LIGHTING BALLAST HAVING BOOST CONVERTER WITH ON/OFF CONTROL AND METHOD OF BALLAST OPERATION.

摘要

A ballast for driving a gas discharge lamp comprising a rectifier stage (12) having an alternating current (AC) input and providing a rectified output voltage, a boost converter stage (14) receiving the rectified output voltage as an input and providing a boosted direct current (DC) output voltage across a DC bus (20), an inverter output stage (50) for converting the DC bus voltage to a high-frequency AC output voltage to drive the lamp (60), further comprising a control stage (15) receiving a desired light level signal controlling the desired light level of the lamp and providing an output control signal for turning the boost converter stage on or off in dependency on the desired light level signal. The ballast thereby has reduced power consumption at low light levels for greater energy efficiency.