METHOD OF AND SYSTEM FOR STABILIZATION OF SENSORS

• US 20110125446A1
• Filed: 01/11/2011
• Published: 05/26/2011
• Est. Priority Date: 12/30/2005
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Hoss, Udo, Schultz, Peter, SHAH, RAJIV, Morgan, Wayne A., Henke, James L., Soundararajan, Gopikrishnan, Choy, David Y., Reghabi, Bahar
• Granted Patent: US 9,549,698 B2
• Time in Patent Office: Days
• US Class Current: 702/104
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61M 2230/201 Glucose concentration
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: G01N 27/327 Biochemical electrodes , e.g. electrical or mechanical details for in vitro measurements
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771

Abstract

A blood glucose sensing system includes a sensor and a sensor electronics device. The sensor includes a plurality of electrodes. The sensor electronics device includes stabilization circuitry. The stabilization circuitry causes a first voltage to be applied to one of the electrodes for a first timeframe and causes a second voltage to be applied to one of the electrodes for a second timeframe. The stabilization circuitry repeats the application of the first voltage and the second voltage to continue the anodic—cathodic cycle. The sensor electronics device may include a power supply, a regulator, and a voltage application device, where the voltage application device receives a regulated voltage from the regulator, applies a first voltage to an electrode for the first timeframe, and applies a second voltage to an electrode for the second timeframe.

Claims

1. A method of stabilizing a sensor having a plurality of electrodes, the method comprising:

applying a first voltage to one of the plurality of electrodes to initiate an anodic cycle in the sensor;

applying a second voltage to said one of the plurality of electrodes to initiate a cathodic cycle in the sensor; and

repeating, for one or more iterations, the application of the first voltage followed by the application of the second voltage.

2. The method of claim 1, wherein the one or more iterations continue until electrochemical byproducts are reduced to a level wherein background current readings are minimized.

3. The method of claim 1, wherein the first voltage has a negative value.

4. The method of claim 1, wherein the one or more iterations continue until a stabilization period has elapsed.

5. The method of claim 1, wherein the one or more iterations continue until a sensor signal produced by the sensor reaches a specific value.

6. The method of claim 1, wherein the first voltage is a voltage waveform selected from the group consisting of a ramp waveform, a sinusoidal waveform, a stepped waveform, and a squarewave waveform.

7. The method of claim 6, wherein, in a first iteration, the first voltage waveform is a first type of waveform and, in a second iteration, the first voltage waveform is a second type of waveform.

8. The method of claim 1, wherein the second voltage is a second voltage waveform.

9. The method of claim 8, wherein the second voltage waveform is one of a ramp waveform, a sinusoid waveform, a stepped waveform, and a squarewave waveform.

10. The method of claim 1, wherein the first voltage is applied for a first timeframe and the second voltage is applied for a second timeframe, said first and second timeframes having different durations.

11. The method of claim 1, wherein the first voltage is applied for a first timeframe, and the duration of the first timeframe for a first iteration is different than the duration of the first timeframe for a subsequent iteration.

12. A program code storage device, comprising:

a computer-readable storage medium; and

a computer-readable program code, the computer-readable program code being stored on the computer-readable storage medium and having instructions which, when executed, cause a controller to;

initiate a stabilization routine; and

transmit a signal to a digital-to-analog converter (DAC) that is coupled to an electrode of a sensor, the signal being representative of a stabilization sequence of voltages that the DAC is to output to said electrode, wherein the stabilization sequence of voltages includes a first voltage applied for a first timeframe followed by a second voltage applied for a second timeframe.

13. The program code storage device of claim 12, the computer-readable program code including instructions which, when executed, cause the controller to instruct the DAC to repeat, for one or more iterations, a cycle of applying the first voltage for the first timeframe followed by application of the second voltage for the second timeframe.

14. The program code storage device of claim 13, the computer-readable program code including instructions which, when executed, cause the controller to change the duration of at least one of said first and second timeframes for at least one of said one or more iterations.

15. The program code storage device of claim 13, the computer-readable program code including instructions which, when executed, cause the controller to change the magnitude of the first voltage for at least one of said one or more iterations.

16. The program code storage device of claim 15, the computer-readable program code including instructions which, when executed, cause the controller to change the magnitude of the second voltage for at least one of said one or more iterations.

17. The program code storage device of claim 13, wherein the first voltage is a voltage waveform selected from the group consisting of a ramp waveform, a sinusoidal waveform, a stepped waveform, and a squarewave waveform.

18. The program code storage device of claim 17, wherein, for an initial cycle, the first voltage waveform is a first type of waveform and, for an iteration subsequent to the initial cycle, the first voltage waveform is a second type of waveform.

19. The program code storage device of claim 17, wherein the second voltage is a second voltage waveform.

20. The program code storage device of claim 19, wherein the second voltage waveform is one of a ramp waveform, a sinusoid waveform, a stepped waveform, and a squarewave waveform.

21. The program code storage device of claim 13, the computer-readable program code including instructions which, when executed, cause the controller to continue said one or more iterations until a stabilization timeframe has elapsed.

22. The program code storage device of claim 21, the computer-readable program code including instructions which, when executed, cause the controller to change the magnitude of the first voltage for at least one of the one or more iterations.

23. The program code storage device of claim 21, the computer-readable program code including instructions which, when executed, cause the controller to change the duration of the first timeframe and the duration of the second timeframe for at least one of the one or more iterations.

24. A method of stabilizing a sensor having a plurality of electrodes, the method comprising:

applying a first plurality of voltage pulses to one of said plurality of electrodes for a first timeframe; and

applying a second plurality of voltage pulses to said one of the plurality of electrodes for a second timeframe, wherein the magnitude of the first plurality of voltage pulses applied for the first timeframe is different than the magnitude of the second plurality of voltage pulses applied for the second timeframe.

25. The method of claim 24, further including repeating, for one or more iterations, a cycle of applying the first plurality of voltage pulses for the first timeframe followed by application of the second plurality of voltage pulses for the second timeframe.

26. The method of claim 25, wherein the number of pluses included in the first plurality of voltage pulses during an initial cycle is different than the number of pulses included in the first plurality of voltage pulses during a subsequent iteration.

27. The method of claim 25, wherein the magnitude of the first plurality of voltage pulses during an initial cycle is different than the magnitude of the first plurality of voltage pulses during a subsequent iteration.

28. The method of claim 24, wherein each of the first plurality of voltage pulses has a different magnitude.

29. The method of claim 24, wherein each of the first plurality of voltage pulses has a short duration timeframe.

30. The method of claim 29, wherein the short duration timeframe is 50 milliseconds.

31. The method of claim 29, wherein each of the second plurality of voltage pulses has a short duration timeframe.

32. The method of claim 24, wherein each of the first plurality of voltage pulses is applied for a different duration within said first timeframe.

33. The method of claim 24, wherein each of the second plurality of voltage pulses is applied for a different duration within said second timeframe.

34. A program code storage device, comprising:

a computer-readable storage medium; and

a computer-readable program code, the computer-readable program code being stored on the computer-readable storage medium and having instructions which, when executed, cause a controller to;

initiate a stabilization routine;

transmit a first electrical signal to a digital-to-analog converter (DAC) that is coupled to an electrode of a sensor, the first electrical signal being representative of a first plurality of pulses and a first magnitude for each of said first plurality of pulses to be applied to said electrode; and

transmit a second electrical signal to the DAC, the second electrical signal being representative of a second plurality of pulses and a second magnitude for each of said second plurality of pulses to be applied to said electrode.

35. The program code storage device of claim 34, the computer-readable program code including instructions which, when executed, cause the controller to repeat, for one or more iterations, a cycle of transmitting the first electrical signal followed by transmission of the second electrical signal.

36. The program code storage device of claim 35, wherein, during an iteration subsequent to an initial cycle, the first electrical signal causes the DAC to output a first magnitude for said first plurality of pulses that is different than the first magnitude during said initial cycle.

37. The program code storage device of claim 35, wherein, during an iteration subsequent to an initial cycle, the first electrical signal causes the DAC to output a different number of pulses for said first plurality of pulses than the number of pulses during said initial cycle.

38. The program code storage device of claim 35, the computer-readable program code including instructions which, when executed, cause the controller to continue said one or more iterations over a specified timeframe.

39. The program code storage device of claim 38, wherein, for at least one of the one or more iterations, the first electrical signal causes the DAC to output at least one of:

(a) a first magnitude for said first plurality of pulses that is different than the first magnitude during an initial cycle; and

(b) a different number of pulses for said first plurality of pulses than the number of pulses for said first plurality of pulses during the initial cycle.

40. The program code storage device of claim 38, wherein said first electrical signal is also representative of a first duration for each of said first plurality of pulses to be applied to said electrode and said second electrical signal is also representative of a second duration for each of said second plurality of pulses to be applied to said electrode.

41. The program code storage device of claim 40, the computer-readable program code including instructions which, when executed, cause the controller to do at least one of the following for at least one of the one or more iterations:

(a) transmit the first electrical signal so as to cause the DAC to output a different magnitude for each of said first plurality of pulses;

(b) transmit the first electrical signal so as to cause the DAC to output each of said first plurality of pulses for a different duration;

(c) transmit the second electrical signal so as to cause the DAC to output a different magnitude for each of said second plurality of pulses; and

(d) transmit the second electrical signal so as to cause the DAC to output each of said second plurality of pulses for a different duration.

42. The program code storage device of claim 34, wherein said first electrical signal is also representative of a first duration for each of said first plurality of pulses to be applied to said electrode and said second electrical signal is also representative of a second duration for each of said second plurality of pulses to be applied to said electrode.

43. The program code storage device of claim 42, the computer-readable program code including instructions which, when executed, cause the controller to do at least one of the following:

(a) transmit the first electrical signal so as to cause the DAC to output a different magnitude for each of said first plurality of pulses;

(b) transmit the first electrical signal so as to cause the DAC to output each of said first plurality of pulses for a different duration;

(c) transmit the second electrical signal so as to cause the DAC to output a different magnitude for each of said second plurality of pulses; and

(d) transmit the second electrical signal so as to cause the DAC to output each of said second plurality of pulses for a different duration.