Low voltage DC supply dimmable ballast for 1 /spl times/ 36 W T8 lamp

Abstract

This paper shows that it is possible to design an effective dimmable ballast based around the IR21592, that is powered from a low voltage DC supply instead of the AC line. A non-dimmable version based around the IR2156 is also possible using the same basic configuration as described here. The following example shows a ballast for a single 36 W T8 lamp driven from a 30 V DC supply. Lower supply voltages are possible, however the IR21592 control IC requires up to 13 V supplied to the VCC pin before it operates, also as the current is high large conductors, are needed to keep losses at an acceptable level (for a 36 W ballast operating from a 30 V supply the input current is around 1.25 A).