公开(公告)号：US20180367897A1

公开(公告)日：2018-12-20

申请号：US16006139

申请日：2018-06-12

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Ylva Ellen Maria BJORK ,  Erik Vilhelm LINDAHL ,  Jason William LAWRENCE ,  Christopher EKBOM

IPC: H04R3/00 ,  H04R29/00 ,  G01K7/16

CPC classification number: H04R3/007 ,  G01K7/16 ,  G01K2217/00 ,  H04R29/001 ,  H04R29/003

Abstract: Methods and Apparatus for estimating a temperature of an electromechanical transducer. The method comprising receiving an audio signal (901); providing an output signal to the electromechanical transducer, based on the audio signal (902); and determining whether a first magnitude of the audio signal in a first frequency band is above a magnitude threshold (903). In response to the first magnitude being above or equal to the magnitude threshold, calculating a first impedance of the electromechanical transducer based on measurements of a first voltage and a first current of the electromechanical transducer within the first frequency band (905), and estimating the temperature of the electromechanical transducer based on the first impedance (907). In response to the first magnitude being below the magnitude threshold, inserting a pilot tone into the audio signal (909), wherein the pilot tone is at a pilot tone frequency, calculating a second impedance of the electromechanical transducer based on measurements of a second voltage and a second current of the electromechanical transducer at the pilot tone frequency (911), and estimating the temperature of the electromechanical transducer based on the second impedance (913).