A detailed analysis of the imperfections of pulsewidth modulated waveforms on the output stage of a class D audio amplifier

[摘要] Although the Class D topology offers several advantages, its use in audio amplificationhas previously been limited by the lack of competitiveness in fidelity compared to its linearcounterparts. During the past decade, technological advances in semiconductor technologyhave awakened new interest since competitive levels of distortion could now be achieved. Theoutput stage of such an amplifier is the primary limiting factor in its performance. In thisdissertation, four non-ideal effects existing in this stage are identified and mathematicallyanalysed. The analytical analysis makes use of a well-established mathematical model, basedon the double Fourier series method, to model the imperfections introduced into a naturallysampled pulsewidth modulated waveform. The analysis is complemented by simulation usinga strategy based on Newton's numerical method. The theory is verified by a comparisonbetween the analytical-, simulated- and experimental results.

[发布机构] Stellenbosch University