Thermal measuring and testing – Thermal calibration system
Reexamination Certificate
1998-09-11
2001-09-04
Gutierrez, Diego (Department: 2859)
Thermal measuring and testing
Thermal calibration system
C374S169000, C374S183000
Reexamination Certificate
active
06283628
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to temperature sensors. More specifically, the present invention relates to intelligent input/output (I/O) temperature sensors. Advantageously, a corresponding method for calibrating the intelligent I/O temperature sensors is also disclosed.
Numerous devices for remotely sensing temperatures, particularly temperatures reflecting the operational parameters of various machines and machine systems have been produced. In recent years, numerous programmable temperature sensors have become available. For example, U.S. Pat. No. 5,781,075 to Bolton, Jr. et al., which is entitled “Temperature Sensing Apparatus,” discloses a programmable temperature sensor supplied with both a biasing current and a voltage from a temperature independent voltage source. In this apparatus, the output voltage generated by the voltage source is programmable; thus, the output of the temperature sensor can be adjusted by programming the output voltage of the temperature independent voltage source. It will be appreciated that temperature sensors utilizing the patented circuit exhibit a significant part count, particularly when it is desirable to output the temperature data in digital form. The latter would require at least an analog-to-digital converter (ADC), since the patented circuit generates an analog output. U.S. Pat. Nos. 5,241,850 and 5,519,354 disclose alternative circuitry for programming the temperature range of a temperature sensor; this circuitry also suffers from the same problems.
When installed in a temperature sensing system where the temperature has to sensed from a plurality of locations, it is often expedient to compensate all of the sensors, not individually at the sensor location but at the controller of the temperature sensing system. This requires not only the storage of temperature compensation data for each sensor at the controller but that the controller dedicate a significant portion of its processing time to correcting temperature data gathered by the temperature sensing system.
U.S. Pat. No. 5,444,637 to Smesny et al., which is entitled “Programmable Semiconductor Wafer For Sensing, Recording and Retrieving Fabrication Process Conditions To Which The Wafer Is Exposed,” discloses a programmable semiconductor wafer device
10
, which, as illustrated in
FIG. 1
, includes numerous circuits formed upon its surface topography to sense, store and retrieve processing conditions exerted upon the wafer. Circuits include sensors
12
placed within select regions
14
configured across the surface of wafer
10
. Each region
14
includes at least one sensor
12
and preferably many sensors capable of reading one or numerous processing conditions. A sensor within each region is configured to detect a single processing condition. If more than one sensor is formed within each region, then numerous processing conditions can be detected based upon the number of sensors so formed. Sensors
12
reads, stores and retrieves one or many processing conditions registered within each region
14
and across the semiconductor wafer. Regions
14
are disposed substantially equi-distant from one another across the entire wafer surface in order to obtain an accurate gradient reading thereon. In
FIG. 1
, four sensors
12
are placed within each of seven regions
14
.
Placed between select regions
14
is a semiconductor power device
16
, i.e., either photoelectronic conversion device or a direct electrical storage device using conventional capacitor arrays or a thin film lithium battery. Placed between select regions
14
and spaced from power supply
16
is a signal acquisition/conditioning circuit
18
and a processor
20
containing read only as well as read/write memory. Acquisition/conditioning circuit
18
is connected between processor
20
and each sensor
12
contained within each region
14
. Circuit
18
provides a data-conversion function, while processor
20
contains digital components which perform computer and/or peripheral interfacing tasks. Acquisition/conditioning circuit
18
includes circuitry necessary to accommodate the input or sensor voltage of each sensor
12
into a digital signal acceptable for processor
20
. To transform the analog signal from each sensor
12
to a digital data stream acceptable by processor
20
, a multiplex circuit as well as an A/D converter and amplifier is needed as part of circuit
18
. Furthermore, to increase the speed at which the information can be accurately converted, a S/H circuit may also be used as part of circuit
18
to compress analog signal information.
Coupled to acquisition/conditioning circuit
18
, as well as processor
20
, is an external control circuit
22
which can be arranged in one or more locations between regions
14
as would be necessary to maximize the use of semiconductor real estate. External control circuit
22
is capable of receiving programmable input from an external device and, based upon that input, provide timing pulses, enables, etc., to circuit
18
as well as processor
20
. Input indicia into external control circuit
22
is provided via an input probe pad
24
. Pad
24
is a conductive, substantially planar structure connected to the input of circuit
22
similar to a bonding pad arrangement normally associated with the periphery of an integrated circuit die. Pad
24
is of sufficient size to allow repeated mechanical alignment and contact with an external probe source. Probe pad
24
allows data to be input into circuit
22
necessary for programming and reprogramming of processor
20
. Wafer
10
also includes an output probe pad
26
, which is configured similar to input probe pad
24
for allowing mechanical access from an external output device necessary for receiving digital information stored within the read/write memory of processor
20
.
The wafer sensor system described immediately above suffers from both of the problems discussed above. First, the system has an unacceptably high part count, by virtue of such elements as the multiplexer, signal conditioning filters and ADCs. Moreover, the processor receives raw data from the sensors, in spite of the fact that the data signals are conditioned a number of times on their way between the sensors and the processor. It will be noted that the data storage associated with the system comprises a central data store.
What is needed is a stand alone temperature sensor that provides both accuracy and linearity compensation. Moreover, what is needed is a stand alone temperature sensor providing storage of historical data, where the storage device is some form of non-volatile memory. Furthermore, what is needed is a stand alone temperature sensor which can be easily linked with a plurality of other stand alone temperature sensors via a serial bus to form a temperature sensor system. Lastly, it would be advantageous to have a temperature sensing system wherein each of the stand alone temperature sensors can be re-programmed over the aforementioned serial bus.
SUMMARY OF THE INVENTION
Based on the above and foregoing, it can be appreciated that there presently exists a need in the art for a stand alone temperature sensor and system incorporating same which overcomes the above-described deficiencies. The present invention was motivated by a desire to overcome the drawbacks and shortcomings of the presently available technology, and thereby fulfill this need in the art.
One object of the present invention is to provide a stand alone temperature sensor having both accuracy and compensation.
Another object according to the present invention is to produce a stand alone temperature sensor capable of storing temperature compensated historical data for subsequent downloading.
Still another object according to the present invention is provide a stand alone temperature sensor for storing temperature compensate historical data in a non-volatile memory.
Yet another object according to the present invention is to provide a stand alone temperature sensor which can be calibrated during fabrication.
Another object acc
Airpax Corporation, LLC
Gutierrez Diego
Milde Hoffberg & Macklin, LLP
Verbitsky Gail
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