Dynamic power efficiency improvement for PWM class-D amplifier

This paper presents the technique to dynamically enhance the power efficiency of PWM class-D amplifier over a wide range of modulation indexes. The power stage of amplifier is segmented into several small stages and selectively enabled according to the power demand (i.e. modulation indexes). The capability of power delivery is dynamically adjusted to minimize the power loss in case of different modulation indexes improving the power efficiency, especially for small modulation index. The simulation results show that the amplifier remains high power efficiency over a wide range of modulation indexes. The maximum improvement on power efficiency is over 27% for the case of small modulation index. Moreover, for the region of power efficiency greater than 80%, the improvement is 13.5% than that of conventional design.