A FULLY DIFFERENTIAL DIGITAL INPUT CLASS D WITH EMI SPREADING METHOD FOR MOBILE APPLICATION

Remy Cellier (1) , Emmanuel Allier (2) , Carlo Crippa (2) , Rossella Bassoli (2) , Gaël Pillonnet (1) , Angelo Nagari (2) , Nacer Abouchi (1)

1 INL - CSH - INL - Conception de Systèmes Hétérogènes
2 STMicroelectronics

Class D audio amplifiers are widely used in embedded system to achieve high efficiency. Digital class D accepts bit stream as input signal to drive loudspeaker. Major drawbacks of such systems are the non linearity due to the switched behavior and EMI radiations issued from the output low pass filter. This paper presents a digital class D amplifier with a local analog feedback loop to improve performances of the power stage and digital method to spread output spectrum in order to reduce EMI radiation. The amplifier, including digital modulator and analog power stage, was integrated in a single chip in 0.13 m CMOS technology. The silicon results confirm the validity of the theoretical analysis.

Domaines: Sciences de l'ingénieur [physics]

Remy Cellier, Emmanuel Allier, Carlo Crippa, Rossella Bassoli, Gaël Pillonnet, et al.. A FULLY DIFFERENTIAL DIGITAL INPUT CLASS D WITH EMI SPREADING METHOD FOR MOBILE APPLICATION. AES International Conference, AES, Aug 2009, Hillerod, Denmark. ⟨hal-01103685⟩