Patent US3836796A successfully refreshed from Google Patents.
US3836796A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor pressure transducer employing novel temperature compensation means
Assignee: National Semiconductor Corp
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Filing: 1973-09-24
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Granted: 1974-09-17
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Expires: 1993-09-24
Abstract
Abstract A semiconductor pressure transducer having a cavity with one thin wall diaphragm on which a piezoresistive bridge is formed of four resistors diffused into the thin wall semiconductor diaphragm and coupled together as a Wheatstone bridge, a voltage regulator including a zener diode coupled to the bridge, and a pair of nVBE circuits coupled to the bridge and the regulator circuit for temperature compensation of the bridge and regulators over the operating temperature range, each of said nVBE circuits comprising a transistor and two associated resistors connected so as to provide an irrational number of VBE voltage drops for temperature compensation.
Inventors
- 👤 J Solomon
- 👤 A Zias
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:43
CPC Classifications
G; G01; G01L; G01L1/00; G01L1/20; G01L1/22; G01L1/2268; G01L1/2281; G01L19/00; G01L19/14; G01L19/148; G01L9/00; G01L9/0041; G01L9/0051; G01L9/0052; G01L9/0054; G01L9/02; G01L9/06; G01L9/065
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
357 words
A semiconductor pressure transducer apparatus comprising a semiconductor body comprising a substrage and a surface layer of a material of a first conductivity type, said body having a cavity region formed therein, said cavity region including a thin wall section formed by a section of said surface layer, said thin wall section being flexible responsive to pressure exerted across said thin wall section, an electrical bridge circuit formed in said thin wall section of said surface layer and comprising four resistor arms, two opposed nodes of said bridge forming a bridge input, the two other opposed nodes of said bridge forming a bridge output, each of said bridge resistors being formed by a diffusion of a dopant of opposite conductivity type to that of the surface layer into said thin semiconducTor wall section, circuit means for applying a voltage to the input nodes of said bridge circuit, said circuit means including a common collector node formed by said layer of said semiconductor material of said first conductivity type, a zener diode formed in said surface layer comprising an emitter, a collector coupled to said common collector node, and a base coupled to one input node of said bridge. a temperature compensation circuit for said zener diode comprising a first transistor formed in said surface layer having an emitter coupled to the emitter of said zener diode, a base, and a collector coupled to said common collector node, and a pair of resistors coupled in series between said common collector node and the emitter of said first transistor, the junction node between said two resistors being coupled to the base of said first transistor, and a temperature compensation circuit coupled between another input node of said bridge and said common collector node comprising a second transistor formed in said surface layer having an emitter coupled to said other bridge input node, a collector coupled to said common collector node, and a base, and a pair of resistors coupled in series between said common collector node and the emitter of said second transistor, the junction node between said two resistors being coupled to the base of said second transistor.
Claim 2
Dependent Claim
357 words
A semiconductor pressure transducer apparatus comprising a semiconductor body comprising a substrage and a surface layer of a material of a first conductivity type, said body having a cavity region formed therein, said cavity region including a thin wall section formed by a section of said surface layer, said thin wall section being flexible responsive to pressure exerted across said thin wall section, an electrical bridge circuit formed in said thin wall section of said surface layer and comprising four resistor arms, two opposed nodes of said bridge forming a bridge input, the two other opposed nodes of said bridge forming a bridge output, each of said bridge resistors being formed by a diffusion of a dopant of opposite conductivity type to that of the surface layer into said thin semiconducTor wall section, circuit means for applying a voltage to the input nodes of said bridge circuit, said circuit means including a common collector node formed by said layer of said semiconductor material of said first conductivity type, a zener diode formed in said surface layer comprising an emitter, a collector coupled to said common collector node, and a base coupled to one input node of said bridge. a temperature compensation circuit for said zener diode comprising a first transistor formed in said surface layer having an emitter coupled to the emitter of said zener diode, a base, and a collector coupled to said common collector node, and a pair of resistors coupled in series between said common collector node and the emitter of said first transistor, the junction node between said two resistors being coupled to the base of said first transistor, and a temperature compensation circuit coupled between another input node of said bridge and said common collector node comprising a second transistor formed in said surface layer having an emitter coupled to said other bridge input node, a collector coupled to said common collector node, and a base, and a pair of resistors coupled in series between said common collector node and the emitter of said second transistor, the junction node between said two resistors being coupled to the base of said second transistor.
Claim 3
Dependent Claim
96 words
A semiconductor pressure transducer apparatus as claimed in claim 1 wherein the collectors of said zener diode and said first and second transistors are formed by the surface layer of said second conductivity on said substrate, the base regions of said zener diode and said first and second transistors are formed by diffusions of a material of said opposite conductivity type into said surface layer, and the emitters of said zener diode and said first and second transistors are formed by a diffusion of a material of said first conductivity type into the associated base regions.
Claim 4
Dependent Claim
86 words
A semiconductor pressure transducer apparatus as claimed in claim 2 including a ceramic plate on which said semiconductor body is mounted, said pair of resistors in said temperature compensation circuit for said zener diode being formed by the diffusion of regions of a material of said opposite conductivity type into said surface layer of said first conductivity type on said substrate, said pair of resistors on said temperature compensation circuit for said bridge circuit being formed by trimmable thick film resistor material on said ceramic plate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |