A ultra-low-power sensor signal processor for high-performance close-loop MEMS accelerometer

This paper presents an Micro-Controller Unit (MCU) based ultra-low-power sensor signal processor design for a close-loop capacitive Micro-Electro-Mechanical Systems (MEMS) accelerometer. The proposed sensor signal processor provides basic sensor micro-system control and advanced signal processing functions, including analogue front-end configuration, digital delta-sigma modulation and decimation filtering. The accelerator design of the digital delta-sigma modulator offers good flexibility and re-configurability to enable a close-loop MEMS accelerometer with a wide dynamic range of up to 109 dB and a low nonlinearity of 0.01% from the system-level simulation. By applying ultra-low-power techniques including clock gating, power gating and ultra-low-voltage operation, a power reduction by two orders of magnitude is achieved as compared to original design in 0.18-μm CMOS technology. Simulation result shows that the digital sensor signal processing core only consumes 25.3 μW at 0.6 V in ultra low power mode.