A new class-D stereo audio amplifier using direct speaker current control

Abstract

This work presents a new class-D stereo audio amplifier using three-phase full bridge circuit configuration, which is controlled by a new switching method for the current control. In the proposed switching method, the switching device of upper arm or lower arm of the bridge circuit independently acts according to the polarity of the reference current without dead time, which is inserted to prevent the arm short. Therefore, the proposed switching method is very useful for high frequency switching. Also three-phase full bridge circuit is proposed as a main circuit for the class-D stereo amplifier. The proposed circuit can reduce two switching devices compared with the conventional stereo amplifier uses two full bridge circuits. In this paper, the specified strategy for driving stereo amplifier with three-phase full bridge circuit is discussed. With the experimental results, usefulness of the proposed amplifier is confirmed.