Loudspeaker overload protection circuit
First Claim
1. A circuit for protecting a loudspeaker from overload by the power output of an amplifier fed thereto comprising:
- sensing circuit means forming a first channel for detecting the amplifier power output and generating a control signal when said power output exceeds a predetermined level,control circuit means for generating a switching signal in response to said control signal,a current limiting device,switch means for placing said current limiting device in circuit with the loudspeaker in response to said switching signal so as to limit the power fed thereto, andpower circuit means forming a second channel separate and apart from said first channel which receives the output of said power amplifier for generating a predetermined reference signal for the sensing circuit means and for providing power for the sensing circuit means and the switch means.
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Accused Products
Abstract
The output of an audio power amplifier fed to a loudspeaker driver is sensed and when this output exceeds a predetermined level, a switch control circuit operates to place a current limiting device, such as a power resistor, in series with one of the driver feed lines, thereby reducing the power fed thereto. An indicator may also be provided to indicate when the overload condition exists. Operation is made more accurate and distortion minimized by employing separate sensing and power channels in the circuit, the first of these channels operating to sense the overload while the second of these channels utilizes a portion of the amplifier output for driving the switch control circuit for placing the power limiter in the speaker line. The sensing channel is designed to sense the average voltage of the amplifier output, thus providing control more directly responsive to power. The power channel is designed to use audio power from the amplifier output only occasionally, thus producing a minimum of distortion.
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Citations
10 Claims
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1. A circuit for protecting a loudspeaker from overload by the power output of an amplifier fed thereto comprising:
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sensing circuit means forming a first channel for detecting the amplifier power output and generating a control signal when said power output exceeds a predetermined level, control circuit means for generating a switching signal in response to said control signal, a current limiting device, switch means for placing said current limiting device in circuit with the loudspeaker in response to said switching signal so as to limit the power fed thereto, and power circuit means forming a second channel separate and apart from said first channel which receives the output of said power amplifier for generating a predetermined reference signal for the sensing circuit means and for providing power for the sensing circuit means and the switch means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification