US4965493A — Electric arrangement for igniting and supplying a…

Claim 1

Independent Claim 151 words

An electric arrangement for igniting and supplying a gas discharge lamp comprising: two input terminals for an AC power supply source, a rectifier bridge connected to the input terminals and having output terminals connected to a DC/AC converter having two input terminals, one terminal of which is connected to the other terminal via a series arrangement of a first semiconductor switching element and a load circuit comprising at least an induction coil and the discharge lamp as well as a capacitor, said load circuit and capacitor being shunted by a circuit comprising a second semiconductor switching element and a third semiconductor switching element, the first and second semiconductor switching elements being shunted by a buffer capacitor, characterized in that the third semiconductor switching element includes a control circuit rendering the third switching element conductive for a given period at the start of each period of the high-frequency cycle of the converter.

Claim 2

Dependent Claim 151 words

An electric arrangement for igniting and supplying a gas discharge lamp comprising: two input terminals for an AC power supply source, a rectifier bridge connected to the input terminals and having output terminals connected to a DC/AC converter having two input terminals, one terminal of which is connected to the other terminal via a series arrangement of a first semiconductor switching element and a load circuit comprising at least an induction coil and the discharge lamp as well as a capacitor, said load circuit and capacitor being shunted by a circuit comprising a second semiconductor switching element and a third semiconductor switching element, the first and second semiconductor switching elements being shunted by a buffer capacitor, characterized in that the third semiconductor switching element includes a control circuit rendering the third switching element conductive for a given period at the start of each period of the high-frequency cycle of the converter.

Claim 3

Dependent Claim 34 words

An electric arrangement as claimed in claim 1, further comprising a current sensor measuring the current through the third semiconductor switching element and coupled to the control circuit of the third semiconductor switching element.

Claim 4

Dependent Claim 27 words

An electric arrangement as claimed in claim 2, wherein the third semiconductor switching element is shunted by a series arrangement of said current sensor and a diode.

Claim 5

Dependent Claim 47 words

An electric arrangement as claimed in claim 2, wherein said control circuit is responsive to said current sensor so as to control the time of conductance of the third semiconductor switching element such that the electric arrangement draws a substantially trapezoidal waveform current from said input terminals.

Claim 6

Dependent Claim 27 words

An electric arrangement as claimed in claim 2, wherein said control circuit includes a sawtooth generator synchronized to zero crossing of current flowing in said current sensor.

Claim 7

Dependent Claim 184 words

A DC/AC converter circuit for operation of an electric discharge lamp comprising: first and second input terminals for connection to a source of DC supply voltage for the converter circuit, first, second and third controlled semiconductor switching elements connected in a first series circuit across said input terminals, a load circuit coupled to a junction point between said first and second semiconductor switching elements and further coupled to said second input terminal, said load circuit comprising a second series circuit that includes an inductor, a discharge lamp and a first capacitor a second capacitor connected in parallel across a part of the first series circuit which includes said first and second semiconductor switching elements, control circuit means coupled to control electrodes of the first and second semiconductor switching elements for triggering said switching elements alternately into conduction at a high frequency, and a control circuit coupled to a control electrode of the third semiconductor switching element for triggering the third switching element into conduction for a short time period near the start of each cycle of a high-frequency current flowing in said load circuit.

Claim 8

Dependent Claim 184 words

A DC/AC converter circuit for operation of an electric discharge lamp comprising: first and second input terminals for connection to a source of DC supply voltage for the converter circuit, first, second and third controlled semiconductor switching elements connected in a first series circuit across said input terminals, a load circuit coupled to a junction point between said first and second semiconductor switching elements and further coupled to said second input terminal, said load circuit comprising a second series circuit that includes an inductor, a discharge lamp and a first capacitor a second capacitor connected in parallel across a part of the first series circuit which includes said first and second semiconductor switching elements, control circuit means coupled to control electrodes of the first and second semiconductor switching elements for triggering said switching elements alternately into conduction at a high frequency, and a control circuit coupled to a control electrode of the third semiconductor switching element for triggering the third switching element into conduction for a short time period near the start of each cycle of a high-frequency current flowing in said load circuit.

Claim 9

Dependent Claim 56 words

A DC/AC converter circuit as claimed in claim 6, further comprising a current sensor connected in the DC/AC converter circuit and coupled to the control circuit for the third semiconductor switching element so as to control the operation of the third semiconductor switching element as a function of a current through said third semiconductor switching element.

Claim 10

Dependent Claim 36 words

A DC/AC converter circuit as claimed in claim 7, further comprising a diode connected in a series arrangement with said current sensor, and means coupling said series arrangement in parallel with said third semiconductor switching element.

Claim 11

Dependent Claim 82 words

A DC/AC converter circuit as claimed in claim 7, wherein said control circuit comprises, a sawtooth generator synchronized with a current flowing in said current sensor, a comparison circuit having a first input coupled to a source of reference voltage and a second input coupled to an output of the sawtooth generator, and means coupling an output of the comparison circuit to the control electrode of the third semiconductor switching element thereby to provide said triggering of the third semiconductor switching element.

Claim 12

Dependent Claim 27 words

A DC/AC converter circuit as claimed in claim 6, further comprising first and second diodes connected in anti-parallel with said first and second semiconductor switching elements, respectively.

Claim 13

Dependent Claim 47 words

A DC/AC converter circuit as claimed in claim 6, wherein said first, second and third semiconductor switching elements are serially connected in the order named across said first and second input terminals, and said load circuit is connected between said junction point and said second input terminal.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-10-22	1994-04-23	1994-10-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-10-22	1998-04-23	1998-10-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-10-22	2002-04-23	2002-10-23	$7700.00	Window Closed / Lapsed

Electric arrangement for igniting and supplying a gas discharge lamp

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