A design of order-adjustable Σ∆ modulator for high performance micro-machined accelerometers

Sigma-delta modulation has been widely used in micro-machined accelerometers. Previous researches are mainly focused on increasing the order of the sigma-delta modulator for the mechanical sensor to improving the performance of the micro-machined accelerometers. These designs performed well in high resolution acceleration measurement, but they are insufficient in balancing the proof mass quickly while the micro-machined accelerometer is working. In this paper, the design of order-adjustable micro-machined accelerometer is proposed. It employs a mechanical sensor to balance the proof mass, and a fifth order MEMS accelerator to measure the acceleration with high resolution. Furthermore, this work shows an optimized design with a SQNR of 156.5 and 73.6 dB which can accurately measure the acceleration input and quickly balance the proof mass, respectively.