Current detector that prevents fluctuatons in detection sensitivity

Patent metadata

Field	Value
Publication number	US-10338105-B2
Application number	US-201514943569-A
Country	US
Kind code	B2
Filing date	Nov 17, 2015
Priority date	Nov 25, 2014
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

A current detector includes a half-bridge configuration including first and second magnetic detection elements that are connected in series and disposed such that a magnetization direction of a magnetic pinned layer thereof is opposite to each other, and a bias magnetic field generating means for applying a bias magnetic field to the first and second magnetic detection elements. The bias magnetic field has a substantially same intensity and is formed in a direction substantially orthogonal to the magnetization direction and opposite to each other.

First claim

What is claimed is:

1. A current detector, comprising:
a full-bridge configuration comprising first to fourth magnetic detection elements, the first and second magnetic detection elements being connected in series and disposed such that a magnetization direction of a magnetic pinned layer thereof is opposite to each other, the third and fourth magnetic detection elements being connected in series and disposed such that a magnetization direction of a magnetic pinned layer thereof is opposite to each other, and the first and second magnetic detection elements being connected in parallel to the third and fourth magnetic detection elements; and
a bias magnetic field generating means for applying a bias magnetic field to two arbitrarily selected from the first to fourth magnetic detection elements and to two remaining magnetic detection elements,
wherein the bias magnetic field has a substantially same intensity, and is formed in a direction substantially orthogonal to the magnetization direction and opposite to each other,
wherein the bias magnetic field generating means applies a first bias magnetic field to first and second detection elements and a second bias magnetic field to third and fourth magnetic detection elements, and
wherein the first and second bias magnetic fields are oriented in a direction substantially orthogonal to the magnetization direction of their respective serially-connected magnetic detection elements.

2. The current detector according to claim 1 , wherein positive and negative voltages of a substantially same intensity are each applied to a junction between the first and third magnetic detection elements and to a junction between the second and fourth magnetic detection elements.

3. The current detector according to claim 2 , wherein the first and second magnetic detection elements have a same magnetoresistance change rate and the third and fourth magnetic detection elements have a same magnetoresistance change rate.

4. The current detector according to claim 1 , wherein a voltage is applied to a junction between the first and third magnetic detection elements, and a junction between the second and fourth magnetic detection elements is grounded.

5. The current detector according to claim 4 , wherein the second and fourth magnetic detection elements have a same magnetoresistance change rate.

6. The current detector according to claim 1 , wherein the bias magnetic field generating means comprises a first bias magnet provided above the first and second magnetic detection elements on a substrate and a second bias magnet provided above the third and fourth magnetic detection elements on the substrate.

7. The current detector according to claim 1 , wherein the bias magnetic field generating means comprises one bias coil provided above the first, second, third and fourth magnetic detection elements on the substrate.

8. The current detector according to claim 1 , wherein the first and second bias magnetic fields have a substantially same intensity.

9. A current detector, comprising:
a full-bridge configuration comprising first to fourth magnetic detection elements, the first and second magnetic detection elements being connected in series and disposed such that a magnetization direction of a magnetic pinned layer thereof is opposite to each other, the third and fourth magnetic detection elements being connected in series and disposed such that a magnetization direction of a magnetic pinned layer thereof is opposite to each other, and the first and second magnetic detection elements being connected in parallel to the third and fourth magnetic detection elements; and
a bias magnetic field generating means for applying a bias magnetic field to two arbitrarily selected from the first to fourth magnetic detection elements and to two remaining magnetic detection elements,
wherein the bias magnetic field has a substantially same intensity, and is formed in a direction substantially orthogonal to the magnetization direction and opposite to each other,
wherein the bias magnetic field generating means applies a first bias magnetic field to first and second detection elements and a second bias magnetic field to third and fourth magnetic detection elements, and
wherein the first and second bias magnetic fields are opposite in polarity to one another.

10. The current detector according to claim 9 , wherein positive and negative voltages of a substantially same intensity are each applied to a junction between the first and third magnetic detection elements and to a junction between the second and fourth magnetic detection elements.

11. The current detector according to claim 10 , wherein the first and second magnetic detection elements have a same magnetoresistance change rate and the third and fourth magnetic detection elements have a same magnetoresistance change rate.

12. The current detector according to claim 9 , wherein a voltage is applied to a junction between the first and third magnetic detection elements, and a junction between the second and fourth magnetic detection elements is grounded.

13. The current detector according to claim 12 , wherein the second and fourth magnetic detection elements have a same magnetoresistance change rate.

14. The current detector according to claim 9 , wherein the bias magnetic field generating means comprises a first bias magnet provided above the first and second magnetic detection elements on a substrate and a second bias magnet provided above the third and fourth magnetic detection elements on the substrate.

15. The current detector according to claim 9 , wherein the bias magnetic field generating means comprises one bias coil provided above the first, second, third and fourth magnetic detection elements on the substrate.

16. The current detector according to claim 9 , wherein the first and second bias magnetic fields have a substantially same intensity.

Assignees

• Hitachi Metals Ltd

Inventors

• Futakuchi Naoki
• Chiwata Naofumi
• Akimoto Katsuya

Classifications

• G01R15/205 Primary

  using magneto-resistance devices, e.g. field plates · CPC title