Abstract: A lighting inverter provides voltage and current to a gas discharge lamp in general and a metal halide lamp in particular with a novel power factor controller. The power factor controller. step down converter having the device stresses of a buck converter, continuous current at its input like a CUK' converter, a high power factor, low input current distortion and high efficiency. The inverter consists of two cyclically rotated CUK' switching cells connected in a half bridge configuration and operated alternately. The inverter is further optimized by using integrated magnetics and a shared energy transfer capacitor. The AC voltage output from the inverter is regulated by varying its frequency. A ballast filter is coupled to the regulated output of the inverter. The ballast filter is formed by a series circuit of a ballast capacitor and a ballast inductor. The lamp is preferably connected across the inductor to minimize the acoustic arc resonance.