Discharge lamp ballast and projector

A discharge lamp ballast, comprising:

• a power converter that includes at least one switching element and is connected between a power source and a high intensity discharge lamp;
• and
• a control circuit that controls an on/off state of the switching element so as to provide prescribed lamp power for the lamp based on lamp power control after the start of the lamp,
• wherein the control circuit controls the on/off state of the switching element so that at least one of an effective value and a peak value of the lamp power provided for the lamp is increased more than that adjusted by constant power control based on high power control after the start of the lamp, said constant power control being control for adjusting the effective value of the lamp power provided for the lamp to a prescribed power value,
• wherein the ballast comprises a state detection means that detects a state of the lamp,
• wherein the control circuit changes the lamp power control to the constant power control or the high power control based on a detection result of the state detection means after the start of the lamp,
• wherein:
• in case of the constant power control, the control circuit controls the on/off state of the switching element so as to adjust the effective value of the lamp power provided for the lamp to the prescribed power value;
• while in case of the high power control, the control circuit controls the on/off state of the switching element so that at least one of the effective value and the peak value of the lamp power provided for the lamp is increased more than that of the constant power control.