Patent ID: 6967449

Claim:
A discharge lamp lighting apparatus comprising: a converter that switches power input thereto, converts the switching output to DC power and outputs the DC power; an inverter that converts the DC power supplied from the converter to AC rectangular wave power and outputs the AC rectangular wave power; and a controller that comprises: first means for generating a power detection signal by calculating power based upon a voltage detection signal and a current detection signal detected on the output side of the converter; second means for outputting an output power command value to be used to control the DC power so as to achieve a target value; third means for generating a correction signal to be used to correct the output power command value in conformance to the power detection signal and outputting the correction signal in synchronization with a polarity inversion of the AC rectangular wave power; fourth means for receiving the output power command value, the correction signal and the power detection signal and outputting a signal corresponding to the error of the power detection signal relative to the output power command value having been corrected by the correction signal; and fifth means for implementing pulse width control on the converter based upon the signal provided by the fourth means.