US4513228A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for generating a sawtooth-shaped current
Assignee: US Philips Corp
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Filing: 1982-04-05
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Granted: 1985-04-23
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Expires: 2002-04-05
Abstract
Abstract A circuit for generating a sawtooth-shaped current through a coil, a plurality of periodically operated switches being arranged in series, by means of which switches the coil is connected to a trace capacitor during the trace period. During the retrace period, the switches are made non-conductive substantially simultaneously and a supply source produces supply energy for replenishing losses. A retrace capacitor is arranged in parallel with each switch and the supply source is connected in parallel with a number of series-arranged switches which is smaller than the total number of switches. The trace voltage is higher than the voltage of the source.
Inventors
- 👤 Dirk J. A. Teuling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:35
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/18; H04N3/185; H03; H03K; H03K4/00; H03K4/06; H03K4/08; H03K4/48; H03K4/60; H03K4/62
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
145 words
A circuit for generating a sawtooth-shaped current, having trace and retrace periods, through a coil which, during the trace period, is connected to a trace capacitor by means of a plurality of series-arranged controllable, periodically operated switches, which switches are nonconductive substantially simultaneously during the retrace period, in which retrace period the coil, the trace capacitor and a retrace capacitance are part of a resonant network the elements of which determine the duration of the retrace period and to which circuit, energy from a supply source is applied for replenishing energy losses, characterized in that a retrace capacitor is arranged in parallel with each switch, the supply source being d.c. connected in parallel with a number of series-arranged switches which is smaller than the total number of switches whereby, the voltage in operation across the trace capacitor is higher than that of the supply source.
Claim 2
Dependent Claim
145 words
A circuit for generating a sawtooth-shaped current, having trace and retrace periods, through a coil which, during the trace period, is connected to a trace capacitor by means of a plurality of series-arranged controllable, periodically operated switches, which switches are nonconductive substantially simultaneously during the retrace period, in which retrace period the coil, the trace capacitor and a retrace capacitance are part of a resonant network the elements of which determine the duration of the retrace period and to which circuit, energy from a supply source is applied for replenishing energy losses, characterized in that a retrace capacitor is arranged in parallel with each switch, the supply source being d.c. connected in parallel with a number of series-arranged switches which is smaller than the total number of switches whereby, the voltage in operation across the trace capacitor is higher than that of the supply source.
Claim 3
Dependent Claim
28 words
A circuit as claimed in claim 1, characterized in that the supply source comprises a supply inductance coupled to the junction of two switches and two retrace capacitors.
Claim 4
Dependent Claim
32 words
A circuit as claimed in claim 2, characterized in that one end of the supply inductance is connected to said junction and the other end to a terminal of a voltage source.
Claim 5
Dependent Claim
21 words
A circuit as claimed in claim 3, characterized in that the supply inductance is connected to said junction via a diode.
Claim 6
Dependent Claim
25 words
A circuit as claimed in claim 3, characterized in that the supply inductance is connected to the terminal of the voltage source via a transistor.
Claim 7
Dependent Claim
31 words
A circuit as claimed in claim 2, characterized in that the supply inductance is coupled to a winding which is connected to a terminal of a voltage source via a transistor.
Claim 8
Dependent Claim
34 words
A circuit as claimed in claim 5 or 6, characterized in that the conduction period of the transistor is adjustable in dependence of the voltage across the trace capacitor or a voltage derived therefrom.
Claim 9
Dependent Claim
16 words
A circuit as claimed in claim 1, characterized in that the retrace capacitors have equal capacitances.
Claim 10
Dependent Claim
16 words
A circuit as claimed in claim 1, characterized in that the retrace capacitors have unequal capacitances.
Claim 11
Dependent Claim
29 words
A circuit as claimed in claim 1, characterized in that a winding is coupled to the coil, a rectifier being connected to the winding for generating a d.c. voltage.
Claim 12
Dependent Claim
30 words
A circuit as claimed in claim 2, characterized in that a winding is coupled to the supply inductance, a rectifier being connected to the winding for generating a d.c. voltage.
Claim 13
Dependent Claim
56 words
A circuit as claimed in claim 1, characterized in that means are provided for alternately coupling a second supply source across the total number of switches for generating across the trace capacitor a voltage which is substantially equal to the voltage present across the said capacitor when the first voltage source is coupled to the circuit.
Claim 14
Dependent Claim
33 words
A circuit as claimed in claim 1 for use in a picture display device, characterized in that the coil is a line deflection coil and that the switches operate at the line frequency.
References Cited (Backward Citations)
US4206388A
Cited
US4361785A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-04-22 | 1988-10-22 | 1989-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-22 | 1992-10-22 | 1993-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-22 | 1996-10-22 | 1997-04-23 | $7700.00 | Window Closed / Lapsed |