TREA

Method of and system for stabilization of sensors

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Information

  • Patent Application
  • 20070173712
  • Publication Number
    20070173712
  • Date Filed
    December 30, 2005
    18 years ago
  • Date Published
    July 26, 2007
    17 years ago
Information
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 cases 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 regulator 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.
Description

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of embodiments of the invention will be made with reference to the accompanying drawings, wherein like numerals designate corresponding parts in the figures.



FIG. 1 is a perspective view of a subcutaneous sensor insertion set and block diagram of a sensor electronics device according to an embodiment of the invention;



FIG. 2(
a) illustrates a substrate having two sides, a first side which contains an electrode configuration and a second side which contains electronic circuitry;



FIG. 2(
b) illustrates a general block diagram of an electronic circuit for sensing an output of a sensor according to an embodiment of the present invention;



FIG. 3 illustrates a block diagram of a sensor electronics device and a sensor including a plurality of electrodes according to an embodiment of the invention;



FIG. 4 illustrates an alternative embodiment of the invention including a sensor and a sensor electronics device according to an embodiment of the present invention;



FIG. 5 illustrates an electronic block diagram of the sensor electrodes and a voltage being applied to the sensor electrodes according to an embodiment of the present invention;



FIG. 6(
a) illustrates a method of applying pulses during stabilization timeframe in order to reduce the stabilization timeframe according to an embodiment of the present invention;



FIG. 6(
b) illustrates a method of stabilizing sensors according to an embodiment of the present invention;



FIG. 6(
c) illustrates utilization of feedback in stabilizing the sensors according to an embodiment of the present invention;



FIG. 7 illustrates an effect of stabilizing a sensor according to an embodiment of the invention;



FIG. 8 illustrates a block diagram of a sensor electronics device and a sensor including a voltage generation device according to an embodiment of the invention;



FIG. 8(
b) illustrates a voltage generation device to implement this embodiment of the invention;



FIG. 8(
c) illustrates a voltage generation device to generate two voltage values according in a sensor electronics device according to implement this embodiment of the invention;



FIG. 9 illustrates a sensor electronics device including a microcontroller for generating voltage pulses according to an embodiment of the present invention;



FIG. 9(
b) illustrates a sensor electronics device including an analyzation module according to an embodiment of the present invention;



FIG. 10 illustrates a block diagram of a sensor system including hydration electronics according to an embodiment of the present invention;



FIG. 11 illustrates an embodiment of the invention including a mechanical switch to assist in determining a hydration time;



FIG. 12 illustrates an electrical detection of detecting hydration according to an embodiment of the invention;



FIG. 13(
a) illustrates a method of hydrating a sensor according to an embodiment of the present invention;



FIG. 13(
b) illustrates an additional method for verifying hydration of a sensor according to an embodiment of the present invention;



FIGS. 14(
a) and (b) illustrate methods of combining hydrating of a sensor with stabilizing a sensor according to an embodiment of the present invention; and



FIG. 14(
c) illustrates an alternative embodiment of the invention where the stabilization method and hydration method are combined.


Claims
  • 1. A method of stabilizing a sensor during initialization of the sensor, comprising: applying a first voltage to an electrode in a sensor for a first predetermined time to initiate an anodic cycle in the sensor;waiting a second predetermined time which initiates a cathodic cycle in the sensor; andrepeating a cycle of applying the first voltage for the first predetermined time and waiting a second predetermined time for a number of iterations.
  • 2. The method of claim 1, wherein the first predetermined time is five minutes and the second predetermined time is two minutes.
  • 3. The method of claim 1, wherein a magnitude of the first voltage is different for each of the number of iterations.
  • 4. A method of stabilizing a sensor, comprising: applying a first voltage to a counter electrode in a sensor to initiate an anodic cycle in the sensor;applying a second voltage to the counter electrode in the sensor to initiate a cathodic cycle in the sensor; andrepeating the anodic-cathodic cycle by applying the first voltage and the second voltage for a number of iterations.
  • 5. The method of claim 4, wherein the applying of the first voltage and the applying of the second voltage is alternated until electrochemical byproducts are reduced to an acceptable level to reduce background current readings.
  • 6. The method of claim 4, wherein the first voltage has a negative value.
  • 7. The method of stabilizing a sensor of claim 4, wherein the cycling between the anodic cycle and the cathodic cycle continues until a stabilization period has elapsed.
  • 8. The method of stabilizing a sensor of claim 4, wherein the cycling between the anodic cycle and the cathodic cycle continues until a sensor signal produced by the sensor reaches a specific value.
  • 9. A method of stabilizing a sensor, comprising: applying a first plurality of voltage pulses to an electrode of the sensor for a first timeframe;applying a second plurality of voltage pulses to the electrode of the sensor for the second timeframe, wherein a magnitude of the first plurality of voltage pulses applied for the first timeframe is the different than the magnitude of the second plurality of voltage pulses applied for the second timeframe.
  • 10. The method of claim 9, further including repeating a cycle of applying the first plurality of voltage pulses for the first timeframe and applying the second plurality of voltages for the second timeframe for a number of iterations.
  • 11. The method of claim 9, wherein each of the first plurality of voltage pulses has a different magnitude.
  • 12. The method of claim 9, wherein each of the first plurality of pulses has a short duration timeframe.
  • 13. The method of claim 12, wherein the short duration timeframe is 50 milliseconds.
  • 14. The method of claim 12, wherein each of the second plurality of pulses has a short duration timeframe.
  • 15. A method of stabilizing a sensor, comprising: applying a first voltage waveform to an electrode in a sensor to initiate an anodic cycle in the sensor;applying a second voltage to the electrode in the sensor to initiate a cathodic cycle in the sensor; andrepeating the anodic-cathodic cycle by applying the first voltage waveform and the second voltage for a number of iterations.
  • 16. The method of claim 15, wherein the first voltage waveform is a one of a ramp waveform, a sinusoidal waveform, a stepped waveform, and a squarewave waveform.
  • 17. The method of claim 15, wherein in a first iteration a first type of waveform is applied to the electrode and in a second iteration a second type of waveform is applied to the electrode.
  • 18. The method of claim 15, wherein a second voltage waveform is applied to the electrode instead of the second voltage.
  • 19. The method of claim 18, wherein the second voltage waveform is one of a group of a ramp waveform, a sinusoid waveform, a stepped waveform, and a squarewave waveform.
  • 20. A program code storage device, comprising: computer-readable storage medium; andcomputer-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; andtransmit a first signal to a digital-to-analog converter (DAC), the DAC being coupled to an electrode of a sensor, the first signal representative of a stabilization sequence of voltages that the DAC is to output to the electrode of the sensor, wherein the stabilization sequence of voltages includes a first voltage applied for a first time frame, a second voltage applied for a second time frame, and a repeating of the application of the first voltage and the second voltage to the electrodes.
  • 21. The program code storage device of claim 20, including instructions, which when executed cause the controller to: repeat the application of the first voltage and the second voltage for a number of iterations.
  • 22. The program code storage device of claim 21, including instructions, which when executed cause the controller to: change a duration of the first amount of time and a duration of the second amount of time for at least one of the number of iterations.
  • 23. The program code storage device of claim 20, including instructions, which when executed cause the controller to: repeat the application of the first voltage and the second voltage for a stabilization timeframe.
  • 24. The program code storage device of claim 20, including instructions, which when executed cause the controller to: instruct the DAC to change a magnitude of the first voltage to be applied to the electrode of the sensor at least once during the repeating of the application of the first voltage.
  • 25. The program code storage device of claim 24, including instructions, which when executed cause the controller to instruct the DAC to change a magnitude of the second voltage to be applied to the electrode of the sensor at least once during the repeating of the application of the second voltage.
  • 26. A program code storage device, comprising: computer-readable storage medium; andcomputer-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), the DAC being coupled to an electrode of a sensor, the first electrical signal being representative of a first number of pulses and a first magnitude of the pulses to be applied to the electrode of the sensor; andtransmit a second electrical signal to the DAC, the second electrical signal being representative of a number of a second number of pulses and a second magnitude of the pulses to be applied to the electrode of the sensor.
  • 27. The program code storage device of claim 26, including instructions, which when executed cause the controller to: repeat the transmitting the first electrical signal to cause an anodic cycle and the second electrical signal to cause a cathodic cycle for a number of iterations.
  • 28. The program code storage device of claim 27, wherein the first electrical signal causes the DAC to output a different first magnitude for the pulses to be applied to the electrode of the sensor during a second iteration.
  • 29. The program code storage device of claim 29, wherein the first electrical signal causes the DAC to output a different number of pulses which are applied to the electrode of the sensor during a second iteration.
  • 30. The program code storage device of claim 26, including instructions, which when executed cause the controller to: repeat the transmitting of the first electrical signal to cause an anodic cycle and of the second electrical signal to cause a cathodic cycle for a specified timeframe.
  • 31. A program code storage device, comprising: computer-readable storage medium; andcomputer-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:transmit a first signal to a digital-to-analog converter (DAC), the DAC being coupled to an electrode of a sensor, the first signal representative of a stabilization sequence of voltages that the DAC is to output to the electrode of the sensor, wherein the stabilization sequence of voltages includes a first voltage applied for a first time frame and a second voltage applied for a second time frame;receive a reading from an analyzation circuit indicating an electrical measurement of the sensor; andcompare the reading indicating the electrical measurement of the sensor to an established set of criteria.
  • 32. The program code storage device of claim 31, including instructions, which when executed cause the controller to: terminate the transmission of the first signal and thus the stabilization sequence of voltages if the reading indicating the electrical measurement of the sensor meets the established set of criteria.
  • 33. The program code storage device of claim 32, wherein the established criteria is being above a threshold measurement.
  • 34. The program code storage device of claim 32, wherein the electrical measurement is one of a group including a voltage, a current, a resistance, and an impedance.
  • 35. The program code storage device of claim 32, including instructions, which when executed cause the controller to: transmit a measurement signal to the analyzation circuit to initiate the reading of the electrical characteristic of the sensor.
  • 36. The program code storage device of claim 32, including instructions, which when executed cause the controller to: transmit a second signal to the DAC, the second signal causing the DAC to apply a testing voltage to the sensor before the analyzation circuit measures the electrical measurement of the sensor.
  • 37. A blood glucose sensing system, comprising: a sensor, the sensor including a plurality of electrodes; anda sensor electronics device, the sensor electronics device including stabilization circuitry to provide a first voltage to one of the plurality of electrodes to initiate an anodic cycle within the sensor, to provide a second voltage to the one of the plurality of electrodes to initiate a cathodic cycle within the sensor, and to repeat the application of the first voltage and the second voltage to continue the anodic-cathodic cycle.
  • 38. The blood glucose sensing system of claim 37, wherein the one of the plurality of electrodes is a counter electrode.
  • 39. The blood glucose sensing system of claim 37, wherein the stabilization circuitry includes a microcontroller, the microcontroller transmitting a first signal indicative of the first voltage to be applied to a sensor and also transmitting a second signal indicative of the second voltage.
  • 40. The blood glucose sensing system of claim 39, wherein the stabilization circuitry further includes a digital-to-analog converter (DAC) to receive the first signal indicative of the first voltage and the second signal indicative of the second voltage and to apply the first voltage and the second voltage to the one of the plurality of electrodes.
  • 41. The blood glucose sensing system of claim 40, wherein the stabilization circuitry further includes an op amp, coupled to the one of the plurality of electrodes, to receive the first voltage and the second voltage from the DAC and to apply the first voltage and the second voltage to the one of the plurality of electrodes.
  • 42. The blood glucose sensing system of claim 39, wherein the stabilization circuitry further includes analyzation circuitry to measure an electrical characteristic of the sensor and to transmit a reading indicating the electrical characteristic measurement to the microcontroller.
  • 43. The blood glucose sensing system of claim 42, wherein the electrical characteristic of is one of a group of voltage, current, resistance, and impedance.
  • 44. The blood glucose sensing system of claim 42, wherein the microcontroller transmits a measurement signal to DAC and the DAC applies a testing voltage to the sensor before the analyzation circuitry measures an electrical characteristic of the sensor.
  • 45. The blood glucose sensing system of claim 37, wherein the first voltage is a plurality of short duration pulses and the application of the plurality of short duration pulses decreases an amount of energy applied to the plurality of electrodes in the sensor.
  • 46. A blood glucose sensing system, comprising: a sensor, the sensor including a counter electrode, a reference electrode, and a working electrode; andsensor electronics device, the sensor electronics device including,a power supply to supply a voltage,a regulator to receive the voltage from the power supply and to generate a regulated voltage, anda voltage application device to receive the regulated voltage, to apply a first voltage to a counter electrode for a first timeframe, and to apply a second voltage to a counter electrode for the second timeframe.
  • 47. The blood glucose sensing system of claim 46, wherein the voltage application device cycles between applying the first voltage for the first timeframe and applying the second voltage for the second timeframe for a number of iterations.
  • 48. The blood glucose sensing system of claim 46, wherein the voltage application device cycles between applying the first voltage for the first timeframe and applying the second voltage for the second timeframe for a stabilization timeframe and completes transmission of a stabilization voltage sequence.
  • 49. The blood glucose sensing system of claim 48, a current-to-frequency converter measures a current at the current electrode and transmits a reading to a processor in the sensor electronics device.
  • 50. The blood glucose sensing system of claim 42, further including comparing the electrical characteristic measurement to set measurement criteria of the electrical characteristic, and if the electrical characteristic measurement matches the set measurement criteria, the microcontroller generates a signal to perform one of the group of the following actions: modify the application of the pulses; modify the timing of the pulses and terminate the stabilization routine.