Paul__B:
If the bulb is quoted as "dimmable" in its specification, you need to use phase control dimming. So get back to your zero-crossing detector and Triac controller with opto-isolators.
I will the parts are on the way i do need to sort this out one day, the issue i am forseeing is that since i want to receive DMX to determine dimming i will have 2 interrupts going and i figure it may be easier to program the PWM dimming in combination with that.
Paul__B:
Possibly. At 500 Hz it might work, no faster.
what makes you say that the use of an opto-coupler would limit the speed a tad i suppose, my concern is actually that the 100Hz phase cutting may cause flicker but is suppose i could put a rectifier-bridge and a capacitor afterwards.
Paul__B:
Now what are you going to use to switch it?
Well i am far from sure, the high voltage is an issue to be considered mainly and a bit of googling pinted me towards a BU406. If i put the rectifier bridge followed by a fair size capacitor(high voltage of course), drive the BU406 with an opto-coupler circuit (PC817 should do) from a PWM output and put another capacitor between the BU406 and the bulb, then am i overlooking something ? (probably.. )
Paul__B:
And your Subject heading is misleading. It is a 220 V bulb.
Ah yes sorry, but i am intending to drive it with 110v DC, i will correct that, it is sold as a 220 AC but since it has a rectifier bridge in there it is actually both.