US3781589A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Field deflection circuit
Assignee: US Philips Corp
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Filing: 1971-11-15
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Granted: 1973-12-25
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Expires: 1991-11-15
Abstract
Abstract A field deflection circuit in which the deflection coil is connected to a direct voltage source during the flyback period so as to reverse the polarity of the deflection current. For this purpose the deflection coil is connected through a switch controllable connected to the direct voltage source, which switch is controlled by the difference between a voltage proportional to the steep-edged sawtooth input signal and a voltage proportional to the deflection current. This difference is considerable during the flyback period and is utilized for switching on the controllable switch; it becomes zero as soon as the deflection current has reached its required value at which the switch is switched off again. It is thus achieved that the polarity reversal is always terminated when the required value is reached, even when the direct voltage fluctuates and also when the inductive load is changed.
Inventors
- 👤 H Brockmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:07
CPC Classifications
H; H03; H03K; H03K4/00; H03K4/06; H03K4/08; H03K4/48; H03K4/60; H03K4/69; H03K4/696
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
196 words
A circuit for generating an output deflection current for a deflection coil from an input sawtooth deflection voltage signal having a polarity changes at the start of the flyback period which are short with respect to said flyback period; said circuit comprising an amplifier having an input adapted to receive said input signal, and an output means adapted to be coupled to said coil for providing said output current; means coupled to said amplifier for generating a control voltage that is the difference between a voltage that is proportional to said input signal and a voltage that is proportional to said output current; a direct voltage source; and means for rendering said output current independent of voltage and load variations comprising means for reversing the polarity of said deflection current at the start of said flyback period including a switch means coupled to said amplifier and said source and having a control input coupled to said means for generating for coupling said coil to said source at the start of said flyback period and separating said coil from said source upon said deflection current reaching a selected value required for the start of the scan period.
Claim 2
Dependent Claim
196 words
A circuit for generating an output deflection current for a deflection coil from an input sawtooth deflection voltage signal having a polarity changes at the start of the flyback period which are short with respect to said flyback period; said circuit comprising an amplifier having an input adapted to receive said input signal, and an output means adapted to be coupled to said coil for providing said output current; means coupled to said amplifier for generating a control voltage that is the difference between a voltage that is proportional to said input signal and a voltage that is proportional to said output current; a direct voltage source; and means for rendering said output current independent of voltage and load variations comprising means for reversing the polarity of said deflection current at the start of said flyback period including a switch means coupled to said amplifier and said source and having a control input coupled to said means for generating for coupling said coil to said source at the start of said flyback period and separating said coil from said source upon said deflection current reaching a selected value required for the start of the scan period.
Claim 3
Dependent Claim
58 words
A circuit as claimed in claim 1, wherein said amplifier comprises a junction having a potential that differs from a threshold value during said flyback period, said switch being coupled to said junction and switching at about said threshold value; and further comprising feedback means for applying said voltage proportional to said deflection current to said amplifier input.
Claim 4
Dependent Claim
27 words
A circuit as claimed in claim 2 wherein said junction potential goes below said threshold value during said flyback period, said switch switching above said threshold value.
Claim 5
Dependent Claim
26 words
A circuit as claimed in claim 2 wherein said junction potential exceeds said threshold value during said flyback period, said switch switching below said threshold value.
Claim 6
Dependent Claim
138 words
A circuit as claimed in claim 2 wherein said amplifier comprises first and second final stage class B push pull transistors, each of said transistors having emitter and collector conduction electrodes, a conduction electrode of one of said transistors being coupled to a like conduction electrode of said other transistor, said first transistor being conductive during said start of said scan period; a pass direction coupled diode having a first end coupled to first transistor conduction electrode, and a second end adapted to receive a first terminal of a power supply; a capacitor having a first end coupled to said diode first end, and a second end coupled to said switch; and a resistor having a first end coupled to said capacitor second end, and a second end adapted to receive a second terminal of said power supply.
Claim 7
Dependent Claim
28 words
A circuit as claimed in claim 5 wherein said like conduction electrodes comprise said collector electrodes and said diode first end is coupled to said first transistor emitter.
Claim 8
Dependent Claim
28 words
A circuit as claimed in claim 5 wherein said like conduction electrodes comprise said emitter electrodes and said diode first end is coupled to said first transistor collector.
Claim 9
Dependent Claim
43 words
A circuit as claimed in claim 5 further comprising a second cut off direction coupled diode having a first end coupled to a conduction electrode of said first transistor, and a second end coupled to the remaiNing conduction electrode of said first transistor.
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) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |