Patent ID: 7449846

Claim:
A ballast lamp with gas discharge of the type comprising: a DC to DC converter supplying a DC voltage at a first predetermined level V 1 from a DC supply source; a DC to AC converter comprising first, second, third and fourth switching elements connected as an inverter bridge, supplied by said DC to DC converter between a first node common to said first and second switching elements and a second node common to said third and fourth switching elements, and supplying during a continuous operating phase of a discharge lamp an AC voltage between a third node common to said first and third switching elements and a fourth node common to said second and fourth switching elements; an ignition voltage generator comprising output terminals connected in series with a lamp to said third and fourth nodes of said bridge, and input terminals subjected, during the initiation of the ignition phase of said discharge lamp, to a voltage difference of a second predetermined level V 2 ; and a control unit supplying first control signals to said DC to DC converter and second control signals to said DC to AC converter according to a control input dependent on said phases; wherein said voltage difference between said input terminals of said ignition voltage generator is generated by a voltage step up circuit of the “self-boosting” type from said DC voltage of said DC to DC converter and an auxiliary voltage source of a predetermined value V 0 , wherein said voltage step up circuit creates a voltage on a capacitor which is higher than said predetermined value V 0 .