INTEGRATORS FOR SENSOR APPLICATIONS

• US 20140174145A1
• Filed: 03/06/2013
• Published: 06/26/2014
• Est. Priority Date: 12/21/2012
• Status: Active Grant

• Current Assignee: Konamite Limited
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Chen, Jun, Gofman, Igor, Wu, Mu, Dionisio, Christopher
• Granted Patent: US 9,417,105 B2
• Time in Patent Office: Days
• US Class Current: 73/1.02
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
• CPC Class Codes: G01N 33/49 Blood chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80

Abstract

Embodiments herein provide processing of sensor signals (e.g., signals representative of a level of an analyte in a body). An electronics assembly may include a sensor contact configured to receive a sensor signal from a sensor assembly, an integrator circuit configured to provide an integrator output signal representative of the sensor signal integrated from a first time to a second time, and a reset circuit configured to reset the integrator output signal in response to a reset signal. The electronics assembly may also include a processor circuit configured to determine a value of the integrator output signal and to provide the reset signal to the reset circuit when an integration interval has elapsed from the first time. The integration interval may be based at least in part on the integrator output signal.

Claims

1. An electronics assembly comprising:

a contact configured to receive a sensor signal from an analyte sensor assembly in contact with a body, the sensor signal representative of a level of an analyte in the body;

an integrator circuit coupled to the contact and configured to provide an integrator output signal representative of the sensor signal integrated from a first time to a second time;

a reset circuit coupled to the integrator circuit and configured to reset the integrator output signal in response to a reset signal; and

a processor circuit coupled to the integrator circuit and the reset circuit, the processor circuit configured to determine a value of the integrator output signal and to provide the reset signal to the reset circuit when an integration interval has elapsed from the first time, the integration interval based at least in part on the integrator output signal.

2. The electronics assembly of claim 1, wherein the analyte sensor assembly includes a continuous glucose monitor configured to generate the sensor signal.

3. The electronics assembly of claim 1, wherein the analyte sensor assembly includes an electrochemical blood glucose monitor or an optical blood glucose monitor configured to generate the sensor signal.

4. The electronics assembly of claim 1, wherein the integrator circuit comprises an amplifier configured to receive the sensor signal at an amplifier input and to provide an amplified sensor signal at an amplifier output, the amplified sensor signal having a voltage dependent on a current of the sensor signal at the amplifier input.

5. The electronics assembly of claim 4, wherein the integrator circuit further comprises a capacitor coupled to the amplifier input and to the amplifier output.

6. The electronics assembly of claim 5, wherein the reset circuit comprises a switch configured to close in response to receiving the reset signal at the reset circuit.

7. The electronics assembly of claim 4, wherein the integrator circuit comprises an analog-to-digital converter (ADC) having an ADC input coupled to the amplifier output and an ADC output coupled to the integrator output.

8. The electronics assembly of claim 7, wherein the ADC has a resolution of less than 18 bits.

9. The electronics assembly of claim 1, wherein the processor circuit is further configured to determine the integration interval based at least in part on a measurement of the integrator output signal.

10. The electronics assembly of claim 1, wherein the processor circuit comprises a comparator circuit coupled to the integrator circuit and configured to:

compare the integrator output signal to a threshold value; and

provide an interrupt signal to a processor of the processor circuit based on the comparison,

wherein the processor is configured to provide the reset signal to the reset circuit in response to receiving the interrupt signal from the comparator circuit.

11. The electronics assembly of claim 10, wherein the threshold value is less than a saturation value of an amplifier included in the integrator circuit.

12. The electronics assembly of claim 10, wherein the processor circuit is further configured to determine an average value of the sensor signal between the first and second times in response to receiving the interrupt signal by determining an elapsed time between the first time and a time at which the interrupt signal is received at the processor.

13. An analyte sensor system, comprising:

a sensor assembly including;

an analyte sensor configured to, when the sensor assembly is positioned against a body, produce a sensor signal that is representative of a level of an analyte in the body,

a housing portion coupled to the sensor assembly, and

a battery disposed within the housing portion; and

an electronics assembly configured to removably couple to the housing portion and the sensor assembly, the electronics assembly including;

battery contacts configured to electrically couple to the battery when the electronics assembly is coupled to the sensor assembly,

a sensor contact configured to receive the sensor signal from the analyte sensor,

an integrator circuit coupled to the sensor contact and configured to provide an integrator output signal representative of the sensor signal integrated from a first time to a second time;

a reset circuit coupled to the integrator circuit and configured to reset the integrator output signal in response to a reset signal; and

a processor circuit coupled to the integrator circuit and the reset circuit, the processor circuit configured to determine a value of the integrator output signal and to provide the reset signal to the reset circuit when an integration interval has elapsed from the first time, the integration interval based at least in part on the integrator output signal.

14. The analyte sensor system of claim 13, wherein the battery is non-rechargeable.

15. The analyte sensor system of claim 13, wherein the battery is molded into the housing portion.

16. The analyte sensor system of claim 13, wherein the analyte sensor comprises a distal end configured to be positioned within the body when the sensor assembly is positioned against the body.

17. The analyte sensor system of claim 13, wherein the analyte sensor includes a continuous glucose monitor.

18. The analyte sensor system of claim 13, wherein the analyte sensor includes an electrochemical blood glucose monitor or an optical blood glucose monitor.

19. A method of processing a sensor signal, comprising:

receiving, by an electronics assembly, a sensor signal from a sensor assembly;

integrating the sensor signal from a first time to a second time to generate an integrator output signal;

determining a value of the integrator input signal;

receiving a reset signal when an integration interval has elapsed from the first time, the integration interval based at least in part on one the integrator output signal; and

in response to receiving the reset signal, resetting the integrated output signal.

20. The method of claim 19, wherein integrating the sensor signal is performed by a transimpedance integrator circuit included in the electronics assembly.

21. The method of claim 20, wherein a voltage-to-current conversion ratio of the transimpedance integrator circuit is greater than 600 μ

V/pA.

22. The method of claim 20, wherein the integration interval is based at least in part on a saturation value of an integrator circuit included in the electronics assembly, an average value of a plurality of measured values of the integrator output signal, and at least one integration interval corresponding to a measured value of the integrator output signal.

23. The method of claim 20, wherein the integration interval varies inversely with a magnitude of a current of the sensor signal.

24. The method of claim 19, wherein determining the value of the integrator output signal includes measuring the value of the integrator output signal prior to resetting the integrated output signal.

25. The method of claim 24, wherein the measured value of the integrator output signal is a digital value represented by fewer than 18 bits.

26. The method of claim 19, further comprising:

comparing the determined value of the integrator output signal to a threshold value; and

when the determined value exceeds the threshold value, providing an interrupt signal to a processor included in the electronics assembly to cause the processor to provide the reset signal.

27. The method of claim 26, wherein the threshold value is less than or equal to a saturation value of an integrator circuit included in the electronics assembly.