Method and apparatus for supplying energy to a medical device

• US 8,798,763 B2
• Filed: 10/10/2008
• Issued: 08/05/2014
• Est. Priority Date: 10/16/2007
• Status: Active Grant

• Current Assignee: Kirk Promotion Ltd.
• Original Assignee: Kirk Promotion Ltd.
• Inventors: Forsell, Peter
• Primary Examiner(s): Patel, Niketa
• Assistant Examiner(s): Hankins, Lindsey G
• Application Number:
  US12/682,327
• Publication Number:
  US 20100211134A1
• Time in Patent Office: 2,125 Days
• Field of Search: 607/33, 607/61
• 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 controlling transmission of wireless energy to a medical device (100) implanted in a mammal patient, the wireless energy is transmitted from an external energy source (104) located outside a patient and is received by an internal energy receiver (102) located inside the patient, for directly or indirectly supplying received energy to the medical device. An ultrasonic feedback control signal (S) is transmitted from an internal ultrasonic signal transmitter (110) located inside the patient to an external ultrasonic signal receiver (112) located outside the patient. The feedback control signal relates to the energy for operating the medical device and is used for controlling the transmission of wireless energy from the external energy source.

Claims

1. An apparatus for controlling transmission of wireless energy supplied to an electrically operable medical device when implanted in a mammal patient, the apparatus comprising:

an external energy source adapted to transmit said wireless energy when located outside the patient,

an internal energy receiver adapted to receive the transmitted wireless energy when located inside the patient, and to directly or indirectly supply received energy to the medical device,

an internal ultrasonic signal transmitter adapted to transmit an ultrasonic feedback control signal when located inside the patient, and

an external ultrasonic signal receiver adapted to receive the transmitted feedback control signal when located outside the patient, where said feedback control signal relates to the energy for operating the medical device and is used for controlling the transmission of wireless energy from the external energy source,

an internal control unit adapted to be located inside the patient and to determine and follow over time, during the transmission of wireless energy, measurements of characteristics, or parameters related to the energy needed for proper operation of the apparatus, such as power consumption, being at least one electrical parameter relating to an energy balance between the energy received by the internal energy receiver and the energy used for the medical device, wherein the energy used comprises the total of energy consumed, energy stored, or energy consumed and energy stored, wherein said feedback control signal is created by the internal control unit comprising information on or relating to the determined energy balance, created intermittently, repeated at certain intervals during ongoing energy transfer executed on a more or less continuous basis during said wireless energy transfer, and

an external control unit adapted to be located outside the patient and using said feedback control signal to control and regulate the transmission of wireless energy from the external energy source based on the determined and during energy transfer over time followed energy balance, repeated intermittently at certain intervals during ongoing energy transfer executed on a more or less continuous basis during the energy transfer, and 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 energy balance is determined as energy per time unit, accumulated energy, or accumulated energy and energy per time unit, wherein the speed and direction of change, the change rate, of the at least one electrical parameter is adapted to relate to the energy balance, measured intermittently, repeated at certain intervals during ongoing energy transfer, executed on a more or less continuous basis during the energy transfer, and wherein the energy balance determined by at least one of;

the internal control unit, further adapted to create the ultrasonic feedback control signal about the energy balance, and

the external control unit, wherein the ultrasonic feedback control signal received from the internal control unit is adapted to carry measurement results from the measured at least one electrical parameter relating to the energy balance, and wherein

the decrease or increase of the wireless energy transmission correspond to the detected change rate of the energy balance.

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

3. The apparatus according to claim 2, wherein the feedback signal is related to a coupling factor between the primary coil and the secondary coil.

4. The apparatus according to claim 3, wherein the external energy source further comprises an indicator, adapted to at least one of;

indicate a level of the coupling factor and indicate an optimal placement of said secondary coil in relation to said primary coil to optimize said coupling factor.

5. The apparatus according to claim 1, further adapted to detect

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 a change of the detected energy difference and 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 the amount of transmitted wireless energy is increased if the detected energy difference implies that the received energy is less than the used energy.

6. The apparatus according to claim 5, further adapted to consume the energy used for the medical device to operate the medical device, after stabilizing the energy in at least one energy stabilizing unit of the medical device or store the energy in at least one energy storage device of the medical device, the apparatus being adapted to use the energy used by the medical device according to at least one of the following alternatives:

to consume substantially all energy used for the medical device to operate the medical device,

to store substantially all energy used for the medical device in said at least one energy storage device, and

to partly consume 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.

7. The apparatus according to claim 6, wherein the energy storage device includes at least one of:

a rechargeable battery, an accumulator and a capacitor; and

the energy stabilizing unit includes at least one of;

an accumulator, a capacitor and a semiconductor adapted to stabilize the received energy, before the energy is supplied directly or indirectly to the medical device.

8. The apparatus according to claim 6, further adapted to directly or indirectly determine over time at least one of:

the difference between the total amount of energy received by the internal energy receiver and at least one of;

the total amount of consumed and stored energy to determine the energy balance based on a detected change in said total amount difference, and

a detected change followed over time in at least one of;

the amount of consumed and stored energy to determine the energy balance based on a detected change of the rate of transmitted energy.

9. The apparatus according to claim 8, further adapted to detect the change in at least one of:

the amount of consumed and stored energy, by determining over time the derivative of a measured electrical parameter related to at least one of;

said amount of 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, said derivative preferably is based on a detected rate of change of the electrical parameter.

10. The apparatus according to claim 8, further adapted to determine the energy balance based on a detected difference between the total amount of energy received by the internal energy receiver and at least one of:

the total amount of consumed and stored energy, said detected difference being related to the integral over time of at least one measured electrical parameter related to said energy balance, by plotting 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, 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 at least one of;

the total amount of consumed and stored energy.

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 constant voltage or at least one constant current, preferably, at least two different voltages and currents, including at least one constant current or at least one constant voltage, wherein the constant voltage is created by a constant voltage circuitry or the constant current by a constant current circuitry.

12. The apparatus according to claim 1, further adapted to accumulate and stabilize the energy received by said internal energy receiver in an energy stabilizing unit before supplying energy to at least one of;

the medical device and energy storage device.

13. The apparatus according to claim 1, further adapted to control the transmission of wireless energy from the external energy source by:

applying to the external energy source electrical pulses from a first electric circuit to transmit the wireless energy, the electrical pulses having leading and trailing edges,

varying the lengths of first time intervals between successive leading and trailing edges of the electrical pulses and/or the lengths of second time intervals between successive trailing and leading edges of the electrical pulses, and

transmitting wireless energy, the transmitted energy generated from the electrical pulses having a varied power, the varying of the power depending on the length of the first time interval, the second time interval or the first and second time intervals, and wherein at least one of;

the frequency of the electrical pulses is substantially constant when varying the first time interval, the second time interval or the first and second time intervals,

the amplitude of the electrical pulses is substantially constant when varying the first time interval, the second time interval or the first and second time intervals,

when applying electrical pulses, the electrical pulses remain unchanged, except for varying the first time interval, the second time interval or the first and second time intervals, the electrical pulses having a substantially constant current and a constant voltage and substantially constant frequency, and

when applying electrical pulses, the electrical pulses are varied by only varying the lengths of first time intervals between successive leading and trailing edges of the electrical pulses, the electrical pulses having a substantially constant current and a constant voltage and substantially constant frequency.

14. The apparatus according to claim 13, further adapted to:

supply a train of two or more electrical pulses in a row, wherein when applying the train of pulses, 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, the electrical pulses within the pulse trains having a substantially constant frequency.

15. The apparatus according to claim 13, further adapted to control the transmission of wireless energy according to at least one the following:

release the electrical pulses from the first electrical circuit with at least one of;

such a frequency and time period between leading edges of the consecutive pulses, so that when the lengths of at least one of;

the first time interval, the second time interval or the first and second time intervals are varied, the resulting transmitted energy are varied, and

having a first characteristic or time period or first time constant in the circuit formed by the first electric circuit and the external energy source, 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.

16. The apparatus according to claim 1, wherein the external energy source further comprises an electronic circuit for comparing the feedback signal with the amount of energy transmitted by the external energy source, the external energy source being adapted to use said feedback signal to adjust the level of said transmitted energy.

17. The apparatus according to claim 1, wherein the external energy source is adapted to transfer data related to the amount of transmitted energy to the receiver, and wherein the feedback signal is related to the amount of energy received in the receiver compared to the amount of said transmitted energy.

18. The apparatus according to claim 1, wherein the internal control unit is adapted to control said ultrasonic transmitter, wherein the feedback control information is at least one of;

including at least one predetermined, variable parameter relating to the received energy, and

relating to the received energy and requires artificial intelligence to be generated and controlled by the internal control unit.