Liaisons Electroniques-mecaniques Lem Sa

Sentron Ag

Lem Intellectual Property Sa

Hubert Blanchard

Radivoje Popovic

Robert Racz

Jan Hrejsa

Marc Pastre

Maher Kayal

A magnetic field sensor comprises a reference magnetic field generator (), a magnetic field sensing cell () including Hall effect sensing elements (), and a signal processing circuit () connected to the output () of the magnetic field sensing cell and comprising one or more feedback lines () for correcting error fluctuations in the transfer characteristic of the magnetic field sensor. The reference magnetic field generator is adapted to generate a frequency modulated reference magnetic field. The signal processing circuit further includes a modulator connected to the magnetic field sensing cell, adapted to modulate the output signal thereof at a frequency different from the modulation frequency of the reference magnetic field generator.

Continuously calibrated magnetic field sensor

A method of making an electrical current sensor having an electrical conducting portion ( ) of rectangular cross-section being surrounded, on three of its lateral faces, by a magnetic circuit portion ( ) which has end portions ( &Prime;) having planar surfaces situated substantially in a plane of a fourth lateral face of the conductor portion ( ), a magnetic field detector ( ) being arranged opposite the fourth lateral face. The conductor portion ( ) is made by photo-lithography and etching in a layer of electrically conducting material applied on a first surface of a flat support member ( &Prime;) or on intermediate layers ( ) deposited on the support member. The magnetic circuit portion ( ) is made by photo-lithography and etching in a layer of magnetically permeable material applied on the conductor portion ( ) on the first surface of the support member ( &Prime;) or of an intermediate layer ( ). The magnetic field detector ( ) is fixed to the support member ( &Prime;) or on intermediate layers ( ) deposited on a second surface of the support member.

Method of making an electrical current sensor

A magnetic field sensor has two flux concentrators which serve to strengthen a magnetic field to be measured and which are separated by an air gap. Two Hall elements are arranged outside the air gap in such a way that at least a part of the field lines which lead from the first to the second flux concentrator pass through the two Hall elements in approximately opposite directions. Such a magnetic field sensor is less sensitive to external interference fields. It is suitable for the measurement of very weak magnetic fields and also for use as a current and/or energy sensor.

Magnetic field sensor comprising two hall elements

Magnetic field sensor and current and/or energy sensor

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Vevey, Switzerland

Hubert Blanchard