Want to drive a E17 3W UV-C bulb (the germicidal one, generating ozone or not depending of the version of the glass) from USB (or any battery)?
Use this DDTCCRUB 4S-2A Battery Charger Module Step Up Boost Li-Polymer
Change the RCS resistor from 50mOhm to 125mOhm (0.125 Ohm) to change the charging current to 300mA.
Remember, these bulb have to be supplied 16V (min) so the filament starts glowing, but once the arc is established, current has to be limited to 300mA (settling at around 10V)
Don’t let it run more than few sec on the front of your naked eye/skin.