Pressure sensor with differential capacitive output
First Claim
1. A micro-electromechanical system (MEMS) pressure sensor comprising:
- a rotating proof mass, wherein the rotating proof mass comprisesa moveable element adapted for motion relative to a rotational axis offset between first and second ends thereof to form a first section between the rotational axis and the first end and a second section between the rotational axis and the second end,the first section comprising an extended portion spaced away from the rotational axis, andthe second section comprising an extended portion spaced away from the rotational axis at a length approximately equal to a length of the extended portion of the first section, such that the rotational axis is at a center of mass of the moveable element;
a diaphragm configured to deform in response to a first fluid pressure external to a package comprising the diaphragm and the rotating proof mass; and
a linkage configured to couple a surface of the diaphragm internal to the package to a point along the first section of the rotating proof mass, whereinthe rotating proof mass is configured to rotate in response to deformation of the diaphragm.
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Accused Products
Abstract
A MEMS pressure sensor device is provided that can provide both a linear output with regard to external pressure, and a differential capacitance output so as to improve the signal amplitude level. These benefits are provided through use of a rotating proof mass that generates capacitive output from electrodes configured at both ends of the rotating proof mass. Sensor output can then be generated using a difference between the capacitances generated from the ends of the rotating proof mass. An additional benefit of such a configuration is that the differential capacitance output changes in a more linear fashion with respect to external pressure changes than does a capacitive output from traditional MEMS pressure sensors.
23 Citations
14 Claims
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1. A micro-electromechanical system (MEMS) pressure sensor comprising:
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a rotating proof mass, wherein the rotating proof mass comprises a moveable element adapted for motion relative to a rotational axis offset between first and second ends thereof to form a first section between the rotational axis and the first end and a second section between the rotational axis and the second end, the first section comprising an extended portion spaced away from the rotational axis, and the second section comprising an extended portion spaced away from the rotational axis at a length approximately equal to a length of the extended portion of the first section, such that the rotational axis is at a center of mass of the moveable element; a diaphragm configured to deform in response to a first fluid pressure external to a package comprising the diaphragm and the rotating proof mass; and a linkage configured to couple a surface of the diaphragm internal to the package to a point along the first section of the rotating proof mass, wherein the rotating proof mass is configured to rotate in response to deformation of the diaphragm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A tire pressure monitoring system comprising:
a wheel module, configured to be mounted in a vehicle tire, comprising a process controller configured to process signals from one or more sensors, a micro-electromechanical system (MEMS) pressure sensor coupled to the process controller, the MEMS pressure sensor comprising a rotating proof mass, wherein the rotating proof mass comprises a moveable element adapted for motion relative to a rotational axis offset between first and second ends thereof to form a first section between the rotational axis and the first end and a second section between the rotational axis and the second end, the first section comprising an extended portion spaced away from the rotational axis, and the second section comprising an extended portion spaced away from the rotational axis at a length approximately equal to a length of the extended portion of the first section, such that the rotational axis is at a center of mass of the moveable element, a diaphragm configured to deform in response to a gas pressure of the vehicle tire, and a linkage configured to couple a surface of the diaphragm internal to the package to a point along the first section of the rotating proof mass, wherein the rotating proof mass is configured to rotate in response to deformation of the diaphragm, and a radio-frequency (RF) transmitter, coupled to the process controller, and configured to transmit sensor information provided by the process controller. - View Dependent Claims (13, 14)
Specification