Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Lumped type parameters
Reexamination Certificate
2006-07-18
2006-07-18
Nguyen, Vincent Q. (Department: 2858)
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Lumped type parameters
C324S684000, C324S686000
Reexamination Certificate
active
07078916
ABSTRACT:
A method for enhancing the linearity of a differential capacitive sensor as a function of beam displacement. An ac-modulated feedback connection from a sensor output terminal to a movable beam electrode is provided through a fix-up capacitor. The output terminal signal is inverted in the feedback connection so that the fix-up capacitor reduces the capacitance from the fixed electrodes to the beam electrode. When the fix-up capacitor value is chosen approximately equal to the fixed capacitance of the differential capacitor, the feedback circuit compensates for the effect of this fixed capacitance. The linearity of the output as a function of the displacement of the beam is improved. Thus, the signal-to-noise ratio of devices such as accelerometers may be increased by allowing sensors to employ a large displacement range. The invention may be used in differential accelerometers and in other types of differential capacitive sensors.
REFERENCES:
patent: 4683754 (1987-08-01), Hirata et al.
patent: 5194819 (1993-03-01), Briefer
patent: 5343766 (1994-09-01), Lee
patent: 5454266 (1995-10-01), Chevroulet et al.
patent: 5612494 (1997-03-01), Shibano
patent: 6257061 (2001-07-01), Nonoyama et al.
patent: 6530235 (2003-03-01), Hallocke et al.
patent: 2706038 (1993-06-01), None
Joseph I. Seeger et al, Jun. 8, 2003, Negative Capacitance for Control of Gap-Closing Electrostatic Actuators.
Yuming Cao et al, Sep. 1994, “High-Accuracy Circuits for On-Chip Capacitance Ratio Testing or Sensor Readout”, IEEE Transactions on Circuits and Systems—II: Analog and Digital, Signal Processing, vol. 41, No. 9.
Yuming Cao et al., 1995, “CMOS Circuits for On-Chip Capacitance Ratio testing or Sensor Readout”, IEEE.
H. Leuthold et al., 1990, “An ASIC for High-resolution Capacitive Microaccelerometers,”, A21-A23 (1990) 278-281.
Jun. 22, 2005, International Search Report.
Analog Devices Inc.
Bromberg & Sunstein LLP
Teresinski John
LandOfFree
Linearity enhancement for capacitive sensors does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Linearity enhancement for capacitive sensors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Linearity enhancement for capacitive sensors will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3603994