VOLTAGE CONVERTER FOR IMPLANTABLE MICROSTIMULATOR USING RF-POWERING COIL

• US 20080208293A1
• Filed: 04/08/2008
• Published: 08/28/2008
• Est. Priority Date: 03/17/2000
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Haller, Matthew I., Parramon, Jordi
• Granted Patent: US 7,904,171 B2
• Time in Patent Office: Days
• US Class Current: 607/61
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

A combination, voltage converter circuit for use within an implantable device, such as a microstimulator, uses a coil, instead of capacitors, to provide a voltage step up and step down conversion functions. The output voltage is controlled, or adjusted, through duty-cycle modulation. In accordance with one aspect of the invention, applicable to implantable devices having an existing RF coil through which primary or charging power is provided, the existing RF coil is used in a time-multiplexing scheme to provide both the receipt of the RF signal and the voltage conversion function. This minimizes the number of components needed within the device, and thus allows the device to be packaged in a smaller housing or frees up additional space within an existing housing for other circuit components. In accordance with another aspect of the invention, the voltage up/down converter circuit is controlled by a pulse width modulation (PWM) low power control circuit. Such operation allows high efficiencies over a wide range of output voltages and current loads.

Claims

1. A method of using an implantable medical device for electrically stimulating tissue in a patient, said method comprising using an inductor to charge a capacitor so as to step up a voltage delivered from said capacitor to electrodes configured to electrically stimulate said tissue in a patient.

2. The method of claim 1, further comprising driving said inductor with a pulse signal according to a duty cycle.

3. The method of claim 1, further comprising selectively stepping down a voltage delivered to said electrodes using said capacitor and a portion of said inductor.

4. The method of claim 1, further comprising selectively receiving energy to be stored in a rechargeable power source of said implantable medical device, wherein said energy is received through said inductor.

5. The method of claim 1, further comprising selectively receiving data from an external source using said inductor to receive a modulated radio-frequency signal from said external source.

6. The method of claim 1, further comprising selectively transmitting data using said inductor to transmit a data modulated radio-frequency signal.

7. An implantable medical device including a voltage converter circuit for electrically stimulating tissue in a patient, said device comprising:

electrodes for delivering electrical stimulation; and

said voltage converter circuit including an inductor and a capacitor, wherein said voltage converter circuit is configured to charge said capacitor using said inductor to selectively step up a voltage delivered to said electrodes.

8. The medical device of claim 7, further comprising a power source configured to drive said inductor with a pulse signal to charge said capacitor.

9. The medical device of claim 8, wherein said voltage converter circuit further comprises a transistor configured to selectively connect said inductor to ground, said transistor being configured to turn ON selectively according to a duty cycle to provide said pulsed signal from said power source to said inductor.

10. The medical device of claim 9, wherein said voltage converter circuit further comprises a diode connected between said inductor and ground.

11. The medical device of claim 7, wherein said voltage converter circuit further comprises a step-down circuit, including a portion of said inductor, to selectively step down said voltage delivered to said electrodes.

12. The medical device of claim 11, wherein said step-down circuit further comprises a transistor being configured to turn ON selectively according to a duty cycle to selectively connect said portion of said inductor with a power source, said portion of said inductor being configured to charge said capacitor and deliver a stepped down voltage to said electrodes.

13. The medical device of claim 7, wherein said voltage converter circuit is also configured to selectively receive energy to be stored in a rechargeable power source, wherein said energy is received through said inductor.

14. The medical device of claim 7, wherein said voltage converter circuit is also configured to selectively receive data from an external source using said inductor to receive a modulated radio-frequency signal from said external source.

15. The medical device of claim 7, wherein said voltage converter circuit is also configured to selectively transmit data using said inductor to transmit a data modulated radio-frequency signal.