Balancing an eddy current effect and a skin effect on a magnetic sensor using die paddle notches

Patent metadata

Field	Value
Publication number	US-9733280-B2
Application number	US-201514847392-A
Country	US
Kind code	B2
Filing date	Sep 8, 2015
Priority date	Sep 8, 2015
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

A magnetic current sensor may include a first sensing element, a second sensing element, and a die paddle. The die paddle may include a first edge and a second edge substantially parallel to a direction of the current. The die paddle may include a first notch, extending from the first edge in a direction of the first sensing element, with a first width in a range of approximately 50 percent to approximately 100 percent of a distance between the first edge and the first sensing element. The die paddle may include a second notch, extending from the second edge in a direction of the second sensing element, with a second width in a range of approximately 50 percent to approximately 100 percent of a distance between the second edge and the second sensing element.

First claim

What is claimed is:

1. A magnetic current sensor, comprising:
a first sensing element to sense a first magnetic field value associated with a current passing through a portion of a current rail;
a second sensing element to sense a second magnetic field value associated with the current passing through the portion of the current rail; and
a die paddle positioned above or below the first sensing element and the second sensing element,
the die paddle having a first edge and a second edge substantially parallel to a direction of the current,
the first edge being closer to the first sensing element than the second sensing element, and
the second edge being closer to the second sensing element than the first sensing element,

the die paddle including a first notch extending from the first edge in a direction of the first sensing element and having a first width in a range of approximately 50 percent to approximately 100 percent of a distance between the first edge and the first sensing element,
the die paddle including a second notch extending from the second edge in a direction of the second sensing element and having a second width in a range of approximately 50 percent to approximately 100 percent of a distance between the second edge and the second sensing element, and
the first notch and the second notch causing a frequency dependence of an amplitude of a magnetic field to be reduced or a frequency dependence of a phase shift of the magnetic field to be reduced,
the magnetic field being associated with the first magnetic field value and the second magnetic field value.

2. The magnetic current sensor of claim 1 , where the first notch and the second notch are substantially identical in shape with respect to each other.

3. The magnetic current sensor of claim 1 , where the die paddle includes a third edge and a fourth edge,
where the first notch and the second notch are similarly positioned along the first edge and the second edge relative to the third edge and the fourth edge.

4. The magnetic current sensor of claim 1 , where the directions of the first notch and the second notch are substantially perpendicular to the direction of the current passing through the portion of the current rail.

5. The magnetic current sensor of claim 1 , where the first sensing element and the second sensing element are Hall-based sensing elements, giant magnetoresistance (GMR)-based sensing elements, anisotropic magnetoresistance (AMR)-based sensing elements, or tunnel magnetoresistance (TMR)-based sensing elements.

6. The magnetic current sensor of claim 1 , where the magnetic current sensor is housed in a package comprising a semiconductor chip.

7. The magnetic current sensor of claim 1 , where the first notch and the second notch are positioned to reduce an eddy current effect induced in the die paddle by the current passing through the portion of the current rail.

8. A magnetic current sensor, comprising:
a first sensing element to determine a first magnetic field value associated with a current passing through a portion of a current rail;
a second sensing element to determine a second magnetic field value associated with the current passing through the portion of the current rail; and
a die paddle positioned above or below the first sensing element and the second sensing element,
the die paddle having a first edge and a second edge substantially parallel to a direction of the current, the first edge being closer to the first sensing element than the second sensing element, and the second edge being closer to the second sensing element than the first sensing element,
the die paddle including a first notch extending from the first edge in a direction substantially perpendicular to the direction of the current and having a first width that is less than a distance between the first edge and the first sensing element,
the die paddle including a second notch extending from the second edge in a direction substantially perpendicular to the direction of the current and having a second width that is less than a distance between the second edge and the second sensing element, and
the first notch and the second notch causing a frequency dependence of an amplitude of a magnetic field to be reduced or a frequency dependence of a phase shift of the magnetic field to be reduced,
the magnetic field being associated with the first magnetic field value and the second magnetic field value.

9. The magnetic current sensor of claim 8 , where the first notch and the second notch are rectangular shaped.

10. The magnetic current sensor of claim 8 , where the first width and the second width are based on a length of the die paddle and a width of the die paddle.

11. The magnetic current sensor of claim 8 , where the first width and the second width are based on a material of the portion of the current rail or a width of the portion of the current rail.

12. A magnetic sensor, comprising:
a first sensing element to determine a first magnetic field value associated with a current passing through a portion of a current rail;
a second sensing element to determine a second magnetic field value associated with the current passing through the portion of the current rail; and
a die paddle positioned above or below the first sensing element and the second sensing element,
the die paddle having a first edge and a second edge substantially parallel to a direction of the current, the first edge being closer to the first sensing element than the second sensing element, and the second edge being closer to the second sensing element than the first sensing element,
the die paddle including a first notch extending from the first edge in a direction substantially perpendicular to the direction of the current and having a first width that is approximately 75 percent of a distance between the first edge and the first sensing element, and
the die paddle including a second notch extending from the second edge in a direction substantially perpendicular to the direction of the current and having a second width that is approximately 75 percent of a distance between the second edge and the second sensing element, and
the first notch and the second notch causing a frequency dependence of an amplitude of a magnetic field to be reduced or a frequency dependence of a phase shift of the magnetic field to be reduced,
the magnetic field being associated with the first magnetic field value and the second magnetic field value.

13. The magnetic sensor of claim 12 , where the first width and the second width are based on a vertical distance between the die paddle and the portion of the current rail.

14. The magnetic sensor of claim 12 , where the first sensing element and the second sensing element form a differential sensor.

15. The magnetic sensor of claim 12 , where the first notch and the second notch are substantially identical in shape with respect to each other.

16. The magnetic sensor of claim 12 , where the die paddle includes a third edge and a fourth edge,
where the first notch and the second notch are similarly positioned along the first edge and the second edge relative to the third edge and the fourth edge.

17. The magnetic current sensor of claim 1 , where the first width of the first sensing element is less than the distance between the first edge and the first sensing element, and
where there the second width of the second sensing element is less than the distance between the second edge and the second sensing element.

18. The magnetic current sensor of claim 8 , where the first not

Assignees

• Infineon Technologies Ag

Inventors

• Hegedus Ákos

Classifications

• G01R15/207 Primary

  Constructional details independent of the type of device used · CPC title

• G01R15/205

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

• G01R19/0092

  Measuring current only · CPC title

• G01R15/202

  using Hall-effect devices (Hall elements in arrangements for measuring electrical power G01R21/08) · CPC title