US3668465A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surge voltage protection for cathode ray tube drivers
Assignee: Seaco Computer Display Inc
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Filing: 1971-02-16
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Granted: 1972-06-06
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Expires: 1991-02-16
Abstract
Abstract Disclosed in a transient voltage protective network for protecting the transistor of a video amplifier coupled to one of the input terminals of a CRT electron gun from the arcing voltages appearing at this input terminal, the protective network including a pair of diodes respectively connected to the output of the transistor and the collector supply voltage and ground terminals thereof, as well as surge voltage protective device coupled through resistive means across one of the diodes.
Inventors
- 👤 William E Evans
- 👤 Robert C Harding
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:40
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
201 words
A cathode ray tube system, comprising: a. electron gun means having an input terminal thereto; b. a video amplifier for providing a driving signal to said input terminal, said video amplifier including a transistor in the output stage, and c. a transient voltage protection network coupled intermediate the output of said video amplifier and said input terminal, said protection network comprising a pair of diodes, each having respective terminals coupled to the output of said transistor, the other terminals of said diodes respectively couPled to a first and second potential source; and a voltage discharge device adapted to conduct solely upon the occurrence of a predetermined minimum voltage appearing across its terminals having one end coupled to the output of said transistor and the said input terminal, the other end of said discharge device being coupled to said second potential source, whereby a transient voltage at said input terminal having a value in excess of said predetermined minimum voltage will initially cause one of said diodes to conduct, thereby clamping the output of said transistor to one of said potential sources, and thereafter triggering said voltage discharge device into conduction, thereby to limit the voltage at the output of said transistor.
Claim 2
Dependent Claim
201 words
A cathode ray tube system, comprising: a. electron gun means having an input terminal thereto; b. a video amplifier for providing a driving signal to said input terminal, said video amplifier including a transistor in the output stage, and c. a transient voltage protection network coupled intermediate the output of said video amplifier and said input terminal, said protection network comprising a pair of diodes, each having respective terminals coupled to the output of said transistor, the other terminals of said diodes respectively couPled to a first and second potential source; and a voltage discharge device adapted to conduct solely upon the occurrence of a predetermined minimum voltage appearing across its terminals having one end coupled to the output of said transistor and the said input terminal, the other end of said discharge device being coupled to said second potential source, whereby a transient voltage at said input terminal having a value in excess of said predetermined minimum voltage will initially cause one of said diodes to conduct, thereby clamping the output of said transistor to one of said potential sources, and thereafter triggering said voltage discharge device into conduction, thereby to limit the voltage at the output of said transistor.
Claim 3
Dependent Claim
68 words
The system as described in claim 1 wherein one of said diodes has its cathode connected to the transistor output and its anode connected to a source of ground potential, and the other of said diodes has its anode connected to the transistor output and its cathode connected to a supply voltage source, the voltage discharge device being coupled in series with resistive means across said one diode.
Claim 4
Dependent Claim
16 words
The system as described in claim 2 wherein said voltage discharge device is a spark gap.
Claim 5
Dependent Claim
28 words
The system as described in claim 3 wherein said transistor has its emitter coupled through a bias resistor to ground potential, and said supply voltage source is positive.
Claim 6
Dependent Claim
119 words
A surge voltage protection network, comprising: a. a common emitter connected transistor having its emitter coupled through a bias resistor to ground potential and its collector coupled through a bias resistor to a positive supply voltage, said collector also being coupled through resistive means to the output terminal of said network, b. a first diode in a normally reverse biased condition connected between said collector and said positive supply voltage, c. a second diode in a normally reverse biased condition connected between said collector and said ground potential, and d. a voltage discharge device adapted to conduct solely upon the occurrence of a minimum voltage appearing across its terminals coupled between ground and the output terminal of said network.
Claim 7
Dependent Claim
119 words
A surge voltage protection network, comprising: a. a common emitter connected transistor having its emitter coupled through a bias resistor to ground potential and its collector coupled through a bias resistor to a positive supply voltage, said collector also being coupled through resistive means to the output terminal of said network, b. a first diode in a normally reverse biased condition connected between said collector and said positive supply voltage, c. a second diode in a normally reverse biased condition connected between said collector and said ground potential, and d. a voltage discharge device adapted to conduct solely upon the occurrence of a minimum voltage appearing across its terminals coupled between ground and the output terminal of said network.
Claim 8
Dependent Claim
16 words
The network as defined by claim 5 wherein said voltage discharge device is a spark gap.
Claim 9
Dependent Claim
42 words
The network as defined by claim 5 wherein said resistive means is of a value that the voltage at said output terminal is substantially identical to the voltage at the collector of said transistor during the conduction of said voltage discharge device.
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) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |