Power Parameters and Efficiency of Class B Audio Amplifiers in Real-World Scenario

Abstract

Consumer audio amplifiers are intended to op¬erate with various loudspeaker loads, i.e. the load imped¬ance profile of the audio amplifier is a priori unknown. We propose the power parameters analysis of the class B audio amplifiers to be carried out in the realistic worst-case (RWC) scenario of operation with the minimal value of the impedance and a RWC type of signal, instead of the nominal impedance of the loudspeaker and a sine-wave signal. Experimental validation, carried out for different types of signals and loudspeaker loads, demonstrate the advantages of the proposed RWC-based power parameters estimation. Furthermore, we provide a way of assessing the safe-operating area (SOA) boundaries, based on the output I-V loci of the amplifier and by means of an equi¬valent load line (ELL).