Abstract: An electronic ballast for an HID lamp is described, comprising: a rectifier circuit; a PFC power factor correction circuit increasing the direct current (DC) voltage coming out from the rectifier circuit; a current converter receiving the high voltage DC and converts it to alternating current (AC) to be supplied to the lamp; an ignition circuit generating ignition pulses being fed to the converter circuit to turn on the lamp, the pulses are generated by a downward frequencies scan, and, a control circuit commanding the operation of the ignition circuit and controlling the power being supplied to the lamp according to a power profile being determined by the lightning conditions desired to be obtained from said lamp to save energy. The operative method for the ballast is also described.