System-Level Power Optimization for a ΣΔ D/A Converter for Hearing-Aid Application

Peter Pracný, Ivan Harald Holger Jørgensen, Erik Bruun

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

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    Abstract

    This paper deals with a system-level optimization of a back-end of audio signal processing chain for hearing-aids, including a sigma-delta modulator digital-to-analog converter (DAC) and a Class D power amplifier. Compared to other stateof-the-art designs dealing with sigma-delta modulator design for audio applications we take the maximum gain of the modulator noise transfer function (NTF) as a design parameter. By increasing the maximum NTF gain the cutoff frequency of modulator loop filter is increased which lowers the in-band quantization noise but also lowers the maximum stable amplitude (MSA). This work presents an optimal compromise between these. Increased maximum NTF gain combined with a multi bit quantizer in the modulator allows lower oversampling ratio (OSR) and results in considerable power savings while the audio quality is kept unchanged. The proposed optimization impacts the entire hearing-aid audio back-end system resulting in less hardware and power consumption in the interpolation filter, in the sigma-delta modulator and reduced switching rate of the
    Class D output stage.
    Original languageEnglish
    Title of host publicationProceedings of the 9th Conference on Ph. D. Research in Microelectronics and Electronics
    PublisherIEEE
    Publication date2013
    Pages57-60
    ISBN (Print)978-1-4673-4580-4
    DOIs
    Publication statusPublished - 2013
    Event9th Conference on Ph. D. Research in Microelectronics and Electronics - Villach, Austria
    Duration: 24 Jun 201327 Jun 2013

    Conference

    Conference9th Conference on Ph. D. Research in Microelectronics and Electronics
    Country/TerritoryAustria
    CityVillach
    Period24/06/201327/06/2013

    Keywords

    • Sigma-Delta modulator
    • Interpolation filter
    • Class D
    • Hearing aid
    • Low voltage
    • Low power

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