"Dimmable" LED downlights?

[Things]

So I've bought a couple of Philips MasterLED downlights to use in a project - problem is I need to be able to dim them from a microcontroller.

Presumably they're designed to handle 50Hz TRIAC phase chopping, but does anyone know if they can just handle plain ol PWM? More specifically, the 2 closest frequencies I can get to 50Hz are ~30Hz and ~122Hz, and I'm not sure whether they'll handle this? They can handle DC input as well, so I'd imagine that most DC based dimmers would just use standard PWM, but I'm not sure about frequency.

Anyone tried it perhaps?

[Mr.B]

Don't know if this will help...
http://www.lighting.philips.co.nz/pwc_li/main/shared/assets/downloads/Dimming_MASTER_LEDlamps_MV.pdf

[Things]

Almost exactly what I was after .. except I should have mentioned I'm using the 12V versions

[bookaboo]

Many of the DC downlighters are just direct connections to the LED itself, so if you knew it's properties you could make an adjustable constant current driver. However it may be a lot easier to just buy a suitable 0-10V driver.

[Things]

The Master LED's do have their own internal drivers, I do know that much.

Just reading the "datasheet" for them, they don't explicitly state they run on 12VDC, just they're compatible with most normal downlight transformers ..

However, my guess is the AC is just instantly rectified once it's inside the unit, which in the case of 50Hz, would give 100Hz. I'd also suspect they don't make different versions for AU and the US, so assuming they can handle 60Hz as well, that'd be 120Hz.

So, I suspect if I PWM them at 122Hz, I should be safe ... maybe

[nukie]

How many watts? I may have internal pics for you.

[Kjelt]

Tear one of them apart and analyze and draw up the inner circuit, then ask advice.
You can speculate for months but knowing whats inside makes it a lot easier than experimenting on a black box and not knowing the long time side effects.

[bookaboo]

The input of the driver is a completely different function to the output, it could be a linear (unlikely) buck or buck boost converter depending of Vf and arrangement of the LEDs, it could also already be utilising it's own PWM (usually via an EN pin on the main IC) or could be configured in a smoother constant current mode depending on the driver IC. I don't know if PWM on the input will work, much better to pull one apart and see if you can interface to it.