US 5,477,471 AGranted

Method of compensating for power supply variation in a sensor output

AssigneeMotorola, Inc.

InventorsJeffery I. Baum, William L. Lucas

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Abstract

A method compensates for power supply voltage variation in a sensor output. The sensor output voltage is calibrated by obtaining the sensor outputs for full-scale and minimum offset sensor input signals at two power supply settings. Linear plots are formed from the full-scale and offset sensor output voltages. The sensor input for each sensor output reading is computed by obtaining the power supply voltage at the time of the sensor output voltage reading. The full-scale and offset output voltages for that power supply voltage are computed from the slopes of the linear plots. Finally, the ratio of the difference between the output voltage and offset output voltage divided by the difference between the full-scale and offset output voltages is computed to provide the compensation factor. The product of the computed ratio and the value of the full-scale sensor input is the compensated sensor input value.

Claims12

Dependent claims

A computer implemented method of compensating for power supply variation in a sensor output, comprising the steps of:

providing a range of offset signals between minimum and maximum supply voltages where said offset signals represent a first state of a physical condition over said minimum and maximum supply voltages;
providing a range of full-scale signals between said minimum and maximum supply voltages where said full-scale signals represent a second state of said physical condition over said minimum and maximum supply voltages;
sensing a sensor output signal from the sensor output operating at a first supply voltage between said minimum and maximum supply voltages in response to a third state of said physical condition between said first and second states of said physical condition;
selecting a first offset signal at said first supply voltage from said range of offset signals;
selecting a first full-scale signal at said first supply voltage from said range of full-scale signals;
and
compensating for the power supply variation in said sensor output signal by normalizing said sensor output signal less said first offset signal by said first full-scale signal less said first offset signal where said normalizing transforms said sensor output signal into a sensor signal that operates independent of the power supply.

4 more elements

A computer implemented method of compensating for power supply variation in a sensor output, comprising the steps of:

establishing a range of offset signals between said minimum and maximum supply voltages based on a minimum pressure;
establishing a range of full-scale signals between said minimum and maximum supply voltages based on a maximum pressure;
sensing a sensor output signal from the sensor output operating at a first supply voltage in response to a first operating pressure;
selecting a first offset signal at said first supply voltage from said range of offset signals;
selecting a first full-scale signal at Said first supply voltage from said range of full-scale signals;
and
compensating for the power supply variation in said sensor output signal by normalizing said sensor output signal less said first offset signal by said first full-scale signal less said first offset signal said normalizing transforms said sensor output signal into a sensor signal that operates independent of the power supply voltage.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/143,035Filed 29 Oct 1993
Granted: 19 Dec 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G01L 1/2268
Using resistance strain gauges: arrangements for correcting or for compensating unwanted effects
G01D 3/02
Indicating or recording apparatus with provision for the special purposes referred to in the subgroups: with provision for altering or correcting…
G01L 19/02
Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or…
G01L 25/00
Testing or calibrating of apparatus for measuring force, torque, work, mechanical power