Magnetic position sensor and calibration thereof

Patent metadata

Field	Value
Publication number	US-2025109973-A1
Application number	US-202318478361-A
Country	US
Kind code	A1
Filing date	Sep 29, 2023
Priority date	Sep 29, 2023
Publication date	Apr 3, 2025
Grant date	—

Abstract

In a described example, a position sensor can include a first magnetic field sensor unit having a first sensor output, a second magnet field sensor unit having a second sensor output, one or more coils having one or more footprints overlapping the first and second magnetic field sensor units, and a processing circuit having a first sensor input, a second sensor input, a current terminal, and a sensing output, the first sensor input coupled to the first sensor output, the second sensor input coupled to the second sensor output, and the current terminal coupled to the one or more coils.

First claim

What is claimed is:

1 . A position sensor, comprising:
a first magnetic field sensor unit having a first sensor output; a second magnet field sensor unit having a second sensor output; one or more coils having one or more footprints overlapping the first and second magnetic field sensor units; and a processing circuit having a first sensor input, a second sensor input, a current terminal, and a sensing output, the first sensor input coupled to the first sensor output, the second sensor input coupled to the second sensor output, and the current terminal coupled to the one or more coils.

2 . The position sensor of claim 1 , wherein the processing circuit is configured to:
provide a calibration current through the one or more coils via the current terminal to cause the one or more coils to provide one or more calibration magnetic fields; receive a first sensor signal representing the one or more first magnetic fields at the first sensor input; receive a second sensor signal representing the one or more first magnetic fields at the second sensor input; determine one or more gains of the first magnetic field sensor unit and the second magnetic field sensor unit based on the first sensor signal and the second sensor signal; and provide a signal representing a position at the sensing output based on the one or more gains.

3 . The position sensor of claim 2 , wherein the one or more gains include an average gain of the first and second magnetic field sensor units.

4 . The position sensor of claim 2 , wherein the one or more gains include a first gain of the first magnetic field sensor and a second gain of the second magnetic field sensor.

5 . The position sensor of claim 3 , wherein the first sensor signal represents the one or more calibration magnetic fields and a second magnetic field, and the second sensor signal represents the one or more calibration magnetic fields and a third magnetic field; and
wherein the processing circuit is configured to:
extract a first measurement of the one or more calibration magnetic fields from the first sensor signal;
extract a second measurement of the one or more calibration magnetic fields from the second sensor signal;
determine one or more magnitudes of the one or more calibration magnetic fields based on the calibration current; and
determine the one or more gains based on the first and second measurements and the one or more magnitudes.

6 . The position sensor of claim 5 , wherein the first and second measurements are extracted based on processing, respectively, the first and second sensor signals using at least one of: a bandpass filter, a root mean square operation, an auto-correlation operation, or a Fourier transform operation.

7 . The position sensor of claim 5 , wherein the processing circuit is configured to:
generate a first intermediate signal based on the first sensor signal and the one or more gains; generate a second intermediate signal based on the second sensor signal and the one or more gains; extract a third measurement of the second magnetic field and the third magnetic field based on combining the first and second intermediate signals; and provide the signal based on the third measurement.

8 . The position sensor of claim 7 , further comprising a third magnetic field sensor unit having a third sensor output and a fourth magnet field sensor unit having a fourth sensor output,
wherein the one or more footprints overlap the third and fourth magnetic field sensor units; wherein the processing circuit has a third sensor input and a fourth sensor input, the third sensor input coupled to the third sensor output, and the fourth sensor input coupled to the fourth sensor output; and wherein the processing circuit is configured to:
receive a third sensor signal representing the one or more first magnetic fields and a fourth magnetic field at the third sensor input;
receive a fourth sensor signal representing the one or more first magnetic fields and a fifth magnetic field at the fourth sensor input;
generate a third intermediate signal based on the third sensor signal and the one or more gains;
generate a fourth intermediate signal based on the fourth sensor signal and the one or more gains;
extract a fourth measurement of the fourth magnetic field and the fifth magnetic field based on combining the third and fourth intermediate signals; and
provide the signal based on a ratio between the third and fourth measurements.

9 . The position sensor of claim 1 , wherein the one or more coils includes a single coil having a single footprint that overlaps the first and second magnetic field sensor units.

10 . The position sensor of claim 9 , wherein the single coil surrounds a core region, and the first and second magnetic field sensor units overlap the core region.

11 . The position sensor of claim 9 , wherein the first and second magnetic field sensor units overlap the single coil.

12 . The position sensor of claim 1 , wherein the one or more coils includes:
a first coil having a first footprint that overlaps the first magnetic field sensor unit; and a second coil having a second footprint that overlaps the second magnetic field sensor unit; and wherein the first coil and the second coil are connected in series.

13 . The magnetic position sensor of claim 11 , wherein the first coil surrounds a first core region and the second coil surrounds a second core region; and
wherein the first magnetic field sensor unit overlaps the first core region and the second magnetic field sensor unit overlaps the second core region.

14 . The magnetic position sensor of claim 11 , wherein the first magnetic field sensor unit overlaps the first coil, and the second magnetic field sensor unit overlaps the second coil.

15 . The magnetic position sensor of claim 10 , further comprising:
a third magnetic field sensor unit having a third sensor output; and a fourth magnet field sensor unit having a third sensor output; wherein the one or more coils further includes:
a third coil having a third footprint that overlaps the third magnetic field sensor unit; and
a fourth coil having a fourth footprint that overlaps the fourth magnetic field sensor unit; and
wherein the first, second, third, and fourth coils are connected in series.

16 . The magnetic position sensor of claim 1 , wherein the first and second magnetic field sensor units are on opposing sides of a semiconductor die, and the one or more coils are on the semiconductor die.

17 . The magnetic position sensor of claim 1 , wherein each of the first and second magnetic field sensor includes in-plane hall-effect elements.

18 . The magnetic position sensor of claim 1 , wherein each of the first and second magnetic field sensor includes out-of-plane hall-effect elements.

19 . The magnetic position sensor of claim 1 , wherein the first magnetic field sensor includes an in-plane hall-effect element, and the second magnetic field sensor includes an out-of-plane hall-effect element.

20 . A sensor device, comprising:
a semiconductor die; a first magnetic field sensor unit having a first sensor output on a first side of the semiconductor die; a second magnet field sensor unit having a second sensor output on a second side of the semiconductor die opposing the first side; one or more coils having one or more footprints overlapping the first and second magnetic field sensor units; and a processing circuit having first and second sensor inputs, a current terminal,

Assignees

• Texas Instruments Inc

Inventors

• Garcha Preetinder
• Cotton Lawrence
• Lee Dok Won
• Haroun Baher

Classifications

• G01D3/036

  on measuring arrangements themselves · CPC title

• G01D18/002

  Automatic recalibration (G01D18/008 takes precedence) · CPC title

• G01D5/145 Primary

  influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06) · CPC title

• G01D18/001 Primary

  Calibrating encoders · CPC title