A fully digital single chip 4x100 W Class D amplifier with high immunity to the demodulation filter effects

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A fully digital single chip 4x100 W Class D amplifier with high immunity to the demodulation filter effects

Adduci, P. / Botti, E. / Gonano, G. / Dallago, E. / Venchi, G.

Nowadays, high energetic efficiency is a key requirement for both integrated circuits and electronic systems. This is particularly true for automotive applications, since the amount of electronics inside a vehicle is constantly growing. This trend is expected to strengthen with the spread of hybrid and electrical vehicles, hence the effort to improve efficiency in this field is well justified. This paper presents a single chip, 4x100 W Bridge Tied Load (BTL), Class-D audio amplifier based on PWM modulation. The high integration level and the on-board signal processing allow excellent audio performances to be achieved, with a dynamic range of about 108 dB and a total harmonic distortion of about 0.03 %. Thanks to the digital signal input and a feedback strategy in the power stage that makes the amplifier robust with respect to the output filter non-idealities the number and size of the external components is minimized. A number of features were also included to reduce Electro Magnetic Interference (EMI), making the system compliant with the stringent limits typical of automotive applications. These characteristics altogether mitigate the drawbacks of Class-D amplifiers and favor its diffusion.