Amplifier and array for measuring small current
First Claim
Patent Images
1. A device comprising:
- a substrate;
an array of biological cell-sized detector electrodes supported by the substrate including plurality of biological cell-sized detector electrodes paired with one reference electrode;
circuitry supported by the substrate and integrated with the array of electrodes configured to measure transient amperometric oxidation currents from the electrodes and including multiple amplifiers formed with a shared half circuit and a non-shared half circuit, wherein the non-shared half circuit of each amplifier is associated with each electrode and the shared half circuit comprises a non-inverting half of the amplifiers and includes a folded cascode amplifier.
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Abstract
An array of electrochemical detectors includes an array of electrodes that provide current responsive to oxidation events. Each electrode is coupled to a transistor, an amplifier coupled to an input of the transistor and having a feedback loop coupled to the electrode and providing a bias voltage to the electrode, an integrating capacitor coupled to the transistor operable to integrate charge from the electrode, and a reset switch coupled to the integrating capacitor. The amplifier may have a shared stage with other detectors. A shared buffer circuit may also provide a sampled output from multiple detectors.
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Citations
25 Claims
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1. A device comprising:
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a substrate; an array of biological cell-sized detector electrodes supported by the substrate including plurality of biological cell-sized detector electrodes paired with one reference electrode; circuitry supported by the substrate and integrated with the array of electrodes configured to measure transient amperometric oxidation currents from the electrodes and including multiple amplifiers formed with a shared half circuit and a non-shared half circuit, wherein the non-shared half circuit of each amplifier is associated with each electrode and the shared half circuit comprises a non-inverting half of the amplifiers and includes a folded cascode amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device for measuring current, the device comprising:
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a cascode transistor for coupling to an input electrode; an amplifier coupled to an input of the cascode transistor and having an external feedback loop for coupling to the electrode and providing a bias voltage to the input electrode, wherein the amplifier comprises a split amplifier comprising a first shared input stage, multiple second input stages, and an output stage common to the shared first input stage and multiple second input stages, wherein the first shared input stage includes an internal feedback loop electrically coupled to a circuit node common to the shared first input stage and multiple second input stages; an integrating capacitor coupled to the cascode transistor for integrating charge from the input electrode; and a reset switch coupled to the integrating capacitor. - View Dependent Claims (12, 13)
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14. An array of electrochemical detectors comprising:
an array of detector electrodes that provides current responsive to oxidation events, wherein a plurality of detector electrodes is paired with one reference electrode, and wherein each detector electrode is biological cell-sized and coupled to; a transistor; a split amplifier coupled to an input of the transistor and having a feedback loop coupled to the electrode and providing a bias voltage to the detector electrode, wherein the split amplifier includes a shared half circuit and a non-shared half circuit, wherein the non-shared half circuit is associated with each electrode and the shared half circuit comprises a non-inverting half of the split amplifier and includes a folded cascode amplifier circuit; an integrating capacitor coupled to the transistor operable to integrate charge from the detector electrode; and a reset switch coupled to the integrating capacitor. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A shared amplifier array comprising:
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a first shared non-inverting amplifier stage coupled to a reference voltage; and multiple second inverting amplifier stages sharing the first shared non-inverting amplifier stage, the inverting amplifier stages formed in a folded cascode arrangement such that it provides a substantially rail to rail output voltage, wherein the first shared non-inverting amplifier stage includes a feedback loop that lowers an impedance at a circuit node that electrically couples the first shared non-inverting amplifier stage and the multiple second inverting amplifier stages, and wherein an output of a second inverting amplifier stage is electrically coupled to a cascode transistor which is for coupling to an input electrode. - View Dependent Claims (22, 23)
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24. A current detector array comprising:
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a plurality of detectors, each having a detector electrode biological cell-sized for providing current from oxidation events, a split amplifier for biasing the detector electrodes to a reference voltage, a cascode transistor, and an integrating capacitor, wherein the split amplifier includes a shared half circuit and a non-shared half circuit, wherein the non-shared half circuit is associated with each electrode and the shared half circuit comprises a non-inverting half of the split amplifier and includes a folded cascode amplifier; a shared output buffer circuit; and a switch coupled to each detector for alternately switching each of the detectors to the shared output buffer circuit, wherein a plurality of detector electrodes of the plurality of detectors is paired with one reference electrode.
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25. A method comprising:
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distributing multiple small current producing entities across a substrate having an array of detector electrodes biological cell-sized and supported by the substrate and circuitry supported by the substrate and integrated with the array of detector electrodes configured to measure transient amperometric oxidation currents from the electrodes using multiple amplifiers formed with a shared half circuit and a non-shared half circuit, wherein the non-shared half circuit of each amplifier is associated with each electrode and the shared half circuit comprises a non-inverting half of the amplifiers and includes a folded cascode amplifier; and measuring current produced by the current producing entities at each electrode in the array of electrodes.
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Specification