This paper presents a low power analog front-end circuit for a 3-axis MEMS capacitive accelerometer. The circuit includes an analog preamplifier to sense the signal coming from the sensor and a successive-approximation A/D converter. Power minimization is achieved by using a continuous-time preamplifier for realizing constant-charge capacitance-to-voltage conversion and a SAR A/D converter with split capacitive array. To cope with potentially large sensor leakage current we used a specific sensor biasing technique, that guarantees ac coupling above 0.1 Hz. The complete analog front-end circuit consumes 90 μW from a single 1.2-V power supply voltage, achieving 65.1 dB of SNR over a 4-kHz bandwidth and − 43. 4 dB of THD.
Malcovati, P., De Matteis, M., Pezzotta, A., Grassi, M., Croce, M., Sabatini, M., et al. (2016). A low-power continuous-time accelerometer front-end. In Wideband Continuous-time Sigma-Delta ADCs, Automotive Electronics, and Power Management: Advances in Analog Circuit Design 2016 (pp. 215-235). Springer International Publishing [10.1007/978-3-319-41670-0_12].
A low-power continuous-time accelerometer front-end
De Matteis, M;Pezzotta, A;Baschirotto, A
2016
Abstract
This paper presents a low power analog front-end circuit for a 3-axis MEMS capacitive accelerometer. The circuit includes an analog preamplifier to sense the signal coming from the sensor and a successive-approximation A/D converter. Power minimization is achieved by using a continuous-time preamplifier for realizing constant-charge capacitance-to-voltage conversion and a SAR A/D converter with split capacitive array. To cope with potentially large sensor leakage current we used a specific sensor biasing technique, that guarantees ac coupling above 0.1 Hz. The complete analog front-end circuit consumes 90 μW from a single 1.2-V power supply voltage, achieving 65.1 dB of SNR over a 4-kHz bandwidth and − 43. 4 dB of THD.
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