Low-power front-end of eddy current sensor interfaces for industrial applications

This paper presents a high-performance electronic interface for eddy current displacement sensors (ECSs). The interface includes a low-power front-end oscillator specifically designed for high-stability performance. The demodulation principle used to detect the input signal (i.e., displacement information) is explained. A switched-channel technique is utilized to suppress the effect of the offset. Post-layout simulations along with primary experimental results confirm the effectiveness of the design approach as well as the validity of the theoretical analyses. The interface system dissipates 9.5 mW and demonstrates a dynamic range of about 75 dB with a 240 ¿s measurement time and with less than 20 ppm/°C thermal drift over the range of 0-85°C.