A high efficiency and wide bandwidth class D switching audio power amplifier with improved output stage and current mode control

Abstract

The pulse width modulated class D power amplifier has the highest efficiency among the various class amplifiers. To obtain high efficiency and wide bandwidth at class D amplifier, there are two important points to be considered most carefully. They are the output driver and the feedback control scheme. Composite oscillation conditions of output driver are studied in detail and a new drive circuit is suggested in this paper. A detailed design procedure of the current mode control is also shown to improve the performances. The new-design class D amplifier provides wide full-power bandwidth and high efficiency with good stability.