Is tube light need dc voltage?
If you mean a Fluorescent tube light then no, you don't need DC.
Household Fluorescent light tubes use AC mains electricity. The
mains AC is passed through a ballast coil which reduces the
current. A ballast coil works best when the AC mains voltage is at
least 2 times the Fluorescent tubes working voltage. So, a simple
inductor ballast can be used in Europe, where the line voltage is
typically 220 to 240 Volts AC, to operate a 4 foot long tube, which
operates at 85 to 100 volts, depending upon design.
In the US and other places that use 120 Volts AC mains, the
ballast is a combination auto transformer (to raise the voltage)
and an inductor (the current limiter).