A 22-dBA Digital Optical MEMS Microphone Milleri, Niccolo de; Valli, Luca; Fueldner, Marc ...
IEEE journal of solid-state circuits,
07/2024, Letnik:
59, Številka:
7
Journal Article
Recenzirano
The market and the applications of micro-electromechanical systems (MEMS)-based microphones have been in continuous growth over the last decades. This article presents a promising acoustic-sensing ...technology that mixes the consolidated MEMS technology with an innovative optical transduction technique of acoustic signals. The proposed method allows to significantly reduce the intrinsic noise of the system and to increase its signal-to-noise ratio (SNR). The designed digital optical microphone reaches an SNR of 71.6 dBA in a <inline-formula> <tex-math notation="LaTeX">5{\times } 5{\times } 2 </tex-math></inline-formula> mm3 package with an output sensitivity of -21 dBFS/Pa. This article describes each section of the system-in-package (SiP) microphone, starting from the physics behind the transduction mechanism, covering the application-specified integrated circuit (ASIC) and package design, and the optical stack structure. A final analysis of the obtained experimental results is provided and compared with the state-of-art reported in the literature.
A 22dBA digital optical MEMS microphone Milleri, Niccolo de; Wiesbauer, Andreas; Baschirotto, Andrea
ESSCIRC 2023- IEEE 49th European Solid State Circuits Conference (ESSCIRC),
2023-Sept.-11
Conference Proceeding
Optical microphones represent a promising alternative to the conventional capacitive MEMS microphones, especially when aiming at ultra-low noise applications. This paper reports the design and ...development of a SiP (System-in-Package) digital optical microphone with 71.6dBA SNR in 5×5×2mm 3 package with output sensitivity of -21dBFS/Pa. The system concept is introduced, the design and modeling of the main blocks are presented and the measured results are analyzed.
This article focuses on a proposed Switched-Capacitor Dual-Slope based CDC. Special attention is paid to the measurement setup using a real pressure sensor. Performance scaling potential as well as ...dead zones are pointed out and discussed. In depth knowledge of the physical sensor behavior is key to design an optimal readout circuit. While this is true for high-end applications, low-performance IoT (Internet of Things) sensors aim at moderate resolution with very low power consumption. This article also provides insights into basic MEMS (Micro-Electro-Mechanical-System) physics. Based on that, an ambient air pressure sensor model for SPICE (Simulation-Program-with-Integrated-Circuit-Emphasis) circuit simulators is presented. The converter concept was proven on silicon in a 0.13 μ m process using both a real pressure sensor and an on-chip dummy MEMS bridge. A 3.2-ms measurement results in 13-bit resolution while consuming 35 μ A from a 1.5-V supply occupying 0.148 mm
. A state-of-the-art comparison identifies potential room for improvements towards hybrid solutions, which is proposed in subsequent publications already.
Acoustic sensing through optical transduction represents a promising alternative to the conventional capacitive sensing used in MEMS microphones, especially when aiming at ultra-low noise ...applications. In fact, the traditional acoustic to electrical transduction stages are decoupled by the intermediate conversion of the signal into the optical domain. As a result, the mechanical design of the sensor has no direct influence on the electrical readout performance, this allows for a significant reduction of the MEMS transducer noise through aggressive acoustically semi-transparent stator designs, that represent one of the limits of the standard capacitive technologies. This paper reports the design and the modeling of the sensing elements of a MEMS optical microphone. The basic transduction mechanism is presented and the main design parameters and challenges are explained and analyzed with advanced modeling techniques, the measurement results are finally compared to the expected performance.
MEMS optical microphone based on light phase modulation De Milleri, Niccolo; Onaran, Guclu; Wiesbauer, Andreas ...
ESSDERC 2022 - IEEE 52nd European Solid-State Device Research Conference (ESSDERC),
2022-Sept.-19
Conference Proceeding
Acoustic sensing through optical transduction represents a promising alternative to the conventional capacitive sensing used in MEMS microphones, especially when aiming at ultra-low noise (i.e. high ...DR) applications. This paper reports the design and the modeling of the sensing elements of a MEMS optical microphone. The basic transduction mechanism is presented and the main design parameters and challenges are explained and analyzed with advanced modeling techniques.
MEMS microphones are usually DC biased with a voltage exceeding 10V and a large resistance, requiring a charge pump and a high-ohmic link between the ASIC and the MEMS. This DC biasing is needed to ...obtain enough sensitivity for medium to high quality microphones. This manuscript inves-tigates capacitance-controlled oscillators which allow to directly connect the MEMS sensor to the oscillator; this solution is prone to scaling. A new type of configuration (referred to as Cross-Connected Sensor) is presented and discussed. Its main advantage is the increase in the sensitivity and, when integrated in an ADC architecture, in the achievable SNR. The proposed solution is intended for Human-Machine Interface applications given their moderate SNR requirements.
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