FET-based gas sensor system
AssigneeHoneywell International Inc.
InventorPeter Tobias
Life of this patent
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Abstract
A sensor system for detection of gas with a modified ion selection FET. The FET may have a gate of low conductivity material for detection of a species in a fluid. A component such as a capacitor may be connected to an electrode of the FET, such as a source, in conjunction with the FET to reduce noise of the detection signal of the species. One or more current sources may provide a current through the FET, and through a resistor to provide a constant source-to-drain voltage. The system may have a bulk voltage selection of either that of a voltage approximately equal to the FET source voltage or greater than the FET source voltage. Also, a guard ring may be implemented in the FET for preventing leakage currents relative to the source or drain.
Claims16
A sensor comprising:
- a FET for sensing a low conductivity fluid;
- a first circuit component connected to the FET;
- an amplifier having an output connected to a drain of the FET;
- and
- a second circuit component connected between a source of the FET and an input of the amplifier;
- and
- wherein:
- the first circuit component and the FET are for providing filtering of FET signals of sensing;
- the FET comprises a resistive gate;
- and
- the first circuit component is connected between the source of the FET and a reference voltage terminal.
A fluid sensor system comprising:
- a FET sensor having a gate of conductivity;
- a capacitive component having a first end connected to a source of the FET, and a second end connected to a reference terminal;
- a first buffer amplifier having an output connected to a drain of the FET;
- a resistive component having a first end connected to the source of the FET and having a second end connected to an input of the first buffer amplifier;
- and
- a second buffer amplifier having an input connected to the source of the FET and an output connected to a bulk of the FET.
A sensor comprising:
- a FET for sensing a low conductivity fluid;
- and
- a first circuit component connected to the FET;
- and
- wherein:
- the first circuit component is a capacitor;
- the first circuit component and the FET are for providing filtering of FET signals of sensing;
- the FET comprises a resistive gate;
- and
- the first circuit component is connected between a source of the FET and a reference voltage terminal.
Dependencies are inferred from the claim text.