Xicor Corporation

Intersil Americas Inc.

Intersil Corporation

Precision Linear Systems, Inc.

William H Owen

James M Jaffe

Joseph Drori

John M Caywood

Ping Wang

Isao Nojima

Jeffrey Sung

Laurence Clifford

William S Jennings Check

In an exemplary embodiment, a temperature sensor and a 4-20 mA transmitter on a single flexible circuit subassembly with a separate housing suitable for use in industrial control or HVAC applications. In a preferred embodiment, a narrow flex circuit substrate includes a silicon diode-based surface-mount sensor at a sensor end, a surface-mount programmable transmitter IC on a flex circuit substrate in the transmitter section, conductive traces connecting the sensor to the transmitter IC, and two conductive pads at an output end for connecting the 4-20 mA output to a pair of external wires. Additional traces on the flex subassembly are provided for testing and programming the transmitter IC and sensor. The sensor end of the flex subassembly is mounted in a metal sensor tube, filled and sealed in the same manner as RTD or thermistor sensors with leads are currently assembled for use in industrial control or HVAC applications.

Temperature-sensing and transmitting assemblies, programmable temperature sensor units, and methods of making and using them

A circuit for setting a reference voltage in a floating gate circuit is configured as a precise voltage comparator circuit with a built-in programmable voltage reference. Once the one or more floating gates in the floating gate circuit are set during the a SET operation, the floating gate circuit is configured during a READ mode as a comparator circuit with a built-in voltage reference.

Comparator circuit with built-in programmable floating gate voltage reference

A system and method is provided for improving the accuracy of the voltage reference output of a floating gate voltage reference circuit by minimizing the temperature coefficient, Tc. The system and method provides a minimized Tc on output reference voltage, for a wide variety of such output voltages. In a dual floating gate voltage reference circuit wherein a voltage reference output (Vref) is generated as a function of the difference in charge of said floating gates, a method includes causing each of the floating gates to change voltage substantially the same amount as a function of temperature such that, during a read mode of the reference circuit, the temperature coefficient, Tc, of the voltage reference output is substantially reduced. The system and method achieves very low Tc over a wide range of reference or comparator voltages using low cost analog test equipment and methods.

Temperature compensation for floating gate circuits

A method and apparatus for stabilizing the charge on a floating gate in a floating gate reference voltage generator. After an initial high voltage set mode, the method and apparatus allows for a controlled ramp down sequence to ramp down the voltages at the floating gate erase and program electrode generated by first and second bias sources coupled thereto, such that, when these bias sources are completely shut down in the generator, a more accurate voltage is set on the floating gate. The first bias source is preferably a voltage source and the second bias source is preferably a current source. The voltage at the erase electrode that is coupled to the floating gate is controlled during the ramp down sequence by shutting off the current source coupled thereto while allowing a feedback circuit in the generator to remain active. For the method and apparatus, charge may be coupled to the floating gate and removed therefrom using suitable means including, but not limited to, avalanche injection and electron tunneling.

Ramp down method and apparatus for stabilizing charge on a floating gate

A floating gate circuit having a floating gate and a level shift circuit. A first tunneling device formed between a first and second tunnel electrode is included for removing electrons from the floating gate. Electrons are injected onto the floating gate without the use of a tunneling device, e.g., using avalanche injection. A first circuit is coupled to the floating gate for generating an output voltage at an output terminal. The level shift circuit has a second tunnel device coupled between the output terminal and the first tunnel electrode. The second tunnel device is for tracking changes in the characteristics of the first tunneling device connected to the floating gate. The level shift circuit level shifts the output of the floating gate circuit to a voltage that enables the tunnel device coupled to a floating gate to precisely set the floating gate to a desired voltage during a set mode.

Tunnel device level shift circuit

A floating gate voltage level shift circuit is disclosed for generating a voltage reference which can operate on a low supply voltage Vcc by providing a circuit that enables the floating gate to be set accurately to a positive voltage during a SET operation and subsequently shifted down to a lower voltage for a READ operation. The floating gate voltage level shift circuit comprises a differential amplifier with two floating gates, a first floating gate and a second floating gate where the second floating gate is capacitively coupled to either a READ voltage or a Vshift voltage. The floating gate voltage level shift circuit operates in two primary modes, a SET operation and a READ operation. During the SET operation, the C1p capacitor of the second floating gate is connected to a Vshift voltage, rather than ground, while accurately setting the floating gate a positive voltage. The output of the differential amplifier typically swings a volt or more above and below the voltage of the second floating gate while settling to a desired voltage. During the READ operation, the C1p capacitor of the second floating gate is connected to ground, thereby causing the floating gate to shift down to a lower voltage which enables the voltage reference to work on low supply voltage.

Floating gate analog voltage level shift circuit and method for producing a voltage reference that operates on a low supply voltage

A floating gate circuit has a level shift circuit. The floating gate circuit includes: a floating gate; a first and second tunnel device formed respectively between a first and second tunnel electrode; a first circuit coupled to the floating gate for generating an output voltage at an output terminal; a level shift circuit having a third tunnel device coupled between the output terminal and the first tunnel electrode; and a second circuit for causing a first current to flow through the first and second tunnel devices and for causing a second current to flow through the third tunnel device. The floating gate circuit then settles to a steady state condition during the set mode such that the first and second currents are approximately equal and the floating gate voltage and the output voltage are approximately equal.

A method and circuit for setting a reference voltage in a dual floating gate circuit is disclosed. During a set mode, a first and second floating gate are programmed to different charge levels that are a function of an input set voltage capacitively coupled to the first floating gate during the set mode. During a read mode, this difference in charge level is used by the dual floating gate circuit to generate a reference voltage that is a function of the input set voltage, and is preferably equal to the input set voltage.

Differential dual floating gate circuit and method for programming

An apparatus and method is provided for adjusting a reference voltage at an output terminal of a floating gate reference voltage generator circuit in order to improve the accuracy of the reference voltage at an input terminal of a load circuit. The apparatus and method compensates for the voltage drop produced between the output terminal of the reference voltage generator circuit and the input terminal of the load circuit, and includes a capacitor for capacitively coupling the voltage at the input terminal of said load circuit to a floating gate, and a differential amplifier operatively coupled to the floating gate which acts in response to the capacitively coupled load circuit input voltage to adjust the voltage at the output terminal such that the voltage at the input terminal of the load circuit becomes equal to the reference voltage.

Output voltage compensating circuit and method for a floating gate reference voltage generator

A floating gate circuit in a read mode that includes at least one floating gate and an analog feedback circuit is disclosed. The feedback circuit causes the floating gate circuit to reach a steady state condition in the read mode such that a reference voltage is generated that is a predetermined function of an input set voltage used to set the at least one floating gate. In a preferred embodiment, the reference voltage generated is approximately equal to the input set voltage.

Floating gate analog voltage feedback circuit

A method and apparatus for setting a floating gate in a floating gate circuit using dual conduction of Fowler-Nordheim tunnel devices is disclosed. In one embodiment, the present invention comprises a floating gate circuit having a single floating gate. During a set mode, the charge level on the floating gate is modified until it is set to a predetermined charge level that is a function of an input set voltage. In another embodiment, the floating gate circuit comprises two floating gates. During a set mode the charge level on each of the floating gates is modified until the difference in charge level between the two floating gates is a predetermined function of an input set voltage that is capacitively coupled to one of the floating gates during the set mode.

Method and apparatus for dual conduction analog programming

An apparatus for using feedback to set a floating gate to a desired voltage during a set mode is disclosed. The apparatus includes a floating gate, a first and second tunnel device formed respectively between the floating gate and a first and second electrode, a first circuit coupled to the floating gate for comparing the voltage on the floating gate to a third voltage and for generating an output voltage at an output terminal, and a feedback circuit coupled between the output terminal and the floating gate. The feedback circuit includes the first tunnel device and a third tunnel device for causing the floating gate voltage to be modified as a function the output voltage until the floating gate voltage, the third voltage and the output voltage are approximately equal.

Apparatus for feedback using a tunnel device

A method and circuit for programming a floating gate in a differential floating gate circuit to an input set voltage. The circuit includes a differential amplifier circuit for comparing the voltage on a floating gate with an input set voltage, and a gain stage for amplifying any voltage differential between those two voltages. During a set mode, an erase and a program tunnel device operate in a dual conduction mode for modifying the voltage on the floating gate. The output at the gain stage is used to modify the voltage across the erase tunnel device via a feedback loop until the differential floating gate circuit settles to a steady state condition such that the floating gate voltage is approximately equal to the input set voltage. Thereafter, during a read mode, the differential floating gate circuit may be reconfigured to preferably function as a voltage comparator with a built-in voltage reference.

Differential floating gate circuit and method for programming

A method for sensing the voltage on a floating gate in a floating gate circuit during a set mode is disclosed. The method includes the steps of: a) causing the floating gate circuit to enter into a set mode, wherein a first predetermined voltage is coupled to the gate of a second transistor in the floating gate circuit; b) causing the voltage on the floating gate to be sensed relative to the first voltage by a first transistor; c) causing an output voltage to be generated by the floating gate circuit; and d) causing the voltage on the floating gate to be modified as a function of the output voltage, including modifying the charge level on said floating gate under the control of a first tunnel device and a second tunnel device operating in dual conduction during said set mode, said first tunnel device formed between said floating gate and a first tunnel electrode and said second tunnel device formed between said floating gate and a second tunnel electrode; and e) repeating steps b) through d) until the voltage on the floating gate is approximately equal to the first voltage.

Analog floating gate voltage sense during dual conduction programming

A wireless communication system for communicating between a host system and a stand-alone device through an electromagnetic coupling medium is disclosed. The communication system has the capabilities of bi-directional data communications between the host and the stand-alone device and of powering the stand-alone device with energy pulses coupled through the electromagnetic coupling medium from the host. The electromagnetic medium is capable of supporting the bi-directional flow of energy pulses and energy transitions thereof between the host and stand-alone device. In one embodiment, bi-directional communication is provided by transmitting and detecting predetermined numbers of consecutive energy transitions coupled through the medium. Resting durations immediately precede and follow each predetermined number of consecutive energy transitions. In a preferred embodiment of the present invention, the host communicates a first binary value to the stand-alone device by coupling a first predetermined number of consecutive energy transitions to the device and a second binary value to the device by coupling a second predetermined number of consecutive energy transitions. Additionally, the host system receives data from the stand-alone device by first coupling a third predetermined number of consecutive energy transitions to the stand-alone device. The stand-alone device then responds by coupling a predetermined number of energy transitions to the medium during the resting duration following the host's transmission of the third predetermined number of consecutive energy transitions. The number of energy transitions sent by the stand-alone device during this resting duration is related to the value of the data digit being sent to the host.

Growing community of inventors

Los Altos Hills, CA, United States of America

William H Owen