I've seen these generic CCFL inverters on ebay quite regularly, and wondered how good they would be for running neon-art based on a few short sections of tubing.
The original purpose of these high voltage inverters is to run long thin backlight tubes for LCD panel illumination. They have two control inputs, both of which seem to be designed for logic level. One is the ENABLE input and is basically operated with a high logic level. I found it turned on at about one and a half volts. The ADJUST input controls the intensity over a limited range by varying the voltage from 0V (brightest) to 5V (dimmest).
You can fudge the controllers to run at full intensity by tying the ADJUST wire to the negative supply wire and the ENABLE wire to the positive supply wire, although I'm not sure if it's really rated to be raised to the full supply voltage.
The circuit uses a common switch-mode control chip to drive the transformer primaries using dual MOSFET packages that are either operating as a push-pull driver (one chip) on a winding centre tapped to the positive rail or ganged up as a pair of double MOSFETs (two chips) doing the same thing.
Each transformer drives a pair of series tubes that are commoned through some sense circuitry at their mid-point on the low voltage side of the circuit. I think this senses tube current for regulation purposes, and also detects if a tube breaks, as the circuit will go into standby mode if a tube is disconnected, although it depends on which tube is disconnected!
On some of the units there is a small capacitor connected between the secondary outputs, possibly to give a small load to limit open circuit voltage if the tubes fail or get damaged.
The modules seem to be able to drive at least a few feet of neon on each output and the current drawn at 12V adjusts to the load. I tried a couple of short 2' (600mm) argon/mercury tubes and a longer 2.5' (750mm) neon filled tube and then both in series and it lit them no problem. This suggests it may have an estimated driving ability of about 5' (1.5m) on each output for 12mm diameter argon/mercury tube and less for neon. Intensity is good for indoor use.
Since the circuit is intended for matched length tubes for current regulation and sensing purposes, it would probably be best to keep all tubes connected to it at a similar length.
The original purpose of these high voltage inverters is to run long thin backlight tubes for LCD panel illumination. They have two control inputs, both of which seem to be designed for logic level. One is the ENABLE input and is basically operated with a high logic level. I found it turned on at about one and a half volts. The ADJUST input controls the intensity over a limited range by varying the voltage from 0V (brightest) to 5V (dimmest).
You can fudge the controllers to run at full intensity by tying the ADJUST wire to the negative supply wire and the ENABLE wire to the positive supply wire, although I'm not sure if it's really rated to be raised to the full supply voltage.
The circuit uses a common switch-mode control chip to drive the transformer primaries using dual MOSFET packages that are either operating as a push-pull driver (one chip) on a winding centre tapped to the positive rail or ganged up as a pair of double MOSFETs (two chips) doing the same thing.
Each transformer drives a pair of series tubes that are commoned through some sense circuitry at their mid-point on the low voltage side of the circuit. I think this senses tube current for regulation purposes, and also detects if a tube breaks, as the circuit will go into standby mode if a tube is disconnected, although it depends on which tube is disconnected!
On some of the units there is a small capacitor connected between the secondary outputs, possibly to give a small load to limit open circuit voltage if the tubes fail or get damaged.
The modules seem to be able to drive at least a few feet of neon on each output and the current drawn at 12V adjusts to the load. I tried a couple of short 2' (600mm) argon/mercury tubes and a longer 2.5' (750mm) neon filled tube and then both in series and it lit them no problem. This suggests it may have an estimated driving ability of about 5' (1.5m) on each output for 12mm diameter argon/mercury tube and less for neon. Intensity is good for indoor use.
Since the circuit is intended for matched length tubes for current regulation and sensing purposes, it would probably be best to keep all tubes connected to it at a similar length.
So glad you showed a simple method for kicking it on. I have a project where I really just want the lighting elements of an old display, removed the display bits, might do LED, but since it has the 4 bulb driver already with the simple pinning I should give it a go at least. Cool technology. LED just seems like cheating 😂
The tv has a halfway decent power supply as well, has a 12v and 5v out I may reuse.
I just love neon lighting
Crocodile clips. Does that mean they're from down under?
No need to buy complicated circuitry.
All you need is 2000VAC to drive these CCFL tubes. 10mA.
Hm, after scrapping several laser printers, a couple of big-screen TVs, and several flatbed scanners I do believe that I have some stuff around here to experiement with…
No neon, though. 🙁
The really cheap driver versions always kill themselves as soon as powered with no load just like the ccfl light bulbs they do exactly same as mass cheap driver production won for drivers of choice
Owner of the bar next door asked if I could get the gas tube in his clock working, and this is the only helpful resource on the entire internet that I could find. Ordered a CCFL inverter, wired it to a 12V wall wart, and bam! Let there be light. 🙂
Very useful for fixing dead or non-working backlights (section of the HV on the Power Board) in LCD screens. 😊😉
If you run 12v through the ENA, what happens? Asking for a friend that got it to light up or a period of time, turned it off, and it never lit back up… maxed out amps on power supply without raising volts practically at all. The inverter started getting so hot the foam tape on the back started melting.
But those LCD CCFLs drivers aren’t powerful enough to produce a bright light.
Can these drive a flyback transformer?
I'm so glad I found this video. I have an old neon sign from a long extinct tube shop. I've been wanting to drive it at low power for decoration (rather than purchase a high power neon sign transformer). These look perfect. FYI, some of the ebay listings do state that the inputs are 0-5 volts only. It's probably best not to apply 12 volts.
But….
… Will they drive a Jacob's Ladder?
My finger discovered my laptop has ccfl. I had the front cover off while half asleep, tried to turn my computer off when I touched the wrong bit. That woke me up.