Voltage limited systems and methods

• US 20050245977A1
• Filed: 04/12/2005
• Published: 11/03/2005
• Est. Priority Date: 04/12/2004
• Status: Abandoned Application

• Current Assignee: Advanced Neuromodulation Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Advanced Neuromodulation Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: Tranchina, Benjamin A., Varrichio, Anthony J.
• Application Number:
  US11/105,190
• Publication Number:
  US 20050245977A1
• Time in Patent Office: Days
• US Class Current: 607/11
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components
• CPC Class Codes: A61N 1/3782 producing a voltage above the power source level
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H02M 3/072 adapted to generate an output voltage whose value is lower than the input voltage
• CPC Class Codes: H02M 3/073 Charge pumps of the Schenkel-type

Abstract

In delivering constant current electrical stimulation pulses to electrodes implanted near a stimulation site, a programmable voltage limited mode of operation according to embodiments precludes unsafe voltage spikes upon substantial changes in resistance due to, for example, patient movement. A voltage multiplier of one embodiment is driven by a clock signal stopped whenever an output voltage reaches a predetermined level, and resumed when the output voltage drops below that level. A comparator receiving a voltage-divided output from the voltage multiplier and a variable input control signal from a digital-to-analog converter controls generation of the clock signal according to embodiments.

Claims

1. A system comprising:

a voltage generator operable to produce an output voltage;

a comparison circuit for comparing at least a portion of said output voltage of said voltage generator with a selected voltage; and

a control circuit operable to cause said voltage generator to cease generating a higher voltage when said comparison circuit indicates said at least a portion of said output voltage is not less than said selected voltage, said control circuit further operable to cause said voltage generator to generate a higher voltage when said comparison circuit indicates said at least a portion of said output voltage is less than said selected voltage.

2. The system of claim 1, wherein said voltage generator comprises:

a fractional voltage converter providing voltages in fractional multiples of a supply voltage.

3. The system of claim 1, wherein the voltage generator comprises:

a capacitive voltage multiplier and said control circuit controls switching of switches within the voltage multiplier.

4. The system of claim 1, wherein said at least a portion of said output voltage is provided by a voltage divider.

5. The system of claim 1, wherein said control circuit comprises:

a clock generator producing a clock signal driving the voltage generator, wherein the voltage generator is stopped when the clock signal is not received at the voltage generator from the clock generator.

6. The system of claim 5, wherein said clock generator comprises:

a clock divider controlled by an output of said comparison circuit.

7. The system of claim 1, wherein said selected voltage is provided by a digital-to-analog converter.

8. The system of claim 1, wherein said voltage generator, said comparison circuit, and said control circuit are part of a therapeutic stimulation pulse generation system.

9. A method comprising:

generating a voltage for output from a voltage generation circuit;

comparing at least a portion of said voltage of said voltage generation circuit with a selected voltage;

controlling said voltage generation circuit to cease generating a higher voltage when said comparison indicates said at least a portion of said voltage is not less than said selected voltage; and

controlling said voltage generation circuit to generate a higher voltage when said comparison indicates said at least a portion of said voltage is less than said selected voltage.

10. The method of claim 9, wherein said generating said voltage comprises:

providing voltages in fractional multiples of a supply voltage.

11. The method of claim 9, wherein said generating said voltage comprises:

switching of switches within a capacitive voltage multiplier.

12. The method of claim 9, further comprising:

dividing said voltage to provide said at least a portion of said voltage for comparing.

13. The method of claim 9, wherein said controlling said voltage generation circuit to generate said higher voltage comprises:

producing a clock signal driving the voltage generation circuit.

14. The method of claim 13, wherein said producing said clock signal comprises:

controlling a clock generator using an output of said comparing.

15. The method of claim 9, further comprising:

providing said selected voltage using a digital-to-analog converter.

16. The method of claim 9, further comprising:

using said voltage to deliver a therapeutic stimulation pulse.

17. The method of claim 16, further comprising:

selecting said selected voltage to prevent a stimulation pulse having an undesired amplitude.

18. A voltage limiter system comprising:

a capacitive voltage multiplier producing, when operating, an output voltage for use in driving a desired pulse output;

a clock divider producing a clock signal controlling operation of the voltage multiplier, wherein the voltage multiplier operates to generate higher voltages as long as the clock signal is received at the voltage multiplier and is stopped while the clock signal is not received at the voltage multiplier; and

a comparator comparing the output voltage to a desired value and controlling the clock divider, the comparator causing the clock divider to produce the clock signal whenever the output voltage is less than the desired value and to not produce the clock signal whenever the output voltage reaches the desired value.

19. The voltage limiter according to claim 18, wherein the comparator causes the clock divider to produce the clock signal when the output voltage drops below the desired value after having been equal to the desired value.

20. The voltage limiter according to claim 18, wherein the voltage multiplier programmably produces fractional multiples of an input power supply voltage.