Amplifier power attenuator and closed loop operation

Abstract

An amplifier power attenuator utilizes an amplified audio feedback signal from an audio amplifier (which is driving a loudspeaker), along with a user-set impedance and a maximum voltage set-point reflective of the operational parameters of the loudspeaker, to attenuate an audio signal prior to amplification thereby preventing damage to the loudspeaker. The impedance of a variable impedance optocoupler is changed to adjust the attenuation of the audio signal to one of a plurality of predetermined attenuation levels responsive to an error between a voltage level of the feedback signal and the maximum voltage set-point. The error is reflected in a counter value having a linear or non-linear relationship with the error dependent upon a magnitude of the error; the counter value is assessed against a plurality of target values associated with respective ones of the predetermined attenuation levels to identify the attenuation to be applied to the audio signal.

Dependencies are inferred from the claim text.