Non-contact biopotential sensor
First Claim
1. A biosensor system for measuring an electric field, said biosensor system comprising:
- a sensing plate capacitively coupled to a living body surface, wherein changes in electrical potential at the body surface generate an electric field that induces change in the electrical potential of the sensing plate, the sensing plate including a sensing node positioned in the electric field for generating an input signal from the electric field, the sensing plate separated from the living body surface by an intervening material;
an amplifier configured to amplify the input signal from the sensing node, the amplifier configured to receive the input signal at the input port and to generate an amplified output signal at the output port; and
a switching circuit connected to the input port and a reference voltage, the switching circuit comprising at least one switching device configured to non-continuously close a shunting path from the sensing node to the reference voltage to reset the sensing node connected to the input port, wherein closing the shunting path from the sensing node to the reference node is performed in response to at least one of the input signal drifting away from the reference voltage by a predetermined amount, and a timing signal.
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Abstract
A capacitive sensor system including a sensing plate, an amplifier, and a switching circuit is described. The sensing plate is capacitively coupled to a body surface. A change in the electric potential on the body surface generates an electric field that induces change in the electric potential of the sensing plate. The sensing plate includes a sensing node positioned in the electric field for generating an input signal from the electric field. The sensing plate is not in contact with the body surface. The amplifier receives the input signal at the input port, amplifies the input signal and generates an output signal at the output port. The switching circuit is connected to the input port and a reference voltage. The switching circuit non-continuously closes a shunting path from the sensing node to the reference voltage to reset the voltage at the sensing node.
35 Citations
38 Claims
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1. A biosensor system for measuring an electric field, said biosensor system comprising:
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a sensing plate capacitively coupled to a living body surface, wherein changes in electrical potential at the body surface generate an electric field that induces change in the electrical potential of the sensing plate, the sensing plate including a sensing node positioned in the electric field for generating an input signal from the electric field, the sensing plate separated from the living body surface by an intervening material; an amplifier configured to amplify the input signal from the sensing node, the amplifier configured to receive the input signal at the input port and to generate an amplified output signal at the output port; and a switching circuit connected to the input port and a reference voltage, the switching circuit comprising at least one switching device configured to non-continuously close a shunting path from the sensing node to the reference voltage to reset the sensing node connected to the input port, wherein closing the shunting path from the sensing node to the reference node is performed in response to at least one of the input signal drifting away from the reference voltage by a predetermined amount, and a timing signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A biosensor system for measuring an electric field, said biosensor system comprising:
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a sensing plate capacitively coupled to a living body surface, wherein changes in electrical potential on the body surface generate an electric field that induces change in the electrical potential of the sensing plate, the sensing plate including a sensing node positioned in the electric field for generating an input signal from the electric field, the sensing plate separated from the living body surface by an intervening material; an amplifier configured to amplify the input signal, the amplifier configured to receive the input signal at the input port and to generate an amplified output signal at the output port; a switching circuit including at least one switching device and a reset circuit including a plurality of capacitors, the plurality of capacitors configured to supply an activation voltage to the at least one switching device to turn on or activate the at least one switching device, the switching circuit connected to the input port and a reference voltage, the switching circuit configured to non-continuously close a shunting path from the sensing node to the reference voltage to reset the sensing node connected to the input port when the at least one switching device is turned on, wherein the activation voltage is triggered by at least one of the input signal drifting away from the reference voltage by a predetermined amount and a timing signal; and a unity gain amplifier having a first input port and a first output port, the first input port coupled to the input port of the amplifier, wherein the unity gain amplifier is configured to generate a first output voltage at the first output port, and wherein the unity gain amplifier is connected to one or more resistors, wherein the one or more resistors are configured to pull the plurality of capacitors to the first output voltage when the at least one switching device is off. - View Dependent Claims (32, 33, 34, 35, 36, 37)
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38. A biosensor system for measuring an electric field generated at a surface of a living body, said biosensor system comprising:
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a non-contact sensing plate capacitively coupled to the living body surface, the sensing plate comprising a sensing node positioned in the electric field for generating an input signal corresponding to the electric field; an amplifier having an input port configured to receive the input signal and generate an amplified output signal; and a switching circuit connected to the input port and a reference voltage, the switching circuit comprising at least one switching device configured to non-continuously close a shunting path from the sensing node to the reference voltage to reset the sensing node connected to the input port, wherein the at least one switching device is responsive to an the activation voltage triggered by at least one of the input signal drifting away from the reference voltage by a predetermined amount and a timing signal.
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Specification