Apparatus and method for sequentially resetting elements of a magnetic sensor array
First Claim
1. A magnetic field sensor comprising:
- 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 including i groups of magnetic sense elements, where i is greater than or equal to 2, and wherein each group of the i groups of magnetic sense elements includes a plurality of magnetic sense elements to sense the magnetic field in the first dimension;
a second bridge circuit including a second plurality of magnetic sense elements configured to sense the magnetic field in a second dimension, the second plurality of magnetic sense elements including j groups of magnetic sense elements, where j is greater than or equal to 2, and wherein each group of the j groups of magnetic sense elements includes a plurality of magnetic sense elements to sense the magnetic field in the second dimension; and
circuitry configured to generate a first plurality of current pulses and a second plurality of current pulses, the first plurality of current pulses sequentially applied adjacent to each of the i groups of the first plurality of magnetic sense elements and thereafter the second plurality of current pulses sequentially applied adjacent to each of the j groups of the second plurality of magnetic sense elements, wherein the sequential application of current pulses adjacent to the i and j groups of magnetic sense elements results in a larger current applied adjacent to each of the i and j groups of magnetic sense elements, for a given voltage, than if the first plurality and second plurality of current pulses had been applied adjacent to the i and j groups of magnetic sense elements simultaneously.
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Accused Products
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.
16 Citations
20 Claims
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1. 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 including i groups of magnetic sense elements, where i is greater than or equal to 2, and wherein each group of the i groups of magnetic sense elements includes a plurality of magnetic sense elements to sense the magnetic field in the first dimension; a second bridge circuit including a second plurality of magnetic sense elements configured to sense the magnetic field in a second dimension, the second plurality of magnetic sense elements including j groups of magnetic sense elements, where j is greater than or equal to 2, and wherein each group of the j groups of magnetic sense elements includes a plurality of magnetic sense elements to sense the magnetic field in the second dimension; and circuitry configured to generate a first plurality of current pulses and a second plurality of current pulses, the first plurality of current pulses sequentially applied adjacent to each of the i groups of the first plurality of magnetic sense elements and thereafter the second plurality of current pulses sequentially applied adjacent to each of the j groups of the second plurality of magnetic sense elements, wherein the sequential application of current pulses adjacent to the i and j groups of magnetic sense elements results in a larger current applied adjacent to each of the i and j groups of magnetic sense elements, for a given voltage, than if the first plurality and second plurality of current pulses had been applied adjacent to the i and j groups of magnetic sense elements simultaneously. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of resetting magnetic sense elements of a magnetic field sensor, the method comprising:
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sequentially 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 first group of magnetic sense elements of the first bridge circuit, and wherein each magnetic sense element of the first group of magnetic sense elements of the first bridge circuit senses a magnetic field in a first dimension, wherein the sequential application of current pulses to the first plurality of reset lines provides a larger current applied to the first plurality of reset lines, for a given voltage, than if current pulses had been simultaneously applied to all the reset lines of the first plurality of reset lines. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. 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 greater than or equal to 2; a first group of reset lines, wherein each reset line of the first group is located adjacent to an associated group of 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 greater than or equal to 2; a second group of reset lines, wherein each reset line of the second group is located adjacent to an associated group of 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 greater than or equal to 2; a third group of reset lines, wherein each reset line of the third group is located adjacent to an associated group of the k groups of magnetic sense elements; and current driver circuitry configured to responsively and sequentially generate a plurality of current pulses and configured to sequentially apply current pulses to the reset lines of the first, second, and third groups of reset lines, wherein the sequential application of current pulses to the reset lines of the first, second, and third groups of reset lines results in a larger current applied adjacent to each of the i, j, and k groups of magnetic sense elements, for a given voltage, than if current pulses had been applied adjacent to the i, j, and k groups of magnetic sense elements simultaneously. - View Dependent Claims (19, 20)
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Specification