Patent ID: 7923941

Claim:
A ballast circuit or driving a discharge lamp, comprising: a power input operative to receive an AC input signal; a rectifier comprising a rectifier input including first and second rectifier input terminals coupled with the power input, a rectifier output coupled to first and second terminals of a DC bus, and at least one rectifier diode coupled between the rectifier input and the rectifier output and operative to convert AC power at the rectifier input to provide DC power to the DC bus; an inverter including first and second Bipolar Junction Transistors (BJTs) coupled in series between the first and second DC bus terminals, the first and second BJTs connected to one another at an inverter central node; a transformer with a primary winding coupled between the inverter central node and a first lamp connection, and first and second secondary windings; a driver circuit including the first and second secondary windings of the transformer, the first secondary winding of the transformer being coupled with a base terminal of the first BJT, and the second secondary winding of the transformer being coupled with a base terminal of the second BJT, the driver circuit operative to drive the first and second BJTs in alternating fashion to provide a high frequency AC inverter output signal at the inverter central node; a first capacitance coupled in series between the first lamp connection and the first rectifier input terminal; and a second capacitance coupled in series between a second lamp connection and the second rectifier input terminal.