Voltage converter for implantable microstimulator using RF-powering coil

• US 7,379,775 B2
• Filed: 01/31/2005
• Issued: 05/27/2008
• Est. Priority Date: 03/17/2000
• Status: Expired due to Term

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Haller, Matthew I., Parramon, Jordi
• Primary Examiner(s): Layno; Carl H.
• Assistant Examiner(s): WU, TONG E
• Application Number:
  US11/047,052
• Publication Number:
  US 20050131496A1
• Time in Patent Office: 1,212 Days
• Field of Search: 607/33, 607/34, 607/61, 607/65, 607/29, 607 55- 57
• 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 for using a single, combination voltage converter circuit configured to operate in any of a plurality of operating modes to perform multiple operating functions in an implantable medical device, the method comprising:

(a) providing an electronic circuitry, including a coil, which electronic circuitry is incorporated in the implantable device;

(b) providing a plurality of operating modes of the combination voltage converter circuit, including;

(i) power receive or data receive, or power receive and data receive, using the coil,

(ii) data transmit using the coil,

(iii) voltage step up conversion using the coil, and

(iv) voltage step down conversion using the coil; and

(c) selecting one of the operating modes of the combination voltage converter circuit,

(d) repeating the step (c) above as many times as necessary to provide a desired sequence of operating modes, thereby implementing each operating mode in a time-multiplexed scheme.

2. The method of claim 1, wherein the step (c) selecting one of the operating modes of the combination circuit is accomplished by using transistor switches, which transistor switches comprise a first, second, third, fourth and fifth transistor switches;

and

wherein the switches are turned on, turned off, or modulated in various switch combinations to configure the combination voltage converter circuit to at least one of four said operating modes.

3. The method of claim 2, wherein the step (c) selecting the operating mode for (iii) the step up voltage conversion or for (iv) the step down voltage conversion is accomplished by applying modulation to one of the transistors;

and

wherein modulation is produced at the modulated transistor from a pulse-width modulated circuit or an On-Off modulation low power modulation circuit.

4. The method of claim 2, wherein the step (c) selecting the operating mode (i) of the combination circuit for the power receive and data receive mode is accomplished by receiving alternating RF energy signals through the coil, rectifying the energy signals and storing the energy in a capacitor and, concurrently, data modulating the received RF energy signals, demodulating the signals through a diode and recovering data at the output of an amplifier;

and

wherein the first, second and third transistor switches are turned OFF and the fourth and fifth transistor switches are turned ON.

5. The method of claim 2, wherein the step (c) selecting the operating mode of the combination circuit for (ii) the data transmit mode is accomplished by turning ON the first, fourth, and fifth transistor switches, turning OFF the second transistor switch, and modulating the third transistor switch to modulate data which is transmitted from the coil.

6. A method for using a circuit configured to operate in any of a plurality of operating modes to perform multiple operating functions in an implantable medical device, the method comprising:

providing a first DC voltage to the circuit, wherein the circuit comprises a single coil;

providing a plurality of operating modes for the circuit, wherein the plurality of operating modes all involve use of the coil and comprise

receiving a wireless transmission from a device external to the implantable medical device, wherein the wireless transmission comprises power or data, or power and data for the implantable medical device,

transmitting a wireless transmission to the device external to the implantable medical device, wherein the wireless transmission comprises data from the implantable medical device,

producing a stepped-up DC voltage for use in the implantable device, wherein the stepped-up DC voltage is higher than the first DC voltage, and

producing a stepped-down DC voltage for use in the implantable device, wherein the stepped-down DC voltage is lower than the first DC voltage; and

selecting one mode from the plurality of operating modes for the circuit via a plurality of control signals coupled to the circuit.

7. The method of claim 6, wherein the implantable medical device comprises an implantable stimulator device.

8. The method of claim 7, wherein either the stepped-up or stepped-down voltage is used as a supply voltage for a pulse generator in the implantable stimulator device.

9. The method of claim 6, wherein the first DC voltage is provided by a battery in the implantable medical device.

10. The method of claim 6, wherein only one operating mode is selected at any given time.

11. The method of claim 6, wherein a magnitude of the stepped-up DC voltage is controlled by pulse width modulation of a first of the control signals, and a magnitude of the stepped-down DC voltage is controlled by pulse width modulation of a second of the control signals.