SPINAL CORD STIMULATOR SYSTEM

• US 20150174415A1
• Filed: 03/10/2015
• Published: 06/25/2015
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Cirtec Medical Corp.
• Original Assignee: Globus Medical, Inc.
• Inventors: Angara, Raghavendra, Khalil, Saif, Curtis, Miles, Biele, Christopher, Fellmeth, Daniel
• Granted Patent: US 9,878,170 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61N 1/025 Digital circuitry features of electrotherapy devices, e.g. memory, clocks, processors
• CPC Class Codes: A61N 1/0553 Paddle shaped electrodes, e.g. for laminotomy
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components
• CPC Class Codes: A61N 1/36142 for improving safety
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/37235 Aspects of the external programmer
• CPC Class Codes: A61N 1/3752 Details of casing-lead connections
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment

Abstract

A wireless charger for inductively charging a rechargeable battery of an implantable pulse generator (IPG) is provided. The charging coil in the charger is wirelessly coupled to a receiving coil of the IPG to charge the rechargeable battery. The alignment circuit continuously detects a reflected impedance of the charging coil through a reflected impedance sensor, and controls a vibrator to output a tactile signal which is indicative of the alignment of the charging coil to the receiving coil based on the detected reflected impedance. Advantageously, the tactile feedback to the patient provides an optimal way to indicate the extent of the charger'"'"'s alignment with the IPG.

Claims

1. A wireless charger for inductively charging a rechargeable battery of an implantable pulse generator (IPG) that generates spinal cord stimulation signals for a human body, the wireless charger comprising:

a charging coil adapted to be wirelessly coupled to a receiving coil of the implantable pulse generator to charge the rechargeable battery;

a reflected impedance sensor coupled to the charging coil to detect a reflected impedance of the charging coil;

a vibrator;

an alignment circuit coupled to the reflected impedance sensor and the vibrator, the alignment circuit adapted to control the vibrator to output a tactile signal indicative of the alignment of the charging coil to the receiving coil based on the detected reflected impedance.

2. The wireless charger of claim 1, wherein the reflected impedance sensor includes a current sensor coupled in series with the charging coil.

3. The wireless charger of claim 1, wherein the reflected impedance sensor includes a transformer having a primary winding in series with the charging coil and a secondary coil coupled to the primary coil.

4. The wireless charger of claim 1, wherein the reflected impedance sensor includes:

a current sensor coupled in series with the charging coil for detecting the voltage across the charging coil; and

a rectifier to rectify the output of the current sensor.

5. The wireless charger of claim 1, further comprising:

a class-E amplifier adapted to generate a charging signal for the charging coil;

a current limiter connected between a power supply and the class-E amplifier to limit the current supplied to the class-E amplifier below a threshold value.

6. The wireless charger of claim 1, further comprising a speaker coupled to the alignment circuit, wherein the alignment circuit controls the speaker to output an audio signal indicative of the alignment of the charging coil to the receiving coil.

7. The wireless charger of claim 1, wherein the alignment circuit controls the vibrator to output a continuous vibrating signal until the alignment circuit determines that the charging coil is in alignment with the receiving coil.

8. The wireless charger of claim 1, wherein the alignment circuit controls the vibrator to increase the rate of the vibration signal as alignment of the charging coil with the receiving coil becomes stronger.

9. The wireless charger of claim 1, further comprising:

a substrate having the charging coil attached on one side of the substrate;

a temperature sensor attached on the other side of the substrate behind the charging coil between an inner winding and outer winding of the charging coil.

10. A method for a wireless charger for inductively charging a rechargeable battery of an implantable pulse generator (IPG) that generates spinal cord stimulation signals for a human body, the method comprising:

continuously detecting a reflected impedance of a charging coil of the wireless charger; and

outputting a tactile signal indicative of the alignment of the charging coil to a receiving coil of the IPG based on the continuously detected reflected impedance.

11. The method of claim 10, wherein the step of continuously detecting includes detecting a current from a current sensor connected in series with the charging coil.

12. The method of claim 10, wherein the step of continuously detecting includes detecting a current from a transformer having a primary winding in series with the charging coil and a secondary coil coupled to the primary coil.

13. The method of claim 10, wherein the step of continuously detecting includes rectifying a sensed current from a current sensor coupled in series with the charging coil.

14. The method of claim 10, further comprising limiting a current draw of a class-E power amplifier of the wireless charger using a current limiter adapted to limit the current below a threshold current value.

15. The method of claim 10, further comprising controlling a speaker to output an audio signal indicative of the alignment of the charging coil to the receiving coil.

16. The method of claim 10, wherein outputting of a tactile signal includes outputting a continuous vibrating signal until an alignment circuit of the wireless charger determines that the charging coil is in alignment with the receiving coil.

17. The method of claim 10, wherein outputting of a tactile signal includes controlling a vibrator to increase the rate of a vibration signal as alignment of the charging coil with the receiving coil becomes stronger.

18. The method of claim 10, wherein the charging coil is attached to one side of a substrate and a temperature sensor is attached on the other side of the substrate, the method further comprising:

continuously reading a temperature from the temperature sensor; and

turning off a power amplifier sending a charging signal to the charging coil when the read temperature exceeds a predetermined threshold value.