Open Source Electronic Ballast

[ResR]

Is there any open source schematic for a 2x36W T8 fluorescent lamp electronic ballast? I have a lot of improving ideas, including higher voltage capacitors and bigger heatsinks for 1300x transistors, but i'm little bit worried for getting sued by reverse engineering bad ballast and improving that to make it better. I have seen and taken apart a lot of ballast from all sort of companies where the main capacitor is overvolted, like 385VDC on a 250VDC electrolytic capacitor and t8 bulbs outlived the ballast almost all the time.

[ddavidebor]

Sincerely, R.E. Some ballast, next kill them, next found what is dead and inprove it.

I think is the easiest way to do it

[ResR]

Luckily I have one specimen from Far East Electronics to play with Bad or overvolted caps at the power source side plus one creepage problem already solved by scraping it off and replacing with 500V 22AWG isolated wire from broken tape recorder. My brother thought it was illegal to R.E. the ballast like that.

[duskglow]

I love how the silkscreen for the capacitors looks like the astrological symbol for "woman", or "venus".

[peter.mitchell]

I love how the silkscreen for the capacitors looks like the astrological symbol for "woman", or "venus".

"Theres yer prawblem"

[westfw]

Chip vendors like International Rectifier will have a bunch of "reference designs": http://www.irf.com/technical-info/refdesigns/lightingkits.html

You'll have to figure out what different between a CFL, TL5, T8 or T12 ballast, though.  Physics wise, I'd think a 32W ballast designed for a filament-start fluorescent bulb wouldn't care if it were skinny, fat, spiral, or straight.  But the app notes are frightfully specific.

[NiHaoMike]

Linear also has a bunch of app notes on fluorescent lamp inverters. Sadly, fluorescents are slowly on their way out, being replaced with LEDs.

[HackedFridgeMagnet]

That's a shame Diligent, seems like an interesting tale, is it possible to elaborate? The idea was obviously good, was the patent any good? Why did it expire?

[ResR]

Investors got greedy, that's a shame, looked like well thought circuit. Thanks for sharing your experience, DilligentMinds.
Fluorescent light bulbs are phased out by LED's already, some of the blame can be pointed at manufacturers, who try to minimize the mercury content of the tube, thus making it less reliable and more prone to mercury starvation. Not to mention the shame of the CFL and methods of how it was forced on makes people more resistance to fluorescent lighting in general and LED is way to show it.

[poorchava]

You're in eastern EU, US patent law doesn't reach there. Do as you please Nobody's going to sue you

[seoiot123,]

You'll have to figure out what different between a CFL, TL5, T8 or T12 ballast, though.  Physics wise, I'd think a 32W ballast designed for a filament-start fluorescent bulb wouldn't care if it were skinny, fat, spiral, or straight.  But the app notes are frightfully specific.