US Patent 7327095 Discharge lamp lighting apparatus

A discharge lamp lighting apparatus includes a DC-DC converter for outputting voltages having respective different potentials from two wirings, a switching circuit having input terminals connected to the two wirings, an output terminal connected to one electrode of a discharge lamp, and a capacitor having one electrode terminal connected to a second electrode of the discharge lamp and a second electrode terminal connected to one of the two wirings of the DC-DC converter. The switching circuit includes a switching element for controlling connections between one of the two wirings and the output terminal. The other wiring is connected to the output terminal.