Patent ID: 7622869
Filing Date: 2009-11-24
Classification: H04N,H05B,Y02B

Abstract:
1. 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, after the start of the lamp, the control circuit is configured: (i) to control the on/off state of the switching element by lamp current control; and then (ii), based on high power control, to control 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, said constant power control being control for adjusting the effective value of the lamp power provided for the lamp to a prescribed power value.