Transcutaneous energy transfer primary coil with a high aspect ferrite core

• US 7,599,744 B2
• Filed: 06/24/2004
• Issued: 10/06/2009
• Est. Priority Date: 06/24/2004
• Status: Expired due to Fees

• Current Assignee: Ethicon Endo-Surgery, Inc. (Johnson & Johnson)
• Original Assignee: Ethicon Endo-Surgery, Inc. (Johnson & Johnson)
• Inventors: Giordano, James R., Hassler, William L. Jr., Dlugos, Daniel F. Jr.
• Primary Examiner(s): Layno; Carl H.
• Assistant Examiner(s): MORALES, JON ERIC C
• Application Number:
  US10/876,313
• Publication Number:
  US 20050288742A1
• Time in Patent Office: 1,930 Days
• Field of Search: 607/33, 607/61, 607/2, 607/34
• US Class Current: 607/61
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

Adjustable gastric band implants contain a hollow elastomeric balloon with fixed end points encircling a patient'"'"'s stomach just inferior to the esophago-gastric junction. These balloons can expand and contract through the introduction of saline solution into the balloon. In current bands, this saline solution must be injected into a subcutaneous port with a needle to reach the port located below the skin surface. The port communicates hydraulically with the band via a catheter. As an alternative to using a percutaneously accessed injection port, a system for regulating the flow of saline that is totally implanted may rely upon bi-directionally pumping fluid from an implant device. This system instead transfers AC magnetic flux energy from an external primary coil to a secondary coil that powers the pump in the implanted reservoir. A magnetically permeable rod centered within the primary coil increases power coupled to the secondary coil.

Claims

1. A transcutaneous energy transfer device for transferring energy from an external device located outside of a patient'"'"'s skin to an internal device implanted below the patient'"'"'s skin, the transcutaneous energy transfer device comprising:

an external device configured to be placed adjacent to skin on the exterior of a patient and to transmit energy into the patient, the external device comprising;

i) a primary transmitter coil comprising at least one wire wrapped around a primary central axis of the primary transmitter coil into a toroid shape encircling the primary central axis, the toroid shape having;

a) an exterior primary surface defined by an elliptical cross section of the toroid shape rotated about the primary central axis,

b) a central gap between the exterior primary surface and the primary central axis,

c) a primary minimum diameter where the primary surface of the toroid shape is closest to the primary central axis, and

d) a primary coil height, wherein the primary coil height is less than the primary minimum diameter;

ii) an elongate member positioned within the central gap of the primary transmitter coil and having a longitudinal axis, wherein the elongate member comprises a plurality of wedge-shaped slender components, wherein each slender component of the plurality of slender components is attached to an adjacent slender component of the plurality of slender components, the elongate member further comprising an electrically insulating material positioned between each of the adjacent slender components such that each of the slender components is electrically isolated from the other slender components, the elongate member and longitudinal axis extending collinearly in a straight line along the primary central axis of the primary transmitter coil with the elongate member formed from a magnetically permeable material, the elongate member having;

e) a member length extending along the primary central axis above and below the primary coil height, and

f) an outer diameter along the length of the elongate member, wherein the outer diameter of the elongate member is smaller than the primary minimum diameter of the primary transmitter coil to define a ring shaped gap between the outer diameter of the elongate member and the primary transmitter coil;

iii) a power supply operably attached to the primary transmitter coil to energize the primary coil, wherein when the primary transmitter coil is energized, the primary transmitter coil is configured to generate a toroidal shaped electromagnetic energy field having a generally circular cross section rotated around the primary central axis of the primary transmitter coil and the elliptical cross section of the primary transmitter coil, and the elongate member is configured to reshape the circular cross section of the toroidal electromagnetic energy field by elongating the circular cross section into an elongated elliptical cross section having an elongated major axis parallel to the primary central axis of the primary transmitter coil, and by moving the elliptically elongated electromagnetic field farther away from the surface of the primary coil in directions along the major axis;

an internal device configured to be implanted beneath the skin of a patient and to inductively receive electromagnetic energy transmitted from the external device, the internal device comprising;

iv) a secondary receiver coil comprising at least one wire wrapped around a secondary central axis of the secondary receiver coil into a toroid shape encircling the secondary central axis, the toroid shape having;

g) an exterior secondary surface defined by an elliptical cross section of the toroid shape rotated about the secondary central axis of the secondary receiver coil, and

h) a secondary central gap between the secondary surface and the secondary central axis,

v) an implant circuit attached to the secondary receiver coil to receive energy inductively transmitted from the primary receiver coil, wherein when the implant circuit and the secondary receiver coil are implanted at a depth below the patients skin with the central axis of the secondary receiver coil oriented perpendicular to the patients skin, and primary transmitter coil is placed outside of the patient'"'"'s skin with the primary central axis coaxially aligned with the secondary central axis of the secondary receiver coil, and the primary transmitter coil is energized to inductively transfer energy directly to the secondary receiver coil, the configuration of the primary transmitter coil with the elongate member generates an elliptically elongated toroidal electromagnetic energy field around the surface of the primary transmitter coil that is elliptically elongated in a direction to penetrate into the patient'"'"'s skin, wherein when the secondary receiver coil inductively receives energy from the elongated toroidal electromagnetic energy field transmitted directly from the primary transmitter coil, the inductive energy transfer is optimized by the elongation of the toroidal electromagnetic energy field to maximize the power transmission between the internal device and the external device and to maximize the implant depth for operative transfer of energy from the external device to the internal device.

2. The transcutaneous energy transfer device of claim 1, wherein the elongate member comprises a ferrite material.

3. The transcutaneous energy transfer device of claim 2, wherein the elongate member comprises a rod.

4. The transcutaneous energy transfer device of claim 2, further comprising a magnetic shield comprising a backplane attached to the elongate member and covering a side of the primary coil opposite to the secondary coil.

5. The transcutaneous energy transfer device of claim 4, wherein the magnetic shield further comprises a cylindrical flange attached and inwardly directed from the backplane to define a ring groove to receive the primary coil.

6. The transcutaneous energy transfer device of claim 1, wherein the elongate member comprises an elongate rod that has a length of between about one inch and four inches.

7. The transcutaneous energy transfer device of claim 6, wherein the elongate member comprises a rod having a length of about three inches and a diameter of about three-quarter inches.

8. The transcutaneous energy transfer device of claim 7, wherein the elongate member comprises a ferrite material.

9. The transcutaneous energy transfer device of claim 1, wherein the plurality of slender components are formed from steel.

10. The transcutaneous energy transfer device of claim 1, wherein the plurality of slender components are formed from ferrite.

11. A transcutaneous energy transfer device for transferring energy from an external device located outside of a patient'"'"'s skin to an internal device implanted below the patient'"'"'s skin, the transcutaneous energy transfer device comprising:

an external primary transmitter coil to which energy to be transferred is applied, wherein the external primary transmitter coil has an outer diameter, wherein the external primary transmitter coil comprises at least one wire wrapped around a primary central axis of the external primary transmitter coil into a toroidal shape encircling the primary central axis, the toroid shape having an elliptical cross section rotated about the primary central axis and defining a center gap, and having a primary minimum diameter where the primary surface of the toroid shape is closest to the primary central axis, wherein the toroid shape further defines a primary coil height, wherein the primary coil height is less than the primary minimum diameter;

an implanted secondary receiver coil comprising at least one wire wrapped around a secondary central axis of the secondary receiver coil into a toroid shape encircling the secondary central axis, wherein the toroid shape of the implanted secondary receiver coil defines an exterior secondary surface defined by an elliptical cross section of the toroid shape rotated about the secondary central axis of the secondary transmitter coil, and further defines a secondary central gap between the secondary surface and the secondary central axis, wherein the implanted secondary coil is configured to be inductively coupled to the external primary transmitter coil when the primary coil is placed adjacent to the skin and the secondary central axis is coaxially aligned with the primary central axis, wherein when the implanted secondary receiver coil is connected to a subcutaneous utilization device, wherein the inductively coupled energy is conducted to the subcutaneous utilization device; and

a slender cylindrical member centered within the center gap of the external primary transmitter coil member, the slender cylindrical member defining a longitudinal axis coaxially aligned with the primary center axis of the external primary transmitter coil, the slender cylindrical member extending above and below the external primary transmitter coil height and having a uniform outer diameter that is smaller than a diameter of the center gap of the external primary transmitter coil member to define a ring shaped gap between the primary surface of the external primary transmitter coil and the outer diameter of the slender cylindrical member, the slender cylindrical member being formed from a ferrite material, wherein the outer diameter of the slender cylindrical member is less than or equal to one fourth of the outer diameter of the external primary transmitter coil;

wherein when the longitudinal axis of the slender cylindrical member and the primary central axis and the secondary central axis of both the external primary transmitter coil and the implanted secondary receiver coil are all coaxially aligned on opposite sides of the patient'"'"'s skin and the external primary transmitter coil is energized, the external primary transmitter coil is configured to generate a toroidal electromagnetic energy field having a generally circular cross section rotated around the primary central axis of the primary transmitter coil and the elliptical cross section of the primary transmitter coil to inductively transfer energy directly to the implanted secondary coil, wherein the elongate member is configured to elongate the circular cross section of the toroidal electromagnetic energy field into an elongated elliptical cross section having an elongated major axis parallel to the longitudinal axis and configured to move the elliptically elongated electromagnetic field farther away from the surface of the external primary transmitter coil, wherein the inductive energy transfer is optimized by the elongation of the toroidal electromagnetic energy field to maximize the power transmission between the internal device and the external device and to maximize the implant depth for operative transfer of energy from the external device to the internal device.

12. A transcutaneous energy transfer device for inductively coupling energy from an external device to an internal device configured to apply energy to a subcutaneous utilization device, the transcutaneous energy transfer device comprising:

an external primary transmitter coil to which energy to be transferred is applied, wherein the external primary transmitter coil comprises at least one wire wrapped around a primary central axis of the primary transmitter coil into a toroidal shape encircling the primary central axis, the toroid shape having an elliptical cross section rotated about the primary central axis, and defining a center gap and a primary minimum diameter where the primary surface of the toroid shape is closest to the primary central axis, wherein the external annular primary coil member further defines a primary coil height and the primary coil height is less than the primary minimum diameter;

a pot core comprising a disk portion and a cylindrical flange, wherein the pot core defines a central axis coaxially aligned with the primary central axis of the primary transmitter coil, wherein the cylindrical flange extends transversely relative to a first face of the disk portion, wherein the cylindrical flange has an inner surface and an outer surface, the pot core further comprising an elongated member, wherein the elongated member extends transversely relative to a first face of the disk portion, wherein the external primary transmitter coil is positioned closer to the inner surface of the cylindrical flange than the external primary transmitter coil is to the elongated member, wherein the elongated member is centered within the circular center gap of the external primary transmitter coil and is formed from a magnetically permeable material, wherein the elongated member defines a longitudinal axis coaxially aligned with the primary central axis of the external primary transmitter coil and the central axis of the pot core, the elongated member having a uniform diameter that is smaller than a diameter of the center gap of the external primary transmitter coil, wherein the elongated member defines a ring shaped center gap between the external primary transmitter coil and the elongated member, wherein the ring shaped center gap between the external primary transmitter coil and the elongated member defines a lateral distance between the external primary transmitter coil and the elongated member, wherein the lateral distance between the external primary transmitter coil and the elongated member is greater than a lateral distance between the external primary transmitter coil and the inner surface of the cylindrical flange, wherein the elongate member is configured to deform a circular cross sectional toroidal electromagnetic field generated by the external primary transmitter coil into an elliptical cross sectional toroidal electromagnetic field, the elliptical cross section of the field having an elongated major axis parallel to the primary central axis of the external primary transmitter coil to thereby move the elliptically elongated electromagnetic field farther away from the surface of the external primary transmitter coil in directions along the major axis;

an implanted secondary receiver coil comprising at least one wire wrapped around a secondary central axis of the implanted secondary receiver coil into a toroid shape encircling the secondary central axis, wherein the toroid shape of the implanted secondary receiver coil has an exterior secondary surface defined by an elliptical cross section of the toroid shape rotated about the secondary central axis of the implanted secondary receiver coil, wherein the toroid shape defines a secondary central gap between the secondary surface and the secondary central axis; and

excitation circuitry operatively configured to selectively energize the external primary transmitter coil to create an elliptical toroidal electromagnetic field to inductively couple energy directly from the external primary transmitter coil to the implanted secondary receiver coil when the primary central axis and the secondary central axis of the respective external primary transmitter coil and the implanted secondary receiver coil are coaxially aligned, wherein the inductive energy transfer is optimized by the elongation of the toroidal electromagnetic energy field to maximize the power transmission between the internal device and the external device and to maximize the implant depth for operative transfer of energy from the external device to the internal device.