This paper presents a comparative study of several multilevel pulse-width modulation (PWM) techniques and their impact on a class-D power amplifier for high-fidelity audio systems. The techniques involved in this analysis are phase (PH), phase opposition (PO), alternate phase oppositions (APO) and phase shifted carrier (PSC) disposition used with a natural-sampled PWM and for the cases of two, five and nine output levels. The analysis takes into account some non-idealities that may arise in the effective implementation of the class-D, particularly jitter and gain error of the PWM carriers, offset and rms noise of the comparators which determine the level of the signal. The system, except for the aforementioned non-idealities, is modeled as an ideal closed-loop class-D amplifier, with a 3rd order loop filter. The simulation results show that the PSC technique has the best robustness against carrier gain error and offset, while the modulation techniques are equivalent when considering the others non-idealities.
A Comparative Study of Multilevel PWM Techniques with Circuit Non-Idealities in Class-D Audio Power Amplifiers
Rossini C.
;Aprile A.;Moisello E.;Bonizzoni E.;Malcovati P.
2026-01-01
Abstract
This paper presents a comparative study of several multilevel pulse-width modulation (PWM) techniques and their impact on a class-D power amplifier for high-fidelity audio systems. The techniques involved in this analysis are phase (PH), phase opposition (PO), alternate phase oppositions (APO) and phase shifted carrier (PSC) disposition used with a natural-sampled PWM and for the cases of two, five and nine output levels. The analysis takes into account some non-idealities that may arise in the effective implementation of the class-D, particularly jitter and gain error of the PWM carriers, offset and rms noise of the comparators which determine the level of the signal. The system, except for the aforementioned non-idealities, is modeled as an ideal closed-loop class-D amplifier, with a 3rd order loop filter. The simulation results show that the PSC technique has the best robustness against carrier gain error and offset, while the modulation techniques are equivalent when considering the others non-idealities.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
