Modular dimming ballast with decoupled half-bridge topology

摘要

An electronic ballast is provided and a method for operating one or more lamps. The ballast and method provide for true parallel lamp operation, with preheating of lamp filaments during a dimming operation. Switching losses are reduced by ensured soft switching operation. An inverter switch driver is arranged to provide first drive signals to a shared line branch having a first switch shared among a plurality of decoupled inverter drive modules and to provide second drive signals to a plurality of independent line branches each having a switch and associated with one of the decoupled inverter drive modules. A soft switching control circuit is coupled to the first switch and configured so as to maintain a soft switching operation for the first switch.