A 10-mW two-channel fully integrated system-on-chip foreddy-current position sensing [in biomedical devices]

摘要

The use of magnetic bearings in small biomedical devices poses newnchallenges for the integration of complex embedded electronic systems.nThis paper describes a low-power fully integrated two-channelnsystem-on-a-chip (SOC) for two-dimensional (2-D) differential positionnsensing in magnetic bearings through two pairs of eddy current sensors.nIt consists of a 312.5 kHz switched-capacitor (SC) sine-wave generator,na two-channel data acquisition unit including a 19-dB quadruplendifference instrumentation amplifier, and a demodulating 12-bitnΣΔ analog-to-digital (A/D) converter with DSP-compatiblenserial interface. A signal-to-noise-plus-distortion ratio (SNDR) of morenthan 60 dB has been achieved, which corresponds to a resolution ofnbetter than 3 Μm at a maximum displacement range of 3 mm. The entirensystem has been integrated in a standard 0.6-Μm CMOS technology andnconsumes 10 mW at a 2.7-V supply