A novel discrete dimming ballast for linear fluorescent lamps

In this paper, new discrete dimming ballast for linear fluorescent lamps is proposed. Dimming control circuit is combined with a ballast module for multiple lamps to realize three discrete lighting levels. Compared with conventional step dimming or on/off control methods, the proposed discrete dimming method has the following advantages: (1) digital signal is generated by the dimming control circuit to control turn on and off which makes the system more reliable and integrated. (2) The proposed discrete dimming system replaces the relays, which are necessary in conventional lamp on/off control. It decreases the cost of the overall system. (3) The proposed dimming ballast can be installed by keeping the original wiring system. This makes the upgrading of lighting systems more effective and efficient. (4) The proposed dimming control circuit also provides a good isolation for operating the low voltage wall switches by hand safely. Both simulation and experimental results are in good agreement.