Magnetic field sensor and related techniques that provide varying current spinning phase sequences of a magnetic field sensing element

Patent metadata

Field	Value
Publication number	US-9377285-B2
Application number	US-201313766341-A
Country	US
Kind code	B2
Filing date	Feb 13, 2013
Priority date	Feb 13, 2013
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

A magnetic field sensor can use a variety of different current spinning phase sequences, and/or can provide an angle error value to correct and/or minimize errors of the magnetic field sensor, A circuit using this magnetic field sensor can process output signals from an angle sensing element to provide an output signal that has a high degree of angle accuracy and a relatively high speed.

First claim

What is claimed is:

1. A method of reducing an error in a magnetic field sensor, comprising:
providing a plurality of magnetic field sensing elements, wherein each one of the plurality of magnetic field sensing elements is configured to generate a respective x-y output signal responsive to a magnetic field in an x-y plane;
sequentially selecting, at an element selection rate with an element selection period, from among the plurality of magnetic field sensing elements, resulting in a plurality of repeating cycles of selected magnetic field sensing elements, each repeating cycle sequentially selecting all of the plurality of magnetic field sensing elements, wherein the repeating cycles repeat at a cycle repetition rate with a cycle repetition period; and
current spinning, within respective element selection periods, each selected one of the plurality of magnetic field sensing elements, wherein the current spinning comprises generating a respective plurality of current spinning phases within the respective element selection periods, each plurality of current spinning phases within an element selection period having a respective phase sequence with a plurality of phases, each phase having a phase period, each phase period less than an element selection period, wherein the sequentially selecting and the current spinning together result in a sequenced-chopped signal representative of an angle of the magnetic field, wherein a first portion of the plurality of magnetic field sensing elements has a first current spinning phase sequence within one of the cycle repetition periods, and a second different portion of the plurality of magnetic field sensing elements has a second different current spinning phase sequence within the same one of the cycle repetition periods.

2. The method of claim 1 , wherein the current spinning comprises:
current spinning the plurality of magnetic field sensing elements with randomly selected phase sequences, randomly selected within a plurality of the cycle repetition periods.

3. The method of claim 1 , wherein the current spinning comprises:
current spinning the plurality of magnetic field sensing elements with pseudo-randomly selected phase sequences, pseudo-randomly selected within a plurality of the cycle repetition periods.

4. The method of claim 1 , wherein the current spinning comprises:
selecting a first set of magnetic field sensing elements from among the plurality of magnetic field sensing elements;
selecting a second different set of magnetic field sensing elements from among the plurality of magnetic field sensing elements;
current spinning the first set of magnetic field sensing elements with a first respective set of phase sequences within a first one of the cycle repetition periods; and
current spinning the second set of magnetic field sensing elements with a second different respective set of phase sequences within a second different one of the cycle repetition periods.

5. The method of claim 1 , wherein the plurality of magnetic field sensing elements comprises a plurality of vertical Hall Effect elements arranged as a circular vertical Hall (CVH) element, wherein each one of the plurality of vertical Hall Effect elements is arranged upon a common circular implant and diffusion region in a first major surface of a semiconductor substrate, wherein the plurality of vertical Hall Effect elements is configured to generate a respective plurality of x-y output signals responsive to a magnetic field having a direction component in an x-y plane parallel to the first surface of the semiconductor substrate, the x-y plane having an x-direction and a y-direction orthogonal to the x-direction.

6. The method of claim 5 , wherein the current spinning comprises:
current spinning the plurality of magnetic field sensing elements with randomly selected phase sequences, randomly selected within a plurality of the cycle repetition periods.

7. The method of claim 5 , wherein the current spinning comprises:
current spinning the plurality of magnetic field sensing elements with pseudo-randomly selected phase sequences, pseudo-randomly selected within a plurality of the cycle repetition periods.

8. The method of claim 5 , wherein the current spinning comprises:
selecting a first set of magnetic field sensing elements from among the plurality of magnetic field sensing elements;
selecting a second different set of magnetic field sensing elements from among the plurality of magnetic field sensing elements;
current spinning the first set of magnetic field sensing elements with a first respective set of phase sequences within a first one of the cycle repetition periods; and
current spinning the second set of magnetic field sensing elements with a second different respective set of phase sequences within a second different one of the cycle repetition periods.

9. A magnetic field sensing sensor, comprising:
a plurality of magnetic field sensing elements, wherein each one of the plurality of magnetic field sensing elements is configured to generate a respective x-y output signal responsive to a magnetic field in an x-y plane;
a sequence switching circuit configured to select, at an element selection rate with an element selection period, from among the plurality of magnetic field sensing elements, resulting in a plurality of repeating cycles of selected magnetic field sensing elements, each repeating cycle sequentially selecting all of the plurality of magnetic field sensing elements, wherein the repeating cycles repeat at a cycle repetition rate with a cycle repetition period; and
a current spinning circuit configured to current spin, within respective element selection periods, each selected one of the plurality of magnetic field sensing elements, wherein the current spinning comprises a respective plurality of current spinning phases within the respective element selection periods, each plurality of current spinning phases within an element selection period having a respective phase sequence with a plurality of phases, each phase having a phase period, each phase period less than an element selection period, wherein the sequentially sequence switching circuit and the current spinning circuit are together configured to generate a sequenced-chopped signal representative of an angle of the magnetic field, wherein a first portion of the plurality of magnetic field sensing elements has a first current spinning phase sequence within one of the cycle repetition periods, and a second different portion of the plurality of magnetic field sensing elements has a second different current spinning phase sequence within the same one of the cycle repetition periods, and
a control circuit configured to control the element selection periods, the cycle repetition periods, and the phase sequences of the current spinning phases.

10. The magnetic field sensor of claim 9 , wherein the control circuit is configured to control the sequence switching circuit and the current spinning circuit to current spin the plurality of magnetic field sensing elements with randomly selected phase sequences, randomly selected within a plurality of the cycle repetition periods.

11. The magnetic field sensor claim 9 , wherein the control circuit is configured to control the sequence switching circuit and the current spinning circuit to current spin the plurality of magnetic field sensing elements with pseudo-randomly selected phase sequences, pseudo-randomly selected within a plurality of the cycle repetition periods.

12. The magnetic field sensor claim 9 , wherein the control circuit is configured to control the sequence switching circuit and the current spinning circuit to: select a first set of m

Assignees

• Romero Hernan D
• Monreal Gerardo A
• Allegro Microsystems Llc

Inventors

• Romero Hernan D
• Monreal Gerardo A

Classifications

• G01B7/023 Primary

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

• G01R33/0029

  Treating the measured signals, e.g. removing offset or noise · CPC title

• G01R33/075 Primary

  Hall devices configured for spinning current measurements · CPC title

• G01R33/0082

  Compensation, e.g. compensating for temperature changes · CPC title

• G01R33/077

  Vertical Hall-effect devices · CPC title