US3823340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for generating a sawtooth-shaped current through a coil by compensating for deflection coil resistance
Assignee: US Philips Corp
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Filing: 1973-02-12
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Granted: 1974-07-09
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Expires: 1993-02-12
Abstract
Abstract A deflection circuit in which a switching element, for example, a thyristor is driven during the flyback period. During the scan a diode automatically becomes conducting so that a constant direct voltage is applied to the deflection coil. An additional source which may be for example a transistor is included between the direct voltage source and the diode, thus enabling the linearity to be improved and/or the East-West correction to be achieved. In a picture display apparatus having an index tube the source may be the output of a control circuit for stabilizing the index frequency.
Inventors
- 👤 P Ketelaar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:14
CPC Classifications
H; H03; H03K; H03K4/00; H03K4/06; H03K4/08; H03K4/83; H03K4/84
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
142 words
A circuit for supplying a sawtooth current having scan and flyback periods to a coil having resistance from a direct voltage first voltage source, said circuit comprising a capacitor having terminal means for coupling said capacitor to said source; a transformer having a primary and a secondary means for coupling to said coil; a switching means having control inpUt means for receiving a turn on control signal during said flyback period and a pair of conduction terminals; means for series coupling together said conduction terminals, said primary, and said capacitor; and means for compensating for said coil resistance comprising a unidirectional conducting means coupled to said secondary for conduction during said scan period and a low impedance variable second voltage source having a first terminal coupled to said unidirectional means and a second terminal means for coupling to said first voltage source.
Claim 2
Dependent Claim
142 words
A circuit for supplying a sawtooth current having scan and flyback periods to a coil having resistance from a direct voltage first voltage source, said circuit comprising a capacitor having terminal means for coupling said capacitor to said source; a transformer having a primary and a secondary means for coupling to said coil; a switching means having control inpUt means for receiving a turn on control signal during said flyback period and a pair of conduction terminals; means for series coupling together said conduction terminals, said primary, and said capacitor; and means for compensating for said coil resistance comprising a unidirectional conducting means coupled to said secondary for conduction during said scan period and a low impedance variable second voltage source having a first terminal coupled to said unidirectional means and a second terminal means for coupling to said first voltage source.
Claim 3
Dependent Claim
18 words
A circuit as claimed in claim 1 wherein the variable voltage during the line scan period is sawtooth-shaped.
Claim 4
Dependent Claim
18 words
A circuit as claimed in claim 1 wherein the variable voltage contains a parabola-shaped component of field frequency.
Claim 5
Dependent Claim
21 words
A circuit as claimed in claim 1 wherein the sawtooth current is amplitude-modulated with field frequency, the envelope being parabola shaped.
Claim 6
Dependent Claim
43 words
A circuit as claimed in claim 1 wherein the source comprises a transistor having an emitter connected to the unidirectional means and a collector connected to the direct voltage source and whose emitterbase diode has the same conductivity direction as the unidirectional means.
Claim 7
Dependent Claim
24 words
A circuit as claimed in claim 5, characterized in that the variable voltage is applied between the base and the collector of the transistor.
Claim 8
Dependent Claim
45 words
A circuit as claimed in claim 1 wherein the second source comprises a transistor whose collector-base diode is the unidirectional means and whose emitter is connected to the direct voltage source, the variable voltage being applied between the base and the emitter of the transistor.
Claim 9
Dependent Claim
28 words
A circuit as claimed in claim 1 wherein the second source comprises a transformer having a secondary winding included between the unidirectional means and the direct voltage source.
Claim 10
Dependent Claim
28 words
A circuit as claimed in claim 1 wherein the second source comprises a transductor having a power winding included between the unidirectional means and the direct voltage source.
Claim 11
Dependent Claim
69 words
Picture display apparatus comprising a circuit as claimed in claim 1 in which the coil is a deflection coil for deflecting an electron beam in a picture display tube belonging to the apparatus, the picture display tube being of the index type, wherein the circuit further comprises a control circuit means for reducing deviations of the index frequency, the output terminals of the control circuit comprising the second source.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-08 | 1978-01-07 | 1978-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-08 | 1982-01-07 | 1982-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-08 | 1986-01-07 | 1986-07-09 | $7700.00 | Window Closed / Lapsed |