A simple and ultra-low power capacitive pressure micro-sensor sensing system design

The aim of this paper is design and fabrication of a novel fully integrated capacitive pressure sensor that can be detected pressure for airtight structure of industrial and biomedical application. This paper also presents the characterization of the sensing signal processing system with readout sensing circuits. The pressure sensor has 42 sensing cells array, each Cs (sensor capacitance) is connects by 14 parallel sensing cells. The HSPICE is used to evaluate the characteristics of the circuits, and the CoventorWare is utilized to simulate the behaviors of the pressure sensor. The TSMC 0.35 mum 2P4M CMOS process is employed for sensor fabrication. The circuit has a pre-simulated initial frequency at 301.5 MHz under no applied force. When under the pressure, the total frequency shift is 179.6 MHz with a corresponding mechanical displacement of 2.64 mum and the Cs change to 448.14 fF. The entire chip power dissipation is about 3.2 mW.