Patent US3978431A successfully refreshed from Google Patents.
US3978431A
Expired / Lapsed
US
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Temperature compensated oscillator
Assignee: Motorola Solutions Inc
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Filing: 1975-07-03
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Granted: 1976-08-31
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Expires: 1995-07-03
Abstract
Abstract An oscillator is provided the frequency of operation of which is controlled by an RC circuit the resistive element of which is an MOS load device and the capacitive element of which is an MOS enhanced capacitor. An important characteristic of this ring oscillator is that its time constant determining elements mutually compensate one another for changes in temperature. A digital enhanced capacitor can be used in this temperature compensated ring oscillator to provide greater flexibility in controlling both the frequency of operation of the oscillator and the wave shape of the output signal.
Inventors
- 👤 William Walter Lattin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:36
CPC Classifications
H; H03; H03B; H03B5/00; H03B5/02; H03B5/04; H03K; H03K3/00; H03K3/02; H03K3/027; H03K3/03; H03K3/0307
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
94 words
A temperature compensated oscillator including a time constant generating circuit and a feedback circuit comprising: impedance means coupled between a voltage conductor and a first node for supplying a current into said node, which current decreases as temperature increases; and enhanced capacitor means forming the second element of the time constant coupled between said first node and a second voltage conductor for being charged through said impedance means, said enhanced capacitor having a capacitance which decreases as temperature increases, such that the RC time constant remains substantially fixed in value with variations in temperature.
Claim 2
Dependent Claim
94 words
A temperature compensated oscillator including a time constant generating circuit and a feedback circuit comprising: impedance means coupled between a voltage conductor and a first node for supplying a current into said node, which current decreases as temperature increases; and enhanced capacitor means forming the second element of the time constant coupled between said first node and a second voltage conductor for being charged through said impedance means, said enhanced capacitor having a capacitance which decreases as temperature increases, such that the RC time constant remains substantially fixed in value with variations in temperature.
Claim 3
Dependent Claim
19 words
A temperature compensated oscillator as recited in claim 1 wherein said enhanced capacitor means includes a digital enhanced capacitor.
Claim 4
Dependent Claim
27 words
The oscillator as recited in claim 2 further including a plurality of digital inputs coupled to said digital enhanced capacitor for controlling the frequency of said oscillator.
Claim 5
Dependent Claim
93 words
A temperature compensated oscillator including a time constant generating circuit comprising: first resistor means coupled between a first voltage supply conductor and a first node for supplying a negative temperature coefficient current into said first node; second resistor means coupled between a second voltage supply conductor and said first node for sinking a negative temperature coefficient current from said first node; an MOS enhanced capacitor means coupled between said first node and voltage supply means for compensating said negative temperature coefficient currents by increasing its value of capacitance as a function of temperature.
Claim 6
Dependent Claim
93 words
A temperature compensated oscillator including a time constant generating circuit comprising: first resistor means coupled between a first voltage supply conductor and a first node for supplying a negative temperature coefficient current into said first node; second resistor means coupled between a second voltage supply conductor and said first node for sinking a negative temperature coefficient current from said first node; an MOS enhanced capacitor means coupled between said first node and voltage supply means for compensating said negative temperature coefficient currents by increasing its value of capacitance as a function of temperature.
Claim 7
Dependent Claim
59 words
A digitally controllable oscillator including a time constant generating circuit comprising impedance means and digital enhanced capacitor means coupled to said impedance means and at least one enhanced capacitor control input for digitally controlling the time constant of a signal generated by said time constant generating circuit as a function of a control signal applied to said control input.
Claim 8
Dependent Claim
59 words
A digitally controllable oscillator including a time constant generating circuit comprising impedance means and digital enhanced capacitor means coupled to said impedance means and at least one enhanced capacitor control input for digitally controlling the time constant of a signal generated by said time constant generating circuit as a function of a control signal applied to said control input.
Claim 9
Dependent Claim
46 words
The oscillator cited in claim 5 wherein said impedance means includes at least one MOS field effect transistor coupled to a source region of said digital enhanced capacitor means for producing a temperature compensated time constant for said signal generated by said time constant generating circuit.
Claim 10
Dependent Claim
78 words
An MOS temperature compensated oscillator comprising: a first MOS inverter having an input coupled to an output of a third MOS inverter; a second MOS inverter having an input coupled to an output of said first MOS inverter; said third MOS inverter having an input coupled to an output of said second MOS inverter; and first, second and third enhanced capacitors coupled between a voltage conductor means and the outputs of said first, second and third stages respectively.
Claim 11
Dependent Claim
78 words
An MOS temperature compensated oscillator comprising: a first MOS inverter having an input coupled to an output of a third MOS inverter; a second MOS inverter having an input coupled to an output of said first MOS inverter; said third MOS inverter having an input coupled to an output of said second MOS inverter; and first, second and third enhanced capacitors coupled between a voltage conductor means and the outputs of said first, second and third stages respectively.
Claim 12
Dependent Claim
34 words
The MOS oscillator as recited in claim 7 further including a plurality of digital inputs coupled to said first, second, and third capacitors, respectively, for controlling the frequency and wave shape of said oscillator.
Claim 13
Independent Claim
93 words
A method of operating an oscillator with impedance means coupled to a node and enhanced capacitor means coupled to said node comprising the steps of: causing a first current to flow through said impedance means into and out of said node, said impedance means having a positive temperature coefficient; causing a second current to flow through said enhanced capacitor means into and out of said node, said enhanced capacitor means having a negative temperature coefficient; and said impedance means and said enhanced capacitor means acting to form a time constant for said oscillator.
Claim 14
Independent Claim
93 words
A method of operating an oscillator with impedance means coupled to a node and enhanced capacitor means coupled to said node comprising the steps of: causing a first current to flow through said impedance means into and out of said node, said impedance means having a positive temperature coefficient; causing a second current to flow through said enhanced capacitor means into and out of said node, said enhanced capacitor means having a negative temperature coefficient; and said impedance means and said enhanced capacitor means acting to form a time constant for said oscillator.
Claim 15
Dependent Claim
94 words
A temperature compensated MOS oscillator, comprising a first active region for providing resistive impedance, wherein the resistance of said impedance is inversely proportional to charge mobility of the region, the second active region for providing capacitive impedance and operatively coupled to said first active region, wherein said second active region is configured to provide a capacitance which is directly proportional to said charge mobility so that the temperature variant nature of the mobility in said first region is compensated by that of said second region whereby said MOS oscillator is rendered substantially temperature invariant.
Claim 16
Dependent Claim
94 words
A temperature compensated MOS oscillator, comprising a first active region for providing resistive impedance, wherein the resistance of said impedance is inversely proportional to charge mobility of the region, the second active region for providing capacitive impedance and operatively coupled to said first active region, wherein said second active region is configured to provide a capacitance which is directly proportional to said charge mobility so that the temperature variant nature of the mobility in said first region is compensated by that of said second region whereby said MOS oscillator is rendered substantially temperature invariant.
References Cited (Backward Citations)
US3388340A
Cited
US3416100A
Cited
US3708757A
Cited
US3748499A
Cited
US3757245A
Cited
US3911466A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-31 | 1980-03-01 | 1980-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-31 | 1984-03-01 | 1984-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-31 | 1988-03-01 | 1988-08-31 | $7700.00 | Window Closed / Lapsed |