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Thursday, October 28 • 9:00pm - Friday, December 3 • 6:00pm
Power Efficiency of Capacitive MEMS Speakers

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Recently introduced MEMS micro speakers target in-ear audio applications such as true wireless earbuds, hearables and hearing aids. A key requirement in these ultra-mobile applications is a high energy efficiency of the components. While wireless communication standards continue to improve and offer low power profiles, audio components remain at the same level in absolute terms, but the share of the total energy budget increases. MEMS speakers, seeking a competitive advantage in the micro speaker market, claim to be more efficient than voice coil speakers, whose efficiency is limited by resistive and magnetization losses. The most advanced approaches to MEMS speakers are based on capacitive transducer technology. Therefore, these speakers can be modeled - to a first approximation - as capacitors and therefore offer negligible resistive losses but introduce a high component of reactive power. This reactive power must be provided by an electronic circuit which has a limited efficiency. Thus, it is desirable to minimize the required reactive power by the transducer. In this contribution, we discuss some fundamental energetic relations that such electroacoustic transducers are subject to, and draw some implications for the requirements of a transducer that can operate at high efficiency.


Lutz Ehrig

Arioso Systems GmbH

Hermann Schenk

Arioso Systems GmbH

Jorge Mario Monsalve Guaracao

Fraunhofer Institute for Photonic Microsystems

Anton Melnikov

Fraunhofer Institute for Photonic Microsystems

Thursday October 28, 2021 9:00pm - Friday December 3, 2021 6:00pm EST