EP0265237A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Control gear for high intensity gas discharge lighting
Assignee: VALOR INTERNATIONAL Ltd
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Filing: 1987-10-21
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Granted: —
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Expires: 2007-10-21
Abstract
Abstract A control gear for a high intensity discharge lamp comprising a switch element (10), and an oscillator (19) connected to drive the switch element through the intermediary of a variable mark-space ratio driver arrangement (20, 15). The switch element (10) switches current in a series resonant circuit (11) including the primary winding of a transformer, across the secondary winding of which the lamp (13) is connected. A feedback circuit (21) which receives signals controls the mark-space ratio to regulate the power consumed by the lamp in a closed loop. Initially, the mark-space ratio is set at a starting level such that a very high voltage is generated in the resonant circuit to cause starting of the lamp.
Inventors
- 👤 John Britton
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 07:00
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/36; H05B41/38; H05B41/39; H05B41/392; H05B41/26; H05B41/28; H05B41/288; H05B41/292; H05B41/2921; H05B41/2925; H05B41/3921; H05B41/3927; H05B41/3928
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
62 words
A control gear for a high intensity gas discharge lighting tube, comprising an oscillator, a high speed switching element driven by said oscillator, a transformer having its primary winding connected in a series resonant circuit tuned to the frequency of the oscillator and controlled by the switching element and means for connecting the secondary winding of the transformer to the lighting tube.
Claim 2
Dependent Claim
62 words
A control gear for a high intensity gas discharge lighting tube, comprising an oscillator, a high speed switching element driven by said oscillator, a transformer having its primary winding connected in a series resonant circuit tuned to the frequency of the oscillator and controlled by the switching element and means for connecting the secondary winding of the transformer to the lighting tube.
Claim 3
Dependent Claim
19 words
A control gear as claimed in claim 1 in which the switching element is a gate turn-off thyristor (GTO).
Claim 4
Dependent Claim
35 words
A control gear as claimed in claim 2 including a driver circuit for the GTO for applying positive-going pulses to the GTO gate for turning the GTO and negative-going pulses thereto for turning it off.
Claim 5
Dependent Claim
20 words
A control gear as claimed in claim 3 in which said driver circuit includes a variable mark-space ratio control means.
Claim 6
Dependent Claim
56 words
A control gear as claimed in claim 4 in which said variable mark-space ratio control means includes means for setting the mark-space ratio to an initial value to provide a high amplitude signal from the series resonant circuit so as to create a high voltage across the lamp for causing initial ionisation of the gas therein.
Claim 7
Dependent Claim
39 words
A control gear as claimed in claim 5 further comprising a feedback circuit sensitive to the power consumed by the lamp for reducing said mark-space ratio below said initial value and controlling the lamp power in a closed loop.
Claim 8
Dependent Claim
46 words
A control gear as claimed in claim 6 further comprising a GTO protection circuit including means sensitive to the peak current in the series resonant circuit and operating to override the closed loop and reduce the mark-space ratio if such peak current exceeds a predetermined value.
Claim 9
Dependent Claim
62 words
A control gear as claimed in claim 6 further comprising first and second power supply units for supplying positive and negative voltages to said driver circuit, and a power supply monitor circuit sensitive to both voltages and operating to override said closed loop and reduce the mark-space ratio to zero in the event of either of said power supply units becoming inoperative.
Claim 10
Dependent Claim
61 words
A control gear as claimed in claim 6 including a starting control circuit for alternately inhibiting and enabling the mark-space ratio control means, means sensitive to lamp current for disabling said starting control circuit on lighting of the lamp and time-out means for disabling the starting control circuit after a predetermined period has elapsed without lighting of the lamp having occurred.
Claim 11
Dependent Claim
22 words
A control gear as claimed in claim 1 in which said transformer comprises primary and secondary windings totally enclosed within a core.
Claim 12
Dependent Claim
25 words
A control gear as claimed in claim 10 in which said core comprises a sleeve portion and a spool shaped portion within said sleeve parts.
Claim 13
Dependent Claim
18 words
A control gear as claimed in claim 11 in which said parts are formed of bonded iron powder.
Claim 14
Dependent Claim
23 words
A control gear as claimed in claim 1 in which said resonant circuit also includes an inductor which is separate from the transformer.
Claim 15
Dependent Claim
73 words
A control gear as claimed in claim 13 in which the primary winding of the transformer, the inductor and the switch element are connected in series, a capacitor is connected in parallel with the switch device, a further capacitor is connected across the series combination of the inductor and the switch element, and a diode connected across said first mentioned capacitor and arranged to conduct in the reverse direction to the switch element.
Claim 16
Dependent Claim
50 words
A control gear as claimed in claim 14 further comprising a snubber circuit connected across said switch element, said snubber circuit comprising a capacitor in series with the parallel combination of a resistor and a diode, said diode being arranged to conduct in the same direction as the switch element.
References Cited (Backward Citations)
No citation records indexed.
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