Systems and methods for integrated shielding in a current sensor
Systems and methods described herein are directed towards integrating a shield layer into a current sensor to shield a magnetic field sensing element and associated circuitry in the current sensor from electrical, voltage, or electrical transient noise. In an embodiment, a shield layer may be disposed along at least one surface of a die supporting a magnetic field sensing element. The shield layer may be disposed in various arrangements to shunt noise caused by a parasitic coupling between the magnetic field sensing element and the current carrying conductor away from the magnetic field sensing element.
1. A current sensor comprising:
a conductor;
an insulation layer in contact with the conductor;
a semiconductor substrate having a shield layer disposed on a first surface proximal to the insulation layer and a second opposing surface distal from the insulation layer, wherein the shield layer is disposed between the substrate and the insulation layer;
a magnetic field sensing circuit, comprising a magnetic field sensing element, supported by the semiconductor substrate; and
a via extending through the semiconductor substrate to couple the shield layer to the second surface of the semiconductor substrate, wherein the shield layer is coupled to a reference potential;
wherein the shield layer is coupled to the reference potential through the via, wherein the magnetic filed sensing circuit is supported by the second surface of the semiconductor substrate and wherein the reference potential to which the shield layer is couples is a reference potential of the magnetic field sensing circuit.
2. The current sensor of claim 1 , wherein the current sensor is provided in the form of an integrated circuit having a lead frame, wherein the conductor comprises a first portion of the lead frame and a plurality of signal leads comprise a second portion of the lead frame.
3. The current sensor of claim 2 , further comprising an interconnect configured to couple the via to at least one of the plurality of signal leads.
4. The current sensor of claim 3 , wherein the interconnect comprises a wire bond.
5. The current sensor of claim 1 , wherein the magnetic field sensing element comprises at least one of a Hall-effect element or a magnetoresistance element.
6. The current sensor of claim 5 , wherein the magnetoresistance element includes at least one of Indium Antimonide (InSb), a giant magnetoresistance (GMR) element, an anisotropic magnetoresistance (AMR) element, a tunneling magnetoresistance (TMR) element or a magnetic tunnel junction (MTJ) element.
7. The current sensor of claim 1 , wherein the insulation layer comprises at least one of a polymer dielectric material or a layer of adhesive.
8. The current sensor of claim 1 , wherein the shield layer comprises a conductive material.
9. The current sensor of claim 8 , wherein the conductive material comprises one or more of copper, aluminum, gold, nickel and aluminum copper alloy.
10. The current sensor of claim 1 , wherein the via comprises a through-silicon via extending from the first surface of the semiconductor substrate to the second surface of the semiconductor substrate.
11. The current sensor of claim 1 , wherein the first surface of the semiconductor substrate supports the magnetic field sensing circuit.
12. The current sensor of claim 11 , wherein the magnetic field sensing circuit comprises a magnetic field sensing element comprising at least one of a Hall-effect element or a magnetoresistance element.
13. The current sensor of claim 12 , wherein the magnetoresistance element includes at least one of Indium Antimonide (InSb), a giant magnetoresistance (GMR) element, an anisotropic magnetoresistance (AMR) element, a tunneling magnetoresistance (TMR) element or a magnetic tunnel junction (MTJ) element.
14. The current sensor of claim 1 , wherein the shield layer comprises a slot aligned with the magnetic field sensing element.
15. The current sensor of claim 14 , wherein the slot reduces a property of an eddy current as sensed by the magnetic field sensing element.
16. The current sensor of claim 2 , wherein the magnetic field sensing circuit is supported by the second surface of the semiconductor substrate and wherein the current sensor further comprises an interconnect configured to couple the second surface of the semiconductor substrate to at least one of the plurality of signal leads.
17. The current sensor of claim 16 , wherein the interconnect comprises a wire bond.
18. The current sensor of claim 1 , wherein the insulation layer extends beyond a length of the conductor.
19. The current sensor of claim 1 , wherein the insulation layer is formed by one or both of a taping process or a deposition process.