Capacitive+sensing

Capacitive+sensing - SEN2MET Capacitive sensing Capacitive...

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SEN2MET Capacitive sensing
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Capacitive sensing Compared to piezoresistive sensing capacitive sensing is getting Increasingly popular. Low power consumption Inherent low drift of performance Compatible with MOS IC fabrication But…. . Parasitic capacitances are relative large and must be controlled and/or minimized
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Capacitive sensing-diode quad sensing-1 Potential at point D inside brackets Potential at point C inside brackets Charge is transformed between point A and B Suppose that the final voltage at B is V p -V 0 /2 and the voltage at A is V p +V 0 /2 after many cycles of driving
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Capacitive sensing-diode quad sensing-2 To reduce error by normal force symmetric structure is used. Also improved linearity Factor 4 is missing More linear than original form Force is reduced
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Capacitive sensing-diode quad sensing-3 Diode voltage V F reduce efficiency and drift with temperature
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Capacitive sensing-opposite driving sensing-1 Problem here is that V i is not a linear function of C s .
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This note was uploaded on 05/30/2011 for the course SEN 2MET taught by Professor Ulrikhanke during the Spring '11 term at VCU.

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Capacitive+sensing - SEN2MET Capacitive sensing Capacitive...

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