Adaptive amplifier voltage with reduced signal chain delay

Abstract

The invention relates to a method for adjusting an adaptive supply voltage for one or more audio amplifiers, the method comprising: receiving a first audio signal (V1); processing the first audio signal (V1) to provide a processed audio signal (V2) with a first delay (1) relative to the first audio signal (V1); providing a sound preset signal (9) controlling the processing of the first audio signal (V1) to provide the processed audio signal (V2); providing the processed audio signal (V2) to one or more audio amplifiers (18); estimating a supply voltage control signal (13) based on the first audio signal (V1) and a sound preset signal (9), the supply voltage control signal (13) indicating a minimum supply voltage (19) required by the one or more amplifiers (18) to avoid voltage clipping of the audio signal (14) received by the one or more amplifiers, wherein the supply voltage control signal (13) has a second delay (2) relative to the first audio signal (V1); using the supply voltage control signal (13) to control a supply voltage (19) for one or more amplifiers; providing a supply voltage (19) to one or more amplifiers; wherein the first delay (1) is greater than the second delay (2). The invention also relates to equipment and a system for implementing the method.

Description

Technical Field

[0001] This invention relates to a method, apparatus, and amplifier, wherein the amplifier requires a supply voltage adapted to the input audio signal in order to extend battery life, reduce power consumption, and avoid voltage clipping in the amplifier. According to the invention, these objectives are achieved with minimal delay in the signal chain of the audio signal. Background of the Invention

[0002] When increasing the output voltage of a DC / DC converter that generates the supply voltage for an amplifier, the capacitors must be charged before the target output voltage is reached. To allow this process to adapt the amplifier's supply voltage to the content of the signal it is amplifying, a delay is typically added to the audio signal chain. Due to requirements such as lip-sync, latency, and similar needs, delay in the audio chain is generally undesirable, thus encouraging its reduction. Purpose of the invention

[0003] Against this background, one object of the present invention is to provide a method and a corresponding device or system that provides reduced power consumption of an amplifier and extended battery life in battery-powered products without adding unnecessary delay to the audio signal chain. Disclosure of this invention

[0004] The aforementioned objectives and further advantages are achieved by adjusting the supply voltage used by the amplifier through controlling a suitable voltage source. A suitable voltage source could be, for example, a DC / DC converter or an AC / DC converter. The control signal is based on the signal content the amplifier will receive, but is estimated using a simple filter upstream of time-consuming signal processing, thus allowing sufficient time to increase the amplifier supply voltage and avoid voltage clipping.

[0005] According to the present invention, the signal extraction for calculating the supply voltage occurs before any constant delay contribution, but as late as possible in the audio signal chain, so that as many dynamic and variable elements as possible act on the audio signal before the supply voltage is calculated. This reduces the filter bank that changes between supply voltage calculations. For example, if a variable gain is arranged in the speaker processing block (which is located after the signal extraction for supply voltage calculation), this gain must be taken into account when calculating the supply voltage. The present invention solves this problem.

[0006] Typically, but not exclusively, the dynamic components in the loudspeaker processing block are only effective at certain loudness levels, where the supply voltage calculation is expected to be fully saturated and therefore have little or no effect on the supply voltage calculation. However, user-changeable filters do need to be considered, and therefore the voltage estimation filter is updated whenever a user-changeable filter in the loudspeaker processing block is changed. Fortunately, the number of user-changeable filter options is limited, so the filters used for voltage estimation can be pre-calculated and stored in a filter bank. Voltage estimation

[0007] For each amplifier channel that shares the same supply voltage, the filter that estimates its voltage is a combination of the amplitude response and group delay of each channel, resulting in a common maximum voltage and average group delay.

[0008] The voltage estimation filter is computed as a simplified version of the combined transfer function processed by the loudspeaker. The frequency response and group delay of the transfer function are considered in the estimation filter.

[0009] The voltage estimation filter is modeled as the envelope of the amplitude response of the loudspeaker processing transfer function, ensuring that the estimated voltage is always equal to or higher than the actual voltage for all frequencies.

[0010] Because the filters in the speaker processing block delay some frequencies more than others, the group delay in the voltage estimation filter simulates the group delay of the transfer function. Otherwise, the estimated voltage changes for some frequencies would occur prematurely, causing the supply voltage calculation to be out of sync with the amplifier output. Envelope calculation

[0011] The result after applying the voltage estimation filter is the maximum expected instantaneous voltage across all channels sharing the same supply voltage. Next, the envelope of this voltage is calculated using fast attack and slow release. This envelope is then clipped to the minimum and maximum voltages that allow the DC / DC converter and amplifier to operate safely and are passed to the hardware. Further details regarding the application of the calculated envelope to control the supply voltage of one or more amplifiers will be given in the detailed description of the invention.

[0012] The above and further objects and advantages are achieved through the following aspects of the present invention.

[0013] According to a first aspect of the invention, a method for adjusting an adaptive supply voltage for one or more audio amplifiers is provided, the method comprising: Receive the first audio signal; The first audio signal is processed to provide a processed audio signal having a first delay relative to the first audio signal; Provide a sound preset signal, which controls the processing of a first audio signal, thereby providing a processed audio signal; Provide processed audio signals to one or more amplifiers; A supply voltage control signal is calculated based on a first audio signal and a sound preset signal. This supply voltage control signal indicates the minimum supply voltage required by one or more amplifiers to avoid voltage clipping of the audio signal received by one or more amplifiers, wherein the supply voltage control signal has a second delay relative to the first audio signal. Use the supply voltage control signal to control the supply voltage for one or more amplifiers; Provide supply voltage to one or more amplifiers; The first delay is greater than the second delay.

[0014] In the embodiment of the first aspect, the calculation of the supply voltage includes: For each group of amplifiers sharing the same supply voltage, each corresponding amplifier in a group of amplifiers is part of a corresponding signal channel that provides a set of filters, wherein the amplitude and group delay of the corresponding filters are based on a combination of the amplitude response and group delay of each channel, thereby providing a combined amplitude response and average group delay. Provide the maximum expected instantaneous audio signal voltage as a result of processing the first audio signal by a filter with a combined amplitude response and group delay; The envelope of the maximum expected instantaneous audio signal voltage is calculated using the rapid rise time and slow release time. The envelope is limited to the minimum and maximum voltage that the entity used to implement the method (e.g., a voltage power supply and / or amplifier) ​​can accept.

[0015] In an embodiment of the first aspect, the processed audio signal and the supply voltage control signal are digital signals.

[0016] In an embodiment of the first aspect, the supply voltage control signal is a DC signal.

[0017] In an embodiment of the first aspect, the method includes: The first processor device receives and optionally processes the digital audio input signal to provide a first digital audio signal. A first digital audio signal is provided to a second processor device, thereby providing a processed digital audio signal having a first delay relative to the first digital audio signal; The processed digital audio signal is converted into a corresponding analog audio signal and the analog audio signal is supplied to one or more audio amplifiers; Provides preset audio signals for controlling the second processor device; Based on a first digital audio signal and a sound preset signal, a DC value is calculated, which indicates the minimum supply voltage required by one or more amplifiers to avoid voltage clipping of the analog audio signal received by one or more amplifiers, wherein the DC value has a second delay relative to the first digital audio signal; Use DC values ​​to control the supply voltage source so that the supply voltage source provides the required supply voltage to one or more amplifiers; The first delay is greater than the second delay plus the charging time of the capacitor in the supply voltage source.

[0018] It should be noted that for supply voltage source devices that do not contain capacitors at all or whose capacitors have very low capacitance, the charging time is zero or negligible.

[0019] In an embodiment of the first aspect, a supply voltage control signal is obtained by providing a first digital audio signal to a set of filters that estimate the output voltage of an amplifier and calculating the envelope of the estimated output voltage.

[0020] In an embodiment of the first aspect, the transfer function of the set of filters is based on the transfer function of the second processor device.

[0021] In an embodiment of the first aspect, the transfer function and / or parameters of the second processor device are controlled according to a preset sound signal.

[0022] According to a second aspect of the invention, a device is provided for adjusting an adaptive supply voltage for one or more audio amplifiers, wherein the device comprises: An input terminal, used to receive the first audio signal; A processing device characterized by a first delay, the processing device receiving a first audio signal and processing the signal to provide a second processed audio signal, the second processed audio signal being used as an input signal for one or more amplifiers configured to be driven by an adaptive supply voltage; A supply voltage estimation unit includes one or more digital filters and envelope calculation devices. The supply voltage estimation unit has a first input terminal, a second input terminal, and an output terminal. The first input terminal receives a first audio signal, the second input terminal is configured to receive a sound preset signal, and the output terminal provides a control signal indicating the required supply voltage based on the first audio signal and the sound preset signal. The supply voltage estimation unit has a second delay. A control signal is provided to a controllable voltage supply device, which provides the required supply voltage based on the control signal; The signal delay associated with the supply voltage estimation filter and envelope calculation, plus the charging time of the capacitors used in the supply voltage source, is less than the signal delay in the processing device.

[0023] In the second aspect of the embodiment, the processed audio signal and the supply voltage control signal are digital signals.

[0024] In a second aspect embodiment, a D / A converter unit is included that receives a processed digital audio signal and converts the signal into a corresponding analog audio signal for supply to one or more audio amplifiers configured to be driven by an adaptive supply voltage.

[0025] In a second aspect embodiment, the device includes a D / A converter unit that receives a control signal and converts the signal into a corresponding analog control signal to provide to a supply voltage source device configured to provide an adaptive supply voltage to one or more amplifiers.

[0026] In the second aspect embodiment, the supply voltage control signal is a DC signal.

[0027] In an embodiment of the second aspect, the transfer function of a set of filters in the supply voltage estimation unit is based on the transfer function and / or parameters of the processing device.

[0028] In a second aspect embodiment, the transfer function and / or parameters of the processing device can be controlled by a user via a user interface device configured to provide a preset sound signal.

[0029] In a second aspect embodiment, the first audio signal is provided by the input processing device when it receives an input signal.

[0030] In a second aspect embodiment, the input processing device has a delay much smaller than the first delay.

[0031] In an embodiment of the second aspect, the device includes means configured as follows: For each group of amplifiers sharing the same supply voltage, each corresponding amplifier in a group of amplifiers is part of a corresponding signal channel that provides a set of filters, wherein the amplitude and group delay of the corresponding filters are based on a combination of the amplitude response and group delay of each channel, thereby providing a combined amplitude response and average group delay. Provide the maximum expected instantaneous audio signal voltage as a result of processing the first audio signal by a filter with a combined amplitude response and group delay; The envelope of the maximum expected instantaneous audio signal voltage is calculated using the rapid rise time and slow release time; The envelope is limited to the minimum and maximum voltage that the entity, such as a voltage source and / or amplifier, can accept.

[0032] According to a third aspect of the invention, a system is provided comprising a plurality of devices according to a second aspect of the invention, each device having a specific input terminal configured to receive a corresponding digital audio input signal (e.g., a left input audio signal and a right input audio signal of a stereo signal), wherein each input signal, after being processed in a corresponding first processor, is provided to a supply voltage estimation unit, which provides a corresponding supply voltage estimate to a supply voltage selection unit configured to select a control signal for a supply voltage source.

[0033] In a third aspect embodiment, the supply voltage selection unit selects the maximum value of the two input supply voltage estimates and uses it as a control signal for the supply voltage source.

[0034] According to a fourth aspect of the present invention, an audio amplifier is provided, comprising: According to the equipment in the second aspect; One or more audio amplifiers, each having an independent input terminal configured to receive an analog audio signal and a common supply voltage terminal configured to receive an adaptable supply voltage from a supply voltage source unit. Brief description of the attached diagram

[0035] One or more embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 A schematic block diagram illustrating the basic functions of an embodiment of a system according to the present invention is shown, which provides an adaptive amplifier supply voltage without increasing signal chain delay; Figure 2 The transfer functions of the loudspeaker processing block are shown, where graphs (a) to (d) show the transfer functions from the input to each of the four outputs, and graph (e) shows the individual transfer functions and the combined transfer functions; Figure 3 (a) shows the magnitude response of the transfer function of the signal processing after the supply voltage calculation and voltage estimation filter. Figure 3 (b) shows the group delay of the transfer function after the supply voltage calculation and voltage estimation filter; Figure 4 (a) shows the calculated envelope signal. Figure 4 (b) shows the signal after applying the voltage estimation filter; Figure 5 The voltage at each of the four amplifier outputs is shown, along with the supply voltage envelope that determines the shared supply voltage. Figure 6 Illustrative examples are shown of the corresponding estimated voltage, envelope signal, and supply voltage variations over time; Figure 7 The oscilloscope measurements are shown for the outputs of two amplifiers sharing the same supply voltage. Figure 8 The oscilloscope measurements of the amplifier output and supply voltage are shown. Figure 9 The oscilloscope measurements of the amplifier output and supply voltage are shown. Figure 10 The oscilloscope measurements of the amplifier output and supply voltage are shown. Figure 11 A block diagram illustrating a non-limiting example of a practical implementation of the system according to the invention; and Figure 12 A flowchart illustrating an embodiment of the method according to the present invention is shown. Detailed description of the invention

[0036] The following detailed description relates to non-limiting embodiments of the invention. However, it should be understood that other practical implementations besides those described below will also fall within the scope of protection defined by the appended claims. This, for example, relates to signals between various functional blocks and the processing performed by these functional blocks. Therefore, the principles of the invention can be implemented using only digital signal processing, a mixture of digital and analog signal processing, or purely analog signal processing. This depends on the specific implementation of the invention.

[0037] refer to Figure 1 (a) and Figure 1 (b) illustrates the main functional blocks of an embodiment 1 of the system according to the invention, and a schematic block diagram of the interactions between these blocks, which constitute two blocks, namely block 2 and block 3. However, it should be understood that this is merely an example, and in any particular embodiment of the invention, all functional blocks may be integrated into one unit or distributed across several units as needed. Figure 1 (a) and Figure 1 (b) In the following description, it is assumed that the signals and processing from input terminal 4 to A and B are digital, but as stated above, this is not necessarily the case in other embodiments of the invention.

[0038] At input terminal 4, the digital audio input signal V is received. in V inThe signal is provided to a first processor 5 (referred to as "stereo processing" in the figure), which may include, for example, volume settings, bass and treble settings, and loudness compensation. The first processor 5 is characterized by virtually no delay in the processed signal; that is, the delay is so low that it is not significant in the context of this application. The first processing block 5 provides an output signal V1, which is the digital audio input signal V at input terminal 4. in The processed version.

[0039] Output signal V1 is provided to a second processor 10 (referred to in the figure as "speaker processing"), which is configured to generate signal V2 that can be used to drive individual speakers in a system using the present invention. Speaker processing block 10 may, for example, divide the output signal V1 from first processing block 5 into multiple driver channels for driving individual speakers. These signals V2 are digital signals, and each of these signals is therefore provided to an independent D / A converter, wherein... Figure 1 The schematic block diagram shows only a single D / A converter 12. Each of these D / A converters provides an independent analog audio signal 14 to a corresponding output amplifier 18. Figure 1 Only one amplifier 18 is shown, which outputs a driver signal 20 to the corresponding speaker. Figure 11 An illustrative example of the invention for driving a stereo system with two three-way speaker units is shown.

[0040] The output signal V1 from the first processor 5 is further provided via line 7 to block 8, which includes a supply voltage estimation filter and an envelope calculation device. The filter and envelope calculation device described herein can be controlled by a user who provides user input at terminal 9. A sound preset signal is provided at terminal 9, which controls the second processor 10. By controlling the supply voltage estimation filter and envelope calculation in block 8 and the second processor 10 providing speaker processing, the parameters of block 8 optimally correspond to the actual speaker processing performed in the second processor 10. Through these devices, the supply voltage estimation filter and envelope calculation block 8 contains a model of the speaker processing performed in block 10, which can estimate the required supply voltage with a delay D2 that is much lower than the delay D1 of the speaker processing block 10, thereby enabling the supply voltage to be stabilized without inserting additional delay into the audio signal chain. Reference will be made below. Figures 2 to 10 Describe the more detailed features of these processor blocks 8 and 10.

[0041] The supply voltage estimation filter and envelope calculation block 8 provide the output signal V on line 13. EIn this embodiment, it indicates the DC value of the supply voltage required by the output amplifier 18 (or multiple such amplifiers driven by the same supply voltage). The output signal 13 is converted into a digital signal in the D / A converter 15 into an analog DC control signal 16, which controls, for example, […]. Figure 1 (b) shows the supply voltage source 17 of the DC / DC converter circuit. The output 19 from the supply voltage source 17 is used to drive the amplifier 18, or as described in the detailed description. Figure 11 Multiple such amplifiers.

[0042] For each group of amplifier channels sharing the same supply voltage (note that this group can consist of only a single amplifier, but typically multiple speakers, each with its own amplifier channel), the filter for estimating its voltage is a combination of the amplitude response and group delay of each channel, resulting in a common maximum voltage and average group delay. This is illustrated below for a system comprising four speakers: one tweeter, one woofer, and two full-range speakers.

[0043] refer to Figure 2 The diagram shows the transfer function of the speaker processing block 10, where graphs (a) to (d) show the transfer function from the corresponding input 6 to each of the four outputs 11, and graph (e) shows the combined transfer function, i.e., the maximum value of the four transfer functions. Figure 2 The graph shown relates to an embodiment of the method / system according to the invention, wherein there are four output channels: one for an LF loudspeaker (woofer) with amplitude response 21, one for an HF loudspeaker (tweeter) with amplitude response 22, and two channels for full-range loudspeakers (full-range 1 and full-range 2) with amplitude responses 23 and 24, respectively. In this embodiment, each loudspeaker is driven by its own independent amplifier 18, and all four amplifiers share the same supply voltage 19.

[0044] refer to Figure 3 (a) shows the combined amplitude response of the transfer function after the supply voltage calculation and voltage estimation filter, and refers to Figure 3 (b) shows the combined group delay of the transfer function after the supply voltage calculation and voltage estimation filter in the signal processing.

[0045] The supply voltage estimation filter is calculated as a simplified version of the combined transfer function of the second processor 10 (speaker processing block). The frequency response and group delay of the combined transfer function are considered in the estimation filter.

[0046] Figure 3 (a) shows Figure 2 (a) to Figure 2 (d) shows the combined transfer function (i) of the four transfer functions and the transfer function (ii) of the resulting voltage estimation filter. Figure 3 (b) shows Figure 2 (a) to Figure 2 (d) shows the combined group delay of the four transfer functions (iii) and the group delay of the resulting voltage estimation filter (iv).

[0047] The supply voltage estimation filter is modeled as the envelope of the amplitude response of the corresponding second processing block 10, ensuring that the estimated voltage is always equal to or higher than the actual voltage for all frequencies.

[0048] Because the filters in the second processing block 10 cause some frequencies to be delayed more than others, the group delay in the voltage estimation filter simulates the group delay of the transfer function of the speaker processing block 10. Otherwise, the estimated voltage changes for some frequencies would occur prematurely, causing the supply voltage calculation to be out of sync with the amplifier output.

[0049] In an embodiment of the invention, the envelope calculation is performed as follows: after applying the voltage estimation filter, the total voltage of all channels is the maximum expected instantaneous voltage for all channels (amplifiers) sharing the same supply voltage. Figure 4 Example of how the resulting voltage changes over time is shown in (b). The envelope of this instantaneous voltage is then calculated. This is as follows: Figure 4 As shown in (a). For this calculation, it is advantageous to use a rapid rise (short rise time) and a slow release (long release time). This application of rise and release times stems from... Figures 6 to 10 It is clearly shown in the text.

[0050] refer to Figure 5 The envelope signal V of each channel sharing the same supply voltage is shown. E .exist Figure 5 In (a), it can be clearly seen that for approximately the first 10% of the time covered by the graph, the woofer signal drives the envelope signal (and thus the supply voltage) until its maximum level, while for the remaining time covered by the graph, the full-range speaker signal drives the envelope signal. The graph also shows the output signal V2 from speaker processing block 10.

[0051] Because amplifiers require a certain amount of overhead in the supply voltage to supply a given amplifier output voltage, the supply voltage should always be at least that overhead higher than the signal level. Figures 7 to 10 This is clearly evident.

[0052] Envelope signal (e.g.) Figure 4 and Figure 5 The envelope signal shown is converted into the corresponding analog signal (in...) Figure 1 In the D / A converter 15 shown in the embodiment, the control signal 16 is then used as the supply voltage source 17. This is because the "supply voltage calculation block" 8 (see...) Figure 1 ) and 78, 80 (see Figure 11 The processing in ) is compared to "Speaker Processing Block" 10 (see Figure 1 ) and 42, 60 (see Figure 11 The processing in ) has a smaller delay, so the envelope signal occurs in signal 14 (see Figure 1 ) and 49, 50, 51, 67, 68, 69 (see Figure 11 Before that. The advance time is used to charge the supply voltage capacitor C (see...). Figure 1 Furthermore, the supply voltage capacitor C will cause the supply voltage to drop more slowly than the envelope signal.

[0053] Figure 6 The diagram illustrates illustrative examples of how the estimated voltage, envelope signal, and supply voltage change over time. Figure 6 (a) shows the estimated voltage. Figure 6 (b) shows the corresponding envelope signal, and Figure 6 (c) shows, for example, by Figure 1 The obtained supply voltage is provided by the supply voltage source 17 in the middle. From Figure 6 (c) It can also be seen that the supply voltage has a rapid rise time and a much slower release time, such as Figure 7 The reference numbers 30(1) and 30(2) are shown in the figure.

[0054] refer to Figures 7 to 10 This shows the amplifier outputs for the woofer and full-range speaker, as well as the common supply voltage (i.e., the output of the DC / DC converter 17 and supplied by...). Figure 1 The capacitor C shown is a capacitor whose supply voltage is smoothed (actual measurement results). The supply voltage appears to generally follow the signal level, increasing rapidly as the signal amplitude increases and decreasing slowly as the signal amplitude decreases.

[0055] refer to Figure 7 The following oscilloscope measurements are shown for the outputs of two amplifiers sharing the same supply voltage 31. The amplifier output signal for the full-range speaker is indicated by 32, and the amplifier output signal for the woofer is indicated by 33. In this example, the maximum value of the supply voltage is 30 VDC, and it appears that the strong signal peak 33 in the woofer signal requires the supply voltage to be at its maximum value. As indicated by 30(1), an increase in signal level results in a rapid increase in the supply voltage (i.e., a rapid rise time), while as indicated by 30(2), a decrease in signal amplitude results in a much slower decrease in the supply voltage (i.e., a long release time).

[0056] exist Figure 8 and Figure 9 In this design, the amplifier outputs for the woofer 33 and the full-range speaker 37 are separated to more clearly show which one of them drives the supply voltage to rise at a given time.

[0057] Figure 10 Another example of a woofer channel 39 is shown, which drives the supply voltage 38 to rise as the signal amplitude increases, and discharges the capacitor C in the supply voltage source 38 when the supply voltage is at a level higher than that required by the amplifier, so as not to limit the signal amplitude.

[0058] refer to Figure 11 The diagram shows a non-limiting example of a practical implementation of the system according to the invention. Figure 11 The entire system shown includes device D and amplifiers 52, 53, 54, 70, 71, 72 according to embodiments of the present invention, and associated loudspeakers 55, 56, 57, 73, 74, 75.

[0059] It should be noted that the exact boundary between "equipment" and "system" may differ. Figure 11 The boundary is indicated by the dashed line D. Therefore, for example, amplifiers can each be equipped with a corresponding D / A converter, making... Figure 11 The D / A converter shown here will therefore not be part of the device.

[0060] Figure 11 The system shown includes systems with signal inputs V. L and V R The left and right stereo channels. In the illustrated embodiment, the left and right signal chains have the same configuration, but it should be understood that this is not necessarily the case.

[0061] Left channel input signal V L The signal 41 is provided to a first processor 40 (“left stereo processing”), where, for example, gain adjustment, dynamic range compression, and / or channel routing and mixing can be performed. In the context of this application, the delay through the first processor 40 can be considered negligible. The processed audio signal 41 from the first processor 40 is provided to a second processor 42 (“left speaker processing”), which typically includes FIR and IIR filters with an inherent constant delay to the signal processed by the second processor 42. In the illustrated embodiment, the second processor 42 splits the received audio signal 41 into a high-frequency signal 43, a mid-frequency signal 44, and a low-frequency signal 45, which, after desired amplification, are provided to a high-frequency speaker (tweeter) 55, a mid-frequency speaker (midrange speaker) 56, and a low-frequency speaker (woofer) 57.

[0062] Signals 43, 44, and 45 are digital audio signals, and these signals are converted into corresponding analog audio signals 49, 50, and 51 in the corresponding D / A converters 46, 47, and 48. The analog audio signals 49, 50, and 51 are provided to the corresponding independent amplifiers 52, 53, and 54, which are driven by the same supply voltage 84.

[0063] Right channel input signal V R The signal 59 is provided to a first processor 58 (“Right Stereo Processing”), where, for example, gain adjustment, dynamic range compression, and / or channel routing and mixing can be performed. In the context of this application, the delay through the first processor 58 can be considered negligible. The processed audio signal 59 from the first processor 58 is provided to a second processor 60 (“Right Speaker Processing”), which typically includes FIR and IIR filters with an inherent constant delay to the signal processed by the second processor 60. In the illustrated embodiment, the second processor 60 splits the received audio signal 59 into a high-frequency signal 61, a mid-frequency signal 62, and a low-frequency signal 63, which, after desired amplification, are provided to a high-frequency speaker (tweeter) 73, a mid-frequency speaker 74, and a low-frequency speaker (woofer) 75.

[0064] Signals 61, 62, and 63 are digital audio signals, and these signals are converted into corresponding analog audio signals 67, 68, and 69 in the corresponding D / A converters 64, 65, and 66. The analog audio signals 67, 68, and 69 are provided to the corresponding independent amplifiers 70, 71, and 72, which are driven by the same supply voltage 84.

[0065] A common supply voltage 84 is provided by a controllable supply voltage source 83 that receives a control signal 85. This control signal 85 is derived from two processed audio signals 41 and 59 and information relating to a sound preset 76 selected by the user via a user interface 77. In this way, it is ensured that the estimated supply voltages 79 and 81 depend on the sound preset actually selected by the user (or preset in the system). In this example, the sound presets may be different for the left and right channels; for example, one sound preset signal controls the right speaker processing 60 and the corresponding supply voltage estimate 80, and a second sound preset signal controls the left speaker processing 42 and the corresponding supply voltage estimate 78. It should be understood that alternative embodiments are conceivable, in which only a single sound preset signal and a single supply voltage estimation block control both channels exist.

[0066] exist Figure 11The diagram illustrates two independent supply voltage estimation blocks. However, it is also possible to use an independent voltage estimation filter for each channel, along with a single envelope calculation device that operates on the maximum signal output from both voltage estimation filters. This can, of course, be extended to any number of channels and will also fall within the scope of this invention.

[0067] In function block 82, supply voltage selection is performed based on the estimated supply voltages 79 and 81. This selection typically involves taking the maximum of the two input supply voltage estimates 79 and 81; however, it should be understood that other selection criteria can be selected. The output signal 85 from supply voltage selection block 82 serves as the control signal for supply voltage source 83.

[0068] refer to Figure 12 A flowchart illustrating a method according to an embodiment of the present invention is shown. The method shown in the flowchart involves a single input audio channel (e.g., in...). Figure 11 It has an input signal V L or V R The input audio signal (digital signal) is received in block 85 and provided to the first DSP unit in block 86, which provides the first processed output signal 87. The processing delay in block 86 is... In block 89, signal 87 (via line 88) is provided to the second DSP unit, which provides the second processed output signal. The delay in block 89 is... In block 90, the output signal from block 89 is converted from a digital signal to an analog signal in a D / A converter. In block 91, the analog signal from the D / A converter in block 90 is provided to an amplifier configured to receive a variable supply voltage.

[0069] In block 92, the user can input a selected sound preset, which is converted into corresponding sound preset parameters in block 93. These parameters are transmitted to processing block 89 and estimation block 95 via line 94.

[0070] In block 95, the first processed output signal 87 is provided to the supply voltage estimate. In block 97, the signal 99 from the supply voltage estimate is used to determine the control signal 102 for the supply voltage source (not shown). In block 100, the desired supply voltage is finally provided to the audio amplifier.

[0071] The flowchart also indicates the relationship between delays in each functional block.

[0072] As mentioned above, Figure 12The flowchart shown pertains to a single input audio channel. However, lines 96 and 98 and block 101 in the flowchart illustrate the possibility of using this method for multiple amplifiers sharing the same supply voltage.

Claims

1. A method for adjusting an adaptive supply voltage for one or more audio amplifiers, the method comprising: Receive the first audio signal (V1); The first audio signal (V1) is processed to provide a processed audio signal (V2) having a first delay (Δ1) relative to the first audio signal (V1); A sound preset signal (9) is provided to control the processing of the first audio signal (V1), thereby providing the processed audio signal (V2). The processed audio signal (V2) is supplied to one or more amplifiers (18); Based on the first audio signal (V1) and the sound preset signal (9), a supply voltage control signal (13) is calculated, the supply voltage control signal (13) indicating the minimum supply voltage (19) required by the one or more amplifiers (18) to avoid voltage clipping of the audio signal (14) received by the one or more amplifiers, wherein the supply voltage control signal (13) has a second delay (Δ2) relative to the first audio signal (V1). The supply voltage control signal (13) is used to control the supply voltage (19) for the one or more amplifiers. The supply voltage (19) is provided to one or more amplifiers. The first delay (Δ1) is greater than the second delay (Δ2).

2. The method according to claim 1, wherein, The calculation of the supply voltage includes: For each group of amplifiers (18; 52, 53, 54, 70, 71, 72) sharing the same supply voltage (19, 84), a set of filters is provided, wherein each corresponding amplifier in the group of amplifiers is part of a corresponding corresponding signal channel (43, 46, 49; 44, 47, 50; 45, 48, 51; 61, 64, 67; 62, 65, 68; 63, 66, 69), wherein the amplitude and group delay of the corresponding filter are based on a combination of the amplitude response (21, 22, 23, 24) and group delay of each channel, thereby providing a combined amplitude response (26(ii)) and an average group delay (27(iv)). Provide the maximum expected instantaneous audio signal voltage as a result of processing the first audio signal (V1) with a filter having the combined amplitude response (26(ii)) and group delay (27(iv)); The envelope of the maximum expected instantaneous audio signal voltage is calculated using the rapid rise time and slow release time (29). The envelope (29) is limited to the minimum and maximum voltage that can be accepted by the entity, such as the voltage source (17) and / or amplifier (18), used to implement the method.

3. The method according to claim 1 or 2, wherein, The processed audio signal (V2) and the supply voltage control signal (13) are digital signals.

4. The method according to claim 1, 2 or 3, wherein, The supply voltage control signal (13) is a DC signal.

5. The method according to claim 1, wherein the method comprises: The first processor device (5) receives a digital audio input signal (V). in ) and optionally process the digital audio input signal (V in ), thereby providing the first digital audio signal (V1); The first digital audio signal (V1) is provided to the second processor device (10) to provide a processed digital audio signal (V2) having a first delay (Δ1) relative to the first digital audio signal (V1). The processed digital audio signal (V2) is converted into a corresponding analog audio signal (14) and the analog audio signal (14) is provided to one or more of the audio amplifiers (18). Provide a preset sound signal (9) for controlling the second processor device (10); Based on the first digital audio signal (V1) and the sound preset signal (9), a DC value (13) is calculated, the DC value (13) indicating the minimum supply voltage (19) required by the one or more amplifiers (18) to avoid voltage clipping of the analog audio signal (14) received by the one or more amplifiers (18), wherein the DC value (13) has a second delay Δ2 relative to the first digital audio signal (V1); The DC value (13) is used to control the supply voltage source (17) so that the supply voltage source (17) provides the required supply voltage (19) to the one or more amplifiers (18); Wherein, the first delay Δ1 is greater than the second delay Δ2 plus the charging time of the capacitor in the supply voltage source (17).

6. The method according to claim 5, wherein, The supply voltage control signal (13) is obtained by providing the first digital audio signal (V1) to a set of filters that estimate the output voltage (20) of the amplifier (18) and calculating the envelope of the estimated output voltage.

7. The method according to claim 5 or 6, wherein, The transfer function of the set of filters is based on the transfer function of the second processor device (10).

8. The method according to claim 5, 6 or 7, wherein, The transfer function and / or parameters of the second processor device (10) are controlled according to the sound preset signal (9).

9. A device for adjusting an adaptive supply voltage for one or more audio amplifiers, wherein, The device includes: Input terminal (6), the input terminal is used to receive a first audio signal (V1); The processing device (10) is characterized by a first delay Δ1, the processing device (10) receiving a first audio signal (V1) and processing the signal (V1) to provide a second processed audio signal (V2), the second processed audio signal (V2) being used as an input signal for one or more amplifiers (18) configured to be driven by an adaptive supply voltage (19); A supply voltage estimation unit (8) includes one or more digital filters and envelope calculation devices. The supply voltage estimation unit (8) has a first input terminal, a second input terminal, and an output terminal. The first input terminal receives a first audio signal (V1), the second input terminal is configured to receive a sound preset signal (9), and the output terminal provides a control signal (13) indicating the required supply voltage (19) based on the first audio signal (V1) and the sound preset signal (9). The supply voltage estimation unit (8) has a second delay Δ2. The control signal (13) is provided to the controllable supply voltage source device (17), which provides the required supply voltage (19) based on the control signal (13). The sum of the signal delay Δ2 associated with the supply voltage estimation filter and envelope calculation, plus the charging time of the capacitor in the supply voltage source (17), is less than the signal delay Δ1 in the processing device (10).

10. The device according to claim 9, wherein, The processed audio signal (V2) and the supply voltage control signal (13) are digital signals.

11. The device according to claim 9 or 10, comprising a D / A converter unit (12) that receives the processed digital audio signal (V2) and converts the signal into a corresponding analog audio signal (14) for supply to one or more audio amplifiers (18) configured to be driven by an adaptive supply voltage (19).

12. The device according to any one of claims 9 to 11, comprising a D / A converter unit (15) receiving the control signal (13) and converting the signal into a corresponding analog control signal (16) to provide to the supply voltage source device (17), the supply voltage source device being configured to provide the adaptive supply voltage (19) to the one or more amplifiers (18).

13. The device according to any one of claims 9 to 12, wherein, The supply voltage control signal (13) is a DC signal.

14. The device according to any one of claims 9 to 13, wherein, The transfer function of a set of filters in the supply voltage estimation unit (8) is based on the transfer function and / or parameters of the processing device (10).

15. The device according to any one of claims 9 to 14, wherein, The transfer function and / or parameters of the processing device (10) can be controlled by the user via a user interface device configured to provide the preset sound signal (9).

16. The device according to any one of claims 9 to 15, wherein, The input processing device (5) receives the input signal (V) in The first audio signal (V1) is provided when the audio signal is provided.

17. The device according to claim 16, wherein, The input processing device has a delay Δ in , where Δ in <<Δ1.

18. The device according to any one of claims 9 to 17, comprising means configured as follows: For each group of amplifiers (18; 52, 53, 54, 70, 71, 72) sharing the same supply voltage (19, 84), a set of filters is provided, wherein each corresponding amplifier in the group of amplifiers is part of a corresponding corresponding signal channel (43, 46, 49; 44, 47, 50; 45, 48, 51; 61, 64, 67; 62, 65, 68; 63, 66, 69), wherein the amplitude and group delay of the corresponding filter are based on a combination of the amplitude response (21, 22, 23, 24) and group delay of each channel, thereby providing a combined amplitude response (26(ii)) and an average group delay (27(iv)). Provide the maximum expected instantaneous audio signal voltage as a result of processing the first audio signal (V1) with a filter having the combined amplitude response (26(ii)) and group delay (27(iv)); The envelope of the maximum expected instantaneous audio signal voltage is calculated using the rapid rise time and slow release time (29); and The envelope (29) is limited to the minimum and maximum voltage that the entity of, for example, voltage source (17) and / or amplifier (18) can accept.

19. A system comprising a plurality of devices, said devices being the devices according to claims 9 to 18, each device having a specific input terminal configured to receive a corresponding digital audio input signal, such as a stereo left input audio signal and a stereo right input audio signal (V... L V R Each input signal is processed in a corresponding first processor (40, 58) and then provided to a supply voltage estimation unit (78, 80), which provides a corresponding supply voltage estimate (79, 81) to a supply voltage selection unit (82), which is configured to select a control signal (85) for a supply voltage source (83).

20. The system according to claim 19, wherein, The supply voltage selection unit (82) selects the maximum value of the two input supply voltage estimates (79, 81) and uses the maximum value as the control signal (85) of the supply voltage source (83).

21. An audio amplifier, comprising: The device according to any one of claims 9 to 18; One or more audio amplifiers (18, 52, 53, 54, 70, 71, 72), each audio amplifier having an independent input terminal configured to receive analog audio signals (14, 49, 50, 51, 67, 68, 69) and a common supply voltage terminal (19, 84) configured to receive an adaptable supply voltage from the supply voltage source unit (17, 83).

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