Energy extraction

• US 9,369,005 B2
• Filed: 03/03/2014
• Issued: 06/14/2016
• Est. Priority Date: 03/01/2013
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Eye And Ear Infirmary (Foundation of The Massachusetts Eye and EAR Infirmary Incorporated), Massachusetts Institute of Technology
• Inventors: Stankovic, Konstantina, Chandrakasan, Anantha, Mercier, Patrick, Bandyopadhyay, Saurav, Lysaght, Andrew
• Primary Examiner(s): Memula, Suresh
• Application Number:
  US14/195,371
• Publication Number:
  US 20140247020A1
• Time in Patent Office: 834 Days
• Field of Search: 320/166
• US Class Current: 1/1
• CPC Class Codes: A61F 2/10 Hair or skin implants
• CPC Class Codes: A61N 1/3785 generated by biological activity or substance, e.g. body movement
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 7/32 for charging batteries from a charging set comprising a non-electric prime mover rotating at constant speed
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

This disclosure describes techniques and systems for extracting energy from the endocochlear potential (EP) in animal subjects (e.g., human subjects) and using the extracted energy to operate circuits (e.g., electronic device, sensors, and transmitters). The subject matter of this disclosure is embodied, for example, in a system for extracting energy from an endocochlear potential of an animal, wherein the system includes a pair of electrodes, and a circuit coupled to the pair of electrodes. The circuit includes a boost converter, an energy buffer component configured to receive voltage from the boost converter, a start-up rectifier configured to provide voltage to the energy buffer component, and a control component configured to provide control signals to the boost converter. The power extracted from the endocochlear potential is equal or larger than the quiescent power of the circuit.

Claims

1. A system for extracting energy from an endocochlear potential of an animal, the system comprising:

a first electrode having an end to contact endolymph within a cochlea of an animal;

a second electrode having an end to contact perilymph within the cochlea of the animal; and

an energy harvesting circuit comprising;

a boost converter that transforms an endocochlear potential across the first electrode and the second electrode to a higher potential;

an energy buffer component connected to the boost converter to store electrical energy transformed by the boost converter;

a control component providing control signals to the boost converter and powered by the energy buffer;

an antenna; and

a start-up rectifier that receives an external signal via the antenna to provide an initial voltage to the energy buffer component.

2. The system of claim 1, wherein the boost converter comprises:

an inductor having a first end coupled to one of the first electrode and the second electrode;

a first switch coupled to a second end of the inductor; and

a second switch coupled between the second end of the inductor and the energy buffer component, wherein the first switch and the second switch receive the control signals from the control component.

3. The system of claim 2, wherein the control component comprises:

a timer generating clock signals; and

a charge pump circuit driving the first switch and the second switch according to the clock signals.

4. The system of claim 1, wherein the boost converter converts the endocochlear potential to a higher potential using a trickle charging mechanism comprising a periodic cycle of storing energy from the endocochlear potential in the boost converter followed by transferring the energy to the energy buffer component.

5. The system of claim 1, further comprising a radio-frequency transmitter coupled to the control component and the antenna, wherein the radio-frequency transmitter operates with a standby power of 46 pW or less, or with an active cycle of equal or less than 0.0001% of a total duty cycle.

6. The system of claim 5, wherein the radio-frequency transmitter is further coupled to the energy buffer component to receive power to operate, the radio-frequency transmitter transmitting radio data that includes information of the endocochlear potential.

7. The system of claim 1, wherein a size of the circuit is 2.4×

2.4 mm² or less, or the quiescent power of the circuit is less than 660 pW.

8. The system of claim 1, wherein the energy harvesting circuit is fully implantable in the animal.

9. The system of claim 1, wherein the first electrode and the second electrode each comprises a glass electrode filled with electrolyte solution contacted with an Ag/AgCl electrode.

10. The system of claim 1, wherein the first electrode and the second electrode each comprises plastic or carbon nanotubes shaped to penetrate cells in a nondestructive manner.

11. A method of using an endocochlear potential of an animal as an energy source, the method comprising:

contacting a first electrode to endolymph within a cochlea of the animal and a second electrode to perilymph within the cochlea of the animal, wherein the first electrode and the second electrode are coupled to an energy harvesting circuit and an endocochlear potential across the first electrode and the second electrode applies an input voltage to the energy harvesting circuit, wherein the energy harvesting circuit comprises;

a boost converter that transforms the endocochlear potential across the first electrode and the second electrode to a higher potential;

an energy buffer component connected to the boost converter to store electrical energy transformed by the boost converter;

a control component providing control signals to the boost converter and powered by the energy buffer;

an antenna; and

a start-up rectifier that receives an external signal via the antenna to provide an initial voltage to the energy buffer component;

applying the external signal to initiate operation of the energy harvesting circuit;

converting the input voltage to the higher voltage within the energy harvesting circuit; and

storing, at the energy buffer component, electrical energy based on the higher voltage.

12. The method of claim 11, further comprising:

using the stored electrical energy to operate at least one component of the energy harvesting circuit.

13. The method of claim 11, further comprising:

using the stored electrical energy to operate a device coupled to the energy harvesting circuit.

14. The method of claim 11, further comprising:

using the stored electrical energy to transmit radio data including information of the endocochlear potential.

15. The method of claim 11, wherein converting the input voltage to the higher voltage within the circuit comprises:

performing a trickle-charging mechanism comprising a periodic cycle of storing energy from the endocochlear potential in the boost converter followed by transferring the energy to the energy buffer component.

16. The method of claim 11, wherein the energy harvesting circuit extracts energy from the endocochlear potential at a power of 1.1 nW or larger.