Controller for operating fluorescent lamps

摘要

A controller for operating fluorescent lamps is provided with a voltage converter which produces AC voltages for operation of the fluorescent lamps. The voltage converter consists essentially of an oscillator having a fixed pulse duration, two pulse-duration modulators, a plurality of drivers and transformers. One of the pulse-duration modulators is used for producing a heating voltage for the fluorescent lamps. The starting/burning voltage for the fluorescent lamps is produced by means of the other pulse-duration modulator, whose pulse duration can be adjusted in order to vary the brightness of the fluorescent lamps. With the aid of a switched-mode regulator or the like it is possible to connect the voltage converter to any desired DC or AC voltages. A regulating device, which is coupled to the fluorescent lamps, can be used to ensure that fluorescent lamps having different operating characteristics can be operated without changing over the voltage converter. A switching-on delay device is provided in order to switch the fluorescent lamps on reliably and gently and with whose aid the starting/burning voltage is not switched on until a predetermined time interval has elapsed after switching on the heating voltage.