A Comparative Study of Conditioning Architectures for Convective Accelerometers

In this paper, we compare three different conditioning and readout electronics for CMOS convective accelerometers. The work is based on both characterization results and high-level simulations. The three following architectures are evaluated: (i) a simple amplifier, (ii) a chopper stabilized amplifier, and (iii) an innovative 1st-order thermal sigma-delta modulator. Experimental data are obtained using the hybrid combination of a 0.8 mum CMOS integrated sensor and discrete electronics. Behavioral simulations were carried-out under Matlabreg/Simulinkreg using small-signal models. The sensor model includes performance-limiting thermal phenomena and 1/f noise contributions. Previous studies describing the modeling of thermal sigma-delta modulators do not address device noise modeling, since most of the time, the performance of those modulators are limited by quantization noise. In our case, we show that the performance is limited by both the noise in the devices and the quantization noise.