US 11,998,327 B2
Methods, systems, and devices for electrode capacitance calculation and application
Wayne A. Morgan, Ventura, CA (US)
Assigned to MEDTRONIC MINIMED, INC., Northridge, CA (US)
Filed by MEDTRONIC MINIMED, INC., Northridge, CA (US)
Filed on Aug. 6, 2019, as Appl. No. 16/533,131.
Application 16/533,131 is a continuation of application No. 15/140,961, filed on Apr. 28, 2016, granted, now 10,426,389.
Prior Publication US 2019/0357814 A1, Nov. 28, 2019
Int. Cl. A61B 5/1473 (2006.01); A61B 5/00 (2006.01); A61B 5/053 (2021.01); A61B 5/145 (2006.01); A61B 5/1486 (2006.01); A61B 5/1495 (2006.01)
CPC A61B 5/1473 (2013.01) [A61B 5/0002 (2013.01); A61B 5/053 (2013.01); A61B 5/14532 (2013.01); A61B 5/14865 (2013.01); A61B 5/1495 (2013.01); A61B 5/6849 (2013.01); A61B 5/7203 (2013.01); A61B 5/7225 (2013.01); A61B 2560/0214 (2013.01); A61B 2560/0223 (2013.01); A61B 2562/0214 (2013.01); A61B 2562/166 (2013.01); A61B 2562/227 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method for real-time monitoring of a subcutaneous glucose sensor, said subcutaneous glucose sensor including physical sensor electronics, a microcontroller, and a working electrode (WE), the method comprising:
(a) measuring, by said physical sensor electronics, a first current level for the working electrode;
(b) after measuring said first current level, open circuiting, by said microcontroller, the working electrode by discontinuing input current to the working electrode for a time period having a predefined duration;
(c) during said time period, measuring, by said physical sensor electronics, a first WE voltage value and a second WE voltage value, said first WE voltage value being measured at a first point in time after open circuiting the working electrode, said second WE voltage value being measured at a second point in time after open circuiting the working electrode, and said first and second WE voltage values being measured when a current level for the working electrode is substantially zero;
(d) calculating, by said physical sensor electronics or said microcontroller, the working electrode's capacitance by a relation C=(I)/(dV/dT), wherein I is the first current level, dV is a difference between said first and second WE voltage values, and dT is a difference between said first and second points in time;
(e) repeating operations of (a)-(d) periodically;
(f) determining, by said physical sensor electronics or said microcontroller, a change in the working electrode's capacitance over a time period;
(g) determining, by said physical sensor electronics or said microcontroller, whether the subcutaneous glucose sensor is previously used based on the change in the working electrode's capacitance over the time period; and
(h) responsive to determining that the subcutaneous glucose sensor is previously used, causing replacement of the subcutaneous glucose sensor.