I'm 'testing the water' if you will on driving a Panasonic TUV PL-S 5W UV lamp with a low-voltage (12 ~ 24 V) DC supply. The lamp is rated at 34 V, 0.18 A.

Since I have a DC source, magnetic ballasts are out. I have read some app notes from ST and Infineon on electronic ballast design, yet these sources are concerned with mains-connected fluorescent lamps (i.e. the artificial sun above your cubicle).

The closest products I could find are the UC3872 and UCC2973 which seem geared towards automotive and laptop computer applications.


Since the lamp is only rated for 34 V I would use a different transformer (1:3 for 12 V, etc.). Other than that I feel a bit clueless. Am I heading in the right direction, or are there simpler slash better paths to take?

EDIT: a dimmable feature is not needed.

  • \$\begingroup\$ Are you trying to produce 34 volts DC for the lamp? \$\endgroup\$
    – Andy aka
    Commented Jul 20, 2018 at 16:27
  • 1
    \$\begingroup\$ @Andyaka I assume the 34 V is high-frequency (~10 kHz) AC, but my knowledge of driving lamps goes back only a few hours ago. \$\endgroup\$ Commented Jul 20, 2018 at 16:29
  • \$\begingroup\$ The lamp is rated with 34 V and 0.18 A, the resulting power is 6.12 W. But the lamp is rated to 5 W only. You may need a power control limiting lamp power. \$\endgroup\$
    – Uwe
    Commented Jul 20, 2018 at 16:30
  • \$\begingroup\$ @calcium3000 I'm noooo expert on these lamps but I'm hoping to learn something nonetheless. Roll-on the answers. \$\endgroup\$
    – Andy aka
    Commented Jul 20, 2018 at 16:50

1 Answer 1


Ignition voltage is unknown yet, may be 68V or 2x conduction voltage , so 1:6 transformer with current sensing regulating seems feasible. Unless centre tap doubles this ratio with Vpp ratio

It seems your 2 pin tube is designed for magnetic ballasts with internal switch while 4 pin versions are for electronic ballasts.

Here is a magnetic entire solution for <20$. https://m.ebay.ca/itm/UV-disinfection-lamp-electronic-ballast-PL-S-5W-9W-11W-universal-lamp-holder/182962632880?hash=item2a996c38b0%3Ag%3A6LsAAOSw0RdaMgVr&_mwBanner=1&_nkw=pl-s+ballast&rt=nc

But it’s not dimmable.

  • \$\begingroup\$ Good catch -- just saw "4-Pin PL-S lamps are designed for use on electronic drivers" on the Panasonic product page. Switching to a 4-pin version shouldn't be a problem. However, your magnetic solution doesn't solve the DC input problem; I would need an additional DC-AC inverter on the front end, which is a no-go. \$\endgroup\$ Commented Jul 20, 2018 at 17:21
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    \$\begingroup\$ It doesn’t say what the ballast input is. Go with electronic ballast for lowest start current longer life and higher efficacy at high frequency. \$\endgroup\$ Commented Jul 20, 2018 at 17:31

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