DISCHARGE LAMP DRIVING BRIDGE CIRCUIT

摘要

A discharge lamp driving circuit includes DC voltage input connections, lamp driving connections, bridge circuitry, and control circuitry. The bridge circuitry is connected to the DC voltage input connections and to the lamp driving connections and includes circuit elements which in one mode of operation deliver a higher frequency AC voltage to the lamp driving connections and in another mode of operation deliver a lower frequency AC voltage to the lamp driving connections. The control circuitry is connected to control the bridge circuitry selectively as either a half-bridge to deliver the higher frequency AC voltage to the lamp driving connections during starting or a full- bridge to deliver only the lower frequency AC operating voltage to the lamp while the lamp is operating normally after starting. A low frequency driver and a high frequency driver are connected to drive the bridge circuitry.