Patent US3763440A successfully refreshed from Google Patents.
US3763440A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature compensated signal generation circuit employing a single temperature sensing element
Assignee: Integrated Systems Technology Inc
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Filing: 1972-04-24
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Granted: 1973-10-02
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Expires: 1992-04-24
Abstract
Abstract A signal generation circuit includes a crystal oscillator for generating an oscillatory signal and a temperature compensation circuit coupled to the oscillator for controlling the capacitance loading of the crystal in the oscillator. The temperature compensation circuit includes a temperature sensing device and operates to develop a first capacitance in a first temperature range, a second capacitance which varies at a ertain rate with the variation in temperature in a second temperature range, and a third capacitance which varies at a different rate with the variation in temperature in a third temperature range.
Inventors
- 👤 H Garcia
- 👤 B Peek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:45
CPC Classifications
H; H03; H03L; H03L1/00; H03L1/02; H03L1/022; H03B; H03B5/00; H03B5/30; H03B5/32; H03B5/36; H03B5/366; H03B5/368; H03B2200/00; H03B2200/003; H03B2200/0048; H03B2200/0056; H03B2201/00; H03B2201/01; H03B2201/018; H03B2201/02; H03B2201/025; H03B2201/0258
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
239 words
A signal generation circuit including a crystal oscillator for generating an oscillatory signal, a loading capacitor one side of which is coupled to said oscillator, a controlled variable impedance means having first and second power electrodes connected in series between said loading capacitor and ground potential and a gate electrode, the impedance between said power electrodes varying in response to a voltage applied to said gate electrode, temperature sensing means for producing a voltage proportional to the ambient temperature, means for producing a control voltage having a substantially fixed level in response to the voltage produced by said temperature sensing means in a first temperature range, means for producing a control voltage which varies at a certain rate in response to variations in the voltage produced by said temperature sensing means in a second temperature range, means for producing a control voltage which varies at a different rate in response to variations in the voltage produced by said temperature sensing means in a third temperature range and including a feedback circuit for applying a portion of said control voltage to said sensing means to thereby vary the voltage produced by said sensing means in accordance with variations in the control voltage to thus change the rate at which the control voltage varies as a result of temperature variations, and means for applying to the gate electrode of said controlled variable impedance means a voltage determined by said control voltage.
Claim 2
Dependent Claim
239 words
A signal generation circuit including a crystal oscillator for generating an oscillatory signal, a loading capacitor one side of which is coupled to said oscillator, a controlled variable impedance means having first and second power electrodes connected in series between said loading capacitor and ground potential and a gate electrode, the impedance between said power electrodes varying in response to a voltage applied to said gate electrode, temperature sensing means for producing a voltage proportional to the ambient temperature, means for producing a control voltage having a substantially fixed level in response to the voltage produced by said temperature sensing means in a first temperature range, means for producing a control voltage which varies at a certain rate in response to variations in the voltage produced by said temperature sensing means in a second temperature range, means for producing a control voltage which varies at a different rate in response to variations in the voltage produced by said temperature sensing means in a third temperature range and including a feedback circuit for applying a portion of said control voltage to said sensing means to thereby vary the voltage produced by said sensing means in accordance with variations in the control voltage to thus change the rate at which the control voltage varies as a result of temperature variations, and means for applying to the gate electrode of said controlled variable impedance means a voltage determined by said control voltage.
Claim 3
Dependent Claim
46 words
A signal generation circuit as in claim 1 wherein said controlled variable impedance means includes a field effect transistor whose source and drain electrodes are connected in series between said loading capacitor and ground potential and whose gate electrode is connected to said voltage applying means.
Claim 4
Dependent Claim
31 words
A signal generation circuit as in claim 2 wherein said controlled variable impedance means further includes a diode connected between the source electrode of the field effect transistor and ground potential.
Claim 5
Dependent Claim
20 words
A signal generation circuit as in claim 1 wherein said temperature sensing means is a positive temperature coefficient impedance means.
Claim 6
Dependent Claim
118 words
A signal generation circuit as in claim 1 wherein said control voltage producing means comprise amplifier means responsive to an input voltage for generating a control voltage inversely proportional to the input voltage, first means for maintaining the input voltage at a substantially fixed level when the voltage produced by said temperature sensing means exceeds a biasing threshold level and for varying the input voltage in accordance with variations in the voltage produced by said temperature sensing means when the voltage produced by said temperature sensing means falls below said biasing threshold level, and second means responsive to the control voltage exceeding an activating threshold level for applying a portion of said control voltage to said Feedback circuit.
Claim 7
Dependent Claim
16 words
A signal generation circuit as in claim 5 wherein said amplifier means comprises an operational amplifier.
Claim 8
Dependent Claim
41 words
A signal generation circuit as in claim 5 wherein said first means comprises a voltage divider network coupled to said temperature sensing means, and a diode interconnecting one leg of the voltage divider network to the input of said amplifier means.
Claim 9
Dependent Claim
35 words
A signal generation circuit as in claim 5 wherein said second means comprises a transistor whose emitter and collector are connected in series between the output of said amplifier means and said temperature sensing means.
Claim 10
Dependent Claim
161 words
A signal generation circuit including a plurality of crystal circuits each comprising a crystal and a capacitor interconnecting one terminal of the crystal with ground potential, a transistor whose base electrode is selectively coupled to the other terminal of each crystal and whose emitter serves as an output terminal, a capacitor interconnecting the base of the transistor with the emitter thereof, a capacitor interconnecting the emitter of the transistor with ground potential, and a temperature compensation circuit coupled to the emitter of the transistor and including temperature sensing means for producing a voltage proportional to the ambient temperature and circuitry operable in response to said temperature sensing means to develop a first capacitance in a first temperature range, to develop a second capacitance which varies at a certain rate with the variation in temperature in a second temperature range, and to develop a third capacitance which varies at a different rate with the variations in temperature in a third temperature range.
Claim 11
Dependent Claim
161 words
A signal generation circuit including a plurality of crystal circuits each comprising a crystal and a capacitor interconnecting one terminal of the crystal with ground potential, a transistor whose base electrode is selectively coupled to the other terminal of each crystal and whose emitter serves as an output terminal, a capacitor interconnecting the base of the transistor with the emitter thereof, a capacitor interconnecting the emitter of the transistor with ground potential, and a temperature compensation circuit coupled to the emitter of the transistor and including temperature sensing means for producing a voltage proportional to the ambient temperature and circuitry operable in response to said temperature sensing means to develop a first capacitance in a first temperature range, to develop a second capacitance which varies at a certain rate with the variation in temperature in a second temperature range, and to develop a third capacitance which varies at a different rate with the variations in temperature in a third temperature range.
Claim 12
Dependent Claim
167 words
A signal generation circuit as in claim 9 wherein said temperature compensation circuit includes a loading capacitor one side of which is connected to the emitter of the transistor, controlled variable impedance means having first and second power electrodes connected in series between the other side of said loading capacitor and ground potential and a gate electrode, the impedance between said power electrodes varying in response to a voltage applied to said gate electrode, means for producing a control voltage having a substantially fixed level in response to the voltage produced by said temperature sensing means in said first temperature range, means for producing a control voltage which varies at a certain rate in response to variations in voltage produced by said temperature sensing means in said second temperature range, means for modifying the rate of variation of the control voltage in said third temperature range, and means for applying to the gate electrode of said controlled variable impedance means a voltage determined by said control voltage.
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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) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |