Abstract
A digital platform for fast assessment and testing of multiple order architectures of electromechanical Sigma-Delta modulators for MEMS capacitive accelerometers is introduced in this paper. It is well known that the introduction of a negative feedback loop on sensors presents significant advantages to improve important characteristics, such as precision, linearity, speed, and dynamic range over open-loop operation (Borovic et al. in J Micromech Microeng 15(10):1917–1924, 2005; Chen et al. in IEEE Sens J 16(17):6476–6495, 2016). In a closed-loop system, the controller is responsible for the aforementioned improvements, enabling the relaxation on the manufactured device specifications. Consequently, it demands better and more complex electronic circuits for the controller. A configurable multi-order (2nd, 3rd, 4th and 5th) ΣΔ module was developed in field-programmable gate array, along with the necessary signal acquisition and actuation modules, using a processor-centric approach, ensuring real-time performance, simple reconfiguration, and fast assessment of different orders and gains for the ΣΔ modulator with real MEMS devices. The system is capable of a measuring cycle lower than 100 ms. The platform was used to perform a comparison between two different types of MEMS accelerometers, evaluating the results obtained with second, third, fourth and fifth modulation orders for two bandwidth values—200 and 1000 Hz. The best noise figure achieved was 4.4 µg/√Hz, using a fifth order ΣΔ modulator and the device with the larger seismic mass. A comparison between three similar devices is also performed, as well as a comparison between simulated and experimental results.
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References
Borovic B, Liu AQ, Popa D, Cai H, Lewis FL (2005) Open-loop versus closed-loop control of MEMS devices: choices and issues. J Micromech Microeng 15(10):1917–1924. https://doi.org/10.1088/0960-1317/15/10/018
Brito N, Ferreira C, Alves F, Cabral J, Gaspar J, Monteiro J, Rocha L (2016) Digital platform for wafer-level MEMS testing and characterization using electrical response. Sensors (Switzerland). https://doi.org/10.3390/s16091553
Chen F, Li X, Kraft M (2016) Electromechanical Sigma-Delta modulators (ΣΔM) force feedback interfaces for capacitive MEMS inertial sensors: a review. IEEE Sens J 16(17):6476–6495. https://doi.org/10.1109/JSEN.2016.2582198
Cifuentes A, Marín E (2015) Implementation of a field programmable gate array-based lock-in amplifier. Measurement (Elsevier Ltd) 69:31–41. https://doi.org/10.1016/j.measurement.2015.02.037
Dong Y, Kraft M, Gollasch C, Redman-White W (2005) A high-performance accelerometer with a fifth-order Sigma-Delta modulator. J Micromech Microeng 15:22–29. https://doi.org/10.1088/0960-1317/15/7/004
Dong Y, Kraft M, Redman-White W (2007) Higher order noise-shaping filters for high-performance micromachined accelerometers. IEEE Trans Instrum Meas 56(5):1666–1674. https://doi.org/10.1109/TIM.2007.904477
Dong Y, Zwahlen P, Nguyen AM, Frosio R, Rudolf F (2011) Ultra-high precision MEMS accelerometer. In: 16th international solid-state sensors, actuators and microsystems conference. IEEE, pp 695–698. https://doi.org/10.1109/transducers.2011.5969218
Henrion W, DiSanza L, Ip M, Terry S, Jerman H (1990) Wide dynamic range direct digital accelerometer. In: IEEE 4th technical digest on solid-state sensor and actuator workshop. IEEE, pp 153–157. https://doi.org/10.1109/solsen.1990.109842
Hoover G, Brewer F, Sherwood T (2007) Towards understanding architectural tradeoffs in MEMS closed-loop feedback control. In: CASES’07: Proceedings of the 2007 international conference on compilers, architecture, and synthesis for embedded systems, pp 95–102. https://doi.org/10.1145/1289881.1289901
Inose H, Yasuda Y, Murakami J (1962) A telemetering system by code modulation—Δ–Σ modulation. In: IRE transactions on space electronics and telemetry, SET, vol 8, no 3, pp 204–209. https://doi.org/10.1109/iret-set.1962.5008839
Lima V, Brito N, Alves FS, Cabral J, Gaspar J, Rocha LA (2016) Performance comparison of Sigma-Delta modulator architectures for MEMS accelerometers using a fully-digital approach. Procedia Eng. https://doi.org/10.1016/j.proeng.2016.11.280
Peluso V, Marques AM, Steyaert M, Sansen W (1997) Optimal parameters for single loop ΔΣ modulators. IEEE Int Symp Circuits Syst 1:57–60. https://doi.org/10.1109/ISCAS.1997.608524
Petkov VP, Boser BE (2004) A fourth-order ΣΔ interface for micromachined inertial sensors. In: 2004 IEEE international solid-state circuits conference. IEEE, pp 320–321. https://doi.org/10.1109/isscc.2004.1332723
Wilcock R, Kraft M (2011) Genetic algorithm for the design of electro-mechanical sigma delta modulator MEMS sensors. Sensors 11(12):9217–9232. https://doi.org/10.3390/s111009217
Acknowledgements
The first and second authors are supported by FCT–Fundação para a Ciência e Tecnologia through the Grants PDE/BDE/114563/2016 and SFRH/BD/91806/2012 respectively.
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Lima, V., Brito, N., Cabral, J. et al. Digital platform for Sigma-Delta accelerometer assessment and test. Microsyst Technol 24, 2265–2276 (2018). https://doi.org/10.1007/s00542-018-3736-2
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DOI: https://doi.org/10.1007/s00542-018-3736-2