Leadless current sensor package with high isolation

Patent metadata

Field	Value
Publication number	US-12265103-B2
Application number	US-202217817796-A
Country	US
Kind code	B2
Filing date	Aug 5, 2022
Priority date	Aug 5, 2022
Publication date	Apr 1, 2025
Grant date	Apr 1, 2025

Abstract

A sensor package comprising a lead frame, a current sensor die, and an interposer. The lead frame includes: (i) a primary conductor, (ii) a plurality of secondary leads, and (iii) a layer of dielectric material that is disposed between the primary conductor and the plurality of secondary leads. The current sensor die includes one or more sensing elements. The current sensor die is configured to measure a level of electrical current through the primary conductor of the lead frame. The interposer is disposed over the layer of dielectric material. The interposer includes a plurality of conductive traces that are configured to couple each of a plurality of terminals of the current sensor die to a respective one of the plurality of secondary leads.

First claim

The invention claimed is:

1. A sensor package comprising:
a lead frame including: (i) a primary conductor, (ii) a plurality of secondary leads, and (iii) a layer of dielectric material that is disposed between the primary conductor and the plurality of secondary leads;
a current sensor die including one or more sensing elements, the current sensor die being configured to measure a level of electrical current through the primary conductor of the lead frame; and
an interposer that is dispose between the current sensor die and the secondary leads, the interposer being spaced apart laterally from the primary conductor and the current sensor die, the interposer being disposed over the layer of dielectric material, the interposer including a substrate and a plurality of conductive traces that are formed on the substrate, the plurality of conductive traces being configured to couple each of a plurality of terminals of the current sensor die to a respective one of the plurality of secondary leads,
wherein: (i) the primary conductor and the current sensor die are disposed in a first end portion of the sensor package, and the current sensor die is disposed over the primary conductor, (ii) the plurality of secondary leads is disposed in a second end portion of the sensor package, and (iii) the interposer is disposed in a middle portion of the sensor package, the middle portion being situated between the first end portion and the second end portion.

2. The sensor package of claim 1 , wherein each of the plurality of conductive traces includes a respective first end a respective second end, the respective first end of any of the plurality of conductive traces being coupled to a different one of the plurality of terminals of the current sensor die via a respective first wire bond, and the respective second end of any of the plurality of conductive traces being coupled to a different one of the plurality of secondary leads via a respective second wire bond.

3. The sensor package of claim 1 , further comprising a plurality of internal conductors that are disposed between the current sensor die and the interposer, wherein:
each of the plurality of terminals of the current sensor die is coupled to a different one of the plurality of internal conductors via a respective first conductive structure; and
each of the plurality of conductive traces of the interposer incudes a first end and a second end, such that the first end of each of the plurality of conductive traces is coupled to a different one of the plurality of internal conductors via a respective second conductive structure, and the second end of each of the plurality of conductive traces is coupled to a different one of the plurality of secondary leads via a respective third conductive structure.

4. The sensor package of claim 3 , wherein any of the first, second, and third conductive structures includes one of a solder ball, a copper pillar, a gold bump, a eutectic or high lead solder bump, a no-lead solder bump, a gold stud bump, a polymeric conductive bump, a layer of anisotropic conductive paste, or a conductive film.

5. The sensor package of claim 1 , further comprising a plurality of internal conductors that are disposed on the lead frame between the current sensor die and the interposer, wherein:
each of the plurality of terminals of the current sensor die is coupled to a different one of the plurality of internal conductors via a respective first conductive structure; and
each of a plurality of conductive traces incudes a first end and a second end, such that the first end of each of the plurality of conductive traces is coupled to a different one of the plurality of internal conductors via a respective second conductive structure, and the second end of each of the plurality of conductive traces is coupled to a different one of the plurality of secondary leads via a respective wire bond.

6. The sensor package of claim 1 , wherein the interposer is part of a flexible printed circuit board (PCB), the flexible PCB having a substrate, such that a part of the substrate is disposed between the primary conductor of the leadframe and the current sensor die to provide the current sensor die with electrical isolation from the primary conductor.

7. The sensor package of claim 5 , wherein:
the interposer includes a plurality of first contact pads that are formed on a first surface of the interposer and a plurality of second contact pads that are formed on a second surface of the interposer, the second surface being opposite to the first surface,
the first end of each of the plurality of conductive traces is coupled to a different one of the plurality of internal conductors via a respective one of the plurality of first contact pads, and
the second end of each of the plurality of conductive traces is coupled to a different one of the plurality of secondary leads via a respective one of the plurality of second contact pads.

8. The sensor package of claim 1 , wherein each of the plurality of conductive traces of the interposer incudes a first end and a second end, such that the first end of each of the conductive traces is coupled to a different one of the plurality of terminals of the current sensor die via a respective wire bond, and the second end of each of the conductive traces is coupled to a different one of the plurality of secondary leads via a respective conductive structure.

9. The sensor package of claim 8 , wherein any of the conductive structures includes one of a solder ball, a copper pillar, a gold bump, a eutectic or high lead solder bump, a no-lead solder bump, a gold stud bump, a polymeric conductive bump, a layer of anisotropic conductive paste, or a conductive film.

10. The sensor package of claim 8 , wherein:
the interposer includes a plurality of first contact pads that are formed on a first surface of the interposer and a plurality of second contact pads that are formed on a second surface of the interposer, the second surface being opposite to the first surface,
the first end of each of the plurality of conductive traces is coupled to different one of the plurality of terminals of the current sensor via a respective one of the plurality of first contact pads, and
the second end of each of the plurality of conductive traces is coupled to a different one of the plurality of secondary leads via a respective one of the plurality of second contact pads.

11. A sensor package comprising:
a lead frame including: (i) a primary conductor, (ii) a plurality of secondary leads, and (iii) a layer of dielectric material that is disposed between the primary conductor and the plurality of secondary leads;
an isolation structure that is disposed over the primary conductor;
a current sensor die including one or more sensing elements, the current sensor die being configured to measure a level of electrical current through the primary conductor of the lead frame;
an interposer that is disposed between the current sensor die and the secondary leads, the interposer being spaced apart laterally from the primary conductor and the current sensor die, the interposer being disposed over the layer of dielectric material, the interposer including substrate and a plurality of conductive traces that are formed on the substrate;
a plurality of first wire bonds, each of the first wire bonds being configured to couple the current sensor die to a different one of the plurality of conductive traces; and
a plurality of second wire bonds, each of the plurality of second wire bonds being configured to couple a different one of the plurality of conductive traces to a respective one of the plurality of secondary leads,
wherein the primary conductor and the plurality of

Assignees

• Allegro Microsystems Llc

Inventors

• Briano Robert A
• Doogue Michael C
• Taylor William P

Classifications

• H10W72/50

  Bond wires · CPC title

• H10W70/479

  on or in insulating or insulated package substrates, interposers, or redistribution layers · CPC title

• H10W90/401

  characterised by multiple insulating or insulated package substrates, interposers or RDLs · CPC title

• H10W74/114

  by a substrate and the encapsulations · CPC title

• H10W72/541

  Dispositions of bond wires · CPC title