Patent US3940659A successfully refreshed from Google Patents.
US3940659A
Expired / Lapsed
US
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Discharge device control circuit including a thyristor
Assignee: Mitsubishi Electric Corp
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Filing: 1974-01-30
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Granted: 1976-02-24
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Expires: 1994-01-30
Abstract
Abstract A main capacitor is connected across a series combination of a flash discharge lamp and a thyristor to flash the flash discharge lamp through the thyristor in its ON state. A commutation circuit connected to the thyristor includes a commutation capacitor and another thyristor turned on upon a flashing light from the flash discharge lamp reaching a predetermined magnitude. When turned on, the latter thyristor permits the commutation capacitor to supply a reverse voltage to the first thyristor to turn it off. A semiconductor diode is connected between the commutation capacitor and the first thyristor to prevent that capacitor from applying a forward voltage to the first thyristor.
Inventors
- 👤 Suzuo Kojima
- 👤 Yoshio Fujimaru
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:58
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32; H05B41/325
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
199 words
A control circuit for controlling an electric discharge device, comprising, in combination: a first circuit branch comprising an electric discharge device and a thyristor connected in series with said discharge device for controlling current flowing through said discharge device and flowing through the node at which said discharge device and said thyristor are connected; a second circuit branch connected in parallel with said first circuit branch, said second circuit branch comprising an impedance element connected to said discharge device and a switching element connected to said thyristor and to said impedance element to define a node therewith; and a third circuit branch connected between the node defined by said discharge device and said thyristor and the node defined by said impedance element and said switching element, said third circuit branch comprising a commutation capacitor for storing and applying a reverse voltage to said thyristor under control of said switching element to bias said thyristor from a conducting to a nonconducting state, and a diode connected in series with said commutation capacitor and having a polarity effective to prevent a voltage opposite the polarity of said reverse voltage and stored on said commutation capacitor from being applied to said thyristor.
Claim 2
Dependent Claim
199 words
A control circuit for controlling an electric discharge device, comprising, in combination: a first circuit branch comprising an electric discharge device and a thyristor connected in series with said discharge device for controlling current flowing through said discharge device and flowing through the node at which said discharge device and said thyristor are connected; a second circuit branch connected in parallel with said first circuit branch, said second circuit branch comprising an impedance element connected to said discharge device and a switching element connected to said thyristor and to said impedance element to define a node therewith; and a third circuit branch connected between the node defined by said discharge device and said thyristor and the node defined by said impedance element and said switching element, said third circuit branch comprising a commutation capacitor for storing and applying a reverse voltage to said thyristor under control of said switching element to bias said thyristor from a conducting to a nonconducting state, and a diode connected in series with said commutation capacitor and having a polarity effective to prevent a voltage opposite the polarity of said reverse voltage and stored on said commutation capacitor from being applied to said thyristor.
Claim 3
Dependent Claim
27 words
A control circuit for a discharge device as claimed in claim 1, wherein said electric discharge device comprises a series combination of a thyristor and a resistor.
Claim 4
Dependent Claim
22 words
A control circuit for a discharge device as claimed in claim 1, wherein said electric discharge device is a flash discharge lamp.
Claim 5
Dependent Claim
55 words
A control circuit for a discharge device as claimed in claim 3, further comprising a first ignition circuit connected to said flash discharge lamp and a second ignition circuit connected to said thyristor and wherein said first and second ignition circuits are responsive to the operation of a camera shutter to produce respective ignition signals.
Claim 6
Dependent Claim
61 words
A control circuit for a discharge device as claimed in claim 4 wherein said switching element is a second thyristor, and further comprising a third ignition circuit connected to said second thyristor, said third ignition circuit comprising means responsive to a quantity of light emitted from said flash discharge lamp reaching a predetermined magnitude to bias said second thyristor to conduct.
Claim 7
Dependent Claim
137 words
A control circuit for a discharge device comprising, in combination: an electric discharge device; a thyristor connected in series with said electric discharge device to control a current flowing through said electric discharge device; a commutation circuit including a commutation capacitor and a switching element for controlling the discharge of said commutation capacitor through said thyristor; said switching element being connected between said thyristor and said commutation capacitor to supply a reverse voltage stored in said commutation capacitor to said thyristor to bias said thyristor from a conductive to a nonconductive state; a semiconductor diode connected between said commutation capacitor and said thyristor to prevent an electrical charge with a polarity opposite that of the reverse voltage accumulated on said commutation capacitor from discharging through said thyristor; and a resistor connected in parallel with said semiconductor diode.
Claim 8
Dependent Claim
137 words
A control circuit for a discharge device comprising, in combination: an electric discharge device; a thyristor connected in series with said electric discharge device to control a current flowing through said electric discharge device; a commutation circuit including a commutation capacitor and a switching element for controlling the discharge of said commutation capacitor through said thyristor; said switching element being connected between said thyristor and said commutation capacitor to supply a reverse voltage stored in said commutation capacitor to said thyristor to bias said thyristor from a conductive to a nonconductive state; a semiconductor diode connected between said commutation capacitor and said thyristor to prevent an electrical charge with a polarity opposite that of the reverse voltage accumulated on said commutation capacitor from discharging through said thyristor; and a resistor connected in parallel with said semiconductor diode.
Claim 9
Dependent Claim
153 words
A control circuit for a discharge device comprising, in combination: an electric discharge device; a thyristor connected in series with said electric discharge device to control a current flowing through said electric discharge device; a commutation circuit including a commutation capacitor and a switching element for controlling the discharge of said commutation capacitor through said thyristor; said switching element being connected between said thyristor and said commutation capacitor to supply a reverse voltage stored in said commutation capacitor to said thyristor to bias said thyristor from a conductive to a nonconductive state; a semiconductor diode connected between said commutation capacitor and said thyristor to prevent an electrical charge with a polarity opposite that of the reverse voltage accumulated on said commutation capacitor from discharging through said thyristor; and a resistor and a reactor connected in series, and wherein the series combination of said resistor and reactor is connected in parallel with said diode.
Claim 10
Dependent Claim
153 words
A control circuit for a discharge device comprising, in combination: an electric discharge device; a thyristor connected in series with said electric discharge device to control a current flowing through said electric discharge device; a commutation circuit including a commutation capacitor and a switching element for controlling the discharge of said commutation capacitor through said thyristor; said switching element being connected between said thyristor and said commutation capacitor to supply a reverse voltage stored in said commutation capacitor to said thyristor to bias said thyristor from a conductive to a nonconductive state; a semiconductor diode connected between said commutation capacitor and said thyristor to prevent an electrical charge with a polarity opposite that of the reverse voltage accumulated on said commutation capacitor from discharging through said thyristor; and a resistor and a reactor connected in series, and wherein the series combination of said resistor and reactor is connected in parallel with said diode.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-23 | 1979-08-25 | 1980-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-23 | 1983-08-25 | 1984-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-23 | 1987-08-25 | 1988-02-24 | $7700.00 | Window Closed / Lapsed |