Biosensor apparatus and method with sample type and volume detection
First Claim
1. An apparatus for measuring the effective capacitance across a biosensor cell having a first conductor connection and a second conductor connection, the biosensor cell configured to receive a sample having a volume, said apparatus comprising:
- a sine wave generator having an output for coupling to the first conductor connection of the biosensor cell, said sine wave generator producing an AC signal;
a current-to-voltage (I/V) converter having an input for coupling to the second conductor connection of the biosensor cell and further having an output;
a phase shifter having an input coupled to the output of said I/V converter and further having an output;
a square wave generator producing a square wave synchronous with said AC signal;
a synchronous demodulator having an output, a first input coupled to said phase shifter, and a second input coupled to said square wave generator; and
a low pass filter (LPF) having an input coupled to the output of said synchronous demodulator, said LPF producing a signal at an output proportional to an effective capacitance across the biosensor cell.
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Abstract
A biosensor apparatus and method with sample type and cell volume detection. The apparatus includes a sine wave generator to apply an AC signal to a biosensor cell containing a sample, a current-to-voltage converter, a phase shifter, a square wave generator, a synchronous demodulator, and a low pass filter which yields a signal proportional to the effective capacitance across the biosensor cell, which is proportional to the volume of the sample. In addition, the current-to-voltage converter yields a signal indicative of the type of sample contained within the biosensor cell. The method includes applying a sine wave to the biosensor cell, shifting the phase of the resultant signal, generating a square wave synchronous with the sine wave, demodulating the resultant signal with the square wave, and filtering the demodulated signal to produce a signal proportional to the effective capacitance across the biosensor cell. The biosensor apparatus and method are capable of determining sample type and measuring glucose levels over a wide range of sample volumes.
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Citations
21 Claims
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1. An apparatus for measuring the effective capacitance across a biosensor cell having a first conductor connection and a second conductor connection, the biosensor cell configured to receive a sample having a volume, said apparatus comprising:
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a sine wave generator having an output for coupling to the first conductor connection of the biosensor cell, said sine wave generator producing an AC signal;
a current-to-voltage (I/V) converter having an input for coupling to the second conductor connection of the biosensor cell and further having an output;
a phase shifter having an input coupled to the output of said I/V converter and further having an output;
a square wave generator producing a square wave synchronous with said AC signal;
a synchronous demodulator having an output, a first input coupled to said phase shifter, and a second input coupled to said square wave generator; and
a low pass filter (LPF) having an input coupled to the output of said synchronous demodulator, said LPF producing a signal at an output proportional to an effective capacitance across the biosensor cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A biosensor for measuring components within a sample, said biosensor comprising:
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a biosensor cell having a first conductor connection and a second conductor connection, said biosensor cell configured to receive the sample;
a sine wave generator coupled to the first conductor connection of said biosensor cell, said sine wave generator producing an AC signal having a determined frequency;
a current-to-voltage (I/V) converter having an input coupled to the second conductor connection of said biosensor cell and further having an output;
a phase shifter having an input coupled to the output of said I/V converter and further having an output;
a square wave generator producing a square wave synchronous with said AC signal;
a synchronous demodulator having an output, a first input coupled to the output of said phase shifter, and a second input coupled to said square wave generator; and
a low pass filter (LPF) having an input coupled to the output of said synchronous demodulator, said LPF producing a signal at an output proportional to an effective capacitance across said biosensor cell. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for measuring the effective capacitance across a biosensor cell having a first conductor connection and a second conductor connection, the biosensor cell configured for use in a biosensor to receive a sample having a volume, said method comprising the steps of:
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applying a sine wave having a determined frequency to the first conductor connection of the biosensor cell to produce an AC signal;
shifting the phase of said AC signal;
generating a square wave synchronous with said sine wave;
demodulating said AC signal with said square wave to produce a demodulated signal; and
filtering said demodulated signal to produce a signal proportional to the effective capacitance across the biosensor cell.
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21-28. -28. (canceled)
Specification