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Title:
CAPACITY TYPE ELECTROSTATIC SERVO ACCELERATION SENSOR
Document Type and Number:
Japanese Patent JP3216455
Kind Code:
B2
Abstract:

PURPOSE: To provide a capacity type electrostatic servo acceleration sensor that unnecessitates a highly accurate oscillator and can detect acceleration with high sensitivity and reduce an error.
CONSTITUTION: A PAM circuit 7 is adopted to perform a pulse amplitude modulation proportional to an acceleration G, and the product of the open gain and voltage feedback rate of an operational amplifier A3 constituting a comparator 5 is sufficiently made larger than one. The measurement mode period and dynamic balance mode period are repeated alternately. In the measurement mode period, a switch &phiv 9 is turned on, a switch &phiv 10 is turned off, a movable electrode 11 is not restricted by servo, a switch &phiv 11 is turned off, a switch &phiv 8 is turned on, and a detection voltage Vsc corresponding to the acceleration G is subject to sample-holding. In the dynamic balance mode period, a switch &phiv 9 is turned off, a switch &phiv 10 is turned on, a switch &phiv 11 is turned on while the electrode 11 is restricted by servo based on the detection voltage Vsc obtained by sample holding, and the electrode 11 is shortcircuited to circuit ground potential.


Inventors:
Tomio Shibano
Application Number:
JP32086094A
Publication Date:
October 09, 2001
Filing Date:
December 22, 1994
Export Citation:
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Assignee:
MURATA MANUFACTURING CO.,LTD.
International Classes:
G01P15/125; G01P15/13; G01R27/26; (IPC1-7): G01P15/13
Domestic Patent References:
JP6281669A
JP5340958A
JP5340960A
JP3501887A
Other References:
H.Leuthold et al.,”An ASIC for High−resolution Capacitive Microaccelerometers”,Sensors and Actuators,Netherlands,1990,Vol.21,No.1/3,p.278−281
Mark Van Paemel,”Interface Circuit for Capacitive Accelerometer”,Sensors and Actuators,Netherlands,1989,Vol.17,No.3/4,p.629−637
Attorney, Agent or Firm:
Shinshiro Arichika