Packaged current sensor integrated circuit

Patent metadata

Field	Value
Publication number	US-11519946-B1
Application number	US-202117409011-A
Country	US
Kind code	B1
Filing date	Aug 23, 2021
Priority date	Aug 23, 2021
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A packaged current sensor integrated circuit includes a primary conductor having an input portion and an output portion configured to carry a current to be measured by a magnetic sensing element supported by a semiconductor die adjacent to the primary conductor. Each of the input portion and output portion of the primary conductor is exposed from orthogonal sides of the package body. A fault signal may be provided to indicate an overcurrent condition in the integrated current sensor package. The primary current path may be made of a thick lead frame material to reduce the primary current path resistance.

First claim

What is claimed is:

1. A packaged current sensor integrated circuit comprising:
a primary conductor having an input portion and an output portion, wherein the primary conductor is configured to carry a current from the input portion of the primary conductor to the output portion of the primary conductor;
at least one secondary lead;
a semiconductor die disposed adjacent to the primary conductor;
at least one magnetic field sensing element supported by the semiconductor die; and
a package body enclosing the semiconductor die and at least a portion of the primary conductor, wherein the input portion of the primary conductor is exposed from a first side of the package body and a second side of the package body that is substantially orthogonal with respect to the first side of the package body, and wherein the output portion of the primary conductor is exposed from the second side of the package body and a third side of the package body that is substantially orthogonal with respect to the second side of the package body and opposite with respect to the first side of the package body.

2. The packaged current sensor integrated circuit of claim 1 wherein the primary conductor has a partial path that forms a straight line across the package body from the first side to the third side of the package.

3. The packaged current sensor integrated circuit of claim 1 wherein the primary conductor further comprises an exposed portion on the bottom of the package body.

4. The packaged current sensor integrated circuit of claim 1 wherein the secondary lead has an exposed portion on the bottom of the package body.

5. The packaged current sensor integrated circuit of claim 1 further comprising at least three secondary leads.

6. The packaged current sensor integrated circuit of claim 5 wherein at least one secondary lead provides an output connection, at least one secondary lead provides a voltage input connection, and at least one secondary lead provides a ground connection.

7. The packaged current sensor integrated circuit of claim 1 further comprising a front-end amplifier, wherein the at least one magnetic field sensing element is connected to the front-end amplifier.

8. The packaged current sensor integrated circuit of claim 1 wherein the at least one magnetic field sensing element is a Hall effect sensor.

9. The packaged current sensor integrated circuit of claim 8 further comprising a Hall effect current drive circuit connected to the Hall effect sensor.

10. The packaged current sensor integrated circuit of claim 1 wherein a front end amplifier is connected to an amplifier to provide an output of the current level in the primary conductor.

11. The packaged current sensor integrated circuit of claim 1 further wherein the at least one secondary lead provides an input fault signal.

12. The packaged current sensor integrated circuit of claim 11 further comprising a threshold circuit having an input configured to receive the input fault signal and an output and a comparator having a first input coupled to the output of the threshold circuit, a second input coupled to an output of the front end amplifier, and an output at which a fault signal is provided, wherein the fault signal is indicative of whether the current exceeds a level of the input fault signal.

13. The packaged current sensor integrated circuit of claim 1 further comprising a wafer backside coating material on a back side of the semiconductor die.

14. The packaged current sensor integrated circuit of claim 13 further comprising a second wafer backside coating material on the back of the semiconductor die.

15. The packaged current sensor integrated circuit of claim 1 wherein a thickness of the primary conductor and a thickness of the at least one secondary lead are between approximately 0.2 mm and 0.5 mm.

16. The packaged current sensor integrated circuit of claim 1 wherein a thickness of the primary conductor and a thickness of the at least one secondary lead are between approximately 0.35 mm and 0.40 mm.

17. The packaged current sensor integrated circuit of claim 3 wherein the primary conductor further comprises a narrowed portion between the input portion and the output portion and wherein the exposed portion of the primary conductor comprises the narrowed portion.

18. The packaged current sensor integrated circuit of claim 17 wherein the exposed narrowed portion of the primary conductor is substantially orthogonal to the first side of the package body, the second side of the package body, and the third side of the package body.

19. The packaged current sensor integrated circuit of claim 3 wherein the secondary lead has an exposed portion on the bottom of the package body and wherein a minimum distance between the exposed portion of the primary conductor and the exposed portion of a nearest at least one secondary lead is at least 1.0 mm.

20. A method of sensing a current in a current sensor integrated circuit package comprising:
providing a primary conductor having an input portion and an output portion, wherein the primary conductor is configured to carry a current from the input portion of the primary conductor to the output portion of the primary conductor; wherein the input portion of the primary conductor is exposed from a first side of a package body of the current sensor integrated circuit package and a second side of the package body that is substantially orthogonal with respect to the first side of the package body, and wherein the output portion of the primary conductor is exposed from the second side of the package body and a third side of the package body that is substantially orthogonal with respect to the second side of the package body and opposite with respect to the first side of the package body;
providing at least one secondary lead;
providing a semiconductor die having at least one magnetic field sensing element disposed adjacent to the primary conductor;
measuring a magnetic field representative of the current in the primary conductor with the at least one magnetic field sensing element; and
providing an output signal representative of the current in the primary conductor.

21. The method of claim 20 further comprising:
providing a fault input voltage at a fault signal pin;
comparing the fault input voltage with an output of a front-end amplifier representative of the current in the primary current conductor; and
providing a fault output.

Assignees

• Allegro Microsystems Llc

Inventors

• Rock Simon E
• Latham Alexander
• Briano Robert A
• Liu Shixi Louis

Classifications

• G01R15/207 Primary

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

• G01R19/1659 Primary

  to indicate that the value is within or outside a predetermined range of values (window) (G01R19/16514, G01R19/16519, G01R19/16528 and G01R19/16533 take precedence) · CPC title

• G01R33/072

  Constructional adaptation of the sensor to specific applications · CPC title

• G01R19/16571

  comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current (G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533, G01R19/1659 take precedence; measuring currents by using elements sensitive to the magnetic field generated G01R15/14; measuring earth resistance G01R27/18; testing for leakage or short circuits in electrical apparatus G01R31/52) · CPC title