Ballast for independent parallel of low pressure gas discharge lamps

摘要

The electronic bias device (1) is used for parallel operation of at least two gas discharge lamps (2a,2b), supplied from a DC source via a half bridge voltage converter (6), with a control stage (11) for operation of the voltage converter when the supply voltage is above a threshold value. A controlled switch (32) is controlled by a monitoring stage (27) for detecting failure of one of the gas discharge lamps for reducing the supply voltage (Vcc) to below the threshold value required by the control stage, a second controlled switch (34) operated when replacement of the lamp is detected.