A new topology for a sigma-delta audio power amplifier

An inverter topology based on high frequency power conversion and sigma-delta modulation is proposed. Sigma-delta technique is particularly an attractive idea in audio power amplifying area. Analysis of this technique is presented. Power modulation is a way to obtain power amplifiers with better efficiency than conventional linear power amplifiers. A quasi-resonant converter with sigma-delta modulation input has been integrated to reduce switching losses, allowing high frequency operation. Audio power amplifier and isolated high power supply are integrated in one unit and analyzed. Simulations are performed to backup the analysis.

1. INTRODUCTION

In the high fidelity audio power amplification field, class-D is currently adopted. Efficiency is the great advantage of this class. Amplification method is totally different than any other classes (class A, AB, …). In the figure Fig. 1, a general scheme of a Class D amplifier is showed.