Title :
Digital cancellation of noise and offset for capacitive sensors
Author :
Kung, Josep T. ; Mills, N. ; Seung Lee, Hae
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., MIT, Cambridge, MA, USA
fDate :
10/1/1993 12:00:00 AM
Abstract :
A digital noise and offset cancellation technique for use with charge-redistribution capacitance sense techniques is presented. It is insensitive to parasitic capacitances, and can cancel the effects of offsets, low-frequency noise sources, and sampled kT/C noise of the MOS switch used in the topology. It represents a significant improvement in capacitance resolution than previous methods. It is currently being used in the readout circuits of experimental pressure sensor chips containing 100 fF air-gap capacitors with a resolution in the 30 aF range at a sampling speed of 11 kHz
Keywords :
capacitance measurement; electric sensing devices; interference suppression; random noise; semiconductor device noise; 100 fF; 11 kHz; MOS switch; air-gap capacitors; capacitive sensors; charge-redistribution capacitance sense techniques; digital noise cancellation; error correction; low-frequency noise sources; offset cancellation; pressure sensor chips; readout circuits; sampled kT/C noise; Air gaps; Capacitive sensors; Circuit noise; Circuit topology; Low-frequency noise; MOS capacitors; Noise cancellation; Parasitic capacitance; Switched capacitor circuits; Switches;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
