Patent ID: 7298095

Claim:
The discharge lamp ballast apparattis, comprising: a DC power supply circuit for supplying a voltage form a DC power supply to a primary side of a transformer of a DC/DC converter, and for converting the voltage to a prescribed DC voltage to be output from a secondary side of said transformer; an AC power supply circuit for converting the prescribed DC voltage from said DC power supply circuit to an AC voltage; a start circuit for generating a high voltage pulse and for superimposing the high voltage pulse on the AC voltage; first load current detecting means for detecting a load current flowing through the primary side of said transformer; second load current detecting means for detecting a load current value flowing through said AC power supply circuit; a total current detector for detecting a total current value of the load current value detected by said first load current detecting means and the load current value detected by said second load current detecting means; and a controller for controlling a current supplied from said DC power supply in response to the total current value detected by said total current detector.