Frequency compensation for rotating target sensor

Abstract

A compensation circuit for compensating for switching point errors in rotating target or gear tooth sensors. The compensation circuit may include a processing unit and a persistent storage device, such as an electrically erasable programmable read-only memory (EEPROM), for storing compensation values that are used to provide automatic compensation of the rotating target sensor after the sensor module is installed by the end user. The actual and compensation values may be determined and stored as linear functions in the form of mX+b, where X is the frequency of the rotating target, m is the slope and b is the y-intercept. In order to provide compensation, the actual slope value m is multiplied by a compensation value. The y intercept (i.e. b) is selected, for example, to be the maximum speed in a given application. The compensation values (i.e. slope m and intercept b) may be determined on a part-by-part basis by the sensor manufacturer or by utilizing averages, in which case, the calibration values can be determined for the application and pre-programmed by the Hall effect IC manufacturer. In operation, the sensor output value is applied to the compensation circuit which processes the actual operate point and provides ideal operate points automatically, thus eliminating the need for the end user to attempt compensate for switching point errors of such digital Hall effect devices.

Dependencies are inferred from the claim text.