Load-induced resonance-shift-keying modulation scheme for simultaneous near-field wireless power and data transmission through a pair of inductive coils
Biomedical implants in accordance with various embodiments of the invention can be implemented in many different ways. The implants can be configured to receive power and transmit data, both wirelessly and simultaneously. Such devices can be configured to receive power from an external source and transmit data, such as but not limited to recorded neural data and/or other biological data, to outside the body. In many cases, the data is transmitted to the device that delivers power to the implant. For example, the power and data transmission system can be implemented with a pair of transceivers. The implant transceiver can receive power wirelessly though an external transceiver while simultaneously transmitting data to the external transceiver. In several embodiments, both forward (power) and reverse (data) links use the same pair of inductive coils in the transceivers, one coil mounted in the implant and the other in the external unit.
1. A wireless inductive telemetry link comprising:
an external transceiver comprising:
a demodulation circuit comprising a counter and a finite state machine circuit for outputting an output data signal; and
an internal transceiver comprising:
a modulation circuit comprising a switch load capacitor for receiving an input data signal, wherein the switch capacitor is capable of receiving a data signal and modulating the data signal under a load-induced resonance-shift-keying modulation scheme;
wherein the external transceiver is configured to transfer power to the internal transceiver while receiving data from the internal transceiver contemporaneously.
2. The wireless inductive telemetry link of claim 1 , wherein:
the external transceiver further comprises a first inductive coil;
the internal transceiver further comprises a second inductive coil; and
the external is configured to transfer power to the internal transceiver while receiving data from the internal transceiver contemporaneously using the first and second inductive coils.
3. The wireless inductive telemetry link of claim 2 , wherein the load-induced resonance-shift-keying modulation scheme is implemented by using a switch capacitor to flip oscillation between two resonant frequencies, ω L and ω H .
4. The wireless inductive telemetry link of claim 1 , wherein the demodulation circuit further comprises an oscillator shut-down switch.
5. The wireless inductive telemetry link of claim 4 , wherein the internal transceiver further comprises a large capacitor for supplying charge at oscillator shut-down.
6. The wireless inductive telemetry link of claim 1 , wherein the external transceiver is configured to provide self-regulated power to the internal transceiver.
7. The wireless inductive telemetry link of claim 6 , wherein the external transceiver is configured to provide self-regulated power to the internal transceiver within a coil separation d c range of 4.2 centimeters.
8. The wireless inductive telemetry link of claim 7 , wherein the external transceiver is configured to provide self-regulated power to the internal transceiver within a coil separation d c range of 0.8 centimeters.
9. The wireless inductive telemetry link of claim 8 , wherein the internal transceiver is configured to transmit data to the external transceiver at a data rate of 5 Mbps.
10. The wireless inductive telemetry link of claim 9 , wherein the power transfer efficiency is above 35%.
11. A method for simultaneous power and data transmission, the method comprising:
transmitting data from an internal transceiver to an external transceiver, wherein:
the external transceiver comprises a demodulation circuit comprising a counter and a finite state machine circuit for outputting an output data signal; and
the internal transceiver comprises a modulation circuit comprising a switch load capacitor for receiving an input data signal, wherein the switch capacitor is capable of receiving a data signal and modulating the data signal under a load-induced resonance-shift-keying modulation scheme; and
transferring power from the external transceiver to the internal transceiver contemporaneously with the transmittal of data from the internal transceiver.
12. The method claim 11 , wherein:
the external transceiver further comprises a first inductive coil;
the internal transceiver further comprises a second inductive coil; and
the transmission of data and transferal of power are performed through the first and second inductive coils.
13. The method of claim 12 , wherein the load-induced resonance-shift-keying modulation scheme is implemented by using a switch capacitor to flip oscillation between two resonant frequencies, ω L and ω H .
14. The method of claim 11 , wherein the demodulation circuit further comprises an oscillator shut-down switch.
15. The method of claim 14 , wherein the internal transceiver further comprises a large capacitor for supplying charge at oscillator shut-down.
16. The method of claim 11 , wherein the external transceiver is configured to provide self-regulated power to the internal transceiver.
17. The method of claim 16 , wherein the external transceiver is configured to provide self-regulated power to the internal transceiver within a coil separation d c range of 4.2 centimeters.
18. The method of claim 17 , wherein the external transceiver is configured to provide self-regulated power to the internal transceiver within a coil separation d c range of 0.8 centimeters.
19. The method of claim 18 , wherein the data is transmitted to the external transceiver at a data rate of 5 Mbps.
20. The method of claim 19 , wherein the power is transferred with a power transfer efficiency above 35%.