Source: http://www.google.com/patents/US4800759?dq=7,194,691
Timestamp: 2014-08-29 13:21:22
Document Index: 97373336

Matched Legal Cases: ['art 11', 'art 12', 'art 11', 'art 13', 'art 12', 'art 12', 'art 13']

Patent US4800759 - Semiconductor pressure converter - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsA semiconductor pressure converter wherein a drive voltage is applied to a power supply end of a shearing type gage formed at the strain generating part of a semiconductor diaphragm, and an output voltage appearing at the output end thereof is amplified with an amplifier. The zero point is adjusted by...http://www.google.com/patents/US4800759?utm_source=gb-gplus-sharePatent US4800759 - Semiconductor pressure converterAdvanced Patent SearchPublication numberUS4800759 APublication typeGrantApplication numberUS 07/091,219Publication dateJan 31, 1989Filing dateAug 31, 1987Priority dateAug 31, 1987Fee statusPaidPublication number07091219, 091219, US 4800759 A, US 4800759A, US-A-4800759, US4800759 A, US4800759AInventorsTerutaka Hirata, Tetsu Odohira, Tadashi NishikawaOriginal AssigneeYokogawa Electric CorporationExport CitationBiBTeX, EndNote, RefManPatent Citations (5), Referenced by (17), Classifications (6), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetSemiconductor pressure converterUS 4800759 AAbstract A semiconductor pressure converter wherein a drive voltage is applied to a power supply end of a shearing type gage formed at the strain generating part of a semiconductor diaphragm, and an output voltage appearing at the output end thereof is amplified with an amplifier. The zero point is adjusted by applying a bias voltage to the amplifier which is related to the drive voltage. The span is adjusted without interference to the zero point by changing the feedback voltage of the amplifier. Linear compensation, temperature zero point compensation and temperature span compensation are attained without any mutual interference.
DETAILED DESCRIPTION OF THE INVENTION Turning now to FIGS. 1(a), 1(b) and 1(c), a diaphragm 10 is formed by an n-type silicon single crystal which includes a recessed part 11. A strain generating part 12 is formed by a thin single crystal due to the formation of recessed part 11 and peripheral fixing part 13 and is fixed to a substrate 15 by an anode junction through a glass thin film 16. Strain generating part 12 is formed as a plane (100) and shearing gage 17 is formed thereon by diffusion of a p-type impurity in the vicinity of the boundary of strain generating part 12 and fixing part 13 in the direction of crystal axis <001> passing the center of plane (100). Moreover, an ordinary type gage 18, which changes resistance when a pressure P is applied, is also formed by diffusion of a p-type impurity in the strain generating part in the axial direction <011> which forms an angle of 45� to the axis <001>.
ZERO POINT ADJUSTMENT First, temperature signal Vt is adjusted to zero by adjusting variable resistors R15 and R16 at reference temperature to.
LINEAR COMPENSATION Thereafter, a pressure P is applied to diaphragm 10 for linear compensation and the relation between pressure P and corresponding output voltage Vs is obtained by changing pressure P.
SPAN ADJUSTMENT After linear compensation, span adjustment is carried out by applying the specified pressure P1 to the diaphragm 10. Variable resistor R12 is adjusted so that voltage Vo at output end 28 indicates 100% for the specified pressure P1. Thereafter, an output voltage fof amplifier Q2 is zero even when specified pressure P1 is set to zero, giving no influence on the zero point. Moreover, no effect is applied to the linearity adjusting result.
TEMPERATURE ZERO POINT ADJUSTMENT AT CHANGED TEMPERATURE Next, adjustment of the zero point at a changed or specified temperature is explained. First, temperature is changed to the specified value t1, for example, 80� C., from reference temperature to, under the condition that the applied pressure P is zero. In this case, an output voltage Vs changes because gage 17 has a temperature coefficient.
TEMPERATURE SPAN ADJUSTMENT AT CHANGED TEMPERATURE Next, pressure P is set to the specified pressure P1 from zero at the specified temperature t1. In this case, since gage 17 has a temperature characteristic, an output voltage is different from that in the reference temperature to.
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