A novel discrete dimming ballast for linear fluorescent lamps is proposed in
this paper.
A proposed dimming control circuit is combined with a ballast module for
multiple lamps to realize control of 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 the
lamps' turn- ON and -OFF, which makes the system more reliable and integrated;
2) the proposed discrete dimming system replaces relays, which are
necessary in conventional lamp ON-OFF control, and therefore
decreases the system cost;
3) the proposed dimming ballast can be installed by keeping the original
wiring system. This makes the upgrading of a lighting system more
effective and efficient;
4) the dimming control circuit also provides a good isolation for operating
the low -voltage wall switches by hand safely. Both theoretical,
simulation, and experimental results are in good agreement.
