Circuit for operating a gas discharge lamp.

摘要

A ballast circuit (10) operates a metal halide lamp (12) by applying DC excitation during its start, glow and run modes. The type and values of the circuit components of the ballast circuit are selected to provide automatic, sequential and desired transfer functions as the impedance value of the metal halide lamp transitions from its value occurring during the start, glow and run modes of operation. The ballast circuit has an input stage (14) that is easily adapted to present a high power factor to the AC power source (20) supplying the metal halide lamp. Further, the ballast circuit generates a signal for more easily starting the lamp and having a relatively high DC level upon which are developed pulse signals.