A METHOD FOR LOAD MEASUREMENT IN SWITCHING AMPLIFIERS, CORRESPONDING DEVICE AND AMPLIFIER

A load driven by a switching amplifier, such as a Class D audio amplifier having a differential input, a LC output demodulator filter and a feedback network between the amplifier output and the differential input is measured by: - AC driving (1000) the amplifier in a differential mode by applying a differential AC signal to the differential input and sensing the output current from the amplifier while driving the amplifier in the differential mode, - AC driving (1002) the amplifier in a common mode by applying a common mode AC signal to the differential input and sensing the AC output current from the amplifier while driving the amplifier in the common mode, and a) with the feedback network providing feedback towards said differential input from downstream the LC demodulator filter, computing (1006) the impedance of the load as a function of the differential mode output current and the common mode output current, b) with the feedback network providing feedback towards the differential input from upstream the LC demodulator filter, measuring (1008a) the impedance value of the inductor of the LC demodulator filter, and computing (1008b) the impedance of the load as a function of the differential mode output current, the common mode output current and the impedance value of the inductor of the LC demodulator filter.