Patent ID: 8354795

Claim:
A program start ballast for one or more lamps coupled in parallel comprising: a main circuit comprising a first inverter circuit and a primary winding of a first transformer; a preheat circuit comprising a second inverter circuit and a primary winding of a second transformer; and a load circuit comprising a secondary winding of the first transformer and lamp terminals coupled in parallel across the secondary winding of the first transformer, the load circuit further comprising a plurality of secondary windings of the second transformer, each secondary winding of the second transformer coupled to respective lamp filament terminals, wherein the main circuit is functional to disable power across the primary and secondary windings of the first transformer during a preheat mode of operation and to provide power across the primary and secondary windings of the first transformer during a steady-state mode of operation, and wherein the preheat circuit is functional to provide power across the primary and secondary windings of the second transformer during the preheat mode of operation and to disable power across the primary and secondary windings of the second transformer during the steady-state mode of operation.