Field effect sensor two wire interconnect method and apparatus
AssigneeTouchsensor Technologies, LLC
InventorTimothy Edward Steenwyk
Life of this patent
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Abstract
A field effect sensor interfaces with a power supply and detection circuit using two wires. The detection circuit can determine which of several parallel-connected field affect sensors is or is not activated at any given time.
Claims14
An apparatus for powering and reading data from a plurality of field effect sensors over two wires, comprising:
- a power supply;
- a first field effect sensor having a first power terminal coupled to a first terminal of said power supply and a second power terminal coupled to a second terminal of said power supply;
- a first load resistor having a first terminal coupled to an output terminal of said first field effect sensor and a second terminal coupled to said second terminal of said power supply, said first load resistor having a first value of resistance;
- a second field effect sensor having a first power terminal coupled to a first terminal of said power supply and a second power terminal coupled to a second terminal of said power supply;
- a second load resistor having a first terminal coupled to an output terminal of said second field effect sensor and a second terminal coupled to said second terminal of said power supply, said second load resistor having a second value of resistance, said second value of resistance being substantially different from said first value of resistance;
- and
- a detection circuit coupled to said first field effect sensor and said second field effect sensor.
An apparatus for powering and reading data from a field effect sensor over two wires, comprising:
- a pulse generator and detection circuit having an input/output terminal;
- a field effect sensor having a first power terminal and an output terminal;
- said first power terminal of said field effect sensor coupled to said input/output terminal;
- a transistor having a power terminal coupled to said input/output terminal;
- a load resistor coupled between said power terminal of said transistor and said input/output terminal;
- a pull-up resistor coupled between a source of power and said input/output terminal;
- and
- said output terminal of said field effect sensor coupled to the control terminal of said transistor.
An apparatus for switching a controlled device over two wires, comprising:
- a field effect sensor having a first power terminal and an output terminal;
- a battery coupled to said first power terminal of said field effect sensor, said battery providing power to said field effect sensor and said battery not providing power to said controlled device;
- and
- means, coupled to said two wires and to said output terminal of said field effect sensor, for switching said controlled device.
An apparatus for powering and reading data from a field effect sensor over two wires, comprising:
- a first field effect sensor having a power terminal and an output terminal;
- a first storage capacitor coupled to said power terminal of said first field effect sensor;
- a pulse generator and detection circuit having an input/output terminal, said input/output terminal coupled to said power terminal of said first field effect sensor and to said output terminal of said first field effect sensor, said control circuit adapted to selectively output a power signal to said power terminal of said first field effect sensor and said first storage capacitor and to selectively receive a data signal corresponding to the state of said output terminal of said first field effect sensor;
- a first diode coupled between (a) said power terminal of said first field effect sensor and said first storage capacitor and (b) said input/output terminal;
- and
- a first transistor coupled between said output terminal of said first field effect sensor and said input/output terminal, said output terminal of said first field effect sensor coupled to the control terminal of said first transistor.
A method for powering and reading data from a field effect sensor having a power terminal coupled to an input/output terminal of a pulse generator and detection circuit and an output terminal coupled to the control terminal of a transistor, said transistor further coupled to said input/output terminal of said pulse generator and detection circuit, comprising the steps of:
- outputting a power signal from said input/output terminal of said pulse generator and detection circuit;
- providing said power signal to a storage capacitor coupled to said power terminal of said field effect sensor;
- powering said field effect sensor by discharging said capacitor through said power terminal of said field effect sensor;
- detecting through said input/output terminal the voltage present at said input/output terminal;
- determining the state of said field effect sensor based on said voltage at said input/output terminal.
A method for powering and reading data from a field effect sensor having a power terminal coupled to an input/output terminal of a pulse generator and detection circuit and an output terminal coupled to the control terminal of a transistor, said transistor further coupled to said input/output terminal of said pulse generator and detection circuit, comprising the steps of:
- outputting a power signal from said input/output terminal of said pulse generator and detection circuit;
- providing said power signal to said power terminal of said field effect sensor;
- detecting through said input/output terminal the voltage present at said input/output terminal;
- and
- determining the state of said field effect sensor based on said voltage at said input/output terminal.
Dependencies are inferred from the claim text.