Methods and apparatus for providing a sufficiently stable power to a load in an energy transfer system

• US 7,155,291 B2
• Filed: 05/01/2002
• Issued: 12/26/2006
• Est. Priority Date: 10/19/1999
• Status: Expired due to Term

• Current Assignee: Abiomed, Inc. (Johnson & Johnson)
• Original Assignee: Abiomed, Inc. (Johnson & Johnson)
• Inventors: Zarinetchi, Farhad, Keville, Stephen J.
• Primary Examiner(s): Pezzuto, Robert E
• Assistant Examiner(s): Oropeza, Frances P.
• Application Number:
  US10/136,089
• Publication Number:
  US 20020123779A1
• Time in Patent Office: 1,700 Days
• Field of Search: 128/899, 128/903, 302/107, 302/108, 323/264, 323/347, 323/911, 607/2, 607/17, 607/32, 607/33, 607/61, 607/62
• US Class Current: 607/61
• CPC Class Codes: A61M 2205/8243 by induction
• CPC Class Codes: A61M 60/165 implantable in, on, or around the heart
• CPC Class Codes: A61M 60/178 drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices
• CPC Class Codes: A61M 60/196 replacing the entire heart, e.g. total artificial hearts [TAH]
• CPC Class Codes: A61M 60/216 including a rotating member acting on the blood, e.g. impeller
• CPC Class Codes: A61M 60/873 specially adapted for wireless or transcutaneous energy transfer [TET], e.g. inductive charging
• CPC Class Codes: A61N 1/00 Electrotherapy; Circuits therefor A61N2/00 takes precedence; irradiation apparatus A61N5/00
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: Y10S 323/911 Medical electronics

Abstract

Methods and apparatus for providing a sufficiently stable power to a load in an energy transfer system that transfers energy from one side of a physical boundary to another side of the boundary. In one example, a power supply and a primary winding are located on a first side of a physical boundary (e.g., external to a body), and a secondary winding and the load are located on a second side of the physical boundary (e.g., internal to the body). A primary voltage across the primary winding is regulated so as to provide a sufficiently stable output power to the load notwithstanding changes in the load and/or changes in a relative position of the primary winding and the secondary winding. One aspect of the invention relates to energy transfer methods and apparatus for use in connection with the human body. In particular, one example of the invention includes a transcutaneous energy transfer (TET) system for transferring power from a power supply external to the body to a device implanted in the body.

Claims

1. An energy receiving system for receiving power transferred from a power supply located on a first side of a physical boundary and delivering the power to a variable load located on a second side of the physical boundary, the energy receiving system comprising:

a secondary winding electrically coupled to the variable load to provide power to the variable load based on a magnetic field received by the secondary winding, the secondary winding adapted to be disposed on the second side of the physical boundary and for magnetic coupling with a primary winding disposed on the first side of the physical boundary to form a power channel between the windings through which the magnetic field is received by the secondary winding;

a secondary control circuit electrically coupled to the secondary winding to provide a detectable indication on the power channel that indicates at least one of changes in the variable load and changes in the relative position of the primary winding and the secondary winding, wherein the detectable indication includes at least one surge on the power channel.

2. The system of claim 1, wherein the secondary control circuit provides the detectable indication on the power channel to indicate a characteristic of the variable load compared to a predetermined threshold for that characteristic.

3. The system of claim 2, wherein the secondary control circuit provides the detectable indication on the power channel to indicate when a load voltage across the variable load one of exceeds and drops below a predetermined threshold load voltage.

4. The system of claim 3, wherein the secondary control circuit includes a comparator electrically coupled to the variable load to compare the load voltage to a predetermined threshold load voltage.

5. The system of claim 1, wherein the secondary control circuit includes a surge generator to generate the at least one surge.

6. The system of claim 5, wherein the secondary control circuit provides the at least one surge on the power channel to indicate a characteristic of the variable load compared to a predetermined threshold for that characteristic.

7. The system of claim 6, wherein the secondary control circuit provides the at least one surge on the power channel to indicate when a load voltage across the variable load one of exceeds and drops below a predetermined threshold load voltage.

8. The system of claim 7, wherein:

the secondary control circuit includes a comparator electrically coupled to the variable load to compare the load voltage to a predetermined threshold load voltage;

the comparator is electrically coupled to the surge generator; and

the secondary control circuit provides the at least one surge on the power channel based on the comparison.

9. The system of claim 8, wherein the surge generator includes a shunt circuit that generates a surge in a current in the secondary winding when an input signal to the shunt circuit reaches a shunt activation level, the comparator providing the input signal having the shunt activation level when the load voltage one of exceeds and drops below the predetermined threshold load voltage.

10. The system of claim 9, wherein:

the second side of the energy receiving system further includes at least one capacitor coupled to the secondary winding to form a secondary resonant circuit; and

the shunt circuit generates the surge in the current in the secondary winding by creating a short circuit across the secondary resonant circuit.

11. The system of claim 1, wherein the physical boundary is a patient'"'"'s skin and the energy receiving system is adapted to be implanted within a patient.

12. In an energy transfer system for transferring power from a power supply located on a first side of a physical boundary to a variable load located on a second side of the physical boundary, the system having a primary winding on the first side for generating a magnetic field based on input power provided by the power supply, the magnetic field permeating the physical boundary for magnetically coupling the primary winding to a secondary winding on the second side, thereby forming a power channel between the windings through which at least a portion of the magnetic field is received by the secondary winding to provide power to the variable load based on the received magnetic field, a system for the second side comprising:

a secondary winding electrically coupled to the variable load;

a secondary control circuit electrically coupled to the secondary winding to provide a detectable indication on the power channel that indicates a characteristic of the variable load compared to a predetermined threshold for that characteristic, wherein the detectable indication includes at least one surge on the power channel.

13. The system of claim 12, wherein the secondary control circuit provides the detectable indication on the power channel to indicate when a load voltage across the variable load one of exceeds and drops below a predetermined threshold load voltage.

14. The system of claim 13, wherein the secondary control circuit includes a comparator electrically coupled to the variable load to compare the load voltage to a predetermined threshold load voltage.

15. The system of claim 12, wherein the secondary control circuit includes a surge generator to generate the at least one surge.

16. The system of claim 15, wherein the secondary control circuit provides the at least one surge on the power channel to indicate a characteristic of the variable load compared to a predetermined threshold for that characteristic.

17. The system of claim 16, wherein the secondary control circuit provides the at least one surge on the power channel to indicate when a load voltage across the variable load one of exceeds and drops below a predetermined threshold load voltage.

18. The system of claim 17, wherein:

the secondary control circuit includes a comparator electrically coupled to the variable load to compare the load voltage to a predetermined threshold load voltage;

the comparator is electrically coupled to the surge generator; and

the secondary control circuit provides the at least one surge on the power channel based on the comparison.

19. The system of claim 18, wherein the surge generator includes a shunt circuit that generates a surge in a current in the secondary winding when an input signal to the shunt circuit reaches a shunt activation level, the comparator providing the input signal having the shunt activation level when the load voltage one of exceeds and drops below the predetermined threshold load voltage.

20. The system of claim 19, wherein:

the second side of the energy receiving system further includes at least one capacitor coupled to the secondary winding to form a secondary resonant circuit; and

the shunt circuit generates the surge in the current in the secondary winding by creating a short circuit across the secondary resonant circuit.

21. The system of claim 12, wherein the physical boundary is a patient'"'"'s skin and the system for the secondary side is adapted to be implanted within a patient.

22. In an energy transfer system for transferring power from a power supply located on a first side of a physical boundary to a variable load located on a second side of the physical boundary, the energy receiving system having a primary winding disposed on the first side and electrically coupled to the power supply to generate a magnetic field based on input power provided by the power supply, the magnetic field permeating the physical boundary for magnetically coupling a secondary winding disposed on the second side to the primary winding, thereby forming a power channel between the windings through which at least a portion of the magnetic field is received by the secondary winding, the secondary winding electrically coupled to the variable load to provide power to the variable load based on the received magnetic field, a method of providing power to the variable load comprising:

providing power to the variable load based on a magnetic field received by the secondary winding from the primary winding;

comparing a characteristic of the variable load to a predetermined threshold for that characteristic on the second side of the physical boundary; and

generating a detectable indication on the power channel based on the comparison for transmission across the physical boundary, wherein the generating a detectable indication on the power channel includes generating at least one surge on the power channel based on the comparison.

23. The method of claim 22, wherein the comparing is of a load voltage across the variable load to a predetermined threshold load voltage.

24. The method of claim 23, wherein the comparing indicates when the load voltage one of exceeds and drops below the predetermined threshold load voltage.

25. The method of claim 22, wherein the generating at least one surge on the power channel based on the comparison includes generating a surge in a current in the secondary winding.

26. The method of claim 25, wherein the generating the surge in the current in the secondary winding includes diverting power away from the variable load and into the secondary winding when the comparison reaches an activation level.

27. The method of claim 26, wherein the diverting power away from the variable load and into the secondary winding includes generating a short circuit across the secondary winding when the comparison reaches the activation level.

28. The method of claim 27, wherein the activation level is when the comparison indicates that a load voltage across the variable load one of exceeds and drops below a predetermined threshold load voltage.

29. The system of claim 22, wherein the physical boundary is a patient'"'"'s skin and the step of providing power includes transferring power across the patient'"'"'s skin.