# US 2013/0158631 A1 · Automatic power regulation for transcutaneous energy transfer charging system

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- Number: US 2013/0158631 A1
- Document ID: US20130158631A1
- Status: Published application
- Kind: A1
- Application number: 13/328,568
- Filed: 2011-12-16
- Published: 2013-06-20
- Earliest claimed: 2011-12-16
- Assignees: ABIOMED, Inc.
- Inventors: Arthur Shea; Ralph D. Ambrosio
- Web page: https://patentgrep.com/patent/US20130158631A1

## CPC

- A61N 1/3787: {from an external energy source}
- 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
- A61M 60/216: including a rotating member acting on the blood, e.g. impeller
- A61M 60/873: specially adapted for wireless or transcutaneous energy transfer [TET], e.g. inductive charging
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}

## Abstract

Methods and systems for controlling power output from an external power source in a transcutaneous energy transfer (TET) system are provided to prevent inadvertent energy transfer when no secondary coil is present. The system operates by transmitting power transcutaneously from an external primary coil and determining whether a response from a secondary coil implanted within a patient is detected. If no response is detected, the power output of the primary coil is decreased. The decrease in power output can be accomplished by operating the primary coil at a lower average power level, which can include variations in power level, duty cycle, etc. The system can also be configured to periodically repeat the process in order to continue searching for a coupled secondary coil.

## Claims

### Claim 1

A method of controlling power output from a primary coil in a transcutaneous energy transfer system, comprising:
transcutaneously transmitting power from the primary coil;
determining whether a response from a secondary coil within a patient is detected; and
if no response is received, decreasing the power output of the primary coil.

### Claim 2 (depends on 1)

The method of claim 1, wherein decreasing the power output of the primary coil comprises reducing an average power output of the primary coil.

### Claim 3 (depends on 2)

The method of claim 2, wherein reducing the average power output of the primary coil is accomplished by varying the duty cycle of the primary coil.

### Claim 4 (depends on 2)

The method of claim 2, wherein reducing the average power output of the primary coil is accomplished by reducing the power output of the primary coil by a percentage value.

### Claim 5 (depends on 4)

The method of claim 4, wherein the percentage value is large enough to prevent inadvertent heating of a nearby object.

### Claim 6 (depends on 1)

The method of claim 1, wherein the method further comprises waiting a first period of time before determining that no response has been received.

### Claim 7 (depends on 1)

The method of claim 1, wherein the method further comprises holding or adjusting the power output of the primary coil in response to the requirements of the secondary coil if a response from the secondary coil is received.

### Claim 8 (depends on 6)

The method of claim 6, wherein the first period of time is about 100 milliseconds.

### Claim 9 (depends on 1)

The method of claim 1, wherein the power output of the primary coil is reduced to zero after the first period of time elapses.

### Claim 10 (depends on 1)

The method of claim 1, wherein the power output of the primary coil is decreased at a linear rate after the first period of time elapses.

### Claim 11 (depends on 0, 6)

The method of claim 6, further comprising:
holding the power output of the primary coil at a decreased level for a second period of time if no response is received during the first period of time; and
repeating the method of claim 0 after the second period of time elapses.

### Claim 12 (depends on 11)

The method of claim 11, wherein the decreased level of power output is zero.

### Claim 13 (depends on 11)

The method of claim 11, wherein the second period of time is about 3 seconds.

### Claim 14 (depends on 1)

The method of claim 1, wherein the response from the secondary coil is in the form of one or more detectable feedback indications.

### Claim 15

An external transcutaneous energy transfer system for use with an implanted medical device, comprising:
a primary coil configured to transcutaneously transmit energy to the implanted medical device; and
controlling circuitry connected to the primary coil;
wherein the controlling circuitry comprises a functionality to detect a response from the implanted medical device and the controlling circuitry is configured to:
(a) transmit power transcutaneously through the primary coil;
(b) determine whether a response from the implanted medical device is detected; and
(c) decrease the transmitted power if no response is received.

### Claim 16 (depends on 15)

The system of claim 15, wherein the controlling circuitry is configured to decrease the transmitted power by reducing an average power output of the primary coil.

### Claim 17 (depends on 16)

The system of claim 16, wherein the controlling circuitry is configured to reduce the average power output of the primary coil by varying the duty cycle of the primary coil.

### Claim 18 (depends on 16)

The system of claim 16, wherein the controlling circuitry is configured to reduce the average power output of the primary coil by reducing the power output of the primary coil by a percentage value.

### Claim 19 (depends on 15)

The system of claim 15, wherein the controlling circuitry is further configured to wait a first period of time before determining that no response has been received.

### Claim 20 (depends on 15)

The system of claim 15, wherein the controlling circuitry is further configured to hold or adjust the transmitted power in response to the requirements of the implanted medical device if a response from the implanted medical device is received.

### Claim 21 (depends on 19)

The system of claim 19, wherein the first period of time is about 100 milliseconds.

### Claim 22 (depends on 15)

The system of claim 15, wherein decreasing the transmitted power comprises reducing the transmitted power to zero.

### Claim 23 (depends on 15)

The system of claim 15, wherein decreasing the transmitted power comprises reducing the transmitted power at a linear rate.

### Claim 24 (depends on 19)

The system of claim 19, wherein the controlling circuitry is further configured to:
hold the transmitted power at a decreased level for a second period of time if no response is received during the first period of time; and
repeat steps (a)-(c) after the second period of time elapses.

### Claim 25 (depends on 24)

The system of claim 24, wherein the decreased level is zero.

### Claim 26 (depends on 24)

The system of claim 24, wherein the second period of time is about 3 seconds.

### Claim 27

An external transcutaneous energy transfer system for use with an implanted medical device, comprising:
a primary coil configured to transcutaneously transmit energy to the implanted medical device; and
controlling circuitry connected to the primary coil;
wherein the controlling circuitry comprises a functionality to detect a response from the implanted medical device and the controlling circuitry is configured to operate the primary coil at a lower average power level when no response is detected.

### Claim 28 (depends on 27)

The system of claim 27, wherein the response from the implanted medical device is in the form of one or more detectable feedback indications.

### Claim 29 (depends on 27)

The system of claim 27, wherein the controlling circuitry achieves the lower average power level by varying the duty cycle of the primary coil.

### Claim 30 (depends on 27)

The system of claim 27, wherein the controlling circuitry achieves the lower average power level by reducing the output of the primary coil by a percentage value.

### Claim 31 (depends on 27)

The system of claim 27, wherein the lower average power level is zero power.

### Claim 32 (depends on 27)

The system of claim 27, wherein the controlling circuitry is configured to periodically repeat a process of transmitting power, detecting a response, and lowering the average power level of the primary coil if no response is detected.

### Claim 33

A method of controlling power output from a primary coil in a transcutaneous energy transfer system, comprising:
transcutaneously transmitting power from the primary coil;
determining whether a response from a secondary coil within a patient is detected; and
if no response is received, reducing the average power output of the primary coil.

### Claim 34 (depends on 33)

The method of claim 33, wherein the response from the implanted medical device is in the form of one or more detectable feedback indications.

### Claim 35 (depends on 33)

The method of claim 33, wherein reducing the average power level is accomplished by varying the duty cycle of the primary coil.

### Claim 36 (depends on 33)

The method of claim 33, wherein reducing the average power level is accomplished by reducing the output of the primary coil by a percentage value.

### Claim 37 (depends on 33)

The method of claim 33, wherein the average power output is reduced to zero power.

### Claim 38 (depends on 33)

The method of claim 33, wherein the method steps are repeated.