US3767964A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Driving circuit for magnetic field deflection coil
Assignee: Ampex Corp
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Filing: 1970-12-02
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Granted: 1973-10-23
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Expires: 1990-12-02
Abstract
Abstract A feedback stabilized drive circuit is provided in which the instantaneous current flow through an electron beam deflection coil is measured indirectly by sampling resistors which are electrically isolated from the immediate coil circuit to insure stability of the sampled current. The current sampling is employed to develop a relatively large amount of d.c. feedback across a high gain amplifier having an input for receiving the coil scanning signal and having an output consisting of a pair of transistors connected in a Darlington configuration for providing the necessary drive current to the deflection coil and for isolating the current sampling resistors from the immediate coil circuit.
Inventors
- 👤 G Varian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:36
CPC Classifications
H; H03; H03K; H03K4/00; H03K4/06; H03K4/08; H03K4/48; H03K4/60; H03K4/69; H03K4/693
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
255 words
A circuit for driving a magnetic field deflection coil in response to an input scanning signal including an amplifier having an input for receiving said scanning signal and an output; a pair of first and second transistors connected in a Darlington configuration with a base of the first transistor connected to the output of said amplifier, an emitter of said first transistor connected to a base of the second transistor and collectors of said first and second transistors jointly connected to one end of said deflection coil; and an electrical bias source connected to the other end of said deflection coil; the combination therewith comprising: a feedback network including a first feedback resistor connected between the emitter of said second transistor and an input of said amplifier and a second feedback resistor coupled between an input of said amplifier and the jointly connected one end of said deflection coil and collectors of said transistors; and a sampling network including a first sampling resistor connected between one potential reference and the connection between said first feedback resistor and the emitter of said second transistor and a second sampling resistor connected between a different potential reference and the coupling between said second feedback resistor and the jointly connected one end of said deflection coil and collectors of said transistors whereby negative feedback is provided to said amplifier which responsively controls the current flow through said coil by causing the current flow in said sampling resistors to vary in accordance with the provided input scanning signal and feedback.
Claim 2
Dependent Claim
255 words
A circuit for driving a magnetic field deflection coil in response to an input scanning signal including an amplifier having an input for receiving said scanning signal and an output; a pair of first and second transistors connected in a Darlington configuration with a base of the first transistor connected to the output of said amplifier, an emitter of said first transistor connected to a base of the second transistor and collectors of said first and second transistors jointly connected to one end of said deflection coil; and an electrical bias source connected to the other end of said deflection coil; the combination therewith comprising: a feedback network including a first feedback resistor connected between the emitter of said second transistor and an input of said amplifier and a second feedback resistor coupled between an input of said amplifier and the jointly connected one end of said deflection coil and collectors of said transistors; and a sampling network including a first sampling resistor connected between one potential reference and the connection between said first feedback resistor and the emitter of said second transistor and a second sampling resistor connected between a different potential reference and the coupling between said second feedback resistor and the jointly connected one end of said deflection coil and collectors of said transistors whereby negative feedback is provided to said amplifier which responsively controls the current flow through said coil by causing the current flow in said sampling resistors to vary in accordance with the provided input scanning signal and feedback.
Claim 3
Dependent Claim
47 words
The circuit as defined in claim 1 further comprising, an inductor interposed between the jointly connected collectors of said transistors and the connection between said second feedback resistor and said sampling resistor for facilitating fly-back current drive of said coil in response to a sawtooth scanning sIgnal.
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) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |