System-Level Power Optimization of Digital Audio Back End for Hearing Aids.

This work deals with power optimization of the audio processing back end for hearing aids-the interpolation filter, the sigma-delta ( $$\Sigma \Delta )$$ modulator and the Class D power amplifier (PA) as a whole. Specifications are derived, and insight into the trade-offs involved is used to optimize the interpolation filter and the $$\Sigma \Delta $$ modulator on the system level so that the switching frequency of the Class D PA-the main power consumer in the back end-is minimized. A figure-of-merit which allows judging the power consumption of the digital part of the back end early in the design process is used to track the hardware and power demands as the trade-offs of the system-level parameters are investigated. The result is the digital part of the back end optimized with respect to power which provides audio performance comparable to state-of-the-art. A combination of system-level parameters leading to the lowest switching frequency of the Class D power amplifier reported in the literature for the $$\Sigma \Delta $$ modulator-based back end is derived using this approach. [ABSTRACT FROM AUTHOR]