Method for evaluating signals of magnetoresistive sensors with high band width

US6433545B1 · kind B1 · utility

Assignee

• Lust Antriebstechnik GmbH · DE

Inventors

• Jürgen Kunze · Rutesheim, DE
• Gunter Schepp · Rockenberg, DE
• Fritz Dettmann · Solms, DE
• Uwe Loreit · Wetzlar, DE

Key dates

• Filing date: Jan 26, 2001
• Grant date: Aug 13, 2002
• Expiry date: Jan 26, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R33/09
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention relates to a method for evaluating signals while eliminating an interference signal on magnetoresistive sensor elements which is preferably proportional to the zero offset. The sensor elements can form a sensor element array such as a sensor bridge. According to the invention, the direction of magnetization of the sensor elements is modulated or shifted by applying a magnetic pulse field of a modulated or variable direction, and the output signals of the sensor elements or of the sensor element array are fed to a differential amplifier. Due to the modulation or shift of the operating voltage of the sensor bridge, the modulation or shift resulting at the same time as the magnetization of the sensor elements, a signal often arises which includes a direct component that is proportional to the magnetic field to be measured, and has an alternating component that is proportional to the offset voltage of the sensor element array. The latter is minimized by a feedback or is adjusted to zero. The bandwidth, with which the direct voltage that is proportional to the magnetic field to be measured can follow changes of the input signal, is greater in magnitude than the magnetizati…