achieved by utilizing components that have access to the audio to calculate the amplifier power supply voltage upstream of the amplifier. For example, the calculation can be performed by at least one processor (e.g., at least one application processor) in the playback device, which executes a computer program (e.g., an application) that performs one or more audio processing tasks (e.g., acquiring audio from an external source, decoding audio, etc.). Such a processor already has access to audio content that has not yet been transmitted to the amplifier for playback. Therefore, the processor can use direct access to the future audio content to estimate the amount of voltage required for the amplifier to amplify an audio signal with a specific amplitude without significant distortion, and output control signals to the power supply (e.g., SMPS) to control the amplifier's power supply voltage.

[0040] An example of a playback device employing the power-saving techniques described herein includes a communication interface (e.g., a wireless communication interface, such as a Bluetooth communication interface and / or a wireless local area network (WLAN) interface) configured to facilitate communication via at least one network (e.g., a WLAN and / or Bluetooth network). The playback device includes processor circuitry comprising at least one processor coupled to the communication interface. The playback device also includes at least one non-transitory computer-readable medium coupled to the at least one processor. The computer-readable medium stores program instructions executable by the at least one processor, such that the processor circuitry is configured to receive first audio data representing audio content via the communication interface (e.g., from a computing system). The program instructions may further cause the processor circuitry to generate and output second audio data based on the first audio data, and at least partially, while generating and outputting the second audio data, generate and output control signals (e.g., feedforward control signals) associated with the second audio data to change the power supply voltage of an amplifier (e.g., a Class D amplifier). The playback device also includes a power supply (e.g., an SMPS) coupled to the processor circuitry. The power supply is configured to receive control signals from the processor circuitry and change the power supply voltage of the amplifier based on the control signals. The playback device's amplifier circuitry is coupled to the processor circuitry and the power supply. The amplifier circuitry includes an amplifier powered by a supply voltage from the power supply. The amplifier circuitry is configured to receive second audio data from the processor circuitry and generate an analog audio signal based on the second audio data to drive a speaker (e.g., when the supply voltage from the power supply is changing).

[0041] While some of the examples described herein may involve functions performed by a given participant (such as a “user,” “audience,” and / or other entity), it should be understood that this is for illustrative purposes only. Unless explicitly required by the language of the claims themselves, the claims should not be construed as requiring any such example participant to take action.

[0042] In the accompanying drawings, the same reference numerals denote substantially similar and / or identical elements. For ease of discussion of any particular element, the most significant numeral in the reference numerals refers to the figure in which that element first appears. For example, first refer to... Figure 1A Element 110a is introduced and discussed. Many details, dimensions, angles, and other features shown in the figures are merely illustrative of specific embodiments of the disclosed technology. Therefore, other embodiments may have different details, dimensions, angles, and features without departing from the spirit or scope of the invention. Furthermore, those skilled in the art will understand that other embodiments of the various disclosed technologies can be practiced without the following details.

[0043] II. Suitable operating environment

[0044] Figure 1A This is a partial cross-sectional view of a media playback system 100 distributed in an environment 101 (e.g., a house). The media playback system 100 includes one or more playback devices 110 (identified as playback devices 110a-n, respectively), one or more network microphone devices (“NMD”) 120 (identified as NMD120a-c, respectively), and one or more control devices 130 (identified as control devices 130a and 130b, respectively).

[0045] As used herein, the term "playback device" generally refers to a network device configured to receive, process, and output data from a media playback system. For example, a playback device may be a network device that receives and processes audio content. In some embodiments, a playback device includes one or more transducers or speakers powered by one or more amplifiers. However, in other embodiments, a playback device includes one (or neither) a speaker nor an amplifier. For example, a playback device may include one or more amplifiers configured to drive one or more speakers external to the playback device via corresponding wires or cables.

[0046] Furthermore, as used herein, the term NMD (i.e., "network microphone device") generally refers to a network device configured for audio detection. In some embodiments, the NMD is a standalone device primarily configured for audio detection. In other embodiments, the NMD is incorporated into a playback device (or vice versa).

[0047] The term "control device" can generally refer to a network device configured to perform functions related to facilitating user access, control, and / or configuration of the media playback system 100.

[0048] Each of the playback devices 110 is configured to receive audio signals or data from one or more media sources (e.g., one or more remote servers, one or more local devices) and play back the received audio signals or data in sound form. One or more NMDs 120 are configured to receive spoken word commands, and one or more control devices 130 are configured to receive user input. In response to received spoken word commands and / or user input, the media playback system 100 can play back audio via one or more playback devices 110. In some embodiments, the playback devices 110 are configured to initiate playback of media content in response to a trigger. For example, one or more of the playback devices 110 may be configured to play back a morning playlist when an associated trigger condition is detected (e.g., a user is in the kitchen, coffee machine operation is detected). In some embodiments, for example, the media playback system 100 is configured to play back audio from a first playback device (e.g., playback device 100a) in sync with a second playback device (e.g., playback device 100b). Reference will be made below. Figures 1B to 1M The interaction between the playback device 110, NMD 120 and / or control device 130 of the media playback system 100 configured according to various embodiments of the present invention is described in more detail.

[0049] exist Figure 1A In the illustrated embodiment, environment 101 includes a home with multiple rooms, spaces, and / or playback zones, including (clockwise from the top left) a master bathroom 101a, master bedroom 101b, secondary bedroom 101c, family room or study 101d, office 101e, living room 101f, dining room 101g, kitchen 101h, and outdoor terrace 101i. While some embodiments and examples are described below in the context of a home environment, the techniques described herein can be implemented in other types of environments. For example, in some embodiments, media playback system 100 can be implemented in one or more commercial environments (e.g., restaurants, shopping malls, airports, hotels, retail stores, or other shops), one or more vehicles (e.g., SUVs, buses, cars, ships, aircraft), multiple environments (e.g., a combination of home and vehicle environments), and / or another suitable environment that may require multi-zone audio.

[0050] The media playback system 100 may include one or more playback zones, some of which may correspond to rooms in environment 101. The media playback system 100 may have one or more playback zones established, and additional zones may be added or removed thereafter to form, for example... Figure 1AThe configuration is shown. Each zone can be named according to different rooms or spaces, such as office 101e, master bathroom 101a, master bedroom 101b, secondary bedroom 101c, kitchen 101h, dining room 101g, living room 101f, and / or balcony 101i. In some respects, a single playback zone may include multiple rooms or spaces.

[0051] exist Figure 1A In the illustrated embodiment, the master bathroom 101a, secondary bedroom 101c, office 101e, living room 101f, dining room 101g, kitchen 101h, and outdoor terrace 101i each include a playback device 110, while the master bedroom 101b and study 101d include multiple playback devices 110. In the master bedroom 101b, playback devices 1101 and 110m can be configured, for example, as individual playback devices among playback devices 110, as a combined playback zone, as a combined playback device, and / or any combination thereof, to synchronously play back audio content. Similarly, in the study 101d, playback devices 110h-j can be configured, for example, as individual playback devices among playback devices 110, as one or more combined playback devices, and / or as one or more merged playback devices, to synchronously play back audio content. (Refer to the following...) Figure 1B and Figure 1M Describe additional details regarding combined and merged playback devices.

[0052] In some respects, one or more playback zones in environment 101 can each play different audio content. For example, while one user is preparing food in kitchen 101h and listening to classical music played by playback device 110b, another user can be barbecuing on terrace 101i and listening to hip-hop music played by playback device 110c. In another example, one playback zone can play the same audio content synchronously with another playback zone. For example, a user in office 101e can listen to the same hip-hop music played by playback device 110c as playback device 110c on terrace 101i. In some respects, the synchronous playback of hip-hop music by playback devices 110c and 110f makes the audio content appear seamless (or at least substantially seamless) as the user moves between the different playback zones. Further details regarding audio playback synchronization between playback devices and / or zones can be found, for example, in U.S. Patent No. 8,234,395 entitled “System and method for synchronizing operations among aplurality of independently clocked digital data processing devices,” which is incorporated herein by reference in its entirety.

[0053] a. Suitable media playback system

[0054] Figure 1B This is a schematic diagram of the media playback system 100 and the cloud network 102. For ease of explanation, from... Figure 1B Some devices of the media playback system 100 and the cloud network 102 are omitted. One or more communication links 103 (hereinafter referred to as "link 103") communicatively couple the media playback system 100 and the cloud network 102.

[0055] Link 103 may include, for example, one or more wired networks, one or more wireless networks, one or more wide area networks (WANs), one or more local area networks (LANs), one or more personal area networks (PANs), one or more telecommunications networks (e.g., one or more Global System for Mobile Communications (GSM) networks, Code Division Multiple Access (CDMA) networks, Long Term Evolution (LTE) networks, 5G communication networks, and / or other suitable data transmission protocol networks). Cloud network 102 is configured to deliver media content (e.g., audio content, video content, photos, social media content) to media playback system 100 in response to a request to transmit from media playback system 100 via link 103. In some embodiments, cloud network 102 is also configured to receive data (e.g., voice input data) from media playback system 100 and accordingly transmit commands and / or media content to media playback system 100.

[0056] Cloud network 102 includes computing devices 106 (identified as first computing device 106a, second computing device 106b, and third computing device 106c, respectively). Computing devices 106 may include individual computers or servers, such as, for example, media streaming service servers storing audio and / or other media content, voice service servers, social media servers, media playback system control servers, etc. In some embodiments, one or more of the computing devices 106 include modules of a single computer or server. In some embodiments, one or more of the computing devices 106 include one or more modules, computers, and / or servers. Furthermore, while cloud network 102 has been described above in the context of a single cloud network, in some embodiments, cloud network 102 includes multiple cloud networks that include communicatively coupled computing devices. Furthermore, although cloud network 102 is described in... Figure 1B The cloud network 102 is shown as having three computing devices 106, but in some embodiments, the cloud network 102 includes fewer (or more) three computing devices 106.

[0057] Media playback system 100 is configured to receive media content from network 102 via link 103. The received media content may include, for example, a Uniform Resource Identifier (URI) and / or a Uniform Resource Locator (URL). For example, in some examples, media playback system 100 may stream, download, or otherwise retrieve data from a URI or URL corresponding to the received media content. Network 104 communicatively couples link 103 to at least a portion of the devices of media playback system 100 (e.g., one or more of playback device 110, NMD 120, and / or control device 130). Network 104 may include, for example, wireless networks (e.g., WiFi networks, Bluetooth, Z-Wave networks, ZigBee, and / or other suitable wireless communication protocol networks) and / or wired networks (e.g., networks including Ethernet, Universal Serial Bus (USB), and / or other suitable wired communications networks). As will be understood by those skilled in the art, as used herein, “WiFi” can refer to several different communication protocols, including, for example, IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.11ac, 802.11ad, 802.11af, 802.11ah, 802.11ai, 802.11aj, 802.11aq, 802.11ax, 802.11ay, 802.15, etc., which transmit at frequencies of 2.4 GHz, 5 GHz, and / or another suitable frequency.

[0058] In some embodiments, network 104 includes a dedicated communication network used by media playback system 100 to transmit messages between devices and / or to transmit media content to a media content source (e.g., one or more computing devices 106). In some embodiments, network 104 is configured to be accessible only by devices within media playback system 100, thereby reducing interference and competition with other home appliances. However, in other embodiments, network 104 includes an existing home communication network (e.g., a home Wi-Fi network). In some embodiments, link 103 and network 104 include one or more of the same networks. In some aspects, for example, link 103 and network 104 include telecommunications networks (e.g., LTE networks, 5G networks). Furthermore, in some embodiments, media playback system 100 is implemented without network 104, and devices including media playback system 100 can communicate with each other, for example, via one or more direct connections, PANs, telecommunications networks, and / or other suitable communication links.

[0059] In some embodiments, audio content sources can be periodically added to or removed from the media playback system 100. In some embodiments, for example, when one or more media content sources are updated, added to, and / or deleted from the media playback system 100, the media playback system 100 performs an indexing of media items. The media playback system 100 can scan some or all folders and / or directories accessible by the playback device 110 for identifiable media items and generate or update a media content database, including metadata (e.g., title, artist, album, track length) and other relevant information (e.g., URI, URL) for each identifiable media item found. In some embodiments, for example, the media content database is stored on one or more of the playback device 110, the network microphone device 120, and / or the control device 130.

[0060] exist Figure 1B In the illustrated embodiment, playback devices 1101 and 110m comprise group 107a. Playback devices 1101 and 110m may be located in different rooms of a home and are grouped together in group 107a on a temporary or permanent basis based on user input received at control device 130a and / or another control device 130 of media playback system 100. When arranged in group 107a, playback devices 1101 and 110m can be configured to synchronously play the same or similar audio content from one or more audio content sources. In some embodiments, for example, group 107a includes a combined area where playback devices 1101 and 110m respectively comprise the left and right audio channels of multi-channel audio content, thereby producing or enhancing the stereo effect of the audio content. In some embodiments, group 107a includes an additional playback device 110. However, in other embodiments, media playback system 100 omits further grouping arrangements of group 107a and / or playback devices 110. The following is about... Figures 1I to 1M Additional details regarding the grouping and arrangement of the playback equipment are described in more detail.

[0061] The media playback system 100 includes NMDs 120a and 120d, each NMD including one or more microphones configured to receive voice from a user. Figure 1B In the illustrated embodiment, NMD 120a is a standalone device and NMD 120d is integrated into playback device 110n. For example, NMD 120a is configured to receive voice input 121 from user 123. In some embodiments, NMD 120a transmits data associated with the received voice input 121 to a Voice Assistant Service (VAS), which is configured to (i) process the received voice input data and (ii) transmit the corresponding command to media playback system 100. In some aspects, for example, computing device 106c includes a VAS (e.g., by...). The computing device 106c may receive voice input data from the NMD 120a via network 104 and link 103. In response to receiving the voice input data, the computing device 106c processes the voice input data (i.e., "play Hey Jude" by The Beatles) and determines that the processed voice input includes a command to play the song (e.g., "Hey Jude"). The computing device 106c accordingly transmits a command to the media playback system 100 to play "Hey Jude" by The Beatles from a suitable media service on one or more of the playback devices 110 (e.g., via one or more of the computing devices 106).

[0062] b. Suitable playback equipment

[0063] Figure 1C This is a block diagram of a playback device 110a including input / output 111. Input / output 111 may include analog I / O 111a (e.g., one or more wires, cables, and / or other suitable communication links configured to transmit analog signals) and / or digital I / O 111b (e.g., one or more wires, cables, or other suitable communication links configured to transmit digital signals). In some embodiments, analog I / O 111a is an audio line input connection, including, for example, an automatically detected 3.5mm audio line input connection. In some embodiments, digital I / O 111b includes a Sony / Philips Digital Interface Format (S / PDIF) communication interface and / or cable and / or Toshiba Link (TOSLINK) cable. In some embodiments, digital I / O 111b includes an High Definition Multimedia Interface (HDMI) interface and / or cable. In some embodiments, digital I / O 111b includes one or more wireless communication links, including, for example, radio frequency (RF), infrared, WiFi, Bluetooth, or another suitable communication protocol. In some embodiments, analog I / O 111a and digital I / O 111b include interfaces (e.g., ports, plugs, jacks) of connectors configured to receive cables transmitting analog and digital signals, respectively, without necessarily including cables.

[0064] For example, playback device 110a may receive media content (e.g., audio content including music and / or other sounds) from local audio source 105 via input / output 111 (e.g., cable, wire, PAN, Bluetooth connection, self-organizing wired or wireless communication network and / or another suitable communication link). Local audio source 105 may include, for example, a mobile device (e.g., smartphone, tablet, laptop computer) or another suitable audio component (e.g., television, desktop computer, amplifier, phonograph, Blu-ray player, memory storing digital media files). In some aspects, local audio source 105 includes a local music library on a smartphone, computer, network attached storage device (NAS), and / or another suitable device configured to store media files. In some embodiments, one or more of playback device 110, NMD 120, and / or control device 130 include local audio source 105. However, in other embodiments, the media playback system completely omits local audio source 105. In some embodiments, playback device 110a does not include input / output 111 and receives all audio content via network 104.

[0065] The playback device 110a also includes electronics 112, a user interface 113 (e.g., one or more buttons, knobs, dials, touch-sensitive surfaces, displays, touchscreens), and one or more transducers 114 (hereinafter referred to as "transducers 114"). Electronics 112 are configured to operate from an audio source (e.g., a local audio source 105) via input / output 111 or via network 104. Figure 1B The playback device 110a receives audio from one or more computing devices 106a-c, amplifies the received audio, and uses the amplified audio via one or more outputs of transducers 114 for playback. In some embodiments, the playback device 110a may optionally include one or more microphones 115 (e.g., a single microphone, multiple microphones, a microphone array) (hereinafter referred to as "microphone 115"). In some embodiments, for example, the playback device 110a having one or more optional microphones 115 may operate as an NMD configured to receive voice input from a user and perform one or more operations accordingly based on the received voice input.

[0066] exist Figure 1CIn the illustrated embodiment, electronic device 112 includes one or more processors 112a (hereinafter referred to as "processor 112a"), memory 112b, software component 112c, network interface 112d, one or more audio processing components 112g (hereinafter referred to as "audio component 112g"), one or more audio amplifiers 112h (hereinafter referred to as "amplifier 112h"), and power supply 112i (e.g., one or more power supplies, power cords, power sockets, batteries, induction coils, Power over Ethernet (PoE) interfaces, and / or other suitable power sources). In some embodiments, electronic device 112 may optionally include one or more other components 112j (e.g., one or more sensors, video displays, touchscreens, battery charging docks).

[0067] Processor 112a may include clock-driven computing components configured to process data, and memory 112b may include computer-readable media (e.g., tangible, non-transitory computer-readable media, data storage devices loaded with one or more software components 112c) configured to store instructions for performing various operations and / or functions. Processor 112a is configured to execute instructions stored in memory 112b to perform one or more operations. Operations may include, for example, causing playback device 110a to access an audio source (e.g., computing devices 106a-c). Figure 1B One or more of the playback devices 110a and / or another of the playback devices 110a retrieve audio data. In some embodiments, operation also includes causing the playback device 110a to send audio data to another of the playback devices 110a and / or another device (e.g., one of the NMD 120). Some embodiments include operation of pairing the playback device 110a with another of the playback devices 110a to enable a multi-channel audio environment (e.g., stereo pair, combined region).

[0068] Processor 112a can also be configured to perform operations that cause playback device 110a to play audio content synchronously with another of one or more playback devices 110. As those skilled in the art will understand, during synchronous playback of audio content on multiple playback devices, the listener will preferably not perceive any time delay difference between playback device 110a and the playback of audio content by one or more other playback devices 110. Additional details regarding audio playback synchronization between playback devices can be found, for example, in U.S. Patent No. 8,234,395, which is incorporated herein by reference.

[0069] In some embodiments, memory 112b is also configured to store data associated with playback device 110a, such as one or more zones and / or groups of zones that playback device 110a is a member of, audio sources accessible to playback device 110a, and / or playback queues that playback device 110a (and / or another of one or more playback devices) can be associated with. The stored data may include one or more state variables that are periodically updated and used to describe the state of playback device 110a. Memory 112b may also include data associated with the state of one or more other devices of media playback system 100 (e.g., playback device 110, NMD 120, control device 130). In some aspects, for example, state data is shared among at least a portion of the devices of media playback system 100 during predetermined time intervals (e.g., every 5 seconds, every 10 seconds, every 60 seconds), such that one or more of the devices have the most up-to-date data associated with media playback system 100.

[0070] Network interface 112d is configured to facilitate playback device 110a with data networks (such as, for example, link 103 and / or network 104). Figure 1B Data transfer between one or more other devices on the network interface 112d. The network interface 112d is configured to transmit and receive data corresponding to media content (e.g., audio content, video content, text, photos) and other signals (e.g., non-transient signals), including digital packet data containing an Internet Protocol (IP)-based source address and / or an IP-based destination address. The network interface 112d can parse the digital packet data, enabling the electronics 112 to correctly receive and process data destined for the playback device 110a.

[0071] exist Figure 1C In the illustrated embodiment, network interface 112d includes one or more wireless interfaces 112e (hereinafter referred to as "wireless interface 112e"). Wireless interface 112e (e.g., a suitable interface including one or more antennas) can be configured to wirelessly communicate with one or more other devices (e.g., one or more of other playback devices 110, NMD 120, and / or control devices 130), which are communicatively coupled to network 104 according to a suitable wireless communication protocol (e.g., WiFi, Bluetooth, LTE). Figure 1BIn some embodiments, network interface 112d may optionally include wired interface 112f (e.g., an interface or receptacle configured to receive network cables such as Ethernet, USB-A, USB-C, and / or Thunderbolt cables), which is configured to communicate with other devices via a wired connection according to a suitable wired communication protocol. In some embodiments, network interface 112d includes wired interface 112f and does not include wireless interface 112e. In some embodiments, electronics 112 completely excludes network interface 112d and transmits and receives media content and / or other data via another communication path (e.g., input / output 111).

[0072] Audio component 112g is configured to process and / or filter data comprising media content received by electronics 112 (e.g., via input / output 111 and / or network interface 112d) to generate an output audio signal. In some embodiments, audio processing component 112g includes, for example, one or more digital-to-analog converters (DACs), audio preprocessing components, audio enhancement components, digital signal processors (DSPs), and / or other suitable audio processing components, modules, circuitry, etc. In some embodiments, one or more of audio processing components 112g may include one or more sub-components of processor 112a. In some embodiments, electronics 112 omits audio processing component 112g. In some aspects, for example, processor 112a executes instructions stored on memory 112b to perform audio processing operations to generate an output audio signal.

[0073] Amplifier 112h is configured to receive and amplify audio output signals generated by audio processing component 112g and / or processor 112a. Amplifier 112h may include electronic devices and / or components configured to amplify audio signals to a level sufficient to drive one or more transducers 114. In some embodiments, for example, amplifier 112h includes one or more switching amplifiers (e.g., Class D power amplifiers). However, in other embodiments, the amplifier includes one or more other types of power amplifiers (e.g., Class A, Class B, Class AB, Class C, Class D, Class E, Class F, Class G and / or Class H amplifiers and / or other suitable types of power amplifiers). In some embodiments, amplifier 112h includes suitable combinations of two or more of the above-described types of power amplifiers.

[0074] Furthermore, in some embodiments, each amplifier in amplifier 112h corresponds to a respective transducer in transducer 114. However, in other embodiments, electronics 112 includes a single amplifier 112h configured to output an amplified audio signal to a plurality of transducers 114. In some other embodiments, amplifier 112h is omitted from electronics 112.

[0075] Transducer 114 (e.g., one or more loudspeakers and / or loudspeaker drivers) receives amplified audio signals from amplifier 112h and presents or outputs the amplified audio signals as sound (e.g., audible sound with frequencies between approximately 20 Hz and 20 kHz). In some embodiments, transducer 114 may include a single transducer. However, in other embodiments, transducer 114 includes multiple audio transducers. In some embodiments, transducer 114 includes more than one type of transducer. For example, transducer 114 may include one or more low-frequency transducers (e.g., subwoofer, woofer), mid-frequency transducers (e.g., mid-frequency transducer, mid-bass speaker), and one or more high-frequency transducers (e.g., one or more tweeters). As used herein, “low frequency” can generally refer to audible frequencies below approximately 500 Hz, “mid frequency” can generally refer to audible frequencies between approximately 500 Hz and approximately 2 kHz, and “high frequency” can generally refer to audible frequencies above 2 kHz. However, in some embodiments, one or more transducers 114 may include transducers that do not adhere to the aforementioned frequency range. For example, one of the transducers 114 may include a mid-bass transducer configured to output sound at a frequency between approximately 200 Hz and approximately 5 kHz.

[0076] For illustration, SONOS Ltd. currently offers (or has offered) certain playback devices for sale, including, for example, “SONOS ONE,” “PLAY:1,” “PLAY:3,” “PLAY:5,” “PLAYBAR,” “PLAYBASE,” “CONNECT:AMP,” “CONNECT,” and “SUB.” Other suitable playback devices may be used additionally or alternatively to implement the playback devices of the exemplary embodiments disclosed herein. Furthermore, those skilled in the art will understand that the playback devices are not limited to the examples described herein or the availability of SONOS products. In some embodiments, for example, one or more playback devices 110 include wired or wireless headphones (e.g., ear-hook headphones, in-ear headphones, earbuds). In other embodiments, one or more of the playback devices 110 include a docking station and / or an interface configured to interact with a docking station for personal mobile media playback devices. In some embodiments, the playback device may be integrated into another device or component, such as a television, lighting equipment, or some other device for indoor or outdoor use. In some embodiments, the playback device omits a user interface and / or one or more transducers. For example, Figure 1D It is a block diagram of a playback device 110p that includes input / output 111 and electronics 112 but does not have a user interface 113 or transducer 114.

[0077] Figure 1E This is a block diagram of the combined playback device 110q, which includes components related to playback device 110i (e.g., a subwoofer). Figure 1A Acoustic-integrated playback device 110a Figure 1C In the illustrated embodiment, playback devices 110a and 110i are separate playback devices 110 housed in separate housings. However, in some embodiments, the combined playback device 110q includes a single housing housing both playback devices 110a and 110i. The combined playback device 110q can be configured to function differently from the uncombined playback devices (e.g., Figure 1C Playback device 110a) and / or paired or combined playback devices (e.g., Figure 1B The playback devices 1101 and 110m process and reproduce sound in a manner consistent with the first playback device. In some embodiments, for example, playback device 110a is a full-range playback device configured to present low-frequency, mid-frequency, and high-frequency audio content, and playback device 110i is a subwoofer configured to present low-frequency audio content. In some aspects, when combined with the first playback device, playback device 110a is configured to render only the mid-frequency and high-frequency components of a particular audio content, while playback device 110i renders the low-frequency components of the particular audio content. In some embodiments, the combined playback device 110q includes an additional playback device and / or another combined playback device.

[0078] c. Suitable Network Microphone Equipment (NMD)

[0079] Figure 1F It is NMD 120a ( Figure 1A and Figure 1B The NMD 120a includes one or more voice processing components 124 (hereinafter referred to as "voice components 124") and a playback device 110a. Figure 1C The NMD 120a optionally includes several components described, including a processor 112a, a memory 112b, and a microphone 115. It also includes components in the playback device 110a. Figure 1C Other components in the NMD 120a include, for example, the user interface 113 and / or the transducer 114. In some embodiments, the NMD 120a is configured as a media playback device (e.g., one or more playback devices 110) and also includes, for example, an audio component 112g. Figure 1C The NMD 120a includes one or more of the following components: amplifier 114 and / or other playback device components. In some embodiments, the NMD 120a includes Internet of Things (IoT) devices, such as thermostats, alarm panels, fire and / or smoke detectors, etc. In some embodiments, the NMD 120a includes a microphone 115, voice processing 124, and the components mentioned above. Figure 1B The described electronic device 112 comprises only a portion of its components. In some aspects, for example, the NMD 120a includes a processor 112a and a memory 112b. Figure 1B The NMD 120a omits one or more other components of the electronic device 112. In some embodiments, the NMD 120a includes additional components (e.g., one or more additional sensors, cameras, thermometers, barometers, hygrometers).

[0080] In some embodiments, NMD can be integrated into the playback device. Figure 1G This is a block diagram of a playback device 110r including the NMD120d. The playback device 110r may include many or all of the components of the playback device 110a and also includes a microphone 115 and a voice processing unit 124. Figure 1F The playback device 110r may optionally include an integrated control device 130c. The control device 130c may include, for example, a user interface (e.g., ...). Figure 1B The user interface 113 is configured to receive user input (e.g., touch input, voice input) without a separate control device. However, in other embodiments, the playback device 110r receives input from another control device (e.g., Figure 1B The control device 130a) receives commands.

[0081] Refer again Figure 1FThe microphone 115 is configured to receive signals from the environment (e.g., Figure 1A The environment 101) and / or the room where the NMD 120a is located acquire, capture, and / or receive sound. Received sound may include, for example, speech, audio played by the NMD 120a and / or another playback device, background sound, ambient sound, etc. Microphone 115 converts the received sound into electrical signals to generate microphone data. Voice processing 124 receives and analyzes the microphone data to determine if voice input is present in the microphone data. For example, voice input may include an activation word followed by a utterance including a user request. As will be understood by those skilled in the art, an activation word is a word or other audio cue representing user voice input. For example, in a query... During VAS, the user might say the activation word "Alexa". Other examples include using it to invoke... VAS's "Ok, Google" and the calls VAS's "Hey, Siri".

[0082] After detecting the activation word, the speech processing unit 124 monitors microphone data to look for user requests accompanying the voice input. User requests may include, for example, commands to control third-party devices, such as a thermostat (e.g., [device name]). Thermostats), lighting equipment (e.g., PHILIPS) Lighting equipment) or media playback equipment (e.g., (Playback device). For example, a user might say the activation word "Alexa" and then say "set the thermostat to 68 degrees" to set the temperature in their home (e.g., Figure 1A (Environment 101). A user might say the same activation word and then say "turn on the living room" to turn on the lighting in the living room area of ​​their home. A user could similarly say the activation word and then request that a specific song, album, or music playlist be played on a playback device in their home.

[0083] d. Suitable control equipment

[0084] Figure 1H It is control equipment 130a ( Figure 1A and Figure 1B A partial schematic diagram of the media playback system 100. As used herein, the term "control device" may be used interchangeably with "controller" or "control system". Among other features, the control device 130a is configured to receive user input in relation to the media playback system 100 and, in response, cause one or more devices in the media playback system 100 to perform actions or operations corresponding to the user input. In the illustrated embodiment, the control device 130a includes a smartphone (e.g., an iPhone) with media playback system controller application software installed. TM(e.g., Android phones). In some embodiments, the control device 130a includes, for example, a tablet computer (e.g., an iPad). TM The control device 130a includes a computer (e.g., a laptop computer, a desktop computer) and / or another suitable device (e.g., a television, a car stereo head unit, an IoT device). In some embodiments, the control device 130a includes a dedicated controller for the media playback system 100. In other embodiments, as described above regarding... Figure 1G The control device 130a is integrated into another device in the media playback system 100 (e.g., playback device 110, NMD 120, and / or one or more other suitable devices configured to communicate via a network).

[0085] Control device 130a includes electronics 132, a user interface 133, one or more speakers 134, and one or more microphones 135. Electronics 132 includes one or more processors 132a (hereinafter referred to as "processor 132a"), memory 132b, software components 132c, and a network interface 132d. Processor 132a may be configured to perform functions related to facilitating user access, control, and configuration of media playback system 100. Memory 132b may include data memory that can be loaded with one or more software components executable by processor 302 to perform these functions. Software components 132c may include application programs and / or other executable software configured to facilitate control of media playback system 100. Memory 112b may be configured to store, for example, software components 132c, media playback system controller application software, and / or other data associated with media playback system 100 and the user.

[0086] Network interface 132d is configured to facilitate network communication between control device 130a and one or more other devices and / or one or more remote devices in media playback system 100. In some embodiments, network interface 132d is configured to operate according to one or more suitable communication industry standards (e.g., infrared, radio, wired standards including IEEE 802.3, wireless standards including IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4G, LTE). For example, network interface 132d may be configured to communicate with playback device 110, NMD 120, other devices in control device 130, Figure 1BThe network interface 132d transmits and / or receives data from one of the computing devices 106, including devices such as one or more other media playback systems. The transmitted and / or received data may include, for example, playback device control commands, status variables, playback regions and / or block configurations. For example, based on user input received at user interface 133, network interface 132d can transmit playback device control commands (e.g., volume control, audio playback control, audio content selection) from control device 130 to one or more of the playback devices 100. Network interface 132d can also transmit and / or receive configuration changes, such as, for example, adding or removing one or more playback devices 100 from a region / region, adding or removing one or more regions from a block group / block group, forming a combined or merged player, separating one or more playback devices from a combined or merged player, etc. This can be further explained below regarding... Figures 1I to 1M Find additional descriptions for regions and groups.

[0087] User interface 133 is configured to receive user input and facilitate control of media playback system 100. User interface 133 includes media content art 133a (e.g., album art, lyrics, video), playback status indicators 133b (e.g., elapsed and / or remaining time indicators), media content information area 133c, playback control area 133d, and zone indicators 133e. Media content information area 133c may include a display of information about the currently playing media content and / or media content in the queue or playlist (e.g., title, artist, album, genre, release year). Playback control area 133d may include (e.g., via touch input and / or via a cursor or other suitable selector) selectable icons to cause one or more playback devices in the selected playback zone or group of zones to perform playback actions, such as play or pause, fast forward, rewind, skip to next track, skip to previous track, enter / exit shuffle mode, enter / exit repeat mode, enter / exit crossfade mode, etc. The playback control area 133d may also include optional icons to modify equalizer settings, playback volume, and / or other suitable playback actions. In the illustrated embodiment, the user interface 133 includes a display on a smartphone (e.g., an iPhone). TM The display is on the touchscreen interface of an Android phone. However, in some embodiments, user interfaces of different formats, styles, and interaction sequences may alternatively be implemented on one or more network devices to provide comparable control access to the media playback system.

[0088] One or more speakers 134 (e.g., one or more transducers) may be configured to output sound to a user of control device 130a. In some embodiments, the one or more speakers include individual transducers configured to output low, mid, and / or high frequencies respectively. In some aspects, for example, control device 130a is configured as a playback device (e.g., one of playback devices 110). Similarly, in some embodiments, control device 130a is configured as an NMD (e.g., one of NMD 120) to receive voice commands and other sounds via one or more microphones 135.

[0089] One or more microphones 135 may include, for example, one or more condenser microphones, electret condenser microphones, dynamic microphones, and / or other suitable types of microphones or transducers. In some embodiments, two or more microphones 135 are arranged to capture location information of an audio source (e.g., speech, audible sound) and / or configured to facilitate background noise filtering. Furthermore, in some embodiments, control device 130a is configured to operate as a playback device and an NMD. However, in other embodiments, control device 130a omits one or more speakers 134 and / or one or more microphones 135. For example, control device 130a may include a device (e.g., a thermostat, IoT device, network device) that includes a portion of electronics 132 and a user interface 133 (e.g., a touchscreen) without any speakers or microphones.

[0090] e. Suitable playback equipment configuration

[0091] Figures 1L to 1M Example configurations of playback devices in zones and zones are shown. First refer to... Figure 1M In one example, a single playback device can belong to a zone. For example, bedroom 101c ( Figure 1APlayback device 110g in the diagram can belong to zone C. In some implementations described below, multiple playback devices can be "combined" to form a "combined pair" that together forms a single zone. For example, playback device 1101 (e.g., a left playback device) can be combined with playback device 110l (e.g., a left playback device) to form zone A. The combined playback devices can have different playback responsibilities (e.g., channel responsibilities). In another implementation described below, multiple playback devices can be merged to form a single zone. For example, playback device 110h (e.g., a front playback device) can be merged with playback device 110i (e.g., a subwoofer), and playback devices 110j and 110k (e.g., left surround speaker and right surround speaker, respectively) form a single zone D. In another example, playback devices 110g and 110h can be merged to form a merge group or zone group 108b. The merged playback devices 110g and 110h may not be specifically assigned different playback responsibilities. That is, in addition to playing audio content synchronously, the merged playback devices 110h and 110i can each play audio content as if they were not merged.

[0092] Each zone in the media playback system 100 can be provided for control as a single user interface (UI) entity. For example, zone A can provide a single entity named "Master Bathroom". Zone B can provide a single entity named "Master Bedroom". Zone C can provide a single entity named "Second Bedroom".

[0093] Combined playback devices may have different playback responsibilities, such as responsibilities for certain audio channels. For example, such as... Figure 1I As shown, playback devices 1101 and 110m can be combined to produce or enhance the stereo effect of audio content. In this example, playback device 1101 can be configured to play the left channel audio component, while playback device 110k can be configured to play the right channel audio component. In some implementations, this stereo combination can be referred to as "pairing".

[0094] Furthermore, the combined playback device can have additional and / or different corresponding speaker drivers. For example... Figure 1J As shown, a playback device 110h, referred to as a "front end," can be combined with a playback device 110i, referred to as a "sub." The front end device 110h can be configured to display the mid-to-high frequency range, while the sub device 110i can be configured to display the low frequency range. However, when not combined, the front end device 110h can be configured to display the entire frequency range. As another example, Figure 1KA front-end device 110h and a sub-device 110i are shown, further integrated with the left playback device 110j and the right playback device 110k, respectively. In some implementations, the left device 110j and the right device 110k can be configured to form surround or "satellite" channels for a home theater system. The combined playback devices 110h, 110i, 110j, and 110k can form a single D-zone (…). Figure 1M ).

[0095] The merged playback devices may not have assigned playback responsibilities, and each playback device can present the full range of audio content that the respective playback device is capable of handling. However, the merged devices can be represented as a single UI entity (i.e., a zone as described above). For example, playback devices 110a and 110n in the main bathroom have a single UI entity for zone A. In one embodiment, playback devices 110a and 110n can each synchronously output the full range of audio content that each of their respective playback devices 110a and 110n is capable of outputting.

[0096] In some embodiments, the NMD is combined or integrated with another device to form a zone. For example, the NMD 120b may be combined with the playback device 110e, and together they form zone F, referred to as the living room. In other embodiments, a standalone network microphone device may exist in its own zone. However, in other embodiments, a standalone network microphone device may not be associated with a zone. Additional details regarding associating network microphone devices and playback devices as designated or default devices can be found, for example, in previously cited U.S. Patent Publication No. 15 / 438,749.

[0097] Individual, combined, and / or merged device areas can be grouped to form zones. For example, refer to Figure 1M Area A can be grouped with Area B to form area group 108a, which includes two areas. Similarly, Area G can be grouped with Area H to form area group 108b. As another example, Area A can be grouped with one or more other Areas C-I. Areas A-I can be grouped and ungrouped in a variety of ways. For example, three, four, five, or more (e.g., all) of Areas A-I can be grouped. When grouped, the areas of individual and / or combined playback devices can play audio synchronously with each other, as described in previously cited U.S. Patent No. 8,234,395. Playback devices can dynamically group and ungroup to form new or different groups of synchronously playing audio content.

[0098] In various implementations, the region in the environment can be the default name of a region within a group or a combination of region names within the group. For example, a name such as "Restaurant + Kitchen" can be assigned to region 108b. Figure 1MAs shown in the diagram. In some embodiments, the block group can be assigned a unique name chosen by the user.

[0099] Some data can be stored as one or more state variables in the memory of the playback device (e.g., Figure 1C In the memory 112c), these state variables are periodically updated and used to describe the state of the playback area, playback device, and / or associated groups. The memory may also include data associated with the state of other devices in the media system and is shared between devices from time to time, such that one or more devices have the latest data associated with the system.

[0100] In some embodiments, the memory may store examples of various variable types associated with a state. Variable examples may be stored along with identifiers (e.g., tags) corresponding to the type. For example, some identifiers may be a first type "a1" for identifying playback devices in a region, a second type "b1" for identifying playback devices that can be grouped in a region, and a third type "c1" for identifying the group to which the region may belong. As a related example, an identifier associated with secondary bedroom 101c may indicate that the playback device is the only playback device in zone C and is not in a group. An identifier associated with Den may indicate that Den is not grouped with other regions but includes the grouped playback devices 110h-110k. An identifier associated with the dining room may indicate that the dining room is part of the dining room + kitchen group 108b and that devices 110b and 110d are grouped (…). Figure 1L Since the kitchen is part of the dining room + kitchen area group 108b, the identifiers associated with the kitchen can indicate the same or similar information. Other example area variables and identifiers are described below.

[0101] In yet another example, media playback system 100 may store other associated variables or identifiers representing zones and zone groups, such as identifiers associated with zones, like... Figure 1M As shown in the diagram. A region may involve a set of blocks and / or regions not within those blocks. For example, Figure 1M The diagram shows an upper region 109a comprising areas A-D, and a lower region 109b comprising areas E-I. In one aspect, a region can be used to invoke a region group and / or a cluster of regions that share one or more regions and / or another cluster's region group. In another aspect, this differs from a region group that does not share regions with another region group.

[0102] For example, further examples of techniques for implementing zones can be found in U.S. Patent Publication No. 15 / 682,506, filed August 21, 2017, entitled “Room Association Based on Name,” and U.S. Patent No. 8,483,853, filed September 11, 2007, entitled “Controlling and manipulating groupings in a multi-zone media system.” Each of these applications is incorporated herein by reference in its entirety. In some embodiments, the media playback system 100 may not implement zones, in which case the system may not store variables associated with zones.

[0103] III. Example Techniques for Improving Power Efficiency of Playback Equipment

[0104] As mentioned above, the power efficiency of a playback device can be improved, for example, by changing the power supply voltage of the audio amplifier based on the expected power supply voltage required for the upcoming audio. Figure 2 An example logic diagram of a playback device circuit 200 implementing this power-saving technology is shown. Initially, it should be noted that the logic diagram of circuit 200 is provided for the purpose of describing various aspects of the invention, and it may not represent all aspects of the circuit 200 of a particular playback device. Furthermore, the coupling methods of the various components in the logic diagram may differ.

[0105] refer to Figure 2 Circuit 200 is configured to receive power from power supply 220 and use the power obtained from power supply 220 to drive speaker 235 with audio output 240e based on source audio 240c. Circuit 200 includes a communication interface 215 that facilitates communication with external devices to obtain source audio 240c. Circuit 200 also includes processor circuit 250, which includes processor 205 that receives source audio 240c from communication interface 215 and generates processed audio 240d based on source audio 240c. Processor circuit 250 also generates control signal 240a for power supply 225 integrated into circuit 200 based on one or more of the following: (1) status information 240f about the state of power supply 220; (2) source audio 240c; or (3) processed audio 240d. Power supply 225 uses source voltage 240g from power supply 220 to generate amplifier power supply voltage 240b for amplifier 245 based on control signal 240a. Circuit 200 also includes amplifier circuit 230, which includes amplifier 245 and is configured to generate audio output 240e based on processed audio 240d received from processor circuit 250.

[0106] It should be understood that Figure 2 One or more elements of the logic diagram of circuit 200 can correspond to the elements mentioned above. Figure 1C and / or Figure 1F The aforementioned one or more components. For example, processor 205, communication interface 215, and speaker 235 may correspond to and / or perform one or more of the capabilities of processor 112a, network interface 112d, and speaker 134, respectively.

[0107] Power supply 220 is configured to supply power to components of circuit 200. Examples of power supply 220 may include a power input port of a playback device, such as an AC power port or a USB port (e.g., a USB Type-A port, a USB Type-B port, a USB Type-C port, etc.). The power input port may be directly coupled to a household power outlet (e.g., to receive alternating current (AC) power) via a cable, or indirectly coupled via a power adapter (e.g., a device that converts AC power from a household power outlet into direct current (DC) power).

[0108] Power supply 220 may include a wireless power receiver (e.g., via inductance, resonance, radiation, etc.) that wirelessly receives power from an external wireless charger. For example, power supply 220 may include one or more concentrically arranged coils positioned along the surface of the playback device's housing (e.g., a bottom surface, a top surface positioned opposite the bottom surface, and / or a side surface positioned between the top and bottom surfaces). In this example, the playback device may be mounted on a wireless charging base that wirelessly transmits power to the coils in power supply 220. It should be understood that power supply 220 can wirelessly receive power according to any of a variety of wireless charging standards. Examples of such wireless charging standards include the Qi standard developed by the Wireless Power Consortium, the AIRFUEL Resonant standard developed by AIRFUEL, and the AIRFUEL RF standard developed by AIRFUEL.

[0109] Power source 220 may include an energy harvester. An energy harvester may include devices configured to harvest energy from energy sources in the environment (e.g., solar, thermal, wind, salinity gradients, kinetic energy, etc.). For example, power source 220 may include one or more photovoltaic cells configured to convert received light into voltage. Any of a variety of energy harvesters may be included in power source 220. Examples of such energy harvesters include photovoltaic cells, thermoelectric generators, micro wind turbines, piezoelectric crystals, and kinetic energy harvesters.

[0110] Power source 220 may include a battery (e.g., a rechargeable battery) configured to store energy and facilitate portable operation of the playback device. In this regard, the battery may contain chemicals that promote battery recharging, such as lithium-ion (Li-ion), nickel-metal hydride (NiMH), nickel-cadmium (NiCd), etc. The battery size may be designed such that circuitry 200 can operate on battery power alone for extended periods without requiring battery recharging. For example, the battery may have a 20 watt-hour (Wh) capacity, which facilitates continuous audio playback for at least 4 hours on battery power alone. The battery can be charged using power from one or more other components in power source 220 (e.g., a power input port, a wireless power receiver, an energy harvester, etc.).

[0111] Power supply 220 may include power supply circuitry configured to perform various power-related tasks, including, for example, one or more of the following: (1) power conversion (e.g., AC-AC conversion, AC-DC conversion, DC-AC conversion, and / or DC-DC conversion); (2) power regulation; (3) battery charging; and / or (4) power monitoring (e.g., battery monitoring). Examples of electrical components that may be integrated into the power supply circuitry include transformers, rectifiers, inverters, converters, regulators, battery chargers, and / or power management integrated circuits (PMICs).

[0112] In some examples, the power supply circuitry may include battery circuitry to facilitate monitoring of battery status. In these examples, the battery circuitry may identify battery status information, including information about one or more of the following battery states: state of charge (SoC), temperature, lifetime, and / or internal impedance. The battery circuitry may transmit the battery status information (e.g., as part of status information 240f) to, for example, processor circuitry 250.

[0113] The power supply circuit may include a regulation circuit that facilitates the conversion of a variable voltage (e.g., a variable voltage from a battery, a variable voltage from an energy harvester, etc.) into a stable DC voltage. For example, the regulation circuit may include a switching regulator circuit, such as a buck switching regulator circuit, a boost switching regulator circuit, a buck-boost switching regulator circuit, a flyback switching regulator circuit, a resonant switching regulator circuit, etc. The regulation circuit may include one or more linear voltage regulators, such as low-dropout (LDO) regulators. The regulation circuit can be configured to output one or more fixed DC voltages (e.g., ±5V, ±12V) or AC voltages.

[0114] Various example elements that may be included in power supply 220 have been described, and it should be understood that power supply 220 may include any combination of elements. For example, power supply 220 may include any combination of: (1) one or more power ports; (2) one or more wireless power receivers; (3) one or more energy harvesters; (4) one or more batteries; and / or (5) power supply circuitry (e.g., battery circuitry, regulation circuitry, etc.).

[0115] Power supply 225 is configured to receive power from power supply 220 (e.g., source voltage 240g) and output a regulated voltage suitable for powering amplifier 245 (e.g., amplifier supply voltage 240b). Power supply 225 can be implemented as a switch-mode power supply (SMPS). SMPS can include those power supplies that use one or more switching regulators, for example, when outputting power to a load. Examples of SMPS include: buck converters, boost converters, buck-boost converters, flyback converters, and resonant converters. Additionally or alternatively, power supply 225 can be implemented as a linear power supply, which, for example, includes one or more linear regulators.

[0116] Power supply 225 can change one or more output voltages (e.g., amplifier power supply voltage 240b) based on one or more reference inputs (e.g., control signal 240a). In this regard, power supply 225 may include feedback circuitry configured to drive the output voltage of power supply 225 to a specific value based on the value of the reference input. For example, power supply 225 may output a voltage at or proportional to the reference input value (e.g., 1X reference input, 2X reference input, 1 / 2 reference input).

[0117] Examples of feedback circuits can be configured to control the response time of power supply 225. For instance, the feedback circuit can be configured to have an underdamped or critically damped response to minimize the amount of time it takes for the output voltage value to adjust to a new value based on a change in the reference input value. In another example, the feedback circuit can have a damped response time to facilitate a gradual change in the output voltage value as the value of the reference input changes.

[0118] Amplifier circuit 230 is configured to generate audio output 240e for speaker 234 based on processed audio 240d transmitted from processor circuit 250. Amplifier circuit 230 includes amplifier 245, such as a switching amplifier and / or a linear amplifier, which amplifies the audio signal associated with the processed audio 240d to facilitate the generation of audio output 240e. Amplifier 245 (and / or the entire amplifier circuit 230) may be powered by amplifier supply voltage 240b from power supply 225. It should be understood that amplifier 245 may be implemented as an amplifier other than a switching amplifier, such as a linear amplifier (e.g., a Class A amplifier, Class B amplifier, Class AB amplifier, or Class C amplifier). Amplifier 245 may be, for example, a single-channel amplifier (e.g., a mono amplifier) ​​or a multi-channel amplifier (e.g., a stereo amplifier).

[0119] To facilitate the proper operation of amplifier 245 (i.e., the ability to amplify the audio input signal without significant distortion), the amplifier supply voltage 240b of amplifier 245 can be higher than the amplitude of the highest expected audio output level of amplifier 245. For example, amplifier supply voltage 240b can be 10%, 15%, etc., higher than the amplitude of the highest expected audio output level. Some examples of amplifier 245 may require amplifier supply voltage 240b to be a minimum amount (e.g., 500 millivolts (mV), 1 volt (V), 2 volts, 3 volts, etc.) higher than the amplitude of the highest expected audio output level. In other examples, the amplifier supply voltage 240b required for proper operation can be non-linearly related to the audio level. For example, the minimum amplifier supply voltage 240b required for a particular amplifier 245 to output a 1-volt peak-to-peak voltage (Vp-p) signal could be 2 volts (i.e., 1 volt higher than the amplitude), and the minimum amplifier supply voltage 240b required for the amplifier to output a 10-Vp-p signal could be 15 volts (i.e., 5 volts higher than the amplitude).

[0120] In some embodiments, amplifier circuit 230 may include Figure 2Additional components not shown (e.g., more than amplifier 245). For example, amplifier circuit 230 may include a digital-to-analog converter (DAC). Amplifier 245 and DAC may be integrated into a single integrated circuit (IC) die, or implemented in separate IC dies (e.g., in separate packages, integrated into the same package, or unpackaged). The DAC may be configured to convert processed audio data 240d from processor 205 into an analog signal (e.g., for amplification by amplifier 245). In some examples, processed audio data 240d may be transmitted in parallel from processor 205 to the DAC via a data bus (e.g., an 8-bit wide bus, a 16-bit wide bus). In other examples, processed audio data 240d may be transmitted serially from processor circuit 250 to the DAC. In this case, the DAC may include a serial-to-parallel converter to convert serially processed audio data 240d into parallel processed audio data 240d, facilitating the conversion of processed audio data 240d into an analog audio signal suitable for amplification.

[0121] Processor circuitry 250 may include one or more integrated IC dies in which processor 205 is integrated. As described above, processor 205 may correspond to or include the capabilities of processor 112a described above. Processor 205 may include one or more general-purpose processors (GPPs) and / or one or more dedicated processors (e.g., digital signal processors (DSPs)). Processor circuitry 250 may also include various types of interfaces that facilitate communication with other components of circuitry 200. For example, processor circuitry 250 may include a control signal output that facilitates the transmission of control signal 240a to a reference voltage input of power supply 225. Regulation of control signal 240a may facilitate the regulation of amplifier power supply voltage 240b output from power supply 225.

[0122] Examples of processor circuitry 250 may include an interface facilitating information transmission with power supply 220. For example, processor circuitry 250 may include I... 2 C bus interface, this I 2 The C bus interface can be used to transmit status information such as the temperature, lifespan, and impedance of a battery (e.g., power supply 220).

[0123] Examples of processor circuitry 250 may include one or more interfaces facilitating the transmission of processed audio data 240d to amplifier circuitry 230. For example, processor circuitry 250 may include an analog output interface facilitating the direct transmission of analog audio signals to amplifier circuitry 230. Processor circuitry 250 may include one or more interfaces facilitating the digital transmission of processed audio data 240d to, for example, a DAC via a data bus (e.g., an 8-bit, 16-bit, or 32-bit bus) in parallel, serial, or some combination of serial and parallel. For example, processor circuitry 250 may include an I2S interface and / or an I2C interface to transmit processed audio 240d to amplifier circuitry 230.

[0124] Examples of processor circuitry 250 may include an interface for receiving information from network interface 215. This information may include source audio data 240c received by circuitry 200 from another playback device, audio source (e.g., stereo, television, etc.), control device, or other devices.

[0125] As described above, processor 205 can communicate with memory 210. Memory 210 can store instruction code executable by processor 205 to enable processor circuitry 250 to perform or facilitate the execution of various operations. Operations related to the present invention will be described in further detail below. Memory 210 (or any portion thereof) can be integrated into processor circuitry 250 or separate from processor circuitry 250. Furthermore, memory 210 (or any portion thereof) and processor 205 can be integrated into the same IC die (e.g., processor 205 and memory 210 can be integrated into a single system-on-a-chip (SoC)) or implemented in separate IC dies (e.g., in separate packages, integrated into the same package, or unpackaged).

[0126] Figure 3An example of operation is shown that can be executed by processor circuitry 250 to facilitate the generation of control signals 240a for controlling power supply 225 to output an amplifier power supply voltage 240b at a specific level. These operations can be performed by one or more applications running within an operating system (e.g., executed by processor 205) that facilitates the execution of applications at different abstraction layers (e.g., user mode, drivers, kernel). In this example, the operating system could correspond to RT Linux, VX Works, OSE, etc. Kernel-mode applications can run in memory regions not protected by user-mode applications. Operations implemented by kernel-mode applications can involve direct access to hardware modules of processor circuitry 250. User-mode applications can run in memory regions protected by other user-mode applications and may not be able to directly perform operations involving direct hardware access. Driver applications can be implemented at the kernel level, user level, or both. Driver applications can act as a bridge between user-mode applications and hardware and / or as a bridge between kernel applications, which in turn can access the hardware.

[0127] It should be understood that in other implementation methods, Figure 3 The operations shown can be performed at the same level of abstraction. For example, all of these operations can be performed at the kernel level of the operating system.

[0128] refer to Figure 3 Operation 305 may involve receiving source audio 240c via a user-mode application. For example, the user-mode application may receive source audio 240c from a driver (not shown) configured to receive source audio 240c from communication interface 215. Source audio 240c may correspond to an 8-bit, 16-bit, or 32-bit wide audio sample. Source audio 240c may correspond to audio data received from an audio source (e.g., stereo, television, etc.). Source audio 240c may be an encoded format encoded according to one or more audio codecs such as MP3, AAC, and / or HE-AAC codecs, or it may be an unencoded format such as pulse code modulation (PCM).

[0129] Operation 310 may involve generating control data associated with a control signal 240a for controlling power supply 225 to output a specific level of amplifier power supply voltage 240b by a user-mode application. In this respect, the user-mode application may (e.g., via a driver application and / or a kernel application) transmit the control data to the control signal output of processor circuitry 250. Processor circuitry 250 may be configured to convert the control data into one or more signals (e.g., including pulse width modulation (PWM) signals) that may be transmitted (directly or indirectly) to a reference voltage input of amplifier power supply 225. It should be noted that, in alternative implementations, the user-mode application may transmit the control data directly to the kernel application, or operation 310 may be implemented entirely within the kernel application.

[0130] Operations 315a, 315b, and 315c may involve processing source audio 240c to provide processed audio 240d. Within this example, processing of source audio 240c may involve decoding (e.g., decoding source audio 240c from an encoded format to an unencoded and / or uncompressed format), equalization (e.g., increasing or decreasing the levels of different frequencies in source audio 240c), compression (e.g., reducing the dynamic range of source audio 240c), expansion (e.g., expanding the dynamic range of source audio 240c), and / or limiting (e.g., constraining the levels of source audio 240c to a specified threshold). For example, the audio processing latency associated with the performance of the operations performed between receiving source audio 240c and outputting processed audio 240d can be in the range of 10ms–50ms. This time amount depends on various factors, such as the amount of processing performed and the speed at which the processor processes the instructions. It should be noted that although processing operations 315a, 315b, and 315c are described as spanning multiple abstraction layers, in other implementations, processing operations 315a, 315b, and 315c can be executed within the same abstraction layer.

[0131] like Figure 3As shown, the operation 310 for generating control signals can be performed at least partially in parallel with the source audio 240c being processed and / or the processed audio 240d being output. Performing such operations at least partially in parallel can advantageously allow the generation of feedforward control signals, such as control signal 240a in some examples, without explicitly incorporating delays into the audio signal path (e.g., explicitly incorporating additional delays in audio processes 315a-315c and / or additional delays between the processed audio 240d output by processor 205 and speaker 235). For example, for a given audio block, a user-mode application can generate data indicating the value that should be output as the processed audio 240d in operation 315a and provide that data to the audio driver. Once the data for a given audio block is provided to the audio driver, the audio driver and / or the core may need to perform one or more operations (shown as a second audio process 315b and a third audio process 315c, respectively) before the processor circuitry 250 actually outputs a signal on a port. In this example, the user-mode application can utilize the audio processing delays of the second audio processing 315b and / or the third audio processing 315c to perform operation 310 and generate control signals. The time required to generate the control signals in operation 310 can be less than the time required by the second audio processing 315b and the third audio processing 315c (e.g., a few milliseconds less). Therefore, control signal 240a can be generated to resolve interference in the audio that has not yet been output by the processor circuitry 250 (e.g., events requiring large swings in the amplifier power supply voltage 240b).

[0132] Figures 4A to 4C Various schemes are shown for a processor circuit 250 (e.g., a processor 205 executing a user-mode application) to adjust the amplifier power supply voltage 240b via control signals in operation 310 to improve the power efficiency of circuit 200. Figures 4A to 4C In the diagram, the solid line represents the amplifier supply voltage 240b, while the dashed line represents the voltage envelope of the audio output signal 240e from the amplifier circuit 230 to the speaker 235. The top of the envelope corresponds to the minimum amplifier supply voltage 240b required for proper (i.e., distortion-free) amplification of the processed audio 240d by an ideal amplifier. The difference between the solid line (e.g., representing the amplifier supply voltage 240b) and the dashed line (e.g., representing the voltage envelope of the audio output signal 240e) is the voltage headroom, denoted as "Hr".

[0133] refer to Figure 4AIn the example, processor circuitry 250 can adjust control signal 240a so that power supply 225 outputs an amplifier supply voltage 240b that is a fixed amount higher than the minimum voltage level required by amplifier 230 for amplifying the processed audio 240d. For example, control signal 240a can be configured to adjust amplifier supply voltage 240b to be an absolute amount (e.g., Hr = 1 volt) higher than the minimum required amplifier supply voltage 240b. In some examples, control signal 240a can be configured to adjust amplifier supply voltage 240b to be a percentage (e.g., 5%, 10%) higher than the minimum required amplifier supply voltage 240b.

[0134] In some examples, control signal 240a can be configured to delay or advance the switching of amplifier power supply voltage 240b. For example, in area A, audio output 240e may decrease, thus the amplifier power supply voltage 240b required for amplification may decrease. In this case, control signal 240a can be configured to maintain amplifier power supply voltage 240b for a specific amount of time (e.g., 5 ms) and then decrease amplifier power supply voltage 240b. In area B, audio output 240e may increase, thus the amplifier power supply voltage 240b required for amplification may increase. In this case, control signal 240a can be configured to preemptively increase amplifier power supply voltage 240b (e.g., 5 ms). At this point, the generation and processing of control signal 240a are compared with the output of audio 240d (see...). Figure 3 The audio processing delay generated between the two can facilitate the preemptive adjustment of the amplifier power supply voltage 240b. For example, an audio processing delay of 40ms can facilitate the preemptive adjustment of the amplifier supply voltage 240b by approximately 40ms before the processed audio 240d is transmitted to the amplifier 230.

[0135] exist Figure 4A In this context, control signal 240a suddenly adjusts the amplifier power supply voltage 240b between voltage levels. For example... Figure 4B As shown, in another example, control signal 240a can be configured to gradually adjust amplifier supply voltage 240b between voltage levels. For example, as shown in sections C and D, control signal 240a can be configured to limit (e.g., 0.5 volts / millisecond) the slew rate of amplifier supply voltage 240b to limit the rate of change of amplifier supply voltage 240b.

[0136] like Figure 4CAs shown, in another example, control signal 240a can be configured such that amplifier power supply voltage 240b has specific rise (Ta) time, hold (Th) time, and release (Tr) time. The rise time (Ta) corresponds to the amount of time taken to increase amplifier power supply voltage 240b to the minimum amplifier power supply voltage 240b required for normal operation of amplifier 230 before the expected increase in the amplitude of audio output 240e. The hold time (Th) corresponds to the amount of time for amplifier power supply voltage 240b to maintain its value after the expected decrease in the amplitude of audio output 240e. The release time (Tr) corresponds to the amount of time taken to decrease amplifier power supply voltage 240b to the minimum amplifier power supply voltage 240b required for normal operation of amplifier 230 after the hold time (Th). The rise time (Ta) can be set to facilitate a rapid increase in amplifier power supply voltage 240b in response to the expected increase in the amplitude of audio output 240e. The hold (Th) and release (Tr) times can be set to delay the reduction of the amplifier supply voltage 240b in response to an expected decrease in the amplitude of the audio output 240e. For example, the rise time Ta can be set to a relatively short value (e.g., 1 ms) to facilitate a rapid increase in the amplifier supply voltage when the amplitude of the audio output 240e is expected to increase. The hold and release times can be set to slightly longer values ​​(e.g., 5 ms) to delay the reduction of the amplifier supply voltage 240b. This can be beneficial when it is desired that the amplitude of the audio output 240e be slightly modulated between low and high amplitudes, since in these cases rapid adjustment of the amplifier supply voltage 240b would actually reduce the overall efficiency of the circuit 200. Appropriate specification of the rise (Ta), hold (Th), and release (Tr) times of the control signal 240a can mitigate this problem.

[0137] In addition to the aspects described above, control signal 240a can be configured to adjust amplifier power supply voltage 240b in response to other parameters. For example, control signal 240a can be configured to increase the headroom required for proper operation of amplifier 230 in response to temperature, lifespan, impedance, and / or load presented on the battery. In this respect, control signal 240a can be configured to increase amplifier power supply voltage 240b proportionally to other parameters. For example, besides Figures 4A to 4C In addition to the adjustments described herein, the amplifier supply voltage 240b may be further increased by 5% to compensate for a 5% increase in battery load, temperature, and / or impedance, or a 5% reduction in battery life. The amount and / or percentage of increase or decrease may differ for each type of parameter. The rate at which the amplifier supply voltage 240b is adjusted to compensate for these parameter changes may be determined differently. For example, a lookup table may specify the amount of increase or decrease applied to the amplifier supply voltage 240b for a particular value associated with these parameters.

[0138] Figure 5 The diagram illustrates circuitry that can be, for example, a playback device and / or integrated into a playback device (e.g., Figure 2 The circuit 200 shown is an example of operation 500 performed by the circuit 200. Block 505 may involve receiving first audio data (e.g., source audio 240c) representing audio content from a computing system via a communication interface (e.g., communication interface 215). In one example, the first audio data may be received via a wireless local area network (WLAN) from one or more servers associated with a music service provider (e.g., SPOTIFY, APPLE MUSIC, PANDORA, etc.). In another example, the first audio data may be received via a Bluetooth network from a user equipment. The first audio data may be in an encoded format (e.g., according to one or more codecs) or may be in an unencoded or uncompressed format.

[0139] Block 510 may involve generating and outputting second audio data (e.g., processed audio 240d) based on first audio data by processor circuitry (e.g., processor circuitry 250). Additionally (or alternatively), the second audio data may be generated based on state information (e.g., state information 240f) associated with a power source (e.g., power source 220). In some implementations, one or more audio characteristics (e.g., volume, dynamic range, etc.) may be modified to adjust the power required for playback based on the state information. For example, the power source may include a battery, and one or more audio characteristics may be modified to reduce the power required for playback (e.g., reduce volume, reduce dynamic range, etc.) when one or more of the following conditions occur: (1) the battery voltage is below a threshold; (2) the battery's internal impedance is above a threshold; (3) the battery's lifetime is above a threshold; and / or (4) the battery's state of charge (SoC) is below a threshold.

[0140] Block 515 may at least partially involve generating and outputting a control signal (e.g., control signal 240a) associated with the second audio data by the processor circuitry to change the power supply voltage (e.g., amplifier power supply voltage 240b) of the amplifier (e.g., amplifier 245 in amplifier circuitry 230) while generating and outputting the second audio data. Additionally (or alternatively), the control signal may be generated based on state information (e.g., state information 240f) associated with the power supply (e.g., power supply 220). In some implementations, the voltage headroom supplied to the amplifier for a given audio segment may be adjusted based on the state information. For example, the voltage headroom may increase with increasing battery internal impedance and / or battery life.

[0141] Box 520 may relate to receiving control signals from processor circuitry via a power supply (e.g., power supply 225). The power supply may change the power supply voltage of the amplifier based on the control signals. The control signals may include one or more analog signals and / or one or more digital signals that convey a target output power supply voltage (directly or indirectly) to the power supply. For example, the control signals may include a PWM signal, where the characteristics of the pulse (e.g., pulse width, pulse density, etc.) represent the desired target power supply voltage. In some examples, the PWM signal may be directly transmitted to the power supply (e.g., the power supply directly receives the PWM signal). In other examples, the PWM signal may be filtered (e.g., via a low-pass filter) to generate an analog signal, where the desired target power supply voltage is represented by the amplitude of the analog signal (e.g., instead of the characteristics of the pulse). In these examples, the analog signal generated from the filtered PWM signal may be provided to the power supply.

[0142] Block 525 may involve receiving second audio data from processor circuitry by an amplifier circuit (e.g., amplifier circuit 230) including an amplifier, and generating (e.g., using an amplifier) ​​an analog audio signal (e.g., audio output 240e) based on the second audio data to drive a speaker (e.g., speaker 235).

[0143] In some examples, the second audio data includes a digital audio signal, where the amplifier circuitry also includes a digital-to-analog converter (DAC) coupled in series with the amplifier. The amplifier circuitry can be integrated into one or more IC dies (e.g., a single IC die, two IC dies, etc.). For example, the DAC can be integrated with the amplifier into the same IC die, or the DAC and amplifier can be integrated into separate IC dies with communicative coupling (e.g., using conductive traces, bonding wires, vias, etc.).

[0144] In some examples, the power supply voltage tracks the amplifier audio output voltage associated with the analog audio signal, having a value that is 0.1% to 35% greater than the amplifier audio output voltage. For example, the power supply voltage value can be greater than the amplifier audio output voltage by: (1) between 0.1% and 30%; (2) between 0.1% and 25%; (3) between 0.1% and 20%; (4) between 0.1% and 15%; (5) between 0.1% and 10%; (6) between 0.1% and 5%; (7) between 0.1% and 2.5%; and / or (8) between 0.1% and 1%.

[0145] In some examples, a control signal can be generated such that the power supply voltage has a maximum frequency between 0.1 Hz and approximately 20 kHz. For example, a control signal can be generated such that the maximum frequency of the power supply voltage can be between: (1) 0.1 Hz and 15 kHz; (2) 0.1 Hz and 10 kHz; (3) 0.1 Hz and 5 kHz; (4) 0.1 Hz and 1 kHz; (5) 0.1 Hz and 500 Hz; (6) 0.1 Hz and 100 Hz; (7) 0.1 Hz and 10 Hz; and / or (8) 0.1 Hz and 1 Hz.

[0146] In some examples, the power source is connected to a power source. The power source may include at least one of the following: an energy harvester, a battery, a wireless power receiver, or a power input port.

[0147] Some examples may include receiving information indicating at least one state of the power supply by processor circuitry. The processor circuitry may be configured to generate control signals (and / or second audio data) based on at least one state of the power supply.

[0148] In some examples, the power source includes a battery. In these examples, at least one state of the power source may include at least one of the following: battery temperature, battery state of charge, battery life, load on the battery, or battery internal impedance.

[0149] In some examples, the power supply includes an SMPS. The SMPS may include at least one of the following: a boost converter, a buck converter, a buck-boost converter, a flyback converter, or a resonant converter.

[0150] In some examples, the processor circuitry is configured to predict the amplifier's supply voltage value. In these examples, the processor circuitry can be configured to adjust the amplitude associated with the second audio data based on the predicted supply voltage. For example, it may have been previously determined that the supply response time is not fast enough to raise the amplifier supply voltage to the specific value required for proper amplification at a given time. In this case, the processor circuitry can reduce or compress the amplitude of the second audio data to minimize or prevent distortion of the second audio data by the amplifier. In other examples, a signal representing the actual amplifier supply voltage can be input to the processor circuitry via an interface. The processor circuitry can determine, based on the representative signal, that the amplitude of the second audio data needs to be compressed to prevent distortion.

[0151] While the above examples have been described with reference to playback devices, it is contemplated that the aforementioned aspects may be implemented in a circuit module. For example, a module for a first playback device may include at least one circuit board. A communication interface may be attached to (e.g., disposed on, mounted to, adhered to, embedded in, etc.) at least one circuit board and may be configured to facilitate communication via at least one network. Processor circuitry (including at least one processor) may be attached to at least one circuit board and coupled to the communication interface. At least one non-transitory computer-readable medium may be attached to at least one circuit board and coupled to at least one processor.

[0152] A computer-readable medium may store program instructions executable by at least one processor, such that processor circuitry is configured to receive first audio data representing audio content from a computing system via a communication interface. The processor circuitry may generate and output second audio data based on the first audio data, and at least in part, while generating and outputting the second audio data, generate and output control signals associated with the second audio data to change the power supply voltage of an amplifier (e.g., a Class D amplifier).

[0153] A power supply (e.g., SMPS) may be attached to at least one circuit board and coupled to the processor circuitry. The power supply may be configured to receive control signals from the processor circuitry and, based on these control signals, change the power supply voltage of the amplifier.

[0154] The amplifier circuit may be attached to at least one circuit board and coupled to the processor circuitry and the power supply. The amplifier circuitry may include an amplifier powered by a supply voltage from the power supply. The amplifier circuitry may be configured to receive second audio data from the processor circuitry and generate an analog audio signal based on the second audio data to drive a speaker.

[0155] Figure 6 The logic diagram of circuit 600 is shown, which is... Figure 2 A variant of circuit 200 is shown. Circuit 600 is configured to mitigate problems that may occur when the source voltage 240g supplied by power supply 220 drops below a low voltage threshold Vt (e.g., 3 volts). Reference Figure 6 Circuit 600 includes processor circuit 250, which includes processor 205, memory 210 communicating with processor circuit 250, communication interface 215, power supply 225, and amplifier circuit 230 including amplifier 245 and limiter 605. Processor circuit 250, memory 210, communication interface 215, power supply 225, and amplifier circuit 230 generally correspond to the components described above with corresponding reference numerals. For simplicity, a further description of these components is omitted.

[0156] Compared to Figure 2 Circuit 200, Figure 6 The circuit 600 includes a limiter 605 coupled between the processor circuit 250 and the power supply 225. Specifically, the processor circuit 205 transmits a control signal 240a to the limiter 605, and the limiter 605, under certain conditions, transmits the control signal 240a to a reference voltage input of the power supply 225. The limiter 605 is configured to control the power supply 225 to clamp or limit the amplifier power supply voltage 240b supplied by the power supply 225 to a specific amplifier power supply voltage (e.g., 3 volts) when the source voltage 240g supplied by the power supply 220 drops below a low voltage threshold Vt. For example, the normal operating range of the amplifier power supply voltage 240b may be between approximately 3 volts and 6 volts. When limited, the amplifier power supply voltage 240b may be reduced to 3 volts (e.g., the minimum permissible voltage for amplifier 245 operation), or it may be reduced to a voltage that is a certain percentage (e.g., 5%, 10%, etc.) lower than the maximum voltage observed within the normal operating range. Reducing the amplifier supply voltage 240b lowers the drive level of amplifier 245, which in turn reduces the load on power supply 220. Reducing the load on power supply 220 helps prevent the source voltage 240g supplied by power supply 220 from dropping further below the low voltage threshold Vt. By performing this mitigation, the playback device can avoid a situation where the source voltage 240g drops below the minimum required for the operation of processor circuitry 250 and / or communication interface 215 (e.g., causing the playback device to shut down or otherwise malfunction).

[0157] One example of limiter 605 is configured to receive information indicating the value of source voltage 240g (e.g., source voltage 240g itself, signals associated with source voltage 240g, data specifying the value of source voltage 240g, etc.) and, when appropriate, transmit control signal 240a to the reference voltage input of power supply 225. For example, when source voltage 240g is determined to be at or above a low voltage threshold Vt, limiter 605 is configured to output control signal 240a to the reference voltage input of power supply 225. This, in turn, causes amplifier supply voltage 240b to track the voltage associated with control signal 240a.

[0158] When the source voltage 240g is determined to be below the low voltage threshold Vt, the limiter 605 is configured to perform one or more limiting operations. For example, the limiter 605 is configured to output a low voltage reference signal as a control signal to the input of the power supply 225a, such as a fixed reference voltage, or a scaled-down version of the control signal 240a received from the processor circuitry 250. This controls the power supply 225 to provide a specific amplifier power supply voltage, or a scaled-down version of the amplifier power supply voltage 240 that is lower than the voltage originally provided by the power supply 225.

[0159] Figure 7A and Figure 7BAn example of a limiter 605 is shown. The limiter 605 includes a comparator 705 and a switch 710. The comparator 705 is configured to receive a source voltage 240g and a first reference voltage V. REFI As input, the first reference voltage corresponds to a low voltage threshold Vt, at which limiter 605 begins limiting operation. In one example, when the source voltage 240g is at or above the first reference voltage, the output of comparator 705 changes state (e.g., from low to high). And when the source voltage 240g drops below the first reference voltage, the output of comparator 705 changes state (e.g., from high to low). Comparator 705 does not incorporate hysteresis, such that the output state changes only when the source voltage 240g exceeds the first reference voltage or becomes imperceptibly low below it. That is, after the source voltage 240g exceeds or falls below the first reference voltage, comparator 705 changes state rapidly.

[0160] An example of switch 710 includes a first input, a second input, an output, and a selector input, denoted as SEL. The first input is configured to receive a control signal 240a. Figure 7A In the limiter, the second input is configured to receive the second reference voltage V. REF2 .exist Figure 7B In the limiter, the second input is configured to receive a reduced version of the control signal 240a (e.g., control signal 240a divided by 2).

[0161] In operation, the selector input controls switch 710 to transmit a signal present at one of the first and second inputs to the output based on the state of the selector input (e.g., high or low value). The output of switch 710 is transmitted to the reference voltage input of power supply 225.

[0162] When the source voltage 240g provided by power supply 220 is at or above the low voltage threshold Vt, the output of comparator 705 changes to control switch 710 to transmit the signal at the first input terminal (e.g., control signal 240a) to the output terminal of switch 710 and the reference voltage input terminal of power supply 225.

[0163] When the source voltage 240g supplied by power supply 220 is lower than the low voltage threshold Vt, the output of comparator 705 changes state (e.g., from high to low). This, in turn, controls switch 710 to transmit the signal from the second input terminal to the output terminal of switch 710 and the reference voltage input terminal of power supply 225. Figure 7A In the limiter, the voltage V REF2 The voltage is transmitted to the output of switch 710 and the reference voltage input of power supply 225. Figure 7BIn the limiter, a reduced version of the control signal 240a is transmitted to the output of switch 710 and the reference voltage input of power supply 225.

[0164] Figure 7C Another example of a limiter 605 is shown. Limiter 605 includes a microcontroller 715 and one or more logic gates 720. The microcontroller 715 can execute program instructions to compare a source voltage 240g with one or more thresholds (e.g., a first reference voltage) and output a cancellation signal, represented as OVR, to one or more logic gates 720. The cancellation signal can indicate whether limiter 605 should output a control signal 240a that is substantially the same (or identical) to the reference voltage input of the received power supply 225, or modify some (or all) of the control signal 240a such that the amplifier supply voltage does not exceed a specific voltage (e.g., the maximum voltage before the playback device shuts down or otherwise fails due to the source voltage 240g becoming too low). One or more logic gates 720 can receive the cancellation signal and the control signal 240a from the microcontroller 715. One or more logic gates can be configured to output the control signal 240a or modify the control signal 240a so as not to exceed a specific value based on the cancellation signal.

[0165] It should be understood that one or more logic gates 720 may be implemented in any of a variety of ways depending on the specific implementation. Examples of suitable logic gates that may be used include “OR”, “NOR”, “XOR”, “XNOR”, “AND”, and “NAND” logic gates. Such logic gates may be implemented in hardware (e.g., hardware logic gates) or in software (e.g., executed by the microcontroller 715). In some implementations, one or more logic gates 720 may be configured as OR gates. In these implementations, an OR gate may include a first input terminal configured to receive a control signal 240a, a second input terminal configured to receive an OVR signal from the microcontroller 715, and an output terminal configured to output a signal for a reference voltage input to the power supply 225.

[0166] Figure 8A An example of a source voltage 240g provided by power supply 220 is shown, wherein the source voltage 240g drops instantaneously below the low voltage threshold Vt due to a sudden increase in load on power supply 220. Figure 8BAn example of the amplifier supply voltage 240b and its envelope associated with the audio output 240e during a sudden increase is shown. In the example shown, the sudden increase in load is attributed to a sudden increase in the envelope associated with the audio output 240e, which results in a corresponding increase in the drive current of the speaker 235. However, the increase in load could be attributed to other reasons, such as the processor 205 performing a computationally intensive task, the communication interface 215 transmitting information, etc. Furthermore, the source voltage 240g shown, provided by the power supply 220, varies based on the load on the power supply 220. Typically, this variation is caused by a voltage drop across the output impedance of the power supply 220, which is attributed to the current flowing through the load of the power supply 220 (e.g., the amplifier, processor 205, communication interface 215, etc.).

[0167] During the first time period T1, the source voltage 240g is higher than the low voltage threshold Vt. During this period, the source voltage 240g supplied by power supply 220 is higher than the low voltage threshold Vt. The output of comparator 705 of limiter 605 changes to the state of control switch 710 to transmit the signal at the first input (e.g., control signal 240a) to the output of switch 710 and the reference voltage input of power supply 225. Similarly, microcontroller 715 changes to the state of the overridden signal of one or more logic gates 720 such that one or more logic gates 720 cause control signal 240a to be output without substantial change (e.g., the same). Therefore, as described above, amplifier supply voltage 240b tracks the envelope of audio output 240e.

[0168] During the second time period T2, the envelope of the audio output 240e increases, and the amplifier supply voltage 240b provided by power supply 225 tracks this increase. The increase in the envelope of the audio output 240e causes a corresponding increase in the output of amplifier 245, thus causing a corresponding increase in the drive current of amplifier 245. Consequently, the source voltage 240g begins to decrease and eventually falls below the low voltage threshold Vt.

[0169] During the third time period T3, the source voltage 240g supplied by power supply 220 drops below the low voltage threshold Vt, and the output of comparator 705 changes state (e.g., from high to low). This, in turn, controls switch 710 to transmit the signal at the second input to the output of switch 710 and the reference voltage input of power supply 225. At voltage V... REF2When the voltage is transmitted to the output of switch 710, the corresponding voltage is transmitted to the reference voltage input of power supply 225, which controls power supply 225 to reduce amplifier power supply voltage 240b. Similarly, microcontroller 715 changes the state of the override signal of one or more logic gates 720, causing one or more logic gates 720 to modify control signal 240a so as not to exceed the maximum value (thus reducing amplifier power supply voltage 240b in this case). Reducing amplifier power supply voltage 240b further reduces the drive current of amplifier 245. This reduces the load on power supply 220 and increases the amplifier power supply voltage 240b provided by power supply 220 above the low voltage threshold Vt.

[0170] In some examples, during a third time period T3, the amplitude of the audio output 240e is gradually reduced to further reduce the load on the power supply 220. For example, in one example, the processor circuitry 250 receives an indication that a limiting operation has been triggered. This indicates to the processor circuitry 250 that the voltage supplied by the power supply 220 has dropped to a critical value (e.g., below a low voltage threshold Vt). In response to receiving this indication, the processor circuitry 250 reduces the amplitude of the audio output 240e (e.g., by 50%). In some examples, the amplitude decreases gradually over time (e.g., over a 10-second time period). In some examples, a tone or some other indication is conveyed to the user to make the user aware that the amplifier output is decreasing or limiting, and therefore aware that the power supply 220 (e.g., a battery) needs charging. In some examples, the processor circuitry 250 is configured to maintain the reduction in amplitude until the source voltage 240g supplied by the power supply 220 exceeds an upper limit threshold (such as 20% higher than the low voltage threshold Vt) to provide a form of hysteresis to prevent the amplitude of the audio output 240e from oscillating between limited and unlimited states.

[0171] Furthermore, or alternatively, in some examples, the processor circuitry 250 is configured to maintain the decrease in amplitude until the source voltage 240g supplied by the power supply 220 exceeds the low voltage threshold Vt for a predetermined amount of time (e.g., 10 seconds). In some examples, the processor circuitry 250 is configured to maintain the decrease in amplitude until the power supply 220 has been recharged.

[0172] Figure 9 This illustrates any playback device 110, such as those described herein, and / or any circuitry used for integration into the playback device described herein (such as...). Figure 2 The circuit 200 shown Figure 6Examples of operations 900 performed by circuit 600 shown. These operations help mitigate problems that may occur when the source voltage 240g supplied by power supply 220 is below the low voltage threshold Vt. Examples of operations are implemented via instruction codes of playback device 110 and / or circuits (200 and 600), which are executed by their respective processors 205.

[0173] At block 905, a control signal 240a associated with audio data is received. An example of audio data corresponds to the processed audio 240d described above. As stated above, the control signal 240a is associated with the envelope of the audio data, and the control signal 240a facilitates changing the amplifier power supply voltage 240b supplied by power supply 225 to amplifier 245, which amplifies the audio signal associated with the audio data.

[0174] At block 910, the source voltage 240g supplied by power supply 220 and power supply 225 supplying power to the amplifier is received. For example, the limiter 605 receives information specifying the value of the voltage indicating the source voltage 240g (e.g., the source voltage 240g itself, the signal associated with the source voltage 240g, data specifying the value of the source voltage 240g, etc.).

[0175] At block 915, when the source voltage 240g supplied by power supply 220 is at or above the low voltage threshold Vt, a control signal 240a is transmitted to the reference voltage input of power supply 225 to change the amplifier power supply voltage 240b supplied to amplifier 245 according to the control signal 240a. For example, the control signal 240a controls power supply 225 via the reference voltage input to output amplifier power supply voltage 240b, which is a margin higher than the minimum voltage required for amplifier 245 to amplify the audio signal associated with the audio data without significant distortion.

[0176] At block 920, when the source voltage 240g supplied by power supply 220 is lower than the low voltage threshold Vt, a low voltage reference signal is transmitted to the reference voltage input of power supply 225 to reduce the amplifier power supply voltage 240b supplied by power supply 225 to amplifier 245 according to the low voltage reference signal. For example, limiter 605 is configured to output a fixed voltage or a reduced version of the control signal 240a received from processor circuit 250 to the reference voltage input of power supply 225a. This controls power supply 225 to provide a minimum amplifier power supply voltage, or a reduced version of the amplifier power supply voltage 240b that is lower than the voltage that power supply 225 would normally provide.

[0177] Figure 10An example of a logic diagram 1000 of entities is shown, which cooperate to maximize the likelihood of reducing the aforementioned limiting operation. For example, these entities cooperate to minimize the likelihood that the source voltage 240g provided by power supply 220 will drop below the low voltage threshold Vt. These entities include a gain adjustment module 1000 and a power supply model 1005. Examples of the gain adjustment module 1000 and power supply model 1005 are implemented by instruction code executed by processor circuitry 250 and / or other circuitry 600. It should be understood that these aspects can also be applied to... Figure 2 Circuit 200.

[0178] An example of the gain adjustment module 1000 is configured to receive audio 1015 as input and output an amplified version of audio 1015 as processed audio 240d, which is then sent to amplifier 245. The example of audio 1015 can be pre-processed because equalization, delay, and / or other operations have already been performed on audio 1015 before gain adjustment. However, the gain operation performed by the gain adjustment module 1000 can be applied before or between these other processing operations.

[0179] An example of the gain adjustment module 1000 receives a user gain 1020 and an amplifier reduction amount 1025 as inputs. The user gain 1020 specifies the amount of gain applied to the audio 1015, which can be related to a gain specified by the user via a controller. The amplifier reduction amount 1025 specifies the gain reduction applied to the audio 1015. The gain provided by the gain adjustment module 1000 varies with the user gain 1020 and the amplifier reduction amount 1025. For example, in the example, if the user gain 1020 is 2 and the amplifier reduction amount 1025 is half, the gain adjustment module 1000 provides a gain of 1.

[0180] In some examples, the amplifier reduction 1025 does not apply to all audio frequencies 1015. For instance, the gain associated with low-amplitude audio (e.g., below a given decibel level) may be reduced to a smaller extent (or not reduced at all) compared to the gain associated with high-frequency audio (e.g., below a certain decibel level). In another example, the gain associated with low-frequency audio (e.g., below a certain frequency) may be reduced to a smaller extent (or not reduced at all) compared to the gain associated with high-frequency audio (e.g., above a certain frequency).

[0181] The example of power supply model 1000 facilitates determining the amplifier reduction amount 1025 applied to gain adjustment module 1000 to reduce the load on power supply 220, thereby minimizing the likelihood of limiting operation of limiter 605. For example, power supply model 1000 simulates power supply 220 based on attributes such as power capacity, output impedance, capacitance, and power supply type. Power supply model 1000 takes the current state of power supply 220 (e.g., output voltage, output current, temperature, etc.) as input and outputs an amplifier reduction value 1010 that can be applied to audio 1015 to reduce the gain of audio 1015 to an amount that minimizes the likelihood of limiting operation of limiter 605.

[0182] In operation, when the source voltage 240g supplied by power supply 220 is higher than the low voltage threshold Vt by a predetermined amount, such as 20% higher than the low voltage threshold Vt, the example of power supply model 1000 specifies the gain reduction amount 1025 as zero. In this state, no gain reduction is applied.

[0183] According to this example, when the source voltage 240g provided by power supply 220 falls within 20% of the low voltage threshold Vt, power supply model 1005 outputs a gain reduction amount 1025 greater than zero to reduce the gain provided by gain adjustment module 1000. For example, when status information 240f indicates that the load current on the power supply exceeds a certain current, the battery temperature is below a certain temperature, the battery life exceeds a certain lifespan, etc., power supply model 1000 outputs a gain reduction amount 1025 that reduces the gain applied by gain adjustment module 1000.

[0184] Example of power supply model 1005 includes a table relating different currents, temperatures, lifetimes, etc., to power supply 220 with different gain reductions 1025. In this case, the applied gain reduction increases with increasing current, decreasing temperature, increasing aging time, etc.

[0185] In some examples, the power supply model 1005 is updated from time to time. For example, suppose a gain reduction is being applied for a given state of the battery, but the source voltage 240g provided by power supply 220 still drops below the low voltage threshold Vt, thus triggering the aforementioned limiting operation. In this case, in the example, power supply model 1005 is updated to associate a larger gain reduction with the parameter representing the current state of the power supply. For example, instruction code executed by the processor could increase the gain reduction by 10%.

[0186] Figure 11 This illustrates any playback device 110, such as those described herein, and / or any circuitry used for integration into the playback device described herein (such as...). Figure 2 The circuit 200 shown Figure 6An example of operation 1100 performed by the circuit 600 shown. The example of operation is implemented via instruction codes of the playback device 110 and / or circuits (200 and 600), which are executed by their respective processors 205.

[0187] At box 1105, status information 240f associated with the power supply 220 of playback device 110 is received. Status information 240f specifies the source voltage 240g provided by power supply 220. Examples of status information 240f also include one or more of temperature, lifetime, impedance, etc., associated with the battery or other components of power supply 220.

[0188] At block 1110, when the source voltage 240g supplied by power supply 220 is at or above the low voltage threshold Vt, the audio signal 1015 is adjusted by a first gain amount. For example, the first gain amount corresponds to a gain amount specified by the user via a controller. An example of applying the first gain amount is when the source voltage 240g supplied by power supply 220 is higher than the low voltage threshold Vt by a predetermined amount, such as 20% higher than the low voltage threshold Vt.

[0189] At box 1114, when the source voltage 240g supplied by power supply 220 is below a low voltage threshold, the audio signal 1015 is adjusted by a second gain amount, which is lower than the first gain amount. According to the example above, when the source voltage 240g supplied by power supply 220 falls within 20% of the low voltage threshold Vt, the audio signal 1015 is adjusted by a second gain amount, such as 75% of the first gain amount. In the example, the second gain amount depends on information specified in the status information 240f, such as the load current associated with power supply 220, the temperature of power supply 220, the lifespan of power supply 220, the type or model of power supply 220, etc.

[0190] In some examples, the second gain varies linearly with the difference between the source voltage 240g supplied by power supply 220 and the low voltage threshold Vt. For example, when the source voltage 240g supplied by power supply 220 is equal to the low voltage threshold Vt, the second gain corresponds to the first gain, and thereafter, as the source voltage 240g supplied by power supply 220 deviates below the low voltage threshold Vt, the second gain decreases at a linear rate. In some examples, the second gain varies non-linearly with the difference between the source voltage 240g supplied by power supply 220 and the low voltage threshold Vt. In some examples, the second gain varies in a stepped manner (e.g., through multiple discrete steps) with the difference between the source voltage 240g supplied by power supply 220 and the low voltage threshold Vt.

[0191] At frame 1120, the adjusted audio signal is transmitted to speaker 235 to facilitate the playback of the adjusted audio signal.

[0192] IV. Conclusion

[0193] The above discussion of playback devices, controller devices, playback area configurations, and media content sources provides only some examples of operating environments in which the following functions and methods can be implemented. Other operating environments and configurations of media playback systems, playback devices, and network devices not explicitly described in this document may also be applicable and suitable for implementing the functions and methods.

[0194] It should be understood that the transmission of information to a specific component, device, and / or system mentioned herein is to be understood as including the indirect or direct transmission of information (e.g., signals, messages, requests, responses) to a specific component, device, and / or system. Therefore, information transmitted to a specific component, device, and / or system may pass through any number of intermediate components, devices, and / or systems before reaching its destination. For example, a processor may transmit information to an SMPS by first transmitting the information to an intermediate component, which in turn transmits the information to the SMPS. Furthermore, intermediate components may modify the information. For example, an intermediate component may modify a portion of the information, reformat the information, and / or incorporate additional information.

[0195] Similarly, the reference to receiving information from a specific component, device, and / or system as used herein should be understood to include receiving information (e.g., signals, messages, requests, responses) directly or indirectly from a specific component, device, and / or system. Therefore, information received from a specific component, device, and / or system may pass through any number of intermediate components, devices, and / or systems before being received. For example, an amplifier may indirectly receive information from a processor by receiving information originating from a processor from a digital-to-analog converter. Furthermore, intermediate devices may modify the information. For example, an intermediate device may modify a portion of the information, reformat the information, and / or incorporate additional information.

[0196] The above description discloses, in particular, various example systems, methods, apparatuses, and articles of art, including components such as firmware and / or software executed on hardware. It should be understood that such examples are merely illustrative and should not be considered limiting. For example, it is contemplated that any or all firmware, hardware, and / or software aspects or components may be implemented solely in hardware, solely in software, solely in firmware, or in any combination of hardware, software, and / or firmware. Therefore, the examples provided are not the only ways to implement such systems, methods, apparatuses, and / or articles of art.

[0197] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one exemplary embodiment of the invention. This phrase appearing in various places in the specification does not necessarily refer to the same embodiment, and individual or alternative embodiments are not necessarily mutually exclusive with other embodiments. Therefore, those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0198] This specification is presented primarily using illustrative representations of environments, systems, processes, steps, logic blocks, handling, and other symbolic representations directly or indirectly similar to the operation of data processing devices coupled to a network. These process descriptions and representations are generally used by those skilled in the art to most effectively convey the essence of their work to others skilled in the art. Numerous specific details are set forth to provide a thorough understanding of the invention. However, those skilled in the art will understand that certain embodiments of the invention may be practiced without certain specific details. In other instances, well-known methods, processes, components, and circuits have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments. Therefore, the scope of the invention is defined by the appended claims rather than the description of the foregoing embodiments.

[0199] When any appended claim is interpreted to cover purely software and / or firmware implementations, at least one element in at least one example is hereby explicitly defined as including tangible, non-transitory media for storing the software and / or firmware, such as memory, DVD, CD, Blu-ray, etc.

[0200] Example features

[0201] (Feature 1) A playback device comprising: a communication interface; processor circuitry including at least one processor coupled to the communication interface; at least one non-transitory computer-readable medium coupled to the at least one processor; program instructions stored on the at least one non-transitory computer-readable medium, the program instructions being executable by the at least one processor, such that the processor circuitry is configured to: after receiving first audio data representing audio content via the communication interface, generate and output second audio data based on the first audio data; and at least partially while generating and outputting the second audio data, generate and output a control signal associated with the second audio data to change the power supply voltage of a Class D amplifier; a switch-mode power supply (SMPS) coupled to the processor circuitry, wherein the SMPS is configured to receive the control signal from the processor circuitry and change the power supply voltage of the Class D amplifier based on the control signal; and an amplifier circuitry coupled to the processor circuitry and the SMPS, wherein the amplifier circuitry includes a Class D amplifier powered by the power supply voltage from the SMPS, and wherein the amplifier circuitry is configured to receive the second audio data from the processor circuitry and use the Class D amplifier to generate an analog audio signal based on the second audio data to drive a speaker.

[0202] (Feature 2) The playback device according to feature 1, wherein the second audio data includes a digital audio signal, and wherein the playback device further includes a digital-to-analog converter (DAC) coupled between the processor circuitry and the Class D amplifier.

[0203] (Feature 3) The playback device according to feature 2, wherein the amplifier circuit includes a DAC, and wherein the amplifier circuit is integrated into a single integrated circuit (IC) die.

[0204] (Feature 4) The playback device according to feature 1, wherein the power supply voltage tracks the amplifier audio output voltage associated with the analog audio signal and has a value that is 0.1% to 35% greater than the amplifier audio output voltage.

[0205] (Feature 5) The playback device according to feature 1, wherein the power supply voltage has a maximum frequency between 0.1 Hz and approximately 20 kHz.

[0206] (Feature 6) The playback device according to feature 1 further includes a power source coupled to the SMPS, and said power source includes at least one of the following: an energy harvester, a battery, a wireless power receiver, or a power input port.

[0207] (Feature 7) The playback device according to feature 6, wherein the processor circuit is configured to receive information indicating at least one state of the power supply, wherein program instructions executed by the at least one processor cause the processor circuit to be configured to generate and output control signals, including program instructions executed by the at least one processor causing the processor circuit to be configured to generate control signals based on at least one state of the power supply.

[0208] (Feature 8) The playback device according to feature 7, wherein the power source includes a battery, and wherein at least one state of the power source includes at least one of the following: battery temperature, battery state of charge, battery life, battery load, or battery internal impedance.

[0209] (Feature 9) The playback device according to feature 1, wherein the SMPS includes at least one of a boost converter, a buck converter, a buck-boost converter, a flyback converter, or a resonant converter.

[0210] (Feature 10) The playback device according to feature 1 further includes program instructions stored on at least one non-transitory computer-readable medium, the program instructions being executable by at least one processor to configure processor circuitry to predict a power supply voltage value of the amplifier, and wherein executing the program instructions by at least one processor to configure processor circuitry to generate and output a control signal includes executing the program instructions by at least one processor to configure processor circuitry to generate the control signal based on the predicted value of the power supply voltage.

[0211] (Feature 11) The playback device according to feature 1, wherein the playback device is configured to play back audio content synchronously with at least one other playback device.

[0212] (Feature 12) A method performed by a playback device includes: receiving first audio data representing audio content from a computing system via a communication interface; generating and outputting second audio data based on the first audio data using a processor circuit including at least one processor; generating and outputting a control signal associated with the second audio data to change the power supply voltage of a Class D amplifier using the processor circuit, at least partially while generating and outputting the second audio data; receiving the control signal from the processor circuit via a switch-mode power supply (SMPS); changing the power supply voltage of the Class D amplifier based on the control signal using the SMPS; receiving the second audio data from the processor circuit using an amplifier circuit including a Class D amplifier; and generating a first analog audio signal based on the second audio data using the Class D amplifier to drive a speaker, at least partially while changing the power supply voltage of the Class D amplifier.

[0213] (Feature 13) According to the method of feature 12, wherein the second audio data includes a digital signal, wherein generating the analog audio signal includes: converting the digital signal into an analog signal using a digital-to-analog converter (DAC) integrated into an amplifier circuit, and amplifying the analog signal using a Class D amplifier.

[0214] (Feature 14) The method according to feature 12, wherein changing the power supply voltage includes changing the power supply voltage to track the amplifier audio output voltage associated with the analog audio signal, such that the power supply voltage has a value between 0.1% and 35% greater than the amplifier audio output voltage.

[0215] (Feature 15) The method according to feature 12, wherein generating and outputting the control signal includes generating a control signal such that the power supply voltage has a maximum frequency between 0.1 Hz and approximately 20 kHz.

[0216] (Feature 16) The method according to feature 12 further includes: receiving power from a power source by the SMPS, the power source including at least one of the following: an energy harvester, a battery, a wireless power receiver, or a power input port.

[0217] (Feature 17) The method according to feature 12 further includes receiving information indicating at least one state of the power supply by the processor circuitry, wherein generating and outputting the control signal includes generating the control signal based on at least one state of the power supply.

[0218] (Feature 18) A circuit for a playback device, the circuit comprising: at least one circuit board; a communication interface attached to the at least one circuit board; a processor circuit attached to the at least one circuit board and including at least one processor; at least one non-transitory computer-readable medium attached to the at least one circuit board; program instructions stored on the at least one non-transitory computer-readable medium, the program instructions being executable by the at least one processor such that the processor circuit is configured to: after receiving first audio data representing audio content via the communication interface, generate and output second audio data based on the first audio data; and at least partially while generating and outputting the second audio data, generate and output a control signal associated with the second audio data to change a power supply voltage of an audio amplifier; a power supply attached to the at least one circuit board and coupled to the processor circuit, wherein the power supply is configured to receive the control signal from the processor circuit and change the power supply voltage of the audio amplifier based on the control signal; and an amplifier circuit attached to the at least one circuit board and coupled to the processor circuit and the power supply, wherein the amplifier circuit includes an audio amplifier powered by the power supply voltage from the power supply, and wherein the amplifier circuit is configured to receive the second audio data from the processor circuit and use the audio amplifier to generate an analog audio signal based on the second audio data to drive a speaker.

[0219] (Feature 19) The circuit according to feature 18, wherein the audio amplifier includes a switching amplifier.

[0220] (Feature 20) The circuit according to feature 18, wherein the power supply includes a switch-mode power supply (SMPS).

[0221] (Feature 21) The circuit according to feature 18, wherein the processor circuit includes a system-on-a-chip.

[0222] (Feature 22) The circuit according to feature 21, wherein the at least one non-transitory computer-readable medium includes a memory integrated into a system-on-a-chip.

Claims

1. A playback device, comprising: Wireless communication interface (215); A processor circuit (250) including at least one processor (205), coupled to the wireless communication interface and configured to, upon receiving first audio data (240c) representing audio content via the wireless communication interface (215): A second audio data (240d) is generated and output based on the first audio data (240c), the second audio data (240d) including a digital audio signal; and At least in part during the generation and output of the second audio data (240d), a control signal (240a) associated with the second audio data (240d) is generated and output to change the power supply voltage (240b) of the audio amplifier (245), the control signal (240a) indicating the target power supply voltage of the audio amplifier (245); A switch-mode power supply (SMPS) (225) is coupled to the processor circuit (250) and configured to change the power supply voltage (240b) of the audio amplifier (245) based on the control signal (240a). A power supply (220) is coupled to the SMPS (225); A limiter circuit (605), coupled to the power supply (220), is configured to limit the power supply voltage (240b) of the audio amplifier (245) to a specific maximum voltage when the source voltage of the power supply (220) drops below a low voltage threshold. The limiter circuit (605) is coupled between the processor circuit (250) and the SMPS (225) and is configured to: receive the control signal (240a) from the processor circuit (250); transmit the control signal (240a) to the SMPS (225) when the source voltage is above the low voltage threshold; and modify the control signal (240a) transmitted to the SMPS (225) such that the power supply voltage (240b) does not exceed the specific maximum voltage when the source voltage is below the low voltage threshold. An amplifier circuit (230) coupled to the processor circuit (250) and the SMPS (225) includes an audio amplifier (245) configured to be powered by the power supply voltage (240b) from the SMPS (225), and wherein the amplifier circuit (230) is configured to receive the second audio data (240d) from the processor circuit (250) and use the audio amplifier (245) to generate an analog audio signal (240e) based on the second audio data (240d) to drive the speaker (235).

2. The playback device according to claim 1, wherein: The playback device further includes a digital-to-analog converter (DAC) coupled between the processor circuit (250) and the audio amplifier (245); and The amplifier circuit (230) includes the DAC and is integrated into a single integrated circuit IC die.

3. The playback device according to any one of claims 1 to 2, wherein: The power supply voltage (240b) tracks the amplifier audio output voltage associated with the analog audio signal (240e); and The power supply voltage (240b) has a value between 0.1% and 35% greater than the amplifier audio output voltage.

4. The playback device according to claim 3, wherein the maximum frequency of the power supply voltage (240b) is between 0.1 Hz and approximately 20 kHz.

5. The playback device according to claim 1, wherein: The processor circuit (250) is configured to receive status information (240f) indicating at least one state of the power supply (220) coupled to the SMPS (225); and The processor circuit (250) is configured to generate and output the control signal (240a) based on at least one state of the power supply (220).

6. The playback device according to claim 5, wherein: The power source (220) includes a battery; and The at least one state of the power supply (220) includes at least one of the following: The temperature of the battery, The charging state of the battery, The lifespan of the battery, The load on the battery, or The internal impedance of the battery.

7. The playback device according to claim 1, wherein the SMPS (225) comprises at least one of the following: Boost converter Buck converter Buck-boost converter flyback converter, or Resonant converter.

8. The playback device according to claim 1, wherein the processor circuit (250) is configured to: Predict the value of the power supply voltage (240b) of the amplifier (245), and The control signal (240a) is generated based on the predicted value of the power supply voltage (240b).

9. The playback device according to claim 1, wherein the processor circuit (250) comprises a system-on-a-chip.

10. The playback device of claim 9, further comprising at least one tangible non-transitory computer-readable medium, said at least one tangible non-transitory computer-readable medium comprising a memory integrated into the system-on-chip.

11. The playback device of claim 1, wherein the playback device is configured to play back the audio content synchronously with at least one other playback device.

12. The playback device according to claim 1, wherein the audio amplifier (245) comprises a switching amplifier, optionally a Class D amplifier.

13. A method performed by a playback device, comprising: First audio data (240c) representing audio content is received from the computing system via a wireless communication interface (215). A processor circuit (250) including at least one processor (205) generates and outputs second audio data (240d) based on the first audio data (240c), the second audio data (240d) including digital audio signals; At least in part during the generation and output of the second audio data (240d), the processor circuitry generates and outputs a control signal (240a) associated with the second audio data (240d) to change the power supply voltage (240b) of the audio amplifier (245), the control signal (240a) indicating the target power supply voltage of the audio amplifier (245); The power supply voltage (240b) of the audio amplifier (245) is changed using a switch-mode power supply SMPS (225) based on the control signal (240a). When the source voltage of the power supply (220) drops below a low voltage threshold, a limiter circuit (605) is used to limit the power supply voltage (240b) of the audio amplifier (245) to a specific maximum voltage, wherein the limiter circuit (605) is coupled between the processor circuit (250) and the SMPS (225), and wherein the limitation includes: The control signal (240a) is received from the processor circuit (250); When the source voltage is higher than the low voltage threshold, the control signal (240a) is transmitted to the SMPS (225); and The control signal (240a) transmitted to the SMPS (225) is modified such that when the source voltage is lower than the low voltage threshold, the power supply voltage (240b) does not exceed the specific maximum voltage; The second audio data (240d) is received from the processor circuit (250) by the amplifier circuit (230) including the audio amplifier (245); and At least in part, during the change of the power supply voltage (240b) of the audio amplifier (245), the audio amplifier is used to generate an analog audio signal (240e) based on the second audio data (240d) to drive the speaker (235).

14. The method of claim 13, wherein generating the analog audio signal comprises: The digital signal is converted into an analog signal using a digital-to-analog converter (DAC) integrated into the amplifier circuit (230), and The analog signal is amplified using the audio amplifier (245).

15. The method of any one of claims 13 and 14, wherein changing the power supply voltage (240b) comprises changing the power supply voltage (240b) to track the amplifier audio output voltage associated with the analog audio signal, such that the power supply voltage (240b) has a value between 0.1% and 35% greater than the amplifier audio output voltage.

16. The method of claim 15, wherein generating and outputting the control signal (240a) comprises generating the control signal (240a) such that the power supply voltage (240b) has a maximum frequency between 0.1 Hz and approximately 20 kHz.

17. The method of claim 13, further comprising: The SMPS (225) receives power from the power source (220), the power source comprising at least one of the following: Energy harvester, battery, Wireless power receiver, or Power input port.

18. The method of claim 17, further comprising: The processor circuit (250) receives status information (240f) indicating at least one state of the power supply (220), and The control signal (240a) is generated based on at least one state of the power supply.

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