Method and apparatus for accurately tracking available charge in a transcutaneous energy transfer system
Improved devices and methods for tracking power consumption and available charge in a transcutaneous energy transfer (TET) system are provided. The method includes measuring the available charge in a battery and the current rate of power consumption in an implanted medical device, determining the remaining time before the charge level of the battery reaches a predetermined threshold level, and communicating the remaining time to a user.
1. A method of accurately tracking available charge stored in a transcutaneous energy transfer system, comprising:
utilizing fuel gauge circuitry to record a plurality of metrics of a transcutaneous energy transfer system associated with an implantable device, said plurality of metrics including battery temperature;
utilizing a controller to determine the current charge remaining in a rechargeable battery pack based on said plurality of metrics;
utilizing the fuel gauge circuitry to measure the current rate of power consumption for the implantable device;
utilizing the controller to determine the remaining time before the energy level of the battery pack is below a predetermined threshold level at the measured rate of power consumption; and
utilizing the controller to communicate the remaining time before exhaustion of the battery pack to a user.
2. The method of claim 1 , wherein the steps are repeated in an iterative manner to update the remaining time before exhaustion of the battery pack.
3. The method of claim 1 , wherein the remaining time is communicated to the user via an external display.
4. The method of claim 1 , wherein the remaining time is communicated to the user via an internal vibratory signal.
5. The method of claim 1 , wherein the remaining time is communicated to the user via an external auditory signal.
6. An implantable device, comprising:
an implantable assist device;
a rechargeable battery pack; and
a controller connected to the implantable assist device and rechargeable battery pack;
wherein the controller is configured to measure the charge level of the battery pack, based on a plurality of metrics, said metrics including battery temperature, measure a power consumption rate of the implantable assist device, compute the remaining time before the battery pack energy level reaches a predetermined threshold level, and communicate the remaining time to a user.
7. The device of claim 6 , wherein the controller repeatedly measures the available charge level and power consumption rate and continually communicates the updated remaining time to the user.
8. The device of claim 6 , wherein the controller communicates the remaining time to the user via an external display.
9. The device of claim 6 , wherein the controller communicates the remaining time to the user via a vibratory signal.
10. The device of claim 6 , wherein the controller communicates the remaining time to the user via an auditory signal.
11. The device of claim 6 , wherein the implantable assist device is a ventricular assist device.
12. The device of claim 6 , wherein the controller is further configured to control a charging rate of the rechargeable battery pack based in part on the battery temperature.
13. The method of claim 1 , comprising recharging the rechargeable battery pack at a battery charging rate and controlling the battery charging rate based in part on the battery temperature.