Design Considerations of a Dual-Phase Interleaved Boost Converter in Class-H Audio Amplifier System

Inhalt:
Class-D audio amplifier is widely used in automotive audio amplifier system due to high efficiency and low distortion. A boost converter is utilized to supply a high voltage to the audio amplifier. However, with the fast growing of audio power, even higher efficiency is desired. Envelope tracking is introduced in class-H audio amplifier to improve the efficiency further. In this paper, the input and output character of the audio amplifier is analyzed. The output voltage margin and rated power of the boost converter is discussed. The design of the RC filter is studied. A 40V/1.2kW dual-phase interleaved boost converter is designed as an example. A Class-H audio system is built, key waveforms and test results are obtained to support the analysis.