Method and apparatus for sensor signal conditioning using low- cost, high- accuracy analog circuitry

摘要

The present invention, generally speaking, provides for highly accurate correction of a sensor output using circuitry that is compact and inexpensive. In accordance with one embodiment of the invention, an output signal of a sensor having a sensitivity that varies as a function of temperature and that includes resistors connected to form a bridge is corrected by, first, modeling the sensitivity of the sensor using an expression that is the ratio of two polynomials; applying a voltage across the bridge; and controlling the applied voltage as a function of temperature substantially in accordance with the inverse expression. In accordance with another embodiment of the invention, a circuit for correcting an output signal of a sensor having a sensitivity that varies as a function of temperature and that includes resistors connected to form a bridge, includes circuitry for applying a voltage across the bridge, and circuitry for controlling said voltage as a function of temperature substantially in accordance with an expression that is the ratio of two polynomials, in which constants a and b are chosen such that an inverse expression approximates the sensitivity of the sensor. Preferably, the circuit is an analog integrated circuit.