Data communication in a transcutaneous energy transfer system
Disclosed are systems and methods for use of an inductive link for a communication channel in a transcutaneous energy transfer system. An example system may include a resonant circuit associated with an external primary, a power transistor connected to the resonant circuit and configured to drive the resonant circuit with a first time-varying electrical signal having a frequency, and a power driver connected to the power transistor that is configured to set the frequency of the first time-varying electrical signal to a resonant frequency to enable power transfer from the external primary to an implanted secondary. The example system may further include a communication driver operatively connected to the power transistor and configured to encode the first time-varying electrical signal with a data signal by modulating an attribute of the time-varying electrical signal as electrical power is transferred from the external primary to the implanted secondary.
1. A system for communicating data in an transcutaneous energy transfer system that includes an external primary and an implantable secondary, comprising:
the external primary including:
a direct current power source;
a resonant circuit;
a power transistor connected to the resonant circuit and configured to drive the resonant circuit with a first time-varying electrical signal having a frequency;
a power driver connected to the power transistor and configured to set the frequency of the first time-varying electrical signal to a resonant frequency to enable transfer of electrical power from the external primary to the implantable secondary; and
a communication driver operatively connected to the power transistor;
a transformer having a primary side that is connected to the communication driver and a secondary side that is coupled in series between the direct current power source and a drain of the power transistor;
wherein the communication driver is configured to encode the first time-varying electrical signal with a data signal by modulating an attribute of the first time-varying electrical signal through the transformer as the electrical power is transferred from the external primary to the implanted secondary; and
the implantable secondary including a communication receiver that is configured to receive the data signal from the external primary;
wherein the communication receiver is configured to convert a secondary time-varying electrical signal induced in the implantable secondary by the first time-varying electrical signal by demodulating the secondary time-varying electrical signal as the electrical power is transferred from the external primary to the implantable secondary.
2. The system of claim 1 , wherein the communication driver is further configured to indirectly modulate an amplitude of the first time-varying electrical signal by adjusting a frequency of an output of the power driver to a subharmonic of a fundamental drive frequency.
3. The system of claim 1 , wherein the communication driver is further configured to encode the first time-varying signal with the data signal by modulating the frequency of the first time-varying electrical signal.
4. The system of claim 1 , wherein the communication driver is further configured to encode the first time-varying signal with the data signal by modulating a phase of the first time-varying electrical signal.
5. The system of claim 1 , wherein:
the power driver is configured to alternate the electrical power transfer between a power supply mode and an idle mode responsive to a received indication of power consumption in the implantable secondary; and
the communication driver is further configured to encode the first time-varying signal with the data signal by modulating the attribute of the first time-varying electrical signal during the power supply mode.
6. The system of claim 1 , wherein:
the power driver is configured to alternate the electrical power transfer between a power supply mode and an idle mode responsive to a received indication of power consumption in the implantable secondary; and
the communication driver is further configured to encode the first time-varying signal with the data signal by modulating the attribute of the first time-varying electrical signal during the idle mode.
7. An apparatus for communicating data in an transcutaneous energy transfer system that includes an external primary and an implantable secondary, comprising
the external primary;
a resonant circuit coupled to the external primary;
a direct current power source;
a power transistor coupled to the resonant circuit and configured to cause the resonant circuit to provide a first time-varying electrical signal having a frequency;
a power driver coupled to the power transistor and configured to control the frequency of the first time-varying electrical signal to enable power transfer from the external primary to the implantable secondary;
a communication driver coupled to the power transistor and configured to encode the first time-varying electrical signal with a data signal by modulating an attribute of the first time-varying electrical signal; and
a transformer having a primary side coupled to the communication driver and a secondary side configured to couple the direct current power source to the power transistor, the secondary side coupled in series between the direct current power supply and a drain of the power transistor;
wherein the communication driver is configured to control the transformer to modulate the attribute of the first time-varying electrical signal.
8. The apparatus of claim 7 , wherein the attribute of the first time-varying electrical signal modulated by the communication driver includes an amplitude.
9. The apparatus of claim 7 , wherein the communication driver is configured to adjust a frequency of an output of the power driver to a subharmonic of a fundamental drive frequency to modulate the attribute of the first time-varying electrical signal.
10. The apparatus of claim 7 , wherein the attribute of the first time-varying electrical signal modulated by the communication driver includes at least one of the frequency or the phase of the first time-varying electrical signal.
11. The apparatus of claim 7 , wherein the power driver is configured to alternate the electrical power transfer between a power supply mode and an idle mode responsive to an indication of power consumption of the implantable secondary received from the implantable secondary.
12. The apparatus of claim 11 , wherein the communication driver is configured to encode the first time-varying signal with the data signal during the power supply mode.
13. The apparatus of claim 11 , wherein the communication driver is configured to encode the first time-varying signal with the data signal during the idle supply mode.