APPARATUS AND METHOD FOR SEQUENTIALLY RESETTING ELEMENTS OF A MAGNETIC SENSOR ARRAY
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Abstract
A semiconductor process and apparatus provide a high-performance magnetic field sensor with three differential sensor configurations which require only two distinct pinning axes, where each differential sensor is formed from a Wheatstone bridge structure with four unshielded magnetic tunnel junction sensor arrays, each of which includes a magnetic field pulse generator for selectively applying a field pulse to stabilize or restore the easy axis magnetization of the sense layers to orient the magnetization in the correct configuration. prior to measurements of small magnetic fields. The field pulse is sequentially applied to groups of the sense layers of the Wheatstone bridge structures, thereby allowing for a higher current pulse or larger sensor array size for maximal signal to noise ratio.
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Citations
46 Claims
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1-20. -20. (canceled)
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21. A magnetic field sensor comprising:
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a first bridge circuit including a first plurality of magnetic sense elements, the first plurality of magnetic sense elements including i groups of magnetic sense elements, wherein each group of the i groups of magnetic sense elements includes a plurality of magnetic sense elements to sense a magnetic field in a first dimension; a second bridge circuit including a second plurality of magnetic sense elements, the second plurality of magnetic sense elements including j groups of magnetic sense elements, wherein each group of the j groups of magnetic sense elements includes a plurality of magnetic sense elements to sense the magnetic field in a second dimension; and circuitry configured to generate a first plurality of current pulses and a second plurality of current pulses, wherein the first plurality of current pulses sequentially is applied adjacent to each of the i groups of the first plurality of magnetic sense elements, and wherein the second plurality of current pulses sequentially is applied adjacent to each of the j groups of the second plurality of magnetic sense elements. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A method of operating a magnetic field sensor, the method comprising:
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resetting a first group of magnetic sense elements of a first bridge circuit by sequentially applying current pulses to a first plurality of reset lines, wherein each reset line of the first plurality of reset lines is located adjacent to an associated magnetic sense element of the first group of magnetic sense elements, and wherein each magnetic sense element of the first group of magnetic sense elements senses a magnetic field in a first dimension; and resetting a second group of magnetic sense elements of a second bridge circuit by sequentially applying current pulses to a second plurality of reset lines, wherein each reset line of the second plurality of reset lines is located adjacent to an associated magnetic sense element of the second group of magnetic sense elements, and wherein each magnetic sense element of the second group of magnetic sense elements senses a magnetic field in a second dimension. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42)
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43. A magnetic field sensor comprising:
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a first bridge circuit including a first plurality of magnetic sense elements configured to sense a magnetic field in a first dimension, the first plurality of magnetic sense elements organized into i groups of magnetic sense elements, where i is at least 2; a first reset line located adjacent to the i groups of magnetic sense elements; a second bridge circuit including a second plurality of magnetic sense elements configured to sense a magnetic field in a second dimension, the second plurality of magnetic sense elements organized into j groups of magnetic sense elements, where j is at least 2; a second reset line located adjacent to the j groups of magnetic sense elements; a third bridge circuit including a third plurality of magnetic sense elements configured to sense a magnetic field in a third dimension, the third plurality of magnetic sense elements organized into k groups of magnetic sense elements, where k is at least 2; a third reset line located adjacent to the k groups of magnetic sense elements; and current driver circuitry configured to sequentially generate a plurality of current pulses for sequential application to the first, second, and third reset lines. - View Dependent Claims (44, 45, 46)
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Specification