Speaker load diagnostics for switching automotive audio amplifiers

Audio amplifiers deliver a large amount of power from a supply to a speaker transducer which converts it to sound energy. The Achilles heel of an audio amplifier IC is its connection to the outside world, i.e. the path to the speaker and the speaker itself. Fault conditions in the speaker and the path to it can result in safety hazards when the signal power gets misdirected, say into a short. In this paper, we explore the detection of such scenarios to pre-empt catastrophic events using the implementation of load diagnostics in the TAS5421 from Texas Instruments — the automotive industry's first class-D eCall amplifier.