Method and apparatus for supplying energy to a medical device

• US 8,965,525 B2
• Filed: 07/23/2014
• Issued: 02/24/2015
• Est. Priority Date: 10/16/2007
• Status: Active Grant

• Current Assignee: Peter Forsell
• Original Assignee: Peter Forsell
• Inventors: Forsell, Peter
• Primary Examiner(s): Koharski, Christopher D
• Assistant Examiner(s): EDWARDS, PHILIP CHARLES
• Application Number:
  US14/338,501
• Publication Number:
  US 20140336679A1
• Time in Patent Office: 216 Days
• Field of Search: 607/61, 607/60, 607/33
• US Class Current: 607/61
• CPC Class Codes: A61B 17/12 for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord specially adapted for vas deferens or fallopian tubes A61F6/20; materials for ligaturing blood vessels A61L17/00
• CPC Class Codes: A61B 2560/0214 of power generation or supply
• CPC Class Codes: A61F 2250/0001 Means for transferring electromagnetic energy to implants
• CPC Class Codes: A61N 1/08 Arrangements or circuits for monitoring, protecting, controlling or indicating for external stimulators A61N1/3603; for implantable neurostimulators A61N1/36128; for heart stimulators A61N1/37; for defibrillators A61N1/3925
• 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 50/10 using inductive coupling
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• 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 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

In a method and apparatus for supplying wireless energy to a medical device implanted in a patient, wireless energy is transmitted from an external energy source located outside a patient and is received by an internal energy receiver located inside the patient, for directly or indirectly supplying received energy to the medical device. An energy balance is determined between the energy received by the internal energy receiver and the energy used for the medical device, and the transmission of wireless energy is then controlled based on the determined energy balance. The energy balance thus provides an accurate indication of the correct amount of energy needed, which is sufficient to operate the medical device properly, but without causing undue temperature rise.

Claims

1. An apparatus for controlling transmission of wireless energy supplied to an electrically operable medical device when implanted in a patient, comprising an external energy source, and an internal energy receiver, the apparatus being adapted to transmit said wireless energy from the external energy source located outside the patient which is received by the internal energy receiver located inside the patient, the internal energy receiver being connected to the medical device for directly or indirectly supplying received energy thereto, the apparatus being further adapted to:

determine an energy balance between the energy received by the internal energy receiver and the total energy used for the medical device,

determine the energy balance, by an internal control unit or external control unit, during the transmission of wireless energy,

transmit feed back information from inside the body to be able to control the wireless energy supply sent by the external energy source,

and

control the transmission of wireless energy from the external energy source, based on the determined energy balance, the apparatus is adapted to control the transmission of wireless energy in accordance with at least one of;

an energy reception rate in the internal energy receiver compared to an total rate of used energy being consumption rate, storage rate or combined consumption and storage rate, and

directly or indirectly measuring over time the difference between the total amount of energy received by the internal energy receiver and the total amount of used energy being consumed, stored or combined consumed and stored energy, and determining the energy balance based on at least one of;

said difference and a detected change in said difference.

2. The apparatus according to claim 1, further comprising a primary coil in the external energy source and a secondary coil in the internal energy receiver, the apparatus further adapted to transmit the wireless energy inductively from the primary coil in the external energy source to the secondary coil in the internal energy receiver.

3. The apparatus according to claim 1, further adapted to detect at least at least one of:

a change in said energy balance, and control the transmission of wireless energy based on said detected energy balance change, further adapted to decrease the amount of transmitted wireless energy if the detected energy balance change implies that the energy balance is increasing, or increase the amount of transmitted wireless energy if the detected energy balance change implies that the energy balance is decreasing, wherein the decrease/increase of energy transmission corresponds to a detected change rate, and

a difference between energy received by said internal energy receiver and energy used for the medical device, and control the transmission of wireless energy based on said detected energy difference, further adapted to decrease the amount of transmitted wireless energy if the detected energy difference implies that the received energy is greater than the used energy, or increase the amount of transmitted wireless energy if the detected energy balance change implies that the energy balance is decreasing, wherein the decrease/increase of energy transmission corresponds to the magnitude of said detected energy difference.

4. The apparatus according to claim 3, further adapted to handle the energy used for the medical device in at least one of the following alternatives:

a) consuming substantially all energy used for the medical device to operate the medical device, b) storing substantially all energy used for the medical device in at least one energy storage device and c) partly consuming the energy used for the medical device to operate the medical device and partly store the energy in said at least one energy storage device.

5. The apparatus according to claim 4, further comprising at least one energy stabilizing unit, the apparatus further adapted to consume or store the energy after being stabilized in the at least one energy stabilizing unit of the medical device.

6. The apparatus according to claim 5, adapted to transmit the wireless energy to be first transmitted with a predetermined energy rate, and then transmitted based on the energy balance, the apparatus adapted to determine by detecting the direction and rate of change in the current amount of accumulated energy in the energy stabilizing unit.

7. The apparatus according to claim 5, wherein the at least one energy stabilizing unit includes at least one of:

an accumulator, a capacitor or a semiconductor adapted to stabilize the received energy.

8. The apparatus according to claim 4, further adapted to determine the energy balance based on a detected change followed over time in the amount of consumed, stored or consumed and stored energy.

9. The apparatus according to claim 8, further adapted to detect the change in the amount of consumed, stored or consumed and stored energy by determining over time the derivative of a measured electrical parameter related to said amount of consumed, stored or consumed and stored energy, the derivative at a first given moment corresponding to the rate of the change at the first given moment, wherein the rate of change includes the direction and speed of the change.

10. The apparatus according to claim 9, further adapted to determine said derivative based on a detected rate of change of the electrical parameter.

11. The apparatus according to claim 1, further adapted to supply the energy received by the internal energy receiver to the medical device with at least one of:

at least one constant voltage, wherein the constant voltage is created by a comprised constant voltage circuitry, and at least one constant current, wherein the constant current is created by a comprised constant current circuitry.

12. The apparatus according to claim 11, further adapted to supply the energy with at least one of:

at least two different voltages, including the at least one constant voltage, and at least two different currents, including said at least one constant current.

13. The apparatus according to claim 3, wherein said detected difference being related to the integral over time of at least one measured electrical parameter related to said energy balance, wherein said integral of the electrical parameter relates to the energy balance as an accumulated difference between the total amount of energy received by said internal energy receiver and the total amount of consumed energy, stored energy or consumed and stored energy.

14. The apparatus according to claim 13, further adapted to plot values of said electrical parameter over time as a graph in a parameter-time diagram, and determine said integral from the size of the area beneath the plotted graph.

15. The apparatus according to claim 3, further comprising an energy storage device comprising at least one of:

a rechargeable battery, an accumulator or a capacitor.

16. The apparatus according to claim 1, further comprising:

a first electric circuit to supply electrical pulses to the external transmitting device, said electrical pulses having leading and trailing edges, said transmitting device adapted to supply wireless energy, wherein

the electrical circuit being adapted to vary the lengths of at least one of;

first time intervals between successive leading and trailing edges of the electrical pulses, and

second time intervals between successive trailing and leading edges of the electrical pulses, wherein

the transmitted wireless energy, generated from the electrical pulses having a varied power, the power depending on the lengths of the first, second or first and second time intervals.

17. The apparatus according to claim 16, wherein the frequency of the electrical pulses is substantially constant when varying the first, second or first and second time intervals, wherein

the amplitude of the electrical pulses is substantially constant when varying the first, second or first and second time intervals, when applying electrical pulses, so that the electrical pulses remain unchanged, except for varying the first, second or first and second time intervals.

18. The apparatus according to claim 16, further adapted to:

supply a train of two or more electrical pulses in a row, said train having a first electrical pulse at the start of the pulse train and having a second electrical pulse at the end of the pulse train, and

supply two or more pulse trains in a row, wherein the lengths of the second time intervals between successive trailing edge of the second electrical pulse in a first pulse train and leading edge of the first electrical pulse of a second pulse train are varied.

19. The apparatus according to claim 18, wherein, when applying electrical pulses, at least one of:

the electrical pulses within the pulse trains, and the pulse trains themselves having at least one of;

a substantially constant frequency, a substantially constant current and a substantially constant voltage.

20. The apparatus according to claim 16, further adapted to transmit the wireless energy in a substantially inductive way from the external energy source to the receiver and to release the electrical pulses from the first electrical circuit with at least one of:

a frequency and time period between leading edges of the consecutive pulses, so that when the lengths of the first, second or first and second time intervals are varied, the resulting transmitted energy varied.

21. The apparatus according to claim 20, wherein the circuit formed by the first electric circuit and the external energy source has a first characteristic time period or first time constant, and when effectively varying the transmitted energy, such frequency time period is in the range of the first characteristic time period or time constant or shorter.