Design of a MEMS speaker driver

Hänsler, Markus; Strle, Drago; Auer, Mario

doi:10.1007/s00502-018-0593-8

Cited by 6 publications

(3 citation statements)

References 9 publications

(9 reference statements)

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“…The challenge is to maintain the advantages of the concept regarding ultra-low power consumption. Recently, Hänsler et al have published work on capacitive loads and highly efficient driving circuitry 23 . They describe several amplifier classes as well as an approach to regain energy from reactive power.…”

Section: Discussionmentioning

confidence: 99%

Concept and proof for an all-silicon MEMS micro speaker utilizing air chambers

et al. 2019

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MEMS-based micro speakers are attractive candidates as sound transducers for smart devices, particularly wearables and hearables. For such devices, high sound pressure levels, low harmonic distortion and low power consumption are required for industrial, consumer and medical applications. The ability to integrate with microelectronic circuitry, as well as scalable batch production to enable low unit costs, are the key factors benchmarking a technology. The Nanoscopic Electrostatic Drive based, novel micro speaker concept presented in this work essentially comprises in-plane, electrostatic bending actuators, and uses the chip volume rather than the its surface for sound generation. We describe the principle, design, fabrication, and first characterization results. Various design options and governing equations are given and discussed. In a standard acoustical test setup (ear simulator), a MEMS micro speaker generated a sound pressure level of 69 dB at 500 Hz with a total harmonic distortion of 4.4%, thus proving the concept. Further potential on sound pressure as well as linearity improvement is outlined. We expect that the described methods can be used to enhance and design other MEMS devices and foster modeling and simulation approaches.

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Section: Discussionmentioning

confidence: 99%

Concept and proof for an all-silicon MEMS micro speaker utilizing air chambers

et al. 2019

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“…The piezoelectric modulus is proportional to the state of polarization of the material. Therefore, a non-constant polarization will lead to non-constant electro-mechanical coupling [9]. However, this distortion can be taken care of by designing an equalization circuit at the signal input stage of the speaker.…”

Section: Performancementioning

confidence: 99%

“…Application of DC offset can avoid the polarization switch. As a result, the driving circuit for a piezoelectric speaker must provide the desired audio signal in conjunction with a DC offset [9]. Electrostatic speakers also need a DC offset for stabilizing the diaphragm position, improving linearity, increasing sensitivity, and preventing charge accumulation.…”

Section: Micro-speaker Electrical Circuitrymentioning

confidence: 99%

MEMS audio speakers ^*

Garud,

Pratap

2023

J. Micromech. Microeng.

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Miniaturization of electro-mechanical sensors and actuators has benefited from an advancement in CMOS technology over the years. However, miniaturization of audio speakers has seen considerable development only in the recent times. This paper reviews the developments in MEMS audio speaker research and the initial commercial products available in the market. At first glance, it appears that the relatively slow development of MEMS speakers can be attributed to the fact that the principle of actuation has remained unchanged for several decades. Unfortunately, the physics behind audible sound production holds us back from exclusively adopting miniaturized speakers — sound pressure level is directly proportional to the area of the sound radiating surface. Nevertheless, researchers are continuing to explore new avenues for designing and developing MEMS speakers, without limiting themselves to the existing actuation principles. With newly discovered materials and improving technology, the research in MEMS speakers is gaining attention and new products are emerging. A speaker design based on piezoelectric actuation or electrostatics actuation is favourable at MEMS scale. Indian research community is also contributing to advances in MEMS speakers and near-ultrasonic devices. This paper reviews the development in MEMS audio speakers in India and in the world. The tabulated review findings aim to offer readers an overview of the development of micro-speakers and to provide guidance for designing new micro-speakers.

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Investigation of a new method for sound generation – Advanced Digital Sound Reconstruction

Mayrhofer¹

2021

Elektrotech. Inftech.

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The current loudspeaker market has a high demand for portable audio devices. Hence, the miniaturization of loudspeakers (microspeakers) is of great importance for manufacturers. Traditional loudspeakers – for example the electrodynamic loudspeaker – are the forerunners, but so-called MEMS loudspeakers (Micro-Electro-Mechanical-System) have emerged recently. MEMS devices have already been used for sensors (i.e., microphones) to a great extend due to their advantages regarding form factor and production efficiency. Albeit additional challenges for actuators like moving enough air with a microstructure – as it is the case for a loudspeaker – the usage of MEMS technology for loudspeakers is very attractive.Since especially low-frequency audio signals often pose problems for microspeakers, this article focuses on a new sound generation technique called Advanced Digital Sound Reconstruction (ADSR) which is especially well-suited for low-frequency audio signals since ADSR can generate more volume displacement relative to its size. Based on a general description of the principle, an outlook of the possibilities regarding achievable sound pressure compared to the classical excitation scheme is derived. Furthermore, measurements are presented, which aim to prove the concept of ADSR based on already existing actuators.

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Design of a MEMS speaker driver

Cited by 6 publications

References 9 publications

Concept and proof for an all-silicon MEMS micro speaker utilizing air chambers

Concept and proof for an all-silicon MEMS micro speaker utilizing air chambers

MEMS audio speakers ^*

Investigation of a new method for sound generation – Advanced Digital Sound Reconstruction

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Design of a MEMS speaker driver

Cited by 6 publications

References 9 publications

Concept and proof for an all-silicon MEMS micro speaker utilizing air chambers

Concept and proof for an all-silicon MEMS micro speaker utilizing air chambers

MEMS audio speakers *

Investigation of a new method for sound generation – Advanced Digital Sound Reconstruction

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Product

Resources

About

MEMS audio speakers ^*