Packages for coil actuated position sensors

Patent metadata

Field	Value
Publication number	US-10649042-B2
Application number	US-201916394338-A
Country	US
Kind code	B2
Filing date	Apr 25, 2019
Priority date	May 26, 2017
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

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.

First claim

The invention claimed is:

1. An apparatus comprising:
a first substrate;
two coils supported by the first substrate and arranged next to each other such that a current through each of the coils flows in the same plane, 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; and
one or more magnetic field sensing elements positioned in the area between the coils and configured to detect the reflected magnetic field in order to detect one or more of a position, speed, rotational angle, or direction of the conductive target.

2. The apparatus of claim 1 wherein the one or more magnetic field sensing elements comprise a bridge circuit.

3. The apparatus of claim 1 wherein the one or more magnetic field sensing elements comprise at least two pairs of magnetic field sensing elements.

4. The apparatus of claim 3 wherein a center area of the conductive target is adjacent to one of the pairs of magnetic field sensing elements and an edge of the conductive target is adjacent to another of the pairs of magnetic field sensing elements.

5. The apparatus of claim 1 further comprising a second substrate, wherein the one or more magnetic field sensing elements and/or a processing circuit are supported by the second substrate.

6. The apparatus of claim 5 wherein the second substrate is centered in the area between the coils.

7. The apparatus of claim 5 wherein the first and/or second substrates comprise one or more of: a semiconductor material, a glass material, or a ceramic material.

8. An apparatus comprising:
a first substrate;
a conductive trace supported by the first substrate and having a first portion looped in a first direction to form a first coil and a second portion looped in a second direction to form a second coil, wherein the second direction is opposite the first direction and wherein the first and second coils are 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; and
one or more magnetic field sensing elements positioned in the area between the coils and configured to detect the reflected magnetic field in order to detect one or more of a position, speed, rotational angle, or direction of the conductive target.

9. The apparatus of claim 8 wherein the one or more magnetic field sensing elements comprise a bridge circuit.

10. The apparatus of claim 8 wherein the one or more magnetic field sensing elements comprise at least two pairs of magnetic field sensing elements.

11. The apparatus of claim 10 wherein a center area of the conductive target is adjacent to one of the pairs of magnetic field sensing elements and an edge of the conductive target is adjacent to another of the pairs of magnetic field sensing elements.

12. The apparatus of claim 8 further comprising a second substrate, wherein the one or more magnetic field sensing elements and/or a processing circuit are supported by the second substrate.

13. The apparatus of claim 12 wherein the second substrate is centered in the area between the coils.

14. The apparatus of claim 12 wherein the first and/or second substrates comprise one or more of: a semiconductor material, a glass material, or a ceramic material.

15. An apparatus comprising:
a first substrate;
two coils supported by the first substrate and arranged next to each other such that a current through each of the coils flows in opposite directions with respect 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; and
one or more magnetic field sensing elements positioned in the area between the coils and configured to detect the reflected magnetic field in order to detect one or more of a position, speed, rotational angle, or direction of the conductive target.

16. The apparatus of claim 15 wherein the one or more magnetic field sensing elements comprise a bridge circuit.

17. The apparatus of claim 15 wherein the one or more magnetic field sensing elements comprise at least two pairs of magnetic field sensing elements.

18. The apparatus of claim 17 wherein a center area of the conductive target is adjacent to one of the pairs of magnetic field sensing elements and an edge of the conductive target is adjacent to another of the pairs of magnetic field sensing elements.

19. The apparatus of claim 15 further comprising a second substrate, wherein the one or more magnetic field sensing elements and/or a processing circuit are supported by the second substrate.

20. The apparatus of claim 19 wherein the second substrate is centered in the area between the coils.

21. The apparatus of claim 19 wherein the first and/or second substrates comprise one or more of: a semiconductor material, a glass material, or a ceramic material.

Assignees

• Allegro Microsystems Llc

Inventors

• Latham Alexander
• Doogue Michael C
• Boudreau Jason

Classifications

• G01B7/023

  for measuring distance between sensor and object (G01B7/082 and G01B7/102 take precedence) · CPC title

• G01B7/003

  for measuring position, not involving coordinate determination (coordinate measuring G01B7/004) · CPC title

• G01R33/1284

  Spin resolved measurements; Influencing spins during measurements, e.g. in spintronics devices · CPC title

• G01R33/0011

  comprising means, e.g. flux concentrators, flux guides, for guiding or concentrating the magnetic flux, e.g. to the magnetic sensor · CPC title

• H01F5/003

  Printed circuit coils · CPC title