Reduction of audible artifacts in an audio system
First Claim
1. An audio system comprising:
- a switch mode amplifier that provides an output signal at an output for driving a load based on at least one control signal; and
a control system that provides the at least one control signal to control the amplifier according to an operating mode of the audio system, in a first mode, the control system providing the at least one control signal to actively control an equivalent output impedance at the output of the amplifier, gradually adjusting the equivalent output impedance from a high-impedance state to a low impedance state, so as to mitigate a voltage drop across the load when the amplifier is activated to a second mode corresponding to the low impedance state.
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Accused Products
Abstract
An audio system includes a switch mode amplifier that provides an output signal at an output for driving a load based on at least one control signal. A control system provides the at least one control signal to control the amplifier according to an operating mode of the audio system. In a first mode, the control system providing the at least one control signal to actively control an equivalent output impedance at the output of the amplifier, gradually adjusting the equivalent output impedance from a high-impedance state to a low impedance state, so as to mitigate a voltage drop across the load (e.g., including one or more speakers) when the amplifier is activated to a second mode corresponding to the low impedance state.
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Citations
20 Claims
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1. An audio system comprising:
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a switch mode amplifier that provides an output signal at an output for driving a load based on at least one control signal; and a control system that provides the at least one control signal to control the amplifier according to an operating mode of the audio system, in a first mode, the control system providing the at least one control signal to actively control an equivalent output impedance at the output of the amplifier, gradually adjusting the equivalent output impedance from a high-impedance state to a low impedance state, so as to mitigate a voltage drop across the load when the amplifier is activated to a second mode corresponding to the low impedance state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A modulation system for an audio amplifier comprising:
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means for providing at least one modulated signal to provide audio power to at least one speaker; and means for controlling the means for providing in a first mode such that the at least one modulated signal has a modulation that varies incrementally between a starting modulation and an ending modulation according to a modulation sequence; and means for controlling the means for providing in a second mode, following the first mode, such that, in the absence of audio the at least one modulated signal has a substantially fixed modulation, whereby audible artifacts provided by the at least one speaker are mitigated when the second mode begins. - View Dependent Claims (14, 15, 16, 17)
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18. A method for controlling an audio amplifier to mitigate audible artifacts, the method comprising:
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entering a first modulation mode in response to detecting a transition from a non-switching mode to a switching mode; incrementally adjusting modulation of at least one modulated control signal during the first modulation mode; and providing an output signal that gradually charges a DC blocking element to a predetermined level during the first modulation mode based on the at least one modulated control signal. - View Dependent Claims (19, 20)
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Specification