Determination of sample volume adequacy in biosensor devices
First Claim
1. An electronic circuit configured to be electrically coupled to an electrochemical cell for receiving a biological sample and having a capacitance created by said biological sample upon application of a voltage to said electrochemical cell, said circuit comprising:
- an oscillation circuit configured to receive a voltage input signal resulting from the charging and discharging of the electrochemical cell and comprising a Schmidt trigger circuit for converting said voltage input signal to an oscillating voltage output signal proportional to the capacitance of the cell.
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Accused Products
Abstract
Systems and methods are provided for determining whether a volume of biological sample is adequate to produce an accurate analyte concentration measurement. Certain such systems and methods provide the additional function of compensating for a sample volume determined to be less than adequate in order to proceed with an accurate analyte concentration measurement. The present invention is employed with a biosensor, such as an electrochemical test strip to which the sample volume of biological solution is deposited, and a meter configured to receive such test strip and to measure the concentration of selected analytes within the biological sample.
145 Citations
47 Claims
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1. An electronic circuit configured to be electrically coupled to an electrochemical cell for receiving a biological sample and having a capacitance created by said biological sample upon application of a voltage to said electrochemical cell, said circuit comprising:
an oscillation circuit configured to receive a voltage input signal resulting from the charging and discharging of the electrochemical cell and comprising a Schmidt trigger circuit for converting said voltage input signal to an oscillating voltage output signal proportional to the capacitance of the cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system comprising:
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a meter for receiving an electrochemical cell configured for receiving a biological sample and having a capacitance created by said biological sample when a voltage is applied to said electrochemical cell;
a DC voltage supply configured to be electrically connectable to said electrochemical cell for charging the electrochemical cell, wherein said cell capacitance is created; and
an electronic circuit integrally configured with said meter and configured to be electronically connectable to said electrochemical cell, said circuit comprising an oscillator circuit configured to receive a voltage input signal resulting from the charging and discharging of said electrochemical cell and configured to convert the voltage input signal to an oscillating voltage output signal, wherein the oscillation period of said oscillating voltage output signal is proportional to said cell capacitance. - View Dependent Claims (14, 15, 16, 17)
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18. A system for determining the volume of a biological sample within an electrochemical cell having a surface area and a volume, comprising:
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a voltage supply configured for applying a first voltage to said electrochemical cell;
means for measuring a second voltage generated by said cell when said first voltage is applied to said cell;
means for converting said second voltage into an oscillating voltage;
means for deriving the capacitance of said cell from said oscillating voltage;
means for deriving the volume of said biological sample from said cell capacitance. - View Dependent Claims (19, 20, 21, 22)
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23. A method for determining the volume of a biological sample applied to an electrochemical biosensor, comprising:
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applying a direct current voltage to the biosensor thereby charging the biosensor, wherein a capacitance is created within the biosensor and a voltage is generated by charging the biosensor;
converting the voltage to an oscillating voltage having a period proportional to the capacitance;
determining the capacitance of the biosensor; and
determining the volume of the sample from said capacitance. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31)
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32. An electronic circuit configured to be electrically coupled to an electrochemical cell configured for receiving a biological sample, said circuit comprising:
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means for applying a DC voltage to said electrochemical cell wherein, upon application of said DC voltage, said electrochemical cell generates a capacitance;
means for receiving a signal produced by said electrochemical cell; and
means for converting said signal to an oscillating signal proportional to the capacitance of the cell. - View Dependent Claims (33, 34, 35, 36, 37, 38)
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39. An electronic circuit configured to be electrically coupled to an electrochemical cell for receiving a biological sample and having a capacitance created by said biological sample upon application of a voltage to said electrochemical cell, said circuit comprising:
an oscillation circuit configured to receive a voltage input signal resulting from the charging and discharging of the electrochemical cell and comprising a comparator circuit for converting said voltage input signal to an oscillating voltage output signal proportional to the capacitance of the cell. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47)
Specification