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US3678331A
Expired / Lapsed
US
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Sawtooth current generator
Assignee: Verizon Laboratories Inc
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Filing: 1970-01-22
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Granted: 1972-07-18
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Expires: 1990-01-22
Abstract
Abstract A sawtooth current generator is disclosed which provides a linear time varying current for the coil of a magnetic deflection system of a television display tube. The coil is coupled to the collector of a transistor and the transistor is coupled to a resonant circuit which provides feedback to sustain the circuit oscillations and to actuate the transistor. In addition, a diode is coupled to the collector of the transistor. A constant voltage is maintained across the inductor by the alternate conduction of the transistor and the diode so that a linear time varying current flows in the inductor.
Inventors
- 👤 Martin Fischman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:44
CPC Classifications
H; H03; H03K; H03K4/00; H03K4/06; H03K4/08; H03K4/48; H03K4/60; H03K4/62; H03K4/64; H03K4/66
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
166 words
A sawtooth current generator for producing a periodic sawtooth current, each period thereof being composed of a trace period having first and second segments and a retrace period, said generator comprising a. a semiconductor switching element having first, second and third electrodes, said first electrode being coupled to a reference potential, b. inductance means having first and second terminals, said first terminal being coupled to the third electrode of said switching element, c. capacitance means having first and second terminals, said capacitance means being coupled in parallel with said inductance means, d. first switching means having first and second terminals, said first and second terminals being coupled to the first and third electrodes respectively of said switching element, and e. resonant circuit means having first, second and third terminals, said first, second and third terminals being coupled respectively to the first, second and third electrodes of said switching element whereby a current which varies linearly with time flows through said inductance means during said trace period.
Claim 2
Dependent Claim
166 words
A sawtooth current generator for producing a periodic sawtooth current, each period thereof being composed of a trace period having first and second segments and a retrace period, said generator comprising a. a semiconductor switching element having first, second and third electrodes, said first electrode being coupled to a reference potential, b. inductance means having first and second terminals, said first terminal being coupled to the third electrode of said switching element, c. capacitance means having first and second terminals, said capacitance means being coupled in parallel with said inductance means, d. first switching means having first and second terminals, said first and second terminals being coupled to the first and third electrodes respectively of said switching element, and e. resonant circuit means having first, second and third terminals, said first, second and third terminals being coupled respectively to the first, second and third electrodes of said switching element whereby a current which varies linearly with time flows through said inductance means during said trace period.
Claim 3
Dependent Claim
31 words
The generator of claim 1 further comprising second switching means having first and second terminals, said second switching means being coupled between the first and second electrodes of said switching element.
Claim 4
Dependent Claim
39 words
The generator of claim 2 wherein said first switching means is a first diode, said first diode being poled to provide a low impedance path between its first and second terminals during said first segment of the trace period.
Claim 5
Dependent Claim
127 words
The generator of claim 3 wherein said resonant circuit means comprises a. a first inductor having first and second terminals, said first terminal being coupled to the base of said transistor, b. a second inductor having first and second terminals, said first terminal being coupled to the collector of said transistor, said second terminal being coupled to the second terminal of said first inductor, and c. a capacitor having first and second terminals, said first terminal being coupled to a reference potential, said second terminal being coupled to the second terminal of said first inductor, said resonant circuit having a characteristic frequency of oscillation whereby the time at which the conducting state of said semiconductor switching element is changed is dependent upon said characteristic frequency of oscillation.
Claim 6
Dependent Claim
28 words
The generator of claim 4 wherein said semiconductor switching element is a transistor and said first, second and third electrodes are the emitter, base and collector electrode respectively.
Claim 7
Dependent Claim
41 words
The generator of claim 5 wherein said second switching means is a second diode, said second diode being poled to provide a low impedance path between its first and second terminals during the time in which the switching element is nonconducting.
Claim 8
Dependent Claim
27 words
The generator of claim 6 wherein said inductance means is a magnetic deflection coil and said capacitance means is a retrace capacitor for a television display tube.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |