Design of a Low-Noise Signal Conditioning Circuit for Analog MEMS Accelerometers

Vibration analysis in electrical machines is a widely used practice for fault identification. The most used sensor for this application is the piezoelectric accelerometer. With the advances in technology, microelectromechanical system (MEMS) accelerometers are finding use in applications traditionally dominated by piezoelectric accelerometers. However, the improvement of technology and accuracy of the sensor is useless if the signal conditioning circuit is poorly dimensioned. This paper describes the design of a low-noise signal conditioning circuit for acquiring acceleration signal provided by a MEMS accelerometer. The circuit is basically composed of a gain block implemented with an operational amplifier and a 16-bit low-noise analog-to-digital converter (ADC). After sized, the circuit was validated in an electrical simulation environment. The achieved total noise at the input of the ADC was 3.29 µVRMS for the range of 10 kHz, which is adequate for vibration measurement application in electrical machines.