Packages for coil actuated position sensors
An apparatus comprises a first substrate and two coils supported by the first substrate and arranged next to each other, the coils configured to each generate a magnetic field which produces eddy currents in and a reflected magnetic field from a conductive target, the two coils arranged so their respectively generated magnetic fields substantially cancel each other in an area between the coils. One or more magnetic field sensing elements are positioned in the area between the coils and configured to detect the reflected magnetic field.
1. Apparatus comprising:
one or more substrates;
one or more coils configured to produce a first magnetic field that induces eddy currents in a conductive target that generate a reflected magnetic field;
one or more magnetic field sensing elements supported by the one or more substrates to detect the reflected magnetic field; and
a conductive support structure to directly support the one or more substrates, the conductive support structure having a shape in an area substantially vertically aligned with respect to the one or more coils so that the first magnetic field does not induce eddy currents in the area of the conductive support structure.
2. The apparatus of claim 1 wherein at least one of the one or more coils is supported by at least one of the one or more substrates.
3. The apparatus of claim 2 wherein the conductive support structure supports the at least one of the one or more substrates.
4. The apparatus of claim 1 wherein the one or more magnetic field sensing elements are arranged in a grid pattern on the one or more substrates.
5. The apparatus of claim 1 wherein at least one of the one or more coils comprises a plurality of traces and wherein the one or more magnetic field sensing elements are positioned on one of the one or more substrates in a space between traces of the at least one coil.
6. The apparatus of claim 1 wherein at least one of the one or more coils includes a counter coil to produce a local magnetic field in a direction opposite to the direction of the first magnetic field.
7. The apparatus of claim 6 wherein the counter coil comprises a plurality of traces and wherein the one or more magnetic field sensing elements are positioned in a space between one or more traces of the counter coil.
8. The apparatus of claim 1 wherein the one or more substrates comprise one or more of: a semiconductor material, a glass material, or a ceramic material.
9. The apparatus of claim 1 wherein the one or more substrates comprises a plurality of substrates and a first substrate of the plurality of substrates supports the one or more coils and a second one of the plurality of substrates supports the one or more magnetic field sensing elements.
10. The apparatus of claim 9 wherein a third substrate of the plurality of substrates supports a processing circuit.
11. The apparatus of claim 9 wherein the one or more coils comprises a plurality of coils and wherein the first substrate of the plurality supports two or more of the plurality of coils.
12. The apparatus of claim 1 wherein a first substrate of the one or more substrates supports the one or more coils and the one or more magnetic field sensing elements.
13. The apparatus of claim 12 wherein the one or more substrates comprises a plurality of substrates and wherein a second one of the plurality of substrates supports one or more processing circuits.
14. The apparatus of claim 1 wherein the one or more substrates comprises a plurality of substrates and wherein each of the magnetic field sensing elements is supported by a different substrate.
15. The apparatus of claim 1 wherein the substrates, coils, and magnetic field sensing elements form one or more magnetic field sensors.
16. The apparatus of claim 1 wherein the one or more substrates comprises a plurality of substrates and the apparatus further comprises an adhesive to adhere at least two of the plurality of substrates to each other.
17. The apparatus of claim 1 wherein the conductive support structure comprises a lead frame or a pad frame.
18. The apparatus of claim 1 wherein the shape of the conductive support structure comprises a gap in the area adjacent to the one or more coils.
19. Apparatus comprising:
a plurality of substrates;
a magnetic field sensing element supported by a first one of the plurality of substrates to detect an alternating magnetic field;
a coil supported by a second one of the plurality of substrates and configured to generate the alternating magnetic field; and
a conductive support structure to support the plurality of substrates, the conductive support structure having a shape in an area adjacent to the coil so that the alternating magnetic field does not induce eddy currents in the area of the conductive support structure.
20. The apparatus of claim 19 wherein the one or more magnetic field sensing elements are arranged in a grid pattern on the one or more substrates.
21. The apparatus of claim 19 wherein the one or more substrates comprise one or more of: a semiconductor material, a glass material, or a ceramic material.
22. The apparatus of claim 19 wherein the conductive support structure comprises a lead frame or a pad frame.
23. Apparatus comprising:
a plurality of substrates;
a magnetic field sensing element supported by one of the plurality of substrates to detect an alternating magnetic field;
a coil configured to generate the alternating magnetic field; and
a conductive support structure to support the plurality of substrates, the conductive support structure having a shape in an area adjacent to the coil so that the alternating magnetic field does not induce eddy currents in the area of the conductive support structure, wherein a first substrate of the plurality of substrates supports the coil and the magnetic field sensing element and wherein a second substrate of the plurality of substrates supports a processing circuit.
24. The apparatus of claim 23 wherein the one or more magnetic field sensing elements are arranged in a grid pattern on the one or more substrates.
25. The apparatus of claim 23 wherein at least one of the one or more coils comprises a plurality of traces and wherein the one or more magnetic field sensing elements are positioned on one of the one or more substrates in a space between traces of the at least one coil.
26. The apparatus of claim 23 wherein at least one of the one or more coils includes a counter coil to produce a local magnetic field in a direction opposite to the direction of the alternating magnetic field.
27. The apparatus of claim 26 wherein the counter coil comprises a plurality of traces and wherein the one or more magnetic field sensing elements are positioned in a space between one or more traces of the counter coil.
28. The apparatus of claim 23 wherein the one or more substrates comprise one or more of: a semiconductor material, a glass material, or a ceramic material.
29. The apparatus of claim 23 wherein the conductive support structure comprises a lead frame or a pad frame.
30. Apparatus comprising:
a plurality of substrates;
a plurality of magnetic field sensing elements to detect an alternating magnetic field, wherein each of the plurality of magnetic field sensing elements is supported by a different one of the plurality of substrates;
a coil configured to generate the alternating magnetic field; and
a conductive support structure to support the plurality of substrates, the conductive support structure having a shape in an area adjacent to the coil so that the alternating magnetic field does not induce eddy currents in the area of the conductive support structure.
31. The apparatus of claim 30 wherein at least one of the one or more coils comprises a plurality of traces and wherein a magnetic field sensing element of the plurality of magnetic field sensing elements is positioned on one of the one or more substrates in a space between traces of the at least one coil.
32. The apparatus of claim 30 wherein at least one of the one or more coils includes a counter coil to produce a local magnetic field in a direction opposite to the direction of the alternating magnetic field.
33. The apparatus of claim 32 wherein the counter coil comprises a plurality of traces and wherein a magnetic field sensing element of the plurality of magnetic field sensing elements is positioned in a space between one or more traces of the counter coil.
34. The apparatus of claim 30 wherein the one or more substrates comprise one or more of: a semiconductor material, a glass material, or a ceramic material.
35. The apparatus of claim 30 wherein the conductive support structure comprises a lead frame or a pad frame.