Method and system for digitally controlling a multi-channel audio amplifier
First Claim
Patent Images
1. An audio processing system comprising:
- a digital input gain circuit having at least one input gain block, each input gain block for generating an output signal in response to an audio input signal and a digital gain control signal;
a power amplifier circuit, coupled to an output load, having at least one power amplifier, each power amplifier for generating an audio output signal in response to the output signal;
an overpower detection circuit for generating at least one overpower detection signal in response to the audio output signal from the at least one power amplifier and varying output load and line conditions associated with the power amplifier circuit; and
a microprocessor and a keypad coupled to the microprocessor for selecting an audio output signal and entering input gain levels for a selected audio output signal, the microprocessor programmed for generating the digital gain control signal in response to the input gain levels and for reducing the digital gain control signal according to a gain factor that determines a rate of gain reduction in response to the at least one overpower detection signal indicating an overpower condition, and for setting a limit for the digital gain control signal in response to the at least one overpower detection signal indicating absence of an overpower condition.
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Abstract
Audio signals are processed in a manner that facilitates control for overpower conditions. According to an example embodiment of the present invention, an audio processing circuit is configured and arranged for controlling an output audio signal as a function of an output power and/or clip condition. The audio processing circuit is adapted to approximate output power from an amplifier independent from output load and varying line conditions. When an overpower and/or clip condition is approximated, a signal is generated to reduce the output power by, e.g., reducing the signal gain and/or disconnecting the output.
28 Citations
21 Claims
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1. An audio processing system comprising:
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a digital input gain circuit having at least one input gain block, each input gain block for generating an output signal in response to an audio input signal and a digital gain control signal;
a power amplifier circuit, coupled to an output load, having at least one power amplifier, each power amplifier for generating an audio output signal in response to the output signal;an overpower detection circuit for generating at least one overpower detection signal in response to the audio output signal from the at least one power amplifier and varying output load and line conditions associated with the power amplifier circuit; and a microprocessor and a keypad coupled to the microprocessor for selecting an audio output signal and entering input gain levels for a selected audio output signal, the microprocessor programmed for generating the digital gain control signal in response to the input gain levels and for reducing the digital gain control signal according to a gain factor that determines a rate of gain reduction in response to the at least one overpower detection signal indicating an overpower condition, and for setting a limit for the digital gain control signal in response to the at least one overpower detection signal indicating absence of an overpower condition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An audio processing system comprising:
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a digital input gain circuit having a plurality of input gain blocks, wherein each of the input gain blocks generates an output signal in response to an audio input signal and a digital gain control signal; a power amplifier circuit, coupled to an output load, having a plurality of power amplifiers, wherein each of the power amplifiers generates an audio output signal in response to one of the output signals generated by the input gain blocks; an overpower detection circuit for generating respective overpower detection signals in response the audio output signals generated by the power amplifiers and varying output load and line conditions associated with the power amplifier circuit; a microprocessor and a keypad coupled to the microprocessor for selecting one of the audio output signals and entering input gain levels for the selected audio output signal; and the microprocessor for generating the digital gain control signals in response to the input gain levels and for reducing the digital gain control signal according to a gain factor that determines a rate of gain reduction in response to the at least one overpower detection signals indicating an overpower condition, and for setting a limit for the digital gain control signal in response to the at least one overpower detection signal indicating absence of an overpower condition. - View Dependent Claims (21)
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Specification