Research on Low Power Sigma-Delta Interface Circuit used in Capacitive Micro-accelerometers

Abstract

Accelerometers have a wide range application in many fields, such as airbag deployment system and electronic stability control system in vehicles, and inertial navigation system in aircrafts and rockets. As Micro-Electro-Mechanical System (MEMS) technology advances, accelerometers are made smaller and smaller, often integrated in a single chip, with lower implementation costs and power consumptions. Modern MEMS accelerometers can be used in portable devices such as cell phones, RFID tags and even integrated in other sensors. This paper presents chip-level design and implementation of a second order sigma-delta interface circuit used in capacitive microaccelerometers. The interface circuit provides 1-bit data stream and operates at a sampling frequency of 2.5MHz. The system model considers non-ideal factors in the circuit such as nonlinear distortion and noises. These non-ideal factors have been discussed through system level simulation in MATLAB. The micro-accelerometer, which is a highly integrated MEMS device, is then designed and implemented in silicon-on-insulator (SOI) substrate. Finally, the chiplevel layout of interface circuit is implemented. Results have shown the chip with area of 1.32mm 2 and power consumption of about 5mW.

Voxel Primitive Based Modeling and Simulating Method for Surface Micromachining Technology

“…Usually, physical and geometrical parameters of micro device are considered in lower levels of the design flow [3]. There have been many efforts to focus on system level modeling and simulation that is concerned with the sector of function-to-shape [4,5]. Nevertheless, with respect to the overall design flow of micro device, the research in the stage of shape-to-mask is still insufficient, which is the key point to improve manufacturability [6].…”