Method and apparatus for the determination of absolute pressure and differential pressure therefrom
First Claim
1. A pressure measuring device comprising:
- a first pressure transducer adapted to measure a first pressure and including a first plurality of piezoresistive devices;
a second pressure transducer adapted to measure a second pressure and including a second plurality of piezoresistive devices; and
, means for selectively coupling;
a first set of said first plurality of piezoresistive devices to a first set of said second plurality of piezoresistive devices to measure a difference between said first and second pressures; and
, said first set of said first plurality of piezoresistive devices to a second set of said second plurality of piezoresistive devices to measure a sum of said first and second pressures.
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Accused Products
Abstract
A combination absolute and differential pressure sensing device including a plurality of absolute pressure transducers, each transducer including a plurality of half bridge piezoresistive structures and a device for selectively coupling at least one of the plurality of half bridge piezoresistive structures of a first one of the absolute pressure transducers to at least one resistor to form a half-active full bridge structure adapted to measure an absolute pressure and at least one other of the plurality of half bridge piezoresistive structures of the first one of the plurality of absolute pressure transducers to at least one of the half bridge piezoresistive structure of a second one of the plurality of absolute pressure transducers to form a full bridge structure adapted to measure a differential pressure.
52 Citations
20 Claims
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1. A pressure measuring device comprising:
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a first pressure transducer adapted to measure a first pressure and including a first plurality of piezoresistive devices;
a second pressure transducer adapted to measure a second pressure and including a second plurality of piezoresistive devices; and
,means for selectively coupling;
a first set of said first plurality of piezoresistive devices to a first set of said second plurality of piezoresistive devices to measure a difference between said first and second pressures; and
,said first set of said first plurality of piezoresistive devices to a second set of said second plurality of piezoresistive devices to measure a sum of said first and second pressures. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
said first set of said first plurality of piezoresistive devices to said resistive structure to measure said first pressure; and
,said first set of said second plurality of piezoresistive devices to said at least one resistive structure to measure said second pressure.
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5. The device of claim 1, wherein said first and second pressure transducers are absolute pressure transducers.
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6. The device of claim 5, wherein said first plurality and said second plurality of piezoresistive devices are each respectively configured in two uncoupled half-bridges.
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7. The device of claim 6, wherein each of said half bridge piezoresistive structures comprises two piezoresistors.
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8. The device of claim 4, wherein said resistive structure comprises two resistors coupled in a half-bridge configuration.
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9. The device of claim 8, wherein each of said two resistors has a substantially identical predetermined percentage change of resistance for the same pressure.
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10. A method for measuring pressures comprising the steps of:
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providing a first pressure transducer adapted to measure a first pressure and including a first plurality of piezoresistive devices;
providing a second pressure transducer adapted to measure a second pressure and including a second plurality of piezoresistive devices;
selectively coupling a first set of said first plurality of piezoresistive devices to a first set of said second plurality of piezoresistive devices to measure a difference between said first and second pressures; and
,selectively coupling said first set of said first plurality of piezoresistive devices to a resistive structure to measure said first pressure or said first set of said second plurality of piezoresistive devices to said resistive structure to measure said second pressure. - View Dependent Claims (11, 12)
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13. A combination absolute and differential pressure sensing device comprising:
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a plurality of absolute pressure transducers each respectively comprising a plurality of half bride piezoresistive structures;
at least one resistor; and
a switching device for selectively coupling at least one of said plurality of half bridge piezoresistive structures of a first one of said absolute pressure transducers to said at least one resistor to form a half-active full bridge structure adapted to measure a first absolute pressure; and
said at least one half bridge piezoresistive structures of said first one of said plurality of absolute pressure transducers to at least one of said half bridge piezoresistive structures of a second one of said plurality of absolute pressure transducers to form a full bridge structure adapted to measure a differential pressure.- View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification