Hall sensor and sensing method, and corresponding device

Patent metadata

Field	Value
Publication number	US-9952291-B2
Application number	US-201615142270-A
Country	US
Kind code	B2
Filing date	Apr 29, 2016
Priority date	Jul 28, 2015
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A Hall sensor may include a Hall sensing element configured to produce a Hall voltage indicative of a magnetic field when traversed by an electric current, and a first pair of bias electrodes mutually opposed in a first direction across the Hall sensing element. The Hall sensor may include a second pair of bias electrodes mutually opposed in a second direction across the Hall sensing element. The Hall sensor may include a first pair of sensing electrodes mutually opposed in a third direction across the Hall sensing element, and a second pair of sensing electrodes mutually opposed in a fourth direction across the Hall sensing element. The fourth direction may be orthogonal to the third direction, each sensing electrode being between a bias electrode of the first pair and a bias electrode of the second pair.

First claim

That which is claimed is:

1. A Hall sensor comprising:
a Hall sensing element configured to produce a Hall voltage indicative of a magnetic field when traversed by an electric current;
a first pair of bias electrodes mutually opposed in a first direction across said Hall sensing element;
a second pair of bias electrodes mutually opposed in a second direction across said Hall sensing element, the second direction being orthogonal to the first direction;
a first pair of sensing electrodes mutually opposed in a third direction across said Hall sensing element; and
a second pair of sensing electrodes mutually opposed in a fourth direction across said Hall sensing element, the fourth direction being orthogonal to the third direction, each sensing electrode being between a bias electrode of said first pair and a bias electrode of said second pair.

2. The Hall sensor of claim 1 wherein the third and fourth directions are respectively angularly spaced by 45° from the first and second directions.

3. The Hall sensor of claim 1 wherein each bias electrode comprises a bar-shaped electrode; wherein said first pair of bias electrodes extends in parallel; and wherein said second pair of bias electrodes extends in parallel.

4. The Hall sensor of claim 1 further comprising:
a bias module configured to selectively apply bias currents between the bias electrodes of said first pair and between the bias electrodes of said second pair; and
a readout module configured to selectively sense Hall voltages between the sensing electrodes of said first pair and between the sensing electrodes of said second pair.

5. The Hall sensor of claim 4 further comprising a phase generator coupled with said bias module and said readout module, and configured to produce mutually time-phased operation of said bias module and said readout module.

6. The Hall sensor of claim 4 wherein said bias module is configured to selectively vary a direction of the bias currents between the bias electrodes of said first pair and between the bias electrodes of said second pair.

7. The Hall sensor of claim 4 wherein said readout module comprises first and second differential detectors configured to differentially sense the Hall voltages between the sensing electrodes of said first pair and between the sensing electrodes of said second pair.

8. The Hall sensor of claim 7 wherein said readout module comprises first and second subtraction units coupled to said first and second differential detectors and configured to subtract from each other the Hall voltages of opposed polarity sensed between the sensing electrodes of said first pair and between the sensing electrodes of said second pair.

9. The Hall sensor of claim 8 wherein said first and second subtraction units each comprises a switched-capacitor circuit.

10. The Hall sensor of claim 8 further comprising first and second capacitor circuits configured to store the Hall voltages obtained from said first and second subtraction units.

11. The Hall sensor of claim 10 further comprising a sample and hold circuit configured to sample the Hall voltages from said first and second capacitor circuits, and analog-to-digital circuits configured to convert the Hall voltages from said sample and hold circuit, and compress the Hall voltages.

12. An electronic device comprising:
a circuit; and
a Hall sensor coupled to said circuit and comprising
a Hall sensing element configured to produce a Hall voltage indicative of a magnetic field when traversed by an electric current,
a first pair of bias electrodes mutually opposed in a first direction across said Hall sensing element,
a second pair of bias electrodes mutually opposed in a second direction across said Hall sensing element, the second direction being orthogonal to the first direction,
a first pair of sensing electrodes mutually opposed in a third direction across said Hall sensing element, and
a second pair of sensing electrodes mutually opposed in a fourth direction across said Hall sensing element, the fourth direction being orthogonal to the third direction, each sensing electrode being between a bias electrode of said first pair and a bias electrode of said second pair.

13. The electronic device of claim 12 wherein the third and fourth directions are respectively angularly spaced by 45° from the first and second directions.

14. The electronic device of claim 12 wherein each bias electrode comprises a bar-shaped electrode; wherein said first pair of bias electrodes extends in parallel; and wherein said second pair of bias electrodes extends in parallel.

15. The electronic device of claim 12 wherein said Hall sensor comprises:
a bias module configured to selectively apply bias currents between the bias electrodes of said first pair and between the bias electrodes of said second pair; and
a readout module configured to selectively sense Hall voltages between the sensing electrodes of said first pair and between the sensing electrodes of said second pair.

16. The electronic device of claim 15 wherein said Hall sensor comprises a phase generator coupled with said bias module and said readout module, and configured to produce mutually time-phased operation of said bias module and said readout module.

17. The electronic device of claim 15 wherein said bias module is configured to selectively vary a direction of the bias currents between the bias electrodes of said first pair and between the bias electrodes of said second pair.

18. A method of operating a Hall sensor comprising a Hall sensing element configured to produce a Hall voltage indicative of a magnetic field when traversed by an electric current, a first pair of bias electrodes mutually opposed in a first direction across the Hall sensing element, a second pair of bias electrodes mutually opposed in a second direction across the Hall sensing element, the second direction being orthogonal to the first direction, a first pair of sensing electrodes mutually opposed in a third direction across the Hall sensing element, and a second pair of sensing electrodes mutually opposed in a fourth direction across the Hall sensing element, the fourth direction being orthogonal to the third direction, each sensing electrode being between a bias electrode of the first pair and a bias electrode of the second pair, the method comprising:
performing sequentially first, second, third and fourth biasing phases for the first pair and second pair of bias electrodes;
wherein a bias current between the bias electrodes of the first pair is in a first bias direction in the first and second biasing phases and in a second bias direction in the third and fourth biasing phases, the second bias direction being opposite to the first bias direction;
wherein a bias current between the bias electrodes of the second pair is in a third bias direction in the first and fourth biasing phases and in a fourth bias direction in the second and third biasing phases, the fourth bias direction being opposite to the third bias direction.

19. The method of claim 18 further comprising:
sequential first, second, third and fourth sensing phases synchronized with the first, second, third and fourth biasing phases, respectively;
producing first and second sensing voltages respectively for the first pair of sensing electrodes and the second pair of sensing electrodes;
wherein the first sensing voltage is generated by subtracting from each other the Hall voltages produced by the first pair of sensing electrodes in the second and fourth sensing phases;
wherein the second

Assignees

• St Microelectronics Srl

Inventors

• Crescentini Marco
• Tartagni Marco
• Romani Aldo
• Canegallo Roberto
• Marchesi Marco
• Cristaudo Domenico

Classifications

• G01N27/90

  using eddy currents · CPC title

• G01R33/075 Primary

  Hall devices configured for spinning current measurements · CPC title

• G01R33/028

  Electrodynamic magnetometers · CPC title

• G01R33/07

  Hall effect devices · CPC title

• G01R33/038

  using permanent magnets, e.g. balances, torsion devices · CPC title