Wireless power receiver coil for neuromodulation device
The present disclosure relates to implantable neuromodulation devices, and in particular to a wireless power coil in a low profile environment such as with a neurostimulator. Particularly, aspects of the present disclosure are directed to a medical device that comprises a lossy housing surrounding a power supply, and a receiving coil configured to exchange power wirelessly via a wireless power transfer signal and deliver the power to the power supply. The receiving coil is adjacent the lossy housing. The receiving coil is a helical structure with a total rise that is less than or equal to a height of the lossy housing.
1. A medical device comprising:
a lossy housing surrounding a power supply; and
a receiving coil configured to exchange power wirelessly via a wireless power transfer signal and deliver the power to the power supply,
wherein the receiving coil is external and within a predetermined distance of the lossy housing;
wherein the receiving coil is a helical structure with a total rise that is less than or equal to a height of the lossy housing;
wherein the total rise is determined based on: (i) a first helical angle between a first turn and a second turn of the receiving coil; (ii) a second helical angle between a last turn and a second to last turn of the receiving coil; and (iii) a third helical angle between: (a) remaining turns between the second turn and the second to last turn, or (b) a majority of turns between the second turn and the second to last turn; and
wherein the first helical angle and the second helical angle are less than the third helical angle.
2. The medical device of claim 1 , wherein the receiving coil comprises wound wire formed from conductive material, and the conductive material is comprised of gold (Au), gold/chromium (Au/Cr), platinum (Pt), platinum/iridium (Pt/Ir), titanium (Ti), gold/titanium (Au/Ti), or any alloy thereof.
3. The medical device of claim 1 , wherein the predetermined distance is within 4 mm of the lossy housing, and the lossy housing is made of a material capable of causing attenuation or dissipation of the wireless power transfer signal.
4. A medical device comprising:
a housing;
power supply within the housing and connected to an electronics module; and
a receiving coil configured to exchange power wirelessly via a wireless power transfer signal and deliver the power to the power supply,
wherein the receiving coil is a helical structure with a height that is determined based on: (i) a first pitch between a first turn and a second turn of the receiving coil; (ii) a second pitch between a last turn and a second to last turn of the receiving coil; and (iii) a third pitch between: (a) remaining turns between the second turn and the second to last turn, or (b) a majority of turns between the second turn and the second to last turn, and
wherein the first pitch and the second pitch are less than the third pitch.
5. The medical device of claim 4 , wherein the first pitch is the same as the second pitch.
6. The medical device of claim 4 , wherein the helical structure has a shape of a rounded rectangle and includes from 4 to 15 turns.
7. The medical device of claim 4 , wherein the height of the helical structure is less than or equal to a height of the lossy housing.
8. A neuromodulation system comprising:
a transmitting conductive structure configured to exchange power wirelessly via a wireless power transfer signal;
an implantable neurostimulator including:
a lossy housing;
a connector attached to a hole in the lossy housing;
one or more feedthroughs that pass through the connector;
an electronics module within the lossy housing and connected to the one or more feedthroughs;
a power supply within the lossy housing and connected to the electronics module; and
a receiving conductive structure disposed outside of the housing and connected to the power supply, wherein the receiving conductive structure is configured to exchange power wirelessly with the transmitting conductive structure via the wireless power transfer signal and deliver the power to the power supply,
wherein the receiving conductive structure is external and within a predetermined distance of the lossy housing;
wherein the receiving conductive structure is a helical structure with a total rise that is less than or equal to a height of the lossy housing;
wherein the total rise is determined based on: (i) a first helical angle between a first turn and a second turn of the receiving conductive structure; (ii) a second helical angle between a last turn and a second to last turn of the receiving conductive structure; and (iii) a third helical angle between: (a) remaining turns between the second turn and the second to last turn, or (b) a majority of turns between the second turn and the second to last turn; and
wherein the first helical angle and the second helical angle are less than the third helical angle, and
a lead assembly including:
a lead body including a conductor material;
a lead connector that connects the conductor material to the one or more feedthroughs; and
one or more electrodes connected to the conductor material.