Magnetic field sensor
AssigneeHoneywell International Inc.
InventorsHong Wan, Jay R. Goetz
Life of this patent
Estimating the term…
Abstract
An integrated magnetic field sensing device includes at least two magnetoresistive elements which are biased in a first direction by an integral conductor and are sensitive to magnetic field components in a direction perpendicular to the first direction. The sensitivity of the device to a magnetic field is adjustable and is related to the level of the bias current. In a current measuring application, two of the magnetic field sensing devices are mounted on opposite sides of and perpendicular to a conductor carrying a current to be measured. In a portable current measuring apparatus, two of the magnetic field sensors are mounted in a housing that assists in locating the magnetic field sensors relative to the conductor carrying the current to be measured.
Claims32
An integrated device for sensing external magnetic fields comprising:
- planar magnetic field sensing means having at least a first magnetic field sensing element, a second magnetic field sensing element, and an output terminating region;
- a conductor carrying a bias current for providing a bias field for setting a direction of magnetization in said first magnetic field sensing element and in said second magnetic field sensing element in a first direction with said bias field being sufficient to initially align magnetization in said first magnetic field sensing element and said second magnetic field sensing element;
- and,
- said device having a level of sensitivity to magnetic field components in a direction perpendicular to said first direction and providing an output at said output terminating region with said level of sensitivity being related to a level of said bias current.
An integrated device for sensing external magnetic fields comprising:
- magnetic field sensing means having first, second, third, and fourth magnetoresistive elements and an output terminating region, each of said magnetoresistive elements having first and second terminating regions, said first magnetoresistive element first terminating region being connected to said third magnetoresistive element first terminating region, said first magnetoresistive second terminating region being connected to said second magnetoresistive element second terminating region, said third magnetoresistive element second terminating region being connected to said fourth magnetoresistive element second terminating region and said second magnetoresistive element first terminating region connected to said fourth magnetoresistive element first terminating region;
- an integral coil carrying a bias current, said current providing a magnetic field in a first direction and establishing an initial direction of magnetization in said first, second, third and fourth magnetoresistive elements in said first direction, and;
- said device having a level of sensitivity to magnetic field components in a direction perpendicular to said first direction and providing an output at said output terminating region with said level of sensitivity being related to a level of said bias current.
Apparatus for measuring current within a conductor comprising:
- a first planar magnetic field sensor having magnetoresistive sensing elements, an integral conductor carrying a bias current and an output terminating region, said bias current initially aligning magnetization of said magnetoresistive elements in a first direction;
- a second planar magnetic field sensor having magnetoresistive sensing elements, an integral conductor carrying a bias current, and an output terminating region, said bias current initially aligning magnetization of said magnetoresistive elements in a first direction;
- a housing positioning said first magnetic field sensor on a first side of said conductor and positioning said second magnetic field sensor on an opposite side of said conductor with said first planar sensor and said second planar sensor lying in a common plane perpendicular to said conductor;
- means for determining a combination of an output of said first magnetic field sensor and an output of said second magnetic field sensor with said combination being representative of said current to be measured.
Apparatus for measuring current within a conductor comprising:
- a first magnetic field sensor;
- a second magnetic field sensor
- a housing positioning said first magnetic field sensor on a first side of said conductor and positioning said second magnetic field sensor on an opposite side of said conductor with said first sensor and said second sensor lying in a common plane;
- means for determining a combination of an output of said first magnetic field sensor and an output of said second magnetic field sensor with said combination being representative of said current to be measured.
A method of measuring a current in a conductor comprising the following steps:
- providing a first planar magnetoresistive magnetic field sensor having an integral coil for providing a bias field;
- providing a second planar magnetoresistive magnetic field sensor having an integral coil for providing a bias field;
- positioning said first magnetic field sensor on a first side of said conductor and said second magnetic field sensor on an opposite side of said conductor;
- applying a current to said integral coils;
- determining an output of said first magnetic field sensor and said second magnetic field sensor;
- and
- calculating a current in said conductor.
Dependencies are inferred from the claim text.