SELECTIVE PROTECTION WITH MULTI-SPEAKERS IN SMART AUDIO AMPLIFIER SYSTEMS

Description

BACKGROUND

[0001] It is very common for electronic devices to include one or more integrated audio amplifiers and speakers. Driving a speaker with an excessive amount of power can damage the speaker by causing overheating of circuitry and / or by causing over-excursion of the speaker cone (i.e., excessive movement of the speaker cone). Thus, many modern electronic devices include smart audio amplifiers that seek to provide the speaker or speakers with thermal and / or excursion protection.

[0002] Typically, such smart audio amplifiers monitor current and voltage ("IV") measurements from the speaker, and feed the IV measurements back to a processor. The processor applies the IV measurements to a load model for the speaker (e.g., its impedance) to extract speaker parameters for thermal and excursion protection. The speaker protection provided by the smart audio amplifier uses compute and memory resources. Conventionally, when there are N speakers (i.e., an integer number), the speaker protection provided by the smart audio amplifier uses N times the compute and memory resources. Speaker protection systems are disclosed in WO 2022 / 182741 A1, US 2012 / 020488 A1 and US 2019 / 199307 A1.SUMMARY

[0003] Systems and methods are described for providing multi-speaker-selective protection in smart audio amplifier systems. A claimed solution is specified by a speaker protection system according to claim 1, by an electronic device according to claim 8 and by a method according to claim 9. Dependent claims specify embodiments thereof. Embodiments operate in context of electronic device environments that include multiple speakers all concurrently playing substantially the same audio content. Current-voltage (IV) sense signal feedback from all of the speakers is received by a smart selector. The smart selector identifies one of the IV sense signals as a reference and computes IV deltas between the identified reference and the others of the IV sense signals. A controlling sense signal is selected as the one of the IV sense signals manifesting the largest IV delta. Speaker protection algorithms can be performed based on the controlling sense signal, such that speaker protection is applied to all the speakers based on one set of speaker protection computations. In some embodiments, speakers are grouped (e.g., based on one or more thresholds), a respective controlling sense signal is selected for each group, and speaker protection is computed for and applied to each group based on its respective controlling sense signal.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A further understanding of the nature and advantages of various embodiments may be realized by reference to the following figures. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label. FIG. 1 shows a conventional electronic device environment, including multiple speakers. FIG. 2 shows an electronic device environment that supports multi-speaker-selective protection, according to embodiments described herein. FIG. 3A shows an illustrative speaker protection environment including a smart selector block configured with a preselected reference. FIG. 3B shows an illustrative speaker protection environment that includes a smart selector block configured to selectively determine which IV sense signal to use as the reference sense signal. FIG. 3C shows an illustrative speaker protection environment that includes a smart selector block configured to group speakers based on a threshold signal and to output a respective controlling sense signal for each of one or more of the groups. FIG. 3D shows an illustrative speaker protection environment that includes a smart selector block configured to determine one or more thresholds and to group speakers based on the determined one or more thresholds. FIG. 4 shows a flow diagram of an illustrative method for speaker protection, according to embodiments described herein. DETAILED DESCRIPTION

[0005] Smart audio amplifiers are commonly included in electronic devices to protect integrated speakers from thermal and / or excursion damage. Driving a speaker with an excessive amount of power can damage the speaker by causing overheating of circuitry and / or by causing over-excursion of the speaker cone (i.e., excessive movement of the speaker cone). Smart audio amplifiers monitor current and voltage ("IV") measurements from the speaker and feed the IV measurements back to a processor. The processor applies the IV measurements to a load model for the speaker (e.g., its impedance) to extract speaker parameters for thermal and excursion protection.

[0006] In some systems, rather than integrating a dedicated processor into the audio amplifier (e.g., a built-in digital signal processor, DSP), the speaker protection is performed by a host processor (e.g., a main CPU, separate DSP, system on a chip (SoC), or the like). This tends to provide more flexibility for the speaker protection algorithms and to reduce the cost and complexity of implementation. Conventionally, the host processor receives IV data from each speaker individually and processes the data individually. For example, the IV data from each speaker is applied to a load model for that speaker to extract thermal and excursion protection parameters for that speaker. Processing for each speaker consumes compute and memory resources of the host processor, and processing for N speakers (i.e., an integer number) conventionally consumes N times the compute and memory resources of the host processor. Typically, the host processor has restrictions regarding its compute and memory resources; so it can be desirable to minimize use of those resources, where possible.

[0007] Embodiments described herein preprocess the IV data from each speaker based on one or more references to reduce the compute resources used by the protection algorithm. Embodiments can assume multiple (N) speakers of a same type are integrated into a same electronic device or system and are playing same audio content. For example, a single device can include multiple full-range speakers, sub-woofers, etc. IV data signals are received from the N speakers by the host processor and are compared to a reference. For example, the reference can be a selected one of the IV data signals. In some embodiments, the host processor then determines the IV data signal having the largest delta from the reference, feeds that IV data signal to the speaker protection algorithm to compute speaker protection parameters, and applies the same speaker protection parameters to all N speakers. Such an approach, referred to herein as "multi-speaker-selective" protection, essentially only uses the compute and memory resources for protecting a single speaker plus a small additional amount for the delta computation.

[0008] In other embodiments, where N is greater than 2, the host processor can group the IV data signals as one group having at least a threshold delta from the reference and another group having below the threshold delta from the reference. In such embodiments, the host processor can then determine the IV data signal having the largest delta from the reference in each group, feed that IV data signal to the speaker protection algorithm to compute speaker protection parameters for the group, and apply the same speaker protection parameters for each group to all speakers in that group. Such an approach essentially only uses the compute and memory resources for protecting two speakers (i.e., corresponding to two groups) plus a small additional amount for the delta computations.

[0009] Turning first to FIG. 1, a conventional electronic device environment 100 is shown, including multiple speakers 130. The electronic device environment 100 can be any suitable device environment that includes multiple speakers 130. For example, many modern smartphone, laptop computers, tablet computers, smart speakers (e.g., smart home appliances), home theater systems, gaming consoles, portable (e.g., Bluetooth) speakers, and other types of electronic devices tend to have multiple integrated speakers. In some cases, different speakers in a device can play different audio content, such as where the speakers are associated with different stereo channels, with different surround sound or spatial sound channels, with different frequency bands, etc. However, in some cases, such as assumed herein, some or all of the speakers 130 are configured concurrently to play the same (or substantially the same) audio content.

[0010] As illustrated, the electronic device environment 100 includes a host processor 110. The host processor 110 can be a main processor of the device (e.g., a central processing unit, CPU), a signal processor (e.g., a digital signal processor, DSP), a system on a chip (SoC), or the like. The host processor 110 is configured to implement a speaker protection module 115. The speaker protection module 115 can be implemented by any suitable combination of hardware and / or software. In general, it is assumed herein that the host processor 110 is not dedicated to the speaker protection module 115 or related processing, such that only a small portion of its compute resources is available for implementing the speaker protection module 115.

[0011] As illustrated, each of N speakers 130 (labeled as speakers 130-1 through 130-N) is coupled with a respective amplifier 120 (labeled as amplifiers 120-1 through 120-N). An audio input signal 105 is passed to each of the amplifiers 120, and each amplifier 120 applies gain to the signal to output an amplified version of the signal to its respective speaker 130. Contexts described herein assume that the amplifiers 120 are configured as "smart amplifiers." In this context, smart amplifiers work with the speaker protection module 115 to ensure that the amplifiers 120 are not driving the speakers 130 in a manner that could cause thermal or excursion damage.

[0012] This can involve monitoring current and voltage at each speaker. As illustrated, a respective one of N current-voltage (IV) sense blocks 125 (labeled as IV sense blocks 125-1 through 125-N) is disposed effectively in the path between each amplifier 120 and speaker 130. Although shown as a component separate from the speaker protection module 115, the IV sense blocks 125 can be implemented as part of the speaker protection module 115. In general, each IV sense block 125 senses a current flowing into its connected speaker 130, and a voltage across the terminals of the connected speaker 130. For example, each IV sense block 125 can be implemented using resistors, capacitors, transistors, or other circuit components in a conventional manner to monitor current and voltage and to output a corresponding IV sense signal 135 (labeled as IV sense signals 135-1 through 135-N). The IV sense signal 135 can be a pair of signals (e.g., two analog voltage levels representing a measured current magnitude and a measured voltage magnitude), one or more digital signals, or any other suitable representation of the IV information for the corresponding speaker 130.

[0013] In general, the speaker protection module 115 receives an audio input signal 105 and the IV sense signals 135, and determines based on those signals what types of speaker protection may be needed. Conventionally, as illustrated in FIG. 1, protection for each speaker 130 is handled separately by the speaker protection module 115. For example, for each speaker 130, the speaker protection module 115 receives the corresponding IV sense signal 135 from the corresponding IV sense block 125, determines whether speaker protections are needed for that particular speaker, and outputs an appropriate respective output control signal 107 (labeled output control signals 107-1 through 107-N) to control the corresponding amplifier 120 (e.g., to back of the gain of the amplifier 120, etc.) for that speaker 130. Typically, the speaker protection module 115 outputs the audio input signal 105 (or a delayed version of the audio input signal 105') to each of the amplifiers 120, along with providing each amplifier 120 with the respective output control signal 107 for backing off the gain of the amplifier 120, or otherwise implementing speaker-protective measures.

[0014] This conventional approach of individually determining and applying speaker protection has the benefit of optimally protecting each speaker 130 with minimized degradation to audio quality. However, for a system with N speakers 130, such an approach involves N computations of speaker protection by the speaker protection module 115 (or speaker protection modules, in some conventional implementations). In cases where the speaker protection module 115 is implemented in a host processor 110 with other demands on the processor's resources, it may become impractical or undesirable for the host processor 110 to continually perform multiple speaker protection computations or multiple speakers 130 in parallel. The novel approaches described herein, in contrast, compute and output fewer than N output control signals 107 (e.g., a single output control signal 107) to control all N amplifiers 120.

[0015] FIG. 2 shows an electronic device environment 200 that supports multi-speaker-selective protection, according to embodiments described herein. The electronic device environment 200 can be any suitable device environment that includes multiple speakers 130 that play the same audio at least some of the time, such as multiple full-range speakers, multiple sub-woofers, etc. For example, the illustrated environment 200 includes N speakers 130, where N is an integer greater than one. In some cases, all N speakers 130 concurrently play substantially the same audio. In other cases, the N speakers 130 represents a portion of the total number of speakers 130 in the device. In some cases, where the device has more than N speakers, the speakers 130 can be grouped into two or more sets, each having two or more of the speakers 130 (e.g., each set can include the same or different numbers of the speakers 130), and the speakers 130 of each set concurrently play audio that is substantially the same as the audio of other speakers 130 in the set, but different from the audio of speakers 130 in other sets.'

[0016] Similar to FIG. 1, the electronic device environment 200 includes a host processor 110, which implements a speaker protection module 220. The host processor 110 can be a main processor of the device (e.g., a central processing unit, CPU), a signal processor (e.g., a digital signal processor, DSP), a system on a chip (SoC), or the like. In general, it is assumed herein that the host processor 110 is not dedicated to the speaker protection module 220 or related processing, such that only a small portion of its compute resources is available for implementing the speaker protection module 220. The speaker protection module 220 is coupled with a plurality of speaker paths. In each speaker path, a respective one of N speakers 130 (labeled as speakers 130-1 through 130-N) is coupled with a respective amplifier 120 (labeled as amplifiers 120-1 through 120-N). In each speaker path, the speaker protection module 220 outputs an audio input signal 105 and an output control signal 207. As illustrated, embodiments of the speaker protection module 220 include a delay block 240 to delay the audio input signal 105 and to output a delayed version thereof (labeled as delayed audio input signal 105'). In such embodiments, rather than outputting the audio input signal 105 to the speaker paths directly, the delay module 240 outputs the delayed audio input signal 105' to each of the speaker paths (i.e., to the input of each of the N amplifiers 120.

[0017] Unlike in FIG. 1, where a separate output control signal 107 is computed for and output to each speaker path, the embodiment of FIG. 2 computes and outputs only a single output control signal 207 for all N speakers 130. The output control signal 207 can be a gain control signal, such as for backing off or otherwise controlling the gain of the N amplifiers 120. In general, as described herein, the output control signal 207 is generated based on monitoring current and / or voltage at each speaker 130. As illustrated, a respective one of N current-voltage (IV) sense blocks 125 (labeled as IV sense blocks 125-1 through 125-N) is disposed effectively in the path between each amplifier 120 and speaker 130. As noted with reference to FIG. 1, although shown as a component separate from the speaker protection module 115, the IV sense blocks 125 can be implemented as part of (i.e., integrated with) the speaker protection module 115. In general, each IV sense block 125 senses a current flowing into its connected speaker 130, and a voltage across the terminals of the connected speaker 130. For example, each IV sense block 125 can be implemented using resistors, capacitors, transistors, or other circuit components in a conventional manner to monitor current and voltage and to output a corresponding IV sense signal 135 (labeled as IV sense signals 135-1 through 135-N). The IV sense signal 135 can be a pair of signals (e.g., two analog voltage levels representing a measured current magnitude and a measured voltage magnitude), one or more digital signals, or any other suitable representation of the IV information for the corresponding speaker 130.

[0018] The IV sense signals 135 are fed back to a smart selector block 210 implemented by the host processor 110. As described more fully below, one of the N speakers 130 is determined to be a "reference" speaker 130, and the IV sense signal 135 associated with that speaker 130 is considered as the reference sense signal. The smart selector block 210 compares the IV sense signals 135 (other than the reference sense signal) to the reference sense signal to determine which manifests a largest delta. The IV sense signal 135 manifesting the largest delta relative to the reference sense signal is output by the smart selector block 210 as a controlling sense signal 215. The controlling sense signal 215 is fed back to the speaker protection module 220 for computation of speaker protection, and the output control signal 207 is updated based on the fed-back controlling sense signal 215. As such, the speaker protection module 220 computes speaker protections using only one of the N IV sense signals 135, thereby performing only one set of speaker protection computations for all N speakers 130. Embodiments of the speaker protection module 220 can implement thermal protection and / or excursion protection.

[0019] A thermal protection path of the speaker protection module 220 includes a thermal estimator 222 and a thermal limiter 224. The thermal estimator 222 and / or the thermal limiter 224 is coupled with a stored speaker model 230, which can include a model of each of some or all of the speakers 130. For example, each speaker 130 can be represented as a resistance (e.g., as a resistor of a particular value), as an impedance (e.g., as a resistor in series with an inductor, each having respective values), etc. Thermal parameters in the thermal protection path can be computed based on speaker thermal parameters stored in the speaker model 230, such as thermal resistances of the voice coil and / or the magnet pole, thermal capacitances of the voice coil and / or the magnet pole, etc. The speaker model 230 can be stored in any suitable processor-readable memory accessible to the host processor 110, such as in one or more registers, solid-state drives, programmable memory, etc.

[0020] The thermal estimator 222 can effectively monitor the temperature of the speaker 130 corresponding to the controlling sense signal 215 based on monitoring at least the current flowing into the voice coil of that speaker 130. For example, in context of thermal protection, the speaker model 230 can represent the speaker 130 of interest as a resistor. It is assumed that the resistance of the speaker 130 (i.e., of the voice coil) increases with an increase in temperature. The resistance of the speaker 130 is a function of the ratio of voltage across the resistor to current through the resistor. In some implementations, the voltage-to-current ratio can be monitored by monitoring both voltage and current based on the controlling sense signal 215. In other implementations, the voltage-to-current ratio can be monitored by monitoring only changes in current (of the controlling sense signal 215) and assuming the voltage to be held relatively constant. The thermal limiter 224 compares the monitored temperature of the speaker 130 to a predetermined threshold and outputs a thermal protection signal indicating whether (e.g., and / or by how much) the speaker 130 temperature is exceeding the threshold.

[0021] The thermal protection path protects against thermal damage to the speakers 130. Thermal damage can occur when a speaker is driven with too much power, for too long, and / or when ambient temperature is too high. Each amplifier 120 drives a respective one of the speaker 130 with the delayed audio input signal 105', which energizes the speaker's 130 voice coil and induces a magnetic field. The field interacts with a permanent magnet, causing the voice coil to move. The movement produces sound by moving an attached diaphragm, while also producing heat from the voice coil's electrical resistance. When the speaker 130 is driven with too much power, too much heat can be produced, which can cause thermal damage. This can occur, for example, when the speaker 130 is overdriven by the amplifier 120 (e.g., when the audio has too many loud peaks and / or too many high-frequency components for too long of a duration), when the amplifier 120 is too powerful for the speaker 130, etc. The resulting thermal damage can damage the voice coil, melt insulation on wiring (e.g., causing short or open circuits), damage structures supporting the voice coil and diaphragm (e.g., the "spider" components), adversely impact magnetic properties of magnetic components, etc.

[0022] An excursion protection path of the speaker protection module 220 includes an excursion estimator 226 and an excursion limiter 228. The excursion estimator 226 and / or the excursion limiter 228 is coupled with the stored speaker model 230. The excursion estimator 226 can effectively monitor the excursion of the speaker 130 corresponding to the controlling sense signal 215 based on monitoring voltage across and current through the voice coil of that speaker 130. For example, in context of excursion protection, the speaker model 230 can represent the speaker 130 of interest as an impedance (e.g., a resistor in series with an inductor). Excursion parameters in the excursion protection path can be computed based on speaker physical parameters stored in the speaker model 230, such as DC resistance, mechanical damping factor, force factor, mechanical compliance factor, mechanical mass, etc. An increase in power to the voice coil is reflected by the monitored voltage across and current through the voice coil. The excursion limiter 228 compares the monitored excursion of the speaker 130 to a predetermined threshold and outputs an excursion protection signal indicating whether (e.g., and / or by how much) the speaker 130 excursion is exceeding the threshold.

[0023] The excursion protection path protects against excursion damage to the speakers 130. Excursion damage can occur when a speaker's 130 diaphragm moves beyond a designed range of motion. Components of the speaker 130 are typically designed to support a defined range of linear movement of the diaphragm (i.e., the amount the cone and dome can move back and forth). For example, component sizes and geometries, suspending and supporting structures, etc. can impact the maximum supported excursion of the speaker. Excursion damage typically occurs when the amplifier 120 drives the speaker 130 with too much power, particularly when there is too much high-power, low-frequency content in the audio signal (e.g., loud, bass-heavy audio content). In some cases, excursion damage can also occurs when a speaker 130 is driven too frequently and / or powerfully at resonant frequencies of the speaker's 130 components; or when the speaker 130 is subjected to large impulse shocks, such as if the speaker 130 is driven with a sudden loud noise, or the speaker 130 is dropped. Excursion damage can result in either degradation of the audio output of the speaker 130 (e.g., introducing audible distortion, loss of dynamic range, etc.), or even physical damage (e.g., misalignment of internal speaker 130 components, mechanical failure of speaker 130 structures, etc.).

[0024] The protection outputs from the thermal and / or excursion protection paths are passed to a gain controller 235. The gain controller 235 generates and outputs the output control signal 207 based on the protection outputs. As illustrated, the gain controller 235 can generate and output the output control signal 207 further based on the audio input signal 105. For example, an upcoming portion of the audio input signal 105 includes very loud, very high-frequency or very low-frequency audio content. Accordingly, the gain controller 235 generates the output control signal 207 to back off the gain of the amplifiers 120 by a large enough amount to protect all the speakers 130, even if the result will be an over-protection of some of the speakers 130. The illustrated embodiment shows the output control signal 207 coupled with the amplifiers to adjust the gain (e.g., to effectively attenuate the audio signal driving the speakers 130) in a manner that provides thermal and / or excursion protection for the speakers 130. In other embodiments, the gain controller 235 can output the output control signal 207 in a manner that implements thermal and / or excursion protection in other ways. In some embodiments, the output control signal 207 is used to compress the audio signal in a manner that reduces the dynamic range of the audio signal and thereby reduces power peaks. In other embodiments, the output control signal 207 is used to implement time-limiting and / or frequency-limiting of audio signal. For example, such signals can the limit the duration of duration of potentially dangerous passages in the audio signal, to force cool down periods for the speakers 130, to limit or filter certain dangerous frequency ranges, etc. As such, the component referred to herein as "gain controller 235" can include gain controller, audio equalizer, audio compressor, limiter, and / or other features.

[0025] As noted above, embodiments of the smart selector block 210 can use one of the IV sense signals 135 as a reference sense signal and can determine which of the other IV sense signals 135 to select as the controlling sense signal 215. The smart selector block 210 can be implemented in several ways. FIGS. 3A - 3D show simplified block diagrams of a portion of a speaker protection environment 300 including several illustrative embodiments of a smart selector block 210 in communication with a speaker protection module 220. Each illustrated portion of the speaker protection environment 300 represents an illustrative implementation of the corresponding portion of the electronic device environment 200 of FIG. 2.

[0026] Turning first to FIG. 3A, the illustrated speaker protection environment 300a includes a smart selector block 210 configured with a preselected reference. As described above, the smart selector block 210 can use one of the IV sense signals 135 as a reference sense signal 305 and can determine which of the other IV sense signals 135 to select as the controlling sense signal 215. In the illustrated embodiment of FIG. 3A, the reference sense signal 305 is predetermined as the IV sense signal 135 coming from a particular one of the N speakers 130 coupled in feedback with the smart selector block 210 (as described and illustrated with reference to FIG. 2).

[0027] During calibration and / or testing, each of the N speakers 130 is tested to determine the room temperature impedance (e.g., resistance) of the speaker 130. In one implementation, the speaker 130 determined to have the lowest room temperature impedance is selected as the reference speaker 130 of the N speakers 130, and the IV sense signal 135 fed back from that reference speaker 130 is used as the reference sense signal 305 for the smart selector block 210. In another implementation, the speaker 130 determined to have the highest room temperature impedance is selected as the reference speaker 130 of the N speakers 130, and the IV sense signal 135 fed back from that reference speaker 130 is used as the reference sense signal 305 for the smart selector block 210. The designation in FIG. 3A of the reference sense signal 305 as specifically corresponding to IV sense signal 135-1 is intended generally to indicate that the reference sense signal 305 corresponds to the one of the IV sense signals 135 that is associated with whichever speaker 130 is determined to be the reference speaker (i.e., the illustrated order of IV sense signals 135 is not intended to imply any particular order of speakers 130, etc.).

[0028] The reference sense signal 305 is received by a delta comparison block 310. The delta comparison block 310 computes an IV delta between the IV information of the reference sense signal 305 and the IV information of each of the IV sense signals 135 other than the IV sense signals 135. The IV delta represents an absolute magnitude difference of current and / or voltage information measured for each of the non-reference speakers 130 relative to that of the reference speaker 130. As described above, thermal and / or excursion protection can be based generally on changes in a voltage-to-current ratio. In some implementations, the IV delta is based comparing current magnitudes (e.g., where voltage is assumed to be held relatively constant). In other implementations, the IV delta is based on comparing voltage and current magnitudes (e.g., by computing and comparing the voltage-to-current ratio for each speaker 130).

[0029] The delta comparison block 310 outputs the controlling sense signal 215 based on determining which of the IV sense signals 135 represents the largest IV delta as compared to the reference sense signal 305. In some embodiments, the delta comparison block 310 outputs the controlling sense signal 215 by passing through the one of the IV sense signals 135 determined to represent the largest IV delta as compared to the reference sense signal 305. In other embodiments, the delta comparison block 310 generates the controlling sense signal 215 based on the one of the IV sense signals 135 determined to represent the largest IV delta as compared to the reference sense signal 305. For example, the generated controlling sense signal 215 can be an analog or digital signal indicating the magnitude of the largest delta in voltage-to-current ratio. In some embodiments, the delta comparison block 310 outputs the controlling sense signal 215 to provide a different magnitude value, and / or different information to each of the thermal protection path and the excursion protection path.

[0030] FIG. 3B shows an illustrative speaker protection environment 300b that includes a smart selector block 210 configured to selectively determine which IV sense signal 135 to use as the reference sense signal 305. As illustrated, the smart selector block 210 includes a reference selector block 320 that is coupled with the N IV sense signals 135 in feedback from the N speakers 130 (as described and illustrated with reference to FIG. 2). The reference selector block 320 can determine which of the IV sense signals 135 to use as the reference sense signal 305. In some embodiments, the reference selector block 320 compares each of the IV sense signals 135 with each of the other IV sense signals 135 to determine which one of the IV sense signals 135 yields the largest IV deltas. For example, in the case of four IV sense signals 135 from four speakers 130, the reference selector block 320 can make six comparisons to make this determination.

[0031] The IV sense signal 135 determined to yield the largest IV deltas is selected by the reference selector block 320 to be the reference sense signal 305, and the selected reference sense signal 305 is output to the delta comparison block 310. The delta comparison block 310 can operate substantially as described with reference to FIG. 3A. The delta comparison block 310 determines which of the IV sense signals 135 other than the one selected as the reference sense signal 305 yields the highest IV delta as compared to the reference sense signal 305. The delta comparison block 310 can then generate and / or output the controlling sense signal 215 based on that determination.

[0032] As illustrated, embodiments of the reference selector block 320 take a mode select signal 315 as an additional input. Responsive to the mode select signal 315, the reference selector block 320 can operate in either of an active mode or a bypass mode. In the active mode, the reference selector block 320 operates as described above, actively selecting which of the IV sense signals 135 to provide to the delta comparison block 310 as the reference sense signal 305. In the bypass mode, the reference selector block 320 passes through (as the reference sense signal 305) whichever of the IV sense signals 135 was last determined to be used as the reference sense signal 305 as of the last time the delta comparison block 310 was operating in the active mode. For example, in a first timeframe, the delta comparison block 310 operates in the active mode and determines to use IV sense signal 135-2 as the reference sense signal 305. In a second (subsequent) timeframe, the mode select signal 315 is switched so that the delta comparison block 310 is in bypass mode; and the delta comparison block 310 continues to pass through IV sense signal 135-2 as the reference sense signal 305 without making any further determinations.

[0033] In some embodiments, the state of the mode select signal 315 is directed by a controller 330 responsive to a trigger condition. In some embodiments, the trigger condition is occurrence of a predetermined schedule condition; the controller 330 directs the reference selector block 320 to be in active mode (i.e., to update or confirm which of the IV sense signals 135 to use as the reference sense signal 305) according to scheduled or periodic timing. For example, the reference selector block 320 actively updates or confirms selection of the reference sense signal 305 at a particular time of each week, at a particular time of each month, once per number of hours that the electronic device is in use, or according to any other suitable scheduled or periodic timing. In some embodiments, the trigger condition is detection that a threshold condition is exceeded; the controller 330 directs the reference selector block 320 to be in active mode in response to the detection. For example, the reference selector block 320 actively updates or confirms selection of the reference sense signal 305 whenever a power surge in the electronic device (in which the N speakers 130 are disposed) is detected, whenever a sensor (e.g., an accelerometer) detects that the electronic device was dropped, etc. In some embodiments, the trigger condition is based on an operating status of the electronic device. For example, the controller 330 directs the reference selector block 320 to be in active mode whenever the electronic device is being powered on; whenever the electronic device enters a self-test, diagnostic, calibration, or other mode; etc.

[0034] The embodiments of FIG. 3A and 3B provide a single controlling sense signal 215 to the speaker protection module 220. While using only a single controlling sense signal 215 allows the speaker protection module 220 to perform only one set of speaker protection computations for N speakers 130 (i.e., 1 / N the number of computations performed by conventional approaches), such an approach protects all N speakers 130 based only on the IV information from one (e.g., the worst-case one) of the N speakers 130. The result can be an overcorrection of some or all of the non-reference speakers 130, which can tend to degrade the overall audio performance. Thus, rather than using only a single controlling sense signal 215 for all N speakers 130, some embodiments can output two or more, but fewer than N, controlling sense signals 215 (e.g., or a controlling sense signal 215 representing two or more sets of IV sense information). Particularly in environments with larger IV-related differences between the N speakers 130, using multiple IV sense signals 135 can help to improve audio performance, albeit at the expense of increased computations by the speaker protection module 220.

[0035] FIG. 3C shows an illustrative speaker protection environment 300c that includes a smart selector block 210 configured to group speakers 130 based on a threshold signal 325 and to output a respective controlling sense signal 215 for each of one or more of the groups. As described above, a delta comparison block 310 determines which of the IV sense signals 135 to pass to the speaker protection module 220 based on computing an IV delta relative to a reference sense signal 305. In some embodiments, as described with reference to FIG. 3A, the delta comparison block 310 uses a predetermined one of the IV sense signals 135 as a reference sense signal 305. In other embodiments, as described with reference to FIG. 3B, the smart selector block 210 further includes a reference selector block 320 that determines which IV sense signal 135 to use as the reference sense signal 305 for the delta comparison block 310.

[0036] In FIG. 3C, the smart selector block 210 includes a delta comparison block 310 that groups the N IV sense signals 135 into k groups based on one or more thresholds represented by a threshold signal 325. In some embodiments, the threshold signal 325 sets a minimum protection threshold for the delta comparison block 310. For example, a first group of IV sense signals 135 is identified as having respective IV deltas relative to the reference sense signal 305 that exceed the minimum protection threshold (i.e., indicating those of the N speakers 130 that appear to need protection), and a second group of IV sense signals 135 is identified as having respective IV deltas relative to the reference sense signal 305 that do not exceed the minimum protection threshold (i.e., indicating those of the N speakers that appear not to need protection). The two groups are disjoint, and each group may have as few as zero of the N IV sense signals 135 and as many as N (i.e., all) of the N IV sense signals 135. Such embodiments determine the controlling sense signal 215 based on the IV sense signal 135 from the first group that has the maximum IV delta relative to the reference sense signal 305. Although not explicitly shown in such an embodiment, the output control signal 207 generated by the speaker protection module 220 based on the controlling sense signal 215 is only provided to the amplifiers 120 corresponding to the speakers 130 generating the first group of IV sense signals 135. Essentially, such embodiments use the threshold signal 325 to segregate the IV sense signals 135 into two groups, but speaker protection is only applied to a single one of the groups; a single output control signal 207 is generated for all N speakers 130. Such an approach can help to reduce audio degradation resulting from overcorrection of speakers 130 with a slight increase in computational resource usage, while still protecting at least those of the speakers 130 exceeding the minimum threshold for protection.

[0037] In other embodiments, the threshold signal 325 defines a single threshold for the delta comparison block 310 to form two groups of IV sense signals 135, and speaker protection is applied to both groups. For example, a first group of IV sense signals 135 is identified as having respective IV deltas relative to the reference sense signal 305 that exceed the threshold, and a second group of IV sense signals 135 is identified as having respective IV deltas relative to the reference sense signal 305 that do not exceed the threshold. Assuming the first group includes at least one of the IV sense signals 135 (i.e., that at least one of the IV sense signals 135 exceeds the threshold), a first controlling sense signal 215 is generated based on identifying the one of the first group of IV sense signals 135 having the maximum IV delta relative to the reference sense signal 305. Assuming the second group includes at least one of the IV sense signals 135 (i.e., that at least one of the IV sense signals 135 does not exceed the threshold), a second controlling sense signal 215 is generated based on identifying the one of the second group of IV sense signals 135 having the maximum IV delta relative to the reference sense signal 305. A first output control signal 207 is generated by the speaker protection module 220 based on the first controlling sense signal 215, and the first output control signal 207 is used to provide speaker protection to those of the N speakers 130 corresponding to the first group of IV sense signals 135 (e.g., by controlling the gains of the amplifiers 120 driving those speakers 130). A second output control signal 207 is generated by the speaker protection module 220 based on the second controlling sense signal 215, and the second output control signal 207 is used to provide speaker protection to those of the N speakers 130 corresponding to the second group of IV sense signals 135 (e.g., by controlling the gains of the amplifiers 120 driving those speakers 130). Such embodiments create up to two speaker protection groups based on a single threshold. Such an approach can further reduce audio degradation resulting from overcorrection of speakers 130 at the expense of a further increase in computational resource usage and implementation complexity.

[0038] Generally, embodiments of the threshold signal 325 can define k-1 thresholds by which to segregate the IV sense signals 135 into k groups. The k groups are disjoint, and each of the k groups can include between 0 and N of the IV sense signals 135. For any group that includes at least one of the IV sense signals 135, the delta comparison block 310 outputs a respective controlling sense signal 215 for the group based on identifying which of that group's IV sense signals 135 represents the largest IV delta relative to the reference sense signal 305. For each group that includes at least one of the IV sense signals 135, the speaker protection module 220 generates an output control signal 207 corresponding to the controlling sense signals 215 for the group by which to apply speaker protection to the speakers 130 of that group. For example, a threshold signal 325 defining three thresholds can result in segregation of the IV sense signals 135 into up to four groups (k = 4), thereby resulting in up to four controlling sense signal 215 used to generate up to four output control signals 207. Such an approach can further reduce audio degradation resulting from overcorrection of speakers 130 at the expense of a further increase in computational resource usage and implementation complexity.

[0039] In cases where the threshold signal 325 defines multiple thresholds, the multiple thresholds can be represented by the signal in any suitable manner. In one implementations, the threshold signal 325 is received by the delta comparison block 310 as multiple separate threshold signals 325, each encoding a respective one of the thresholds in a digital or analog manner. In another implementation, the threshold signal 325 uses digital encoding, analog encoding, multiplexing, or any other suitable technique to represent multiple thresholds in a single threshold signal 325. Similarly, cases where there are multiple controlling sense signals 215 can be implemented in any suitable manner. In some implementations, a system configured for up to k groups can multiplex (or otherwise encode) up to k controlling sense signals 215 onto a single analog or digital signal passed to the speaker protection module 220, and the speaker protection module 220 is configured to parse (e.g., de-multiplex) the single signal to obtain the information from the k controlling sense signals 215. In other implementations, the system configured for up to k groups can include k signal paths, each for one of the k controlling sense signals 215 (e.g., some of the paths being inactive when corresponding groups are empty). A system configured for up to k groups also outputs up to k output control signals 207. In some implementations, a single output control signal 207 can carry the speaker protection information for all groups along with associated speaker path identifiers, and each speaker path (e.g., each amplifier 120) can be configured to respond only to the speaker protection information associated with its speaker path identifier. In other implementations, each speaker path includes a multiplexer, or the like, that is coupled with the speaker protection module 220 via k signal paths, each corresponding to a respective one of k output control signals 207; the speaker protection module 220 outputs the k output control signals 207 to the multiplexers and also outputs switching signals to each multiplexer to deliver an appropriately selected one of the output control signals 207 to each of the speaker paths. In other implementations, the speaker protection module 220 (e.g., the gain controller 235) includes a switching network coupled with the speaker paths by which to deliver an appropriately selected one of the output control signals 207 to each of the speaker paths.

[0040] FIG. 3D shows an illustrative speaker protection environment 300d that includes a smart selector block 210 configured to determine one or more thresholds and to group speakers 130 based on the determined one or more thresholds. The embodiments of FIG. 3D are intended to operate in substantially the same manner as described with reference to FIG. 3C, except that the threshold signal 325 is generated by an additional threshold generator block 330. As described herein, the delta comparison block 310 computes IV deltas between the reference sense signal 305 and each of the IV sense signals 135 other than the one used as the reference sense signal 305, resulting in N-1 IV deltas 335.

[0041] As illustrated, the N-1 IV deltas 335 can be passed to the threshold generator block 330 for use in determining one or more thresholds. Embodiments of the threshold generator block 330 use the IV deltas 335 to optimize one or more thresholds at levels that will provide maximum speaker protection with minimum audio degradation. For example, in a system having five speakers, suppose that Speaker 1 corresponds to the reference sense signal 305 (i.e., and has no associated IV delta 335, accordingly), and Speakers 2 - 5 have IV deltas 335 (e.g., normalized to a scale from 0 to 5) of 4.1, 4.3, 2.6, and 1.2, respectively. Several embodiments described with reference to FIG. 3C can be allied to this example to illustrate several illustrative implementations of the threshold generator block 330. Some illustrative implementations of the threshold generator block 330 can generate a single threshold at 3.5, thereby causing the delta comparison block 310 to form a first group with the IV sense signals 135 for Speakers 2 and 3, and a second group with the IV sense signals 135 for Speakers 1, 4, and 5. One such implementation can treat the single threshold as a minimum protection threshold, such that only a single controlling sense signal 215 is output by the delta comparison block 310, and only a single corresponding output control signal 207 is generated by the speaker protection module 220 and applied only to Speakers 2 and 3. Another such implementation can use the single threshold to form two groups, such that up to two controlling sense signals 215 are output by the delta comparison block 310, and up to two corresponding output control signals 207 are generated by the speaker protection module 220 for application to the speakers of the two groups, respectively. Another illustrative implementation of the threshold generator block 330 can generate a first threshold at 3.5 and a second threshold at 2, thereby causing the delta comparison block 310 to form a first group with the IV sense signals 135 for Speakers 2 and 3, a second group with the IV sense signal 135 for Speaker 4, and a third group with the IV sense signals 135 for Speakers 1 and 5. Such an implementation can output up to three controlling sense signals 215 by the delta comparison block 310, and generate up to three corresponding output control signals 207 by the speaker protection module 220 for application to the speakers of the three groups, respectively.

[0042] FIG. 4 shows a flow diagram of an illustrative method 400 for speaker protection, according to embodiments described herein. Embodiments of the method 400 can be performed using any of the systems described above. Embodiments begin at stage 404 by receiving N current-voltage (IV) sense signals from N speaker paths. Each of the N speaker paths has a respective amplifier of N amplifiers coupled with a respective speaker of N speakers. The IV sense signal for each speaker path represents a measured voltage and current for the respective speaker of the speaker path. Embodiments can operate with one or more speaker paths (i.e., N ≥ 1). However, some embodiments assume that N is an integer greater than 2 (i.e., at least three speaker paths.

[0043] At stage 408, embodiments can generate a controlling sense signal based on selecting a first (i.e., any one) of the IV sense signals as having a largest IV delta relative to a second (i.e., any other) of the IV sense signals identified as a reference sense signal. In some embodiments, generating the controlling sense signal at stage 408 involves: computing, for each IV sense signal of the N-1 IV sense signals not identified as the reference sense signal, a respective IV delta between the IV sense signal and the reference sense signal; and generating the controlling sense signal based on selecting one of the N-1 IV sense signals as having the largest IV delta relative to the reference sense signal.

[0044] Some embodiments of the method 400 further include selecting the reference sense signal at stage 420. In some such embodiments, the method 400 can select the second of the N IV sense signals as the reference sense signal by computing respective candidate IV deltas between pairs of the N IV sense signals to determine the reference sense signal as the one of the N IV sense signals yielding the highest candidate IV deltas. Each IV sense signal can be compared to each other IV sense signal to determine which is the farthest away from all the others. As one example, the candidate IV delta between each pair of IV sense signals can be computed as a magnitude difference in respective voltage-to-current ratios derived from the pair of IV sense signals. As another example, the candidate IV delta between each pair of IV sense signals can be computed as a magnitude difference in respective current levels derived from the pair of IV sense signals. As illustrated, in some embodiments, the performance of stage 420 is based on a state of a mode select signal (illustrated as a switch). When the mode select signal is set to an active mode ('A'), the reference sense signal is selected (e.g., updated or confirmed) in stage 420; when the mode select signal is set to a bypass mode ('B'), the reference sense signal can be maintained based on a prior determination. For example, some embodiments of the method include detecting toggling of a mode select signal from a bypass mode to an active mode in a first timeframe; and responsive to the detecting, selecting, at stage 420, one of the N IV sense signals as the reference sense signal by computing respective candidate IV deltas between pairs of the N IV sense signals to determine the reference sense signal as the one of the N IV sense signals yielding the highest candidate IV deltas. Such embodiments can further include detecting toggling of a mode select signal from the active mode to the bypass mode in a second timeframe subsequent to the first timeframe; and responsive to the detecting, maintaining the reference sense signal as the one of the N IV sense signals determined as yielding the highest candidate IV deltas in the first timeframe.

[0045] Some embodiments of the method 400 further include receiving and / or generating one or more thresholds at stage 424. In some such embodiments, at stage 408, the generating involves: computing, for each IV sense signal of the N-1 IV sense signals not identified as the reference sense signal, a respective IV delta between the IV sense signal and the reference sense signal; segmenting the IV sense signals into a first group including those of the N-1 IV sense signals having respective IV deltas that exceed a predetermined minimum protection threshold (received or generated at stage 424) and a second group including those of the N-1 IV sense signals having respective IV deltas that do not exceed the predetermined minimum protection threshold; and generating the controlling sense signal based on whichever of the N-1 IV sense signals in the first group has a largest respective IV delta. In other embodiments, at stage 408, the generating involves: computing, for each IV sense signal of the N-1 IV sense signals not identified as the reference sense signal, a respective IV delta between the IV sense signal and the reference sense signal; receiving a threshold signal defining k-1 thresholds at stage 424, k being a positive integer greater than 1; segmenting the IV sense signals into k groups based on the k-1 thresholds; and for each of the k groups, if the group includes at least one of the IV sense signals, generating the set of controlling sense signals to include a respective controlling sense signal for the group based on whichever of the IV sense signals in the group has a largest respective IV delta. For example, if two thresholds are defined to yield three groups (i.e., k = 3), a first group of IV sense signals are those having respective IV deltas at or below the first threshold, a second group of IV sense signals are those having respective IV deltas above the first threshold and at or below the second threshold, and a third group of IV sense signals are those having respective IV deltas above the second threshold. Alternatively, the first group of IV sense signals are those having respective IV deltas below the first threshold, a second group of IV sense signals are those having respective IV deltas at or above the first threshold and below the second threshold, and a third group of IV sense signals are those having respective IV deltas at or above the second threshold.

[0046] Some embodiments generate the threshold(s) (e.g., by generating a threshold signal) at stage 424 to optimize grouping of the IV sense signals based on the computed respective IV deltas. The threshold(s) can be generated to maximize computational efficiency resulting from grouping of IV sense signals while minimizing audio degradation resulting from the grouping of the IV sense signals. For example, an optimized threshold solution can change based on whether the IV deltas are more evenly spready over a large range versus more tightly grouped in one or more groupings, and / or based on other factors.

[0047] At stage 412, embodiments can generate an output control signal at the control output based on extracting thermal and / or excursion protection parameters by applying the controlling sense signal to a stored load model of the speaker of the N speakers associated with the one of the IV sense signals corresponding to the controlling sense signal. The extracting can be performed using any conventional thermal and / or excursion speaker protection algorithms. As described above, some embodiments of stage 408 result in generation of a set of controlling sense signals that can include more than one controlling sense signal. In such cases, the generating the output control signal at stage 412 can include generating a set of control outputs, each based on extracting thermal and / or excursion protection parameters by applying a respective one of the set of controlling sense signal to the stored load model of the speaker of the N speakers associated with the one of the IV sense signals corresponding to the respective one of the set of controlling sense signals.

[0048] At stage 416, embodiments can control gains of the N speaker paths based on the output control signal. For example, embodiments can use the output control signal to back off the gain of the amplifiers to avoid thermal and / or excursion damage to the speakers.

[0049] The methods, systems, and devices discussed above are examples. Various configurations may omit, substitute, or add various procedures or components as appropriate. For instance, in alternative configurations, the methods may be performed in an order different from that described, and / or various stages may be added, omitted, and / or combined. Also, technology evolves and, thus, many of the elements are examples and do not limit the scope of the disclosure or claims.

[0050] Specific details are given in the description to provide a thorough understanding of example configurations (including implementations). However, configurations may be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary detail in order to avoid obscuring the configurations. This description provides example configurations only, and does not limit the scope, applicability, or configurations of the claims. Rather, the preceding description of the configurations will provide those skilled in the art with an enabling description for implementing described techniques. Various changes may be made in the function and arrangement of elements without departing from the scope of the appended claims.

[0051] Also, configurations may be described as a process which is depicted as a flow diagram or block diagram. Although each may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may have additional steps not included in the figure. Furthermore, examples of the methods may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware, or microcode, the program code or code segments to perform the necessary tasks may be stored in a non-transitory computer-readable medium such as a storage medium. Processors may perform the described tasks.

[0052] Having described several example configurations, various modifications and alternative constructions may be used without departing from the scope of the appended claims. For example, the above elements may be components of a larger system, wherein other rules may take precedence over or otherwise modify the application of the invention. Also, a number of steps may be undertaken before, during, or after the above elements are considered.

Claims

1. A speaker protection system comprising: a smart selector block (210) comprising: N sense inputs, each coupled with a respective one of N speaker paths to receive a respective one of N current-voltage, IV, sense signals (135-1 ... 135-N) from the respective one of N speaker paths, each of the N speaker paths having a respective amplifier of N amplifiers (120-1 ... 120-N) coupled with a respective speaker of N speakers (130-1 ... 130-N), the IV sense signal (135-1 ... 135-N) for each speaker path representing a measured voltage and current for the respective speaker (130-1 ... 130-N) of the speaker path, N being an integer greater than or equal to 2; and a select output, the smart selector block (210) to generate a controlling sense signal (215) at the select output based on determining a first IV sense signal of the IV sense signals (135-1 ... 135-N) as having a largest IV delta relative to a second of the IV sense signals (135-1 ... 135-N) identified as a reference sense signal (305); and a speaker protection module (220) comprising: a feedback input coupled with the select output; and a control output coupled with the N speaker paths, the speaker protection module (220) to generate an output control signal (207) at the control output based on extracting thermal and / or excursion protection parameters by applying the controlling sense signal (215) to a stored load model of the speaker of the N speakers (130-1 ... 130-N) associated with the one of the IV sense signals (135-1 ... 135-N) corresponding to the controlling sense signal (215).

2. The speaker protection system of claim 1, wherein: the smart selector block (210) comprises a delta comparison block (310) to generate the controlling sense signal (215) at the select output by: computing, for each IV sense signal of the N-1 IV sense signals (130-1 ... 130-N) not identified as the reference sense signal (305), a respective IV delta between the IV sense signal (135-1 ... 135-N) and the reference sense signal (305); and generating the controlling sense signal (215) based on selecting one of the N-1 IV sense signals (135-1 ... 135-N) as having the largest IV delta relative to the reference sense signal (305).

3. The speaker protection system of claim 1, wherein: the smart selector block (210) comprises a delta comparison block (310) to generate the controlling sense signal (215) based on a predetermined minimum protection threshold by: computing, for each IV sense signal of the N-1 IV sense signals (130-1 ... 130-N) not identified as the reference sense signal (305), a respective IV delta between the IV sense signal (135-1 ... 135-N) and the reference sense signal (305); segmenting the IV sense signals (135-1 ... 135-N) into a first group including those of the N-1 IV sense signals (130-1 ... 130-N) having respective IV deltas that exceed the predetermined minimum protection threshold and a second group including those of the N-1 IV sense signals (130-1 ... 130-N) having respective IV deltas that do not exceed the predetermined minimum protection threshold; and generating the controlling sense signal (215) based on whichever of the N-1 IV sense signals (135-1 ... 135-N) in the first group has a largest respective IV delta.

4. The speaker protection system of claim 1, wherein: the smart selector block (210) comprises a delta comparison block (310) to generate a set of controlling sense signals at the select output, the set of controlling sense signals including the controlling sense signal (215), by: computing, for each IV sense signal of the N-1 IV sense signals (130-1 ... 130-N) not identified as the reference sense signal (305), a respective IV delta between the IV sense signal (135-1 ... 135-N) and the reference sense signal (305); receiving a threshold signal (325) defining k-1 thresholds, k being a positive integer greater than 1; and segmenting the IV sense signals (135-1 ... 135-N) into k groups based on the k-1 thresholds; for each of the k groups, if the group includes at least one of the IV sense signals (135-1 ... 135-N), generating the set of controlling sense signals to include a respective controlling sense signal (215) for the group based on whichever of the IV sense signals (135-1 ... 135-N) in the group has a largest respective IV delta.

5. The speaker protection system of claim 4, wherein the speaker protection module (220) is to generate a set of control outputs for the N speakers (130-1 ... 130-N), each one of the control outputs generated based on extracting thermal and / or excursion protection parameters by applying a respective one of the set of controlling sense signals to the stored load model of the speaker of the N speakers (130-1 ... 130-N) associated with the one of the IV sense signals (135-1 ... 135-N) corresponding to the respective one of the set of controlling sense signals, optionally wherein the smart selector block (210) further comprises a threshold generator block (330) to generate the threshold signal (325) based on receiving the computed respective IV deltas.

6. The speaker protection system of claim 1, wherein the smart selector block (210) comprises: a reference selector block (320) to identify the second of the IV sense signals (135-1 ... 135-N) as the reference sense signal (305) by computing respective candidate IV deltas between pairs of the N IV sense signals (135-1 ... 135-N) to determine the reference sense signal (135-1 ... 135-N) as the one of the N IV sense signals (135-1 ... 135-N) yielding the highest candidate IV deltas, optionally wherein the reference selector block (320) is configured selectively to operate either in an active mode or in a bypass mode based on receiving a mode select signal (315), the reference selector block (320) performs the computing only when operating in the active mode, optionally further comprising: a controller (330) to toggle a state of the mode select signal (315) based on a predetermined schedule and / or detection of a predefined trigger condition.

7. The speaker protection system of claim 1, further comprising: a host processor (110), wherein the smart selector block (210) and the speaker protection module (220) are implemented by the host processor (110).

8. An electronic device comprising: the speaker protection system of claim 1; the N speaker paths, each comprising a respective one of the N speakers (130-1 ... 130-N) driven by a respective one of the N amplifiers (120-1 ... 120-N), wherein each of the N speaker paths is coupled with a respective one of the N sense inputs of the smart selector block (210), and wherein each of the N amplifiers (120-1 ... 120-N) is coupled with the control output of the speaker protection module (220).

9. A method for speaker protection, the method comprising: receiving N current-voltage, IV, sense signals (135-1 ... 135-N) from N speaker paths, each of the N speaker paths having a respective amplifier of N amplifiers (120-1 ... 120-N) coupled with a respective speaker of N speakers (130-1 ... 130-N), the IV sense signal (135-1 ... 135-N) for each speaker path representing a measured voltage and current for the respective speaker (130-1 ... 130-N) of the speaker path, N being an integer greater than or equal to 2; generating a controlling sense signal (215) based on selecting a first of the IV sense signals (135-1 ... 135-N) as having a largest IV delta relative to a second of the IV sense signals (135-1 ... 135-N) identified as a reference sense signal (305); generating an output control signal (207) at the control output based on extracting thermal and / or excursion protection parameters by applying the controlling sense signal (215) to a stored load model of the speaker of the N speakers (130-1 ... 130-N) associated with the one of the IV sense signals (135-1 ... 135-N) corresponding to the controlling sense signal (215); and controlling gains of the N speaker paths based on the output control signal (207).

10. The method of claim9, wherein the generating the controlling sense signal (215) comprises: computing, for each IV sense signal of the N-1 IV sense signals (135-1 ... 135-N) not identified as the reference sense signal (305), a respective IV delta between the IV sense signal (135-1 ... 135-N) and the reference sense signal (305); and generating the controlling sense signal (215) based on selecting one of the N-1 IV sense signals (135-1 ... 135-N) as having the largest IV delta relative to the reference sense signal (305).

11. The method of claim 9, wherein the generating the controlling sense signal (215) comprises: computing, for each IV sense signal of the N-1 IV sense signals (135-1 ... 135-N) not identified as the reference sense signal (305), a respective IV delta between the IV sense signal (135-1 ... 135-N) and the reference sense signal (305); segmenting the IV sense signals (135-1 ... 135-N) into a first group including those of the N-1 IV sense signals (135-1 ... 135-N) having respective IV deltas that exceed a predetermined minimum protection threshold and a second group including those of the N-1 IV sense signals (135-1 ... 135-N) having respective IV deltas that do not exceed the predetermined minimum protection threshold; and generating the controlling sense signal (215) based on whichever of the N-1 IV sense signals (135-1 ... 135-N) in the first group has a largest respective IV delta.

12. The method of claim 9, wherein the generating the controlling sense signal (215) comprises generating a set of controlling sense signals by: computing, for each IV sense signal of the N-1 IV sense signals (135-1 ... 135-N) not identified as the reference sense signal (305), a respective IV delta between the IV sense signal (135-1 ... 135-N) and the reference sense signal (305); receiving a threshold signal (325) defining k-1 thresholds, k being a positive integer greater than 1; segmenting the IV sense signals (135-1 ... 135-N) into k groups based on the k-1 thresholds; and for each of the k groups, if the group includes at least one of the IV sense signals (135-1 ... 135-N), generating the set of controlling sense signals to include a respective controlling sense signal (215) for the group based on whichever of the IV sense signals (135-1 ... 135-N) in the group has a largest respective IV delta.

13. The method of claim 12, wherein the generating the output control signal (207) comprises generating a set of control outputs for the N speakers (130-1 ... 130-N), each one of the control outputs generated based on extracting thermal and / or excursion protection parameters by applying a respective one of the set of controlling sense signals to the stored load model of the speaker of the N speakers (130-1 ... 130-N) associated with the one of the IV sense signals (135-1 ... 135-N) corresponding to the respective one of the set of controlling sense signals, or further comprising: generating the threshold signal (325) to optimize grouping of the IV sense signals (135-1 ... 135-N) based on the computed respective IV deltas.

14. The method of claim 9, further comprising: selecting the second of the N IV sense signals (135-1 ... 135-N) as the reference sense signal (305) by computing respective candidate IV deltas between pairs of the N IV sense signals (135-1 ... 135-N) to determine the reference sense signal (305) as the one of the N IV sense signals (135-1 ... 135-N) yielding the highest candidate IV deltas.

15. The method of claim 9, further comprising: first detecting toggling of a mode select signal (315) from a bypass mode to an active mode in a first timeframe; and responsive to the first detecting, selecting one of the N IV sense signals (135-1 ... 135-N) as the reference sense signal (305) by computing respective candidate IV deltas between pairs of the N IV sense signals (135-1 ... 135-N) to determine the reference sense signal (305) as the one of the N IV sense signals (135-1 ... 135-N) yielding the highest candidate IV deltas, optionally further comprising: second detecting toggling of a mode select signal (315) from the active mode to the bypass mode in a second timeframe subsequent to the first timeframe; and responsive to the second detecting, maintaining the reference sense signal (305) as the one of the N IV sense signals (135-1 ... 135-N) determined as yielding the highest candidate IV deltas in the first timeframe.