Arrangements for magnetic field sensors that act as movement detectors
First Claim
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1. A magnetic field sensor for sensing a movement of an object, the magnetic field sensor comprising:
- a magnet;
a semiconductor substrate disposed proximate to the magnet in a back biased arrangement, the semiconductor substrate having first and second major opposing surfaces;
a first magnetic field sensing element disposed on or under the first surface of the semiconductor substrate;
a second magnetic field sensing element disposed on or under the first surface of the semiconductor substrate;
a first electronic circuit channel coupled to the first magnetic field sensing element, the first electronic circuit channel operable to generate a first signal having a first phase; and
a second electronic circuit channel coupled to the second magnetic field sensing element, the second electronic circuit channel operable to generate a second signal having a second phase approximately +/−
ninety degrees apart from the first phase regardless of a speed of the movement of the object, wherein a sign of the ninety degrees is indicative of a direction of the movement of the object.
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Abstract
Magnetic field sensors can sense speed of movement and direction of movement of a ferromagnetic object. The magnetic field sensors employ both planar Hall effect elements and vertical Hall effect elements to generate two-state signals in two different signal paths with relative phases that are ninety degrees apart, the ninety degrees having sufficient margin to aid in detection of the direction of motion. Other magnetic field sensors use at least four vertical Hall effect elements to identify a speed of rotation and a direction of rotation of a moving ferromagnetic object.
352 Citations
26 Claims
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1. A magnetic field sensor for sensing a movement of an object, the magnetic field sensor comprising:
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a magnet; a semiconductor substrate disposed proximate to the magnet in a back biased arrangement, the semiconductor substrate having first and second major opposing surfaces; a first magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a second magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a first electronic circuit channel coupled to the first magnetic field sensing element, the first electronic circuit channel operable to generate a first signal having a first phase; and a second electronic circuit channel coupled to the second magnetic field sensing element, the second electronic circuit channel operable to generate a second signal having a second phase approximately +/−
ninety degrees apart from the first phase regardless of a speed of the movement of the object, wherein a sign of the ninety degrees is indicative of a direction of the movement of the object. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A magnetic field sensor for sensing a movement of an object, the magnetic field sensor comprising:
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a magnet; a semiconductor substrate disposed proximate to the magnet in a back biased arrangement, the semiconductor substrate having first and second major opposing surfaces; a first magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a second magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a third magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a fourth magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a first electronic circuit channel coupled to the first magnetic field sensing element and to the third magnetic field sensing element, the first electronic circuit channel operable to generate a first difference signal as a difference of signals generated by the first magnetic field sensing element and the third magnetic field sensing element, the first electronic circuit channel operable to generate the first difference signal having a first phase; and a second electronic circuit channel coupled to the second magnetic field sensing element and to the fourth magnetic field sensing element, the second electronic circuit channel operable to generate a second difference signal as a difference of signals generated by the second magnetic field sensing element and the fourth magnetic field sensing element, the second electronic circuit channel operable to generate the second difference signal having a second phase approximately +/−
ninety degrees apart from the first phase regardless of a speed of the movement of the object, wherein a sign of the ninety degrees is indicative of a direction of the movement of the object. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A magnetic field sensor for sensing a movement of an object, the magnetic field sensor comprising:
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a semiconductor substrate, the semiconductor substrate having first and second major opposing surfaces; a first magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a second magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a third magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a fourth magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a first electronic circuit channel coupled to the first magnetic field sensing element and to the third magnetic field sensing element, the first electronic circuit channel operable to generate a first difference signal as a difference of signals generated by the first magnetic field sensing element and the third magnetic field sensing element, the first electronic circuit channel operable to generate the first difference signal having a first phase; and a second electronic circuit channel coupled to the second magnetic field sensing element and to the fourth magnetic field sensing element, the second electronic circuit channel operable to generate a second difference signal as a difference of signals generated by the second magnetic field sensing element and the fourth magnetic field sensing element, the second electronic circuit channel operable to generate the second difference signal having a second phase approximately +/−
ninety degrees apart from the first phase regardless of a speed of the movement of the object, wherein a sign of the ninety degrees is indicative of a direction of the movement of the object, wherein the first and third magnetic field sensing elements comprise planar Hall effect elements and the second and fourth magnetic field sensing elements comprise vertical Hall effect elements or magnetoresistance elements.
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23. A magnetic field sensor for sensing a movement of an object, the magnetic field sensor comprising:
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a semiconductor substrate, the semiconductor substrate having first and second major opposing surfaces; a first magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a second magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a third magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a fourth magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a first electronic circuit channel coupled to the first magnetic field sensing element and to the third magnetic field sensing element, the first electronic circuit channel operable to generate a first difference signal as a difference of signals generated by the first magnetic field sensing element and the third magnetic field sensing element, the first electronic circuit channel operable to generate the first difference signal having a first phase; and a second electronic circuit channel coupled to the second magnetic field sensing element and to the fourth magnetic field sensing element, the second electronic circuit channel operable to generate a second difference signal as a difference of signals generated by the second magnetic field sensing element and the fourth magnetic field sensing element, the second electronic circuit channel operable to generate the second difference signal having a second phase approximately +/−
ninety degrees apart from the first phase regardless of a speed of the movement of the object, wherein a sign of the ninety degrees is indicative of a direction of the movement of the object, wherein the first magnetic field sensing element comprises an axis of maximum sensitivity substantially perpendicular to the first opposing surface of the substrate, wherein the second magnetic field sensing element comprises an axis of maximum sensitivity substantially parallel to the first opposing surface of the substrate, wherein the third magnetic field sensing element comprises an axis of maximum sensitivity substantially perpendicular to the first opposing surface of the substrate, and wherein the fourth magnetic field sensing element comprises an axis of maximum sensitivity substantially parallel to the first opposing surface of the substrate.
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24. A magnetic field sensor for sensing a movement of an object, the magnetic field sensor comprising:
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a semiconductor substrate, the semiconductor substrate having first and second major opposing surfaces; a first magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a second magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a third magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a fourth magnetic field sensing element disposed on or under the first surface of the semiconductor substrate; a first electronic circuit channel coupled to the first magnetic field sensing element and to the third magnetic field sensing element, the first electronic circuit channel operable to generate a first difference signal as a difference of signals generated by the first magnetic field sensing element and the third magnetic field sensing element, the first electronic circuit channel operable to generate the first difference signal having a first phase; and a second electronic circuit channel coupled to the second magnetic field sensing element and to the fourth magnetic field sensing element, the second electronic circuit channel operable to generate a second difference signal as a difference of signals generated by the second magnetic field sensing element and the fourth magnetic field sensing element, the second electronic circuit channel operable to generate the second difference signal having a second phase approximately +/−
ninety degrees apart from the first phase regardless of a speed of the movement of the object, wherein a sign of the ninety degrees is indicative of a direction of the movement of the object, wherein the axes of maximum sensitivity of the second and fourth magnetic field sensing elements are substantially parallel to a first orthogonal axis, the magnetic field sensor further comprising;a fifth magnetic field sensing element, disposed on the first surface of the semiconductor substrate, wherein the fifth magnetic field sensing element comprises an axis of maximum sensitivity substantially parallel to the first opposing surface of the substrate and substantially parallel to a second orthogonal axis perpendicular to the first orthogonal axis; and a sixth magnetic field sensing element disposed on the first surface of the semiconductor substrate, wherein the sixth magnetic field sensing element comprises an axis of maximum sensitivity substantially parallel to the first opposing surface of the substrate and substantially parallel to the second orthogonal axis. - View Dependent Claims (25, 26)
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Specification