Adjustment of a magneto-resistive angle sensor

• US 6,943,544 B2
• Filed: 06/25/2002
• Issued: 09/13/2005
• Est. Priority Date: 06/27/2001
• Status: Expired due to Term

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Waffenschmidt, Eberhard
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): Aurora, Reena
• Application Number:
  US10/179,324
• Publication Number:
  US 20030042894A1
• Time in Patent Office: 1,176 Days
• Field of Search: 324/202, 324/207.12, 324/207.2, 324/207.21, 324/207.25, 324/252
• US Class Current: 324/207.21
• CPC Class Codes: G01B 7/30 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01D 18/001 Calibrating encoders
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G01D 5/2449 using hard-stored calibration data

Abstract

The present invention relates to an angle sensor and a method for adjustment of an angle sensor.

The angle sensor has two bridge circuits (1, 2), at which a pair of voltage values (U₁, U₂) is measurable during an angle measurement. The pair of voltage values are used together with at least one correction value for the computation of an angle.

The angle sensor also has an analysis circuit that is provided for the computation of the correction value from several of the pairs of voltage values (U₁, U₂). The pairs of voltage values lie on the periphery of a circle or an ellipse when respectively plotted against each other, and the correction value is derived from a center point computation of the circle of the ellipse.

Claims

1. An angle sensor comprising:

two bridge circuits at which a pair of voltage values (U₁, U₂) is measurable during an angle measurement, which pair of voltage values is used together with at least one correction value for the computation of an angle, and

an analysis circuit for computing the at least one correction value from several of the pairs of voltage values (U₁, U₂), which pairs of voltage values lie on the periphery of a circle or an ellipse when respectively plotted against each other, and which at least one correction value is derived from a center point computation of the circle or the ellipse, wherein the pairs of voltage values (U₁, U₂) used for the computation of the correction value lie in a mechanical angle range of 10°

on the periphery of the circle or ellipse; and

wherein a corrective adjustment to the angle sensor by the correction value occurs during said angle measurement by said angle sensor.

2. The angle sensor of claim 1, wherein the bridge circuits have magneto-resistive components (R₁₁, R₁₂, R₁₃, R₁₄, R₂₁, R₂₂, R₂₃, R₂₄) and that the bridge circuits are arranged so as to be rotated against each other by an angle of 45°

.

3. The angle sensor of claim 2, wherein the microprocessor processes 16-bit floating point numbers.

4. The angle sensor of claim 1, wherein the analysis circuit of the angle sensor includes a microprocessor for computing the center coordinates of the circle or the ellipse as correction values and for computing the angle by means of the correction values.

5. A method of adjusting an angle sensor, comprising the steps of:

measuring a pair of voltage values (U₁, U₂) at two bridge circuits during an angle measurement; and

computing an angle using the pair of voltage values and at least one correction value, determining the correction value from several of the pairs of voltage values (U₁, U₂), which values lie on the periphery of a circle or an ellipse when respectively plotted against each other, using a center-point computation of the circle or tie ellipse, wherein the pairs of voltage values (U₁, U₂) used for the computation of the correction value lie in a mechanics angle range of 10°

on the periphery of the circle or ellipse; and

including the step of making a corrective adjustment to the angle sensor by the correction value during said angle measurement by said angle sensor.