US5513235A
Expired / Lapsed
US
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Integrated circuit thermometer
Assignee: Dallas Semiconductor Corp
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Filing: 1994-10-24
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Granted: 1996-04-30
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Expires: 2014-10-24
Abstract
Abstract An integrated circuit temperature detector (thermometer) uses a temperature dependent oscillator to count up to a fixed number and thereby generate a time interval indicative of the temperature (a temperature-to-time converter). The time-to-number converter provides a numeric temperature output. Counting oscillations of a relatively temperature independent oscillator for the time interval may digitize the temperature measurement. Calibration and successive approximation iterations permit simple hardware to achieve good accuracy.
Inventors
- 👤 James M. Douglass
- 👤 Gary V. Zanders
- 👤 Robert D. Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:42
CPC Classifications
G; G06; G06F; G06F1/00; G06F1/16; G06F1/20; G06F1/206; G01; G01K; G01K1/00; G01K1/02; G01K1/028; G01K7/00; G01K7/16; G01K7/22; G01K7/24; G01K7/245
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
161 words
A temperature detector, comprising: (a) a temperature-to-time first converter, said temperature-to-time first converter outputting a time interval with length depending upon an input temperature; (b) a time-to-number second converter, said time-to-number second converter with input coupled to receive said time interval outputted by said temperature-to-time first converter, said time-to-number second converter approximates a number version of said input temperature by fitting a linear model to said time interval and outputs said number version of said input temperature; (c) said temperature-to-time first converter including a first oscillator with a temperature dependent period coupled to a first counter for providing a temperature dependent time interval, said time interval for said first counter determined by the number of oscillations counted for a predetermined count; and (d) said time-to-number second converter including a second oscillator coupled to a time-to-number second counter, with said time-to-number second counter in response to said second oscillator input producing a digital number during said time interval of said first counter.
Claim 2
Dependent Claim
161 words
A temperature detector, comprising: (a) a temperature-to-time first converter, said temperature-to-time first converter outputting a time interval with length depending upon an input temperature; (b) a time-to-number second converter, said time-to-number second converter with input coupled to receive said time interval outputted by said temperature-to-time first converter, said time-to-number second converter approximates a number version of said input temperature by fitting a linear model to said time interval and outputs said number version of said input temperature; (c) said temperature-to-time first converter including a first oscillator with a temperature dependent period coupled to a first counter for providing a temperature dependent time interval, said time interval for said first counter determined by the number of oscillations counted for a predetermined count; and (d) said time-to-number second converter including a second oscillator coupled to a time-to-number second counter, with said time-to-number second counter in response to said second oscillator input producing a digital number during said time interval of said first counter.
Claim 3
Dependent Claim
22 words
The temperature detector of claim 1, wherein said temperature-to-time first converter and said time-to-number second converter are combined into an integrated circuit.
Claim 4
Dependent Claim
42 words
The temperature detector of claim 1, further wherein said time-to-number second converter has at least one output terminal, said at least one output terminal coupled to an electrical device selected from the group consisting of microcontrollers and microprocessors, and/or any combination thereof.
Claim 5
Dependent Claim
31 words
The temperature detector of claim 1, wherein said number version outputted by said time-to-number second converter is a binary representation of said temperature detector in standard units of measurement of temperature.
Claim 6
Dependent Claim
19 words
The temperature detector of claim 1, wherein said second oscillator of said time-to number second converter is not variable.
Claim 7
Dependent Claim
17 words
The temperature detector of claim 4, wherein said standard units of measurement of temperature are Celsius degrees.
Claim 8
Dependent Claim
49 words
The temperature detector of claim 1 further comprising: (c) control circuitry coupled to said temperature-to-time first converter and to said time-to-number second converter to activate said temperature-to-time first converter and said time-to-number second converter and to synchronize communication between said temperature-to-time first converter and to said time-to-number second converter.
Claim 9
Dependent Claim
14 words
The temperature detector of claim 1, wherein said time-to-number second converter is continuously running.
Claim 10
Dependent Claim
45 words
The temperature detector of claim 1, wherein said input temperature sensed by a temperature sensor ranges between a first temperature and a second temperature, said first temperature is approximately equal to -55 degrees Celsius and said second temperature is approximately equal to +125 degrees Celsius.
Claim 11
Dependent Claim
173 words
A thermometer embedded in a single integrated circuit, comprising: (a) delay circuitry to produce a signal delayed by a length of time corresponding to a temperature output sensed by a temperature sensor; (b) said delay circuitry including a first oscillator to generate oscillations at a first oscillation rate, said first oscillation rate having a sensitivity to temperature, and a first counter coupled to said first oscillator to count said oscillations for a predetermined count to determine said length of time; (c) timing circuitry coupled to receive said signal, said timing circuitry fits a linear mathematical model to said signal to generate a digital output corresponding to said temperature output; and (d) said timing circuitry including a second oscillator to generate oscillations at a second oscillation rate, said second oscillation rate having an insensitivity to temperature, and a second counter coupled to said first counter of said delay line circuitry to count said oscillations generated by said second oscillator to produce a digital number during said length of time determined by said first counter.
Claim 12
Dependent Claim
173 words
A thermometer embedded in a single integrated circuit, comprising: (a) delay circuitry to produce a signal delayed by a length of time corresponding to a temperature output sensed by a temperature sensor; (b) said delay circuitry including a first oscillator to generate oscillations at a first oscillation rate, said first oscillation rate having a sensitivity to temperature, and a first counter coupled to said first oscillator to count said oscillations for a predetermined count to determine said length of time; (c) timing circuitry coupled to receive said signal, said timing circuitry fits a linear mathematical model to said signal to generate a digital output corresponding to said temperature output; and (d) said timing circuitry including a second oscillator to generate oscillations at a second oscillation rate, said second oscillation rate having an insensitivity to temperature, and a second counter coupled to said first counter of said delay line circuitry to count said oscillations generated by said second oscillator to produce a digital number during said length of time determined by said first counter.
Claim 13
Dependent Claim
41 words
The thermometer of claim 10, further comprising: (c) control circuitry coupled to said timing circuitry and to said delay circuitry to activate said delay circuitry and said timing circuitry and synchronize all communication between said timing circuitry and said delay circuitry.
Claim 14
Dependent Claim
21 words
The thermometer of claim 10, wherein said timing circuitry has a reset as to turn on and off said timing circuitry.
Claim 15
Dependent Claim
18 words
The thermometer of claim 10, wherein said timing circuitry and said delay circuitry are powered by a battery.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-04-30 | 1999-10-30 | 2000-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-04-30 | 2003-10-30 | 2004-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-04-30 | 2007-10-30 | 2008-04-30 | $7700.00 | Window Closed / Lapsed |