Patent ID: 9301071
Filing Date: 2016-03-29
CPC Classification: H04R

Claim Text:
1. An audio system comprising: an audio driver configured to receive a target audio signal and a feedback signal and to generate an adjusted audio signal responsive to the target audio signal and the feedback signal; a loudspeaker configured to convert the adjusted audio signal into acoustical sound; a test signal generator coupled to a power supply input of the audio driver, the test signal generator being configured to generate a test signal having a higher frequency than the target audio signal and adjust a power supply of the audio driver with the test signal to generate an adjusted power supply for the audio driver that introduces variations in the adjusted audio signal causing a test current to flow through the loudspeaker; a current sensing circuit configured to measure the test current flowing through the loudspeaker and to generate a current sense signal indicative of the test current; and a feedback circuit configured to generate the feedback signal responsive to the current sense signal.