Current output architecture for an implantable stimulator device

• US 20070038250A1
• Filed: 07/08/2005
• Published: 02/15/2007
• Est. Priority Date: 07/08/2005
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: He, Yuping, Peterson, David
• Granted Patent: US 8,606,362 B2
• Time in Patent Office: Days
• US Class Current: 607/2
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration

Abstract

Disclosed herein are current output architectures for implantable stimulator devices. Current source and sink circuitry is divided into a plurality of stages, each of which is capable via an associated switch bank of sourcing or sinking an amount of current to or from any one of the electrodes of the device. The current source circuitry is distinct from the current sink circuitry, and the two share no common circuit nodes prior to connection to the electrodes. In other words, the current source circuitry and the current sink circuitry do not share a common node other than the electrodes. Each stage is preferably formed of a current mirror for receiving a reference current and outputting a scaled version of current to that stage'"'"'s switch bank. The scalar at each stage can be set by wiring a desired number of output transistors in parallel. Preferably, the reference current to the current mirrors in the stages is controllable via a digital-to-analog converter (DAC), to globally control the overall magnitude of the current supply to the electrodes.

Claims

1. An implantable stimulator device, comprising:

a plurality of electrode nodes implantable adjacent to tissue to be stimulated;

current source circuitry comprising a plurality of first stages each for outputting an output current, wherein each first stage is controllable to send its output current to more than one of the plurality of electrode nodes; and

current sink circuitry comprising a plurality of second stages each for outputting an output current, wherein each second stage is controllable to sink its output current from more than one of the plurality of electrode nodes,

wherein the current source circuitry and the current sink circuitry do not share a common node other than the electrode nodes.

2. The implantable stimulator device of claim 1, wherein each stage of the first and second stages comprises:

a current converter circuit for converting a reference current into the output current, wherein the output current represents a scaled version of the reference current; and

a switch bank, wherein each switch bank comprises a plurality of switches for receiving the output current.

3. The implantable stimulator device of claim 2, further comprising a digital-to-analog converter for converting another current into the reference current in accordance with digital control signals.

4. The implantable stimulator device of claim 2, wherein the current converter circuit comprises a current mirror.

5. The implantable stimulator device of claim 4, wherein a scalar between the output current and the reference current is set by a number of parallel output transistors in the current mirror.

6. An implantable stimulator device, comprising:

a plurality of electrode nodes implantable adjacent to tissue to be stimulated;

current source circuitry comprising a plurality of first stages each for converting a reference current into a plurality of output currents, wherein the output currents represent scaled versions of the reference current, wherein each first stage is controllable to send its output current to more than one of the plurality of electrode nodes; and

current sink circuitry comprising a plurality of second stages each for converting a reference current into a plurality of output currents, wherein the output currents represent scaled versions of the reference current, wherein each second stage is controllable to sink its output current from more than one of the plurality of electrode nodes,

wherein the current source circuitry and the current sink circuitry do not share a common node other than the electrode nodes.

7. The implantable stimulator device of claim 6, wherein each stage of the first and second stages comprises:

a current converter circuit for converting the reference current into the output current; and

a switch bank, wherein each switch bank comprises a plurality of switches for receiving the output current.

8. The implantable stimulator device of claim 7, wherein the current converter circuit comprises a current mirror.

9. The implantable stimulator device of claim 8, wherein a scalar between the output current and the reference current is set by a number of parallel output transistors in the current mirror.

10. The implantable stimulator device of claim 6, further comprising a digital-to-analog converter for converting another current into the reference current in accordance with digital control signals.

11. Circuitry for an implantable stimulator device, comprising:

a plurality of electrode nodes implantable adjacent to tissue to be stimulated;

a digital-to-analog converter for converting a first reference current to a second reference current;

a plurality of current converters each for converting the second reference current into a plurality of output currents, wherein the output currents represent scaled versions of the second reference current; and

a switch bank associated with each of the plurality of current converters, wherein each switch bank comprises a plurality of switches for receiving the output current from its associated current converter, wherein each switch in each switch bank is capable of sending or sinking the output current from its associated current converter to or from an electrode node.

12. The circuitry of claim 11, wherein the digital-to-analog converter converts the first reference current into a particular magnitude of the second reference current in accordance with digital control signals.

13. The circuitry of claim 11, wherein the current converters comprise current mirrors.

14. The circuitry of claim 13, wherein a scalar between the output current and the second reference current is set by a number of parallel output transistors in the current mirrors.

15. The circuitry of claim 11, wherein the circuitry comprises either current source circuitry or current sink circuitry.

16. The circuitry of claim 11, wherein each switch in each switch bank is capable of sending or sinking the output current from its associated current converter to or from more than one of the plurality of electrode nodes.

17. Circuitry for an implantable stimulator device, comprising:

a plurality of electrode nodes implantable adjacent to tissue to be stimulated;

a plurality of non-selectable current converters each for converting a reference current into a plurality of output currents, wherein the output currents represent scaled versions of the reference current; and

a switch bank associated with each of the plurality of current converters, wherein each switch bank comprises a plurality of switches for receiving the output current from its associated current converter, wherein each switch in each switch bank is capable of sending or sinking the output current from its associated current converter to or from an electrode node.

18. The circuitry of claim 17, further comprising a digital-to-analog converter for converting another current into the reference current.

19. The circuitry of claim 17, wherein the current converters comprise current mirrors.

20. The circuitry of claim 19, wherein a scalar between the output current and the reference current is set by a number of parallel output transistors in the current mirrors.

21. The circuitry of claim 17, wherein the circuitry comprises either current source circuitry or current sink circuitry.

22. The circuitry of claim 17, wherein each switch in each switch bank is capable of sending or sinking the output current from its associated current converter to or from more than one of the plurality of electrode nodes.